# Initial charge on Eneloops, charging strategies.



## Muse (Feb 14, 2009)

I just bought 2 four-pack Eneloop AAA's from Amazon.com and the initial charge on every one showed at 1.30v. I popped one into my Sandisk Sansa m250 MP3 player and only got 3 hours out of it before the player shut down. I popped in another Eneloop and got only 35 minutes or so. 

Is this typical? The player should give 10 hours or better with a well charged cell.

Which cycle should I do in my La Crosse BC-900 charger? Refresh or Discharge? Should I use the lowest voltages (i.e. 100 ma discharge and 200 ma charge) while doing so?


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## Marduke (Feb 14, 2009)

*Re: Initial charge on Eneloops (AAA)*

Eneloop ship only partially full. Just charge them up and enjoy.


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## Mr Happy (Feb 14, 2009)

*Re: Initial charge on Eneloops (AAA)*

The AAA's may have been old--they may even date from 2006 (the AAA size is much less popular than AA). I would just charge them up and try again before worrying about refresh cycles, especially with such a low drain device.


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## Muse (Feb 14, 2009)

*Re: Initial charge on Eneloops (AAA)*



Mr Happy said:


> The AAA's may have been old--they may even date from 2006 (the AAA size is much less popular than AA). I would just charge them up and try again before worrying about refresh cycles, especially with such a low drain device.


OK, thanks. I almost always do a discharge/charge cycle with my BC-900 instead of a Charge cycle so that I get a display of capacity. I keep records of capacity for all my rechargeables.

When charging AAA's in the BC-900 charger, I wonder if I should use the lowest rates (100/200) instead of the 250/500 many recommend for AA cells because of the charger's sometime problem of missing cutoff at top charge when using the low rates. I'm concerned that 250/500 might be too much for such small cells. I've been using 100/200 with 8 Rayovac Hybrid NiMH AAA's for a year or so, and AFAIK the charger has not missed a cutoff (?). Can someone speak to that? Thanks.

Based on the advice above, I changed the charger from Refresh to Discharge (using 100/200 rates).


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## Marduke (Feb 14, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> OK, thanks. I almost always do a discharge/charge cycle with my BC-900 instead of a Charge cycle so that I get a display of capacity. I keep records of capacity for all my rechargeables.
> 
> When charging AAA's in the BC-900 charger, I wonder if I should use the lowest rates (100/200) instead of the 250/500 many recommend for AA cells because of the charger's sometime problem of missing cutoff at top charge when using the low rates. I'm concerned that 250/500 might be too much for such small cells. I've been using 100/200 with 8 Rayovac Hybrid NiMH AAA's for a year or so, and AFAIK the charger has not missed a cutoff (?). Can someone speak to that? Thanks.
> 
> Based on the advice above, I changed the charger from Refresh to Discharge (using 100/200 rates).



Using the BC-900, to get a reading of capacity, you need to run a "test" cycle. "Discharge" will not give you the cell's stored capacity.


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## SilverFox (Feb 14, 2009)

*Re: Initial charge on Eneloops (AAA)*

Hello Muse,

Although the BC-900 reportedly terminates properly at low charge rates, eventually charging at low charge rates will result in a missed termination and possible damage to your cells.

The usual recommended charge rate is 0.5 - 1.0C. For Eneloop AAA cells, that would be in the 400 - 800 mA range.

Tom


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## Muse (Feb 15, 2009)

*Re: Initial charge on Eneloops (AAA)*



SilverFox said:


> Hello Muse,
> 
> Although the BC-900 reportedly terminates properly at low charge rates, eventually charging at low charge rates will result in a missed termination and possible damage to your cells.
> 
> ...


Thanks Tom. In the future I will charge at 500 ma (both AA and AAA). I don't know why the Discharge cycle would not give as accurate a reading of cell capacity as the Test cycle, but will do the Test cycle as recommended. If anyone can speak additionally to the subject, please do! Am I going to have less lifetime service out of my rechargables if I routinely do the Test cycle?


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## Muse (Feb 15, 2009)

*Re: Initial charge on Eneloops (AAA)*



Marduke said:


> Using the BC-900, to get a reading of capacity, you need to run a "test" cycle. "Discharge" will not give you the cell's stored capacity.


The Discharge cycle gives a reading of stored capacity. You are saying that it's not an *accurate *reading?


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## N162E (Feb 15, 2009)

*Re: Initial charge on Eneloops (AAA)*



SilverFox said:


> Hello Muse,
> 
> Although the BC-900 reportedly terminates properly at low charge rates, eventually charging at low charge rates will result in a missed termination and possible damage to your cells.
> 
> Tom


Sorry Tom but, I have never heard this, seen it or experienced it. I have always used low rates and never had a cell "Eventually" miss a termination. Higher rates on the BC-900 mean more heat at the end of charge.


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## Marduke (Feb 15, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> The Discharge cycle gives a reading of stored capacity. You are saying that it's not an *accurate *reading?



The "discharge" starts with discharging the cell, and then charging it. The capacity displayed is how much energy went into the cell, which is an overestimate since not all of that energy is actually stored.

"Test" first charges the cell, then discharges, then charges again. The capacity shown is a measure of the discharge portion, which is an accurate representation of how much energy is actually stored inside the cell.

You do not need to always do a cell "test", so it does not use many cycles up. Just when you want to check the cell health. Simply charging a cell is sufficient most of the time.


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## Muse (Feb 15, 2009)

*Re: Initial charge on Eneloops (AAA)*



Marduke said:


> The "discharge" starts with discharging the cell, and then charging it. The capacity displayed is how much energy went into the cell, which is an overestimate since not all of that energy is actually stored.
> 
> "Test" first charges the cell, then discharges, then charges again. The capacity shown is a measure of the discharge portion, which is an accurate representation of how much energy is actually stored inside the cell.
> 
> You do not need to always do a cell "test", so it does not use many cycles up. Just when you want to check the cell health. Simply charging a cell is sufficient most of the time.


Why is the capacity shown during a Discharge cycle not actually going into the cell? I do see that the capacities shown when using the Discharge cycle do look too high, often far to high to be believed. Why is this? Isn't the charger only counting energy going into the cell *after *the discharge process is complete?


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## SilverFox (Feb 15, 2009)

*Re: Initial charge on Eneloops (AAA)*

Hello Fred,

I borrowed some "abused" cells from my neighbor and charged them up on the BC-900 at 200 mA. These were AA and AAA cells. 6 of 8 cells missed termination.

I take very good care of my cells and always charge AA cells at 1000 mA and AAA cells at 500 mA when I use the BC-900. At these charge rates, and with vibrant cells, I haven't had any problems with missed terminations.

I picked up some AAA cells that had open circuit voltages in the 0.2 - 0.8 volt range. The first charge on the BC-900 at 200 mA has all cells missing the end of charge termination.

I took some of these same AAA cells and tried them on my Schulze charger at 250 mA. All the cells I tried terminated early at that rate, but when I charged them at 500 mA they terminated properly.

If you don't think you are having any issues with proper termination while charging at 200 mA, your cells must all be new or they are in very good condition. As soon as the develop some additional internal resistance, your BC-900 will miss the termination.

If you would like to switch BC-900 chargers with me, I would be happy to put some of my very limited crap cells through your charger and document that your charger misses terminations too.

Tom


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## SilverFox (Feb 15, 2009)

*Re: Initial charge on Eneloops (AAA)*

Hello Muse,

When charging you will always end up putting a little extra into the cells. At 1C, you end up putting around 105% back in. At 0.5C it goes up to around 110%. At lower charge rates you can get all the way up to 120%, but if your are seeing amounts greater than that it means your charger missed termination.

Tom


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## N162E (Feb 16, 2009)

*Re: Initial charge on Eneloops (AAA)*



SilverFox said:


> Hello Fred,
> 
> If you don't think you are having any issues with proper termination while charging at 200 mA, your cells must all be new or they are in very good condition. As soon as the develop some additional internal resistance, your BC-900 will miss the termination.
> 
> ...


Yes, this is all true. My cells are all in good condition. My question here is why would anyone continue to use known bad cells. Maybe I'm wrong but, one of the reasons I test is to find and eliminate failing cells before they create a problem. However, I am not believing that low charge rates will be the cause of missed termination in good cells.


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## Muse (Feb 16, 2009)

*Re: Initial charge on Eneloops (AAA)*



SilverFox said:


> Hello Muse,
> 
> When charging you will always end up putting a little extra into the cells. At 1C, you end up putting around 105% back in. At 0.5C it goes up to around 110%. At lower charge rates you can get all the way up to 120%, but if your are seeing amounts greater than that it means your charger missed termination.
> 
> Tom


Well, I hope I haven't already screwed up my "new" Eneloop AAAs. Just got two 4 packs from Amazon. I charged 4 of them (2 had crapped out early in my MP3 player), one was used for a while in it and the other I hadn't used yet) in my BC-900 using the Discharge cycle at the lowest dis/charge rate and evidently they all missed termination based on your criteria. The capacities shown in the BC-900 were from 1166 up to 1292.:mecry:However, the charger showed Full for all cells.


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## SilverFox (Feb 16, 2009)

*Re: Initial charge on Eneloops (AAA)*

Hello Fred,

I agree that people shouldn't use crap cells, but this slow charge issue has to do with transforming good cells to crap cells.

You should really take this up with all the battery manufacturers. They are the ones that made the observation. I simply confirmed it... 

It isn't always the case where a manufacturer will supply you with good information, but when they do, you get better results by following it. After spending years slow charging and being dissapointed with cycle life and other cell performance issues, I decided to follow the manufacturers recommendations and charge at their recommended rates. I have, for the past few years, enjoyed wonderful performance from my cells and they last much longer than my cells did when I used slow charging.

I wear out 40 - 50 NiMh cells in about 2 years. Prior to following the manufacturers recommendations, I would go through that many cells in under a year. I am very pleased with this. Not only do I save some money, but I am also seeing much better performance from my cells during the time they are in use. 

I will never go back to slow charging.

Tom


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## SilverFox (Feb 16, 2009)

*Re: Initial charge on Eneloops (AAA)*

Hello Muse,

Time will tell...

Tom


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## Muse (Feb 16, 2009)

*Re: Initial charge on Eneloops (AAA)*



SilverFox said:


> Hello Muse,
> 
> Time will tell...
> 
> Tom


 
I just charged the other 4 Eneloop AAAs I just bought but with these did a Test cycle using 250/500 dis/charge. The reported capacities are:

781
772
757
783

Big difference. I just hope the other 4 aren't already ruined. Too bad the electronics in the BC-900 are so weak.

Dan


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## N162E (Feb 16, 2009)

*Re: Initial charge on Eneloops (AAA)*



SilverFox said:


> Hello Fred,
> 
> I agree that people shouldn't use crap cells, but this slow charge issue has to do with transforming good cells to crap cells.
> 
> ...


Hi again Tom

Once again, Thanks for more of an explanation than I probably deserve. I sincerely appreciate your experience and patience. I'm going to continue to slow charge and see how it goes.

Thanks again,

Fred


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## N162E (Feb 16, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> Big difference. I just hope the other 4 aren't already ruined. Too bad the electronics in the BC-900 are so weak.
> 
> Dan


Hi Dan,

What part of the BC-900 electronics do you consider weak?

Fred


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## Muse (Feb 16, 2009)

*Re: Initial charge on Eneloops (AAA)*



N162E said:


> Hi Dan,
> 
> What part of the BC-900 electronics do you consider weak?
> 
> Fred


I figure the not infrequent failure of the unit to initiate termination when using the low charge rate is indicative of inadequate engineering. How else can this be explained?


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## Marduke (Feb 16, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> I figure the not infrequent failure of the unit to initiate termination when using the low charge rate is indicative of inadequate engineering. How else can this be explained?




I've never really heard of any issues of missed termination with the BC-900. It uses several methods, so unless all 3 fail...


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## N162E (Feb 16, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> I figure the not infrequent failure of the unit to initiate termination when using the low charge rate is indicative of inadequate engineering. How else can this be explained?


Maybe the cells. The BC-900 typically terminates really well at low rates as long as high quality cells in good condition are used. The cells that come with this charger are a hit and miss proposition.


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## was.lost.but.now.found (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*

I think this has been one of the most informative threads I have seen on the whole rate of charge debate. Can someone tack it to the welcome mat or some other useful place?


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## Muse (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*



N162E said:


> Maybe the cells. The BC-900 typically terminates really well at low rates as long as high quality cells in good condition are used. The cells that come with this charger are a hit and miss proposition.


I had one of the 4 La Crosse AAA cells that came with the charger die on me early on. My records indicate (not certain this is correct) that I'd only charged the cell once in the charger, a Refresh cycle using the lowest dis/charge rate. 

However, in general for AAA cells I've been charging Rayovac Hybrid AAA cells (I have 8 such cells), always at the lowest dis/charge rates, and my records appear to indicate that termination has been missed at least 50% of the time. I'm no longer going to use the lowest rates but the 250/500 rate. :naughty: Not sure at this point but figure I'll use Charge cycle 2/3 of the time, Test cycle every 3rd time to keep tabs on each individual cell.



Marduke said:


> I've never really heard of any issues of missed termination with the BC-900. It uses several methods, so unless all 3 fail...


Silverfox makes a pretty convincing case that the BC-900 misses termination frequently using the 100/200 dis/charge cycles, at least when the cells aren't in excellent condition (have internal resistance problems). See post #12 in this thread. This happened to me with "new" Eneloop AAA's.


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## Cemoi (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*

Dear Tom,



SilverFox said:


> 6 of 8 cells missed termination.
> 
> (...)The first charge on the BC-900 at 200 mA has all cells missing the end of charge termination.



What are the exact symtoms of a missed termination?
Does that mean the charger never reaches the "Full" status for this cell?

I have a RS-700 (the European version of the BC-700), version 36. I have done many Refresh 200/100 mA cycles on new and used cells, and they all eventually reached a "Full" status. Sometimes after a looong time and reaching 1.51 or even 1.52 V, but they did reach "Full".


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## Mr Happy (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*

I think it matters how much charge was fed into the cell before the charger switched to full. You would not normally want to see more than a 10% overcharge. If it were an 800 mAh cell for instance, you would hope to see a charge less than 900 mAh. If you get numbers over 1000 mAh on charging, it probably is not doing much good to the cell.


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## Muse (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*

Yes, the charger eventually says Full for the cells, but the mah rating shown when you keep pressing the Display button and it comes to capacity can be way more than the rated cap and if these guys are right (I imagine they are), the cell was not terminated when conditions called for it. Thus, the cells were being given 200 ma for a while when they were indeed fully charged, not good for the cells. Here are the records for one of my cells, and they appear to indicate that in all but two instances, the cell was not terminated properly:

AAA RH 4 Rayovac Hybrid purchased 03/15/2007 Initial charge 1.29v Rated cap: 800
----------------------------------------------------------------------------------------------------
Date Mode Charge rate Measured capacity
08/07/2007 Test 200 763
Can't explain the incredible increase in charge capacity in 10/07. One cell showed Null and I had to start it on a different charger, not the La Crosse.
10/19/2007 Discharge 200 1057
02/09/2008 Discharge 200 1032
05/24/2008 Discharge 200 1295
07/05/2008 Discharge 500 896
08/01/2008 Discharge 200 867
08/30/2008 Discharge 200 1293
09/21/2008 Discharge 200 1211
12/26/2008 Discharge 200 1300

Notice, that the time that the chargerate was 500, the termination appears to have been proper. Also, the next charge even though at 200 ma, the termination was evidently OK. The first charge was a Test cycle at 200 ma charge rate and the reported capacity was probably measured off the energy dissipated during the discharge portion of the cycle. Likely, the ensuing charge termination was missed. Every other time termination was missed.


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## rhymemaze (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*



was.lost.but.now.found said:


> I think this has been one of the most informative threads I have seen on the whole rate of charge debate. Can someone tack it to the welcome mat or some other useful place?



+1
Good thread to subscribe to and keep available.


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## Marduke (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> Yes, the charger eventually says Full for the cells, but the mah rating shown when you keep pressing the Display button and it comes to capacity can be way more than the rated cap and if these guys are right (I imagine they are), the cell was not terminated when conditions called for it. Thus, the cells were being given 200 ma for a while when they were indeed fully charged, not good for the cells. Here are the records for one of my cells, and they appear to indicate that in all but two instances, the cell was not terminated properly:
> 
> AAA RH 4 Rayovac Hybrid purchased 03/15/2007 Initial charge 1.29v Rated cap: 800
> ----------------------------------------------------------------------------------------------------
> ...



Two things
1) Those are the charge in capacities, not the charge out, which is one reason they are high

2) Depending on how you discharged them to begin with, they may have been over discharged, which is why they required more energy be put back in.

If you drained them in a device which sucked them to an unhealthy low, that would explain part of it.


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## 555BUK (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*

My first pack of Eneloop AAA's (received last weekend) are dated 2006-09 and display the following results:-

Out of pack capacity (discharge @ 500mAh)
#1 - 545
#2 - 547
#3 - 537
#3 - 545

After 1st cycle (charge/discharge 500/500)
#1 - 763
#2 - 759
#3 - 753
#3 - 745

After 2nd cycle (manually charged @ 60mAh for 16hours / discharge @ 500mAh)
#1 - 814
#2 - 821
#3 - 808
#3 - 811

The charger used is a MH-C9000. During normal charging it restricts max voltage to 1.47v before terminating cycle. During the manual (Break-in) mode, voltage is not terminated at 1.47v and the cells were charged to a fuller capacity. Hence the noticeable difference 1st and 2nd cycles.

The 1.47v limit during normal charging limits the C9000. I am sure it helps protect and improves battery longevity, but it probably only allows charging to 90-95% of achievable capacity.

I think the eneloops are great. For cells that have been sitting on the shop shelf for 29months, they show remarkable charge retention out of the box (~70%) and amazing consistency (+/- 2%). I do own more powerful AAA's, but these are my current fav's.


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## Muse (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*

Marduke, I understand (I think), but are you also thinking that the figures don't conclusively suggest that termination was missed?


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## Mr Happy (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> Yes, the charger eventually says Full for the cells, but the mah rating shown when you keep pressing the Display button and it comes to capacity can be way more than the rated cap and if these guys are right (I imagine they are), the cell was not terminated when conditions called for it. Thus, the cells were being given 200 ma for a while when they were indeed fully charged, not good for the cells. Here are the records for one of my cells, and they appear to indicate that in all but two instances, the cell was not terminated properly:
> 
> AAA RH 4 Rayovac Hybrid purchased 03/15/2007 Initial charge 1.29v Rated cap: 800
> ----------------------------------------------------------------------------------------------------
> ...


This post is very interesting and shows the value of keeping such records. I do believe that when the supplied charge is in the 1200-1300 range for an 800 mAh cell it is overcharging the cells. Do this once or twice and you might not notice much degradation, but if you charge cells like this routinely I think that over time the damage is going to mount up and the operating life of the cells will be shortened.

Based on the above notes I would recommend charging at 500 mA every time.


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## SilverFox (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*

I find it very rewarding to find that through careful observation the information that the battery manufacturers provide is actually pretty good... :nana:

It is also important to understand that all chargers miss termination at some time. That is why it is important to attend to your charging. That is another feature that the hobby chargers have. You can input a maximum charge amount. When the charger misses termination, it will only go until the maximum charge amount is met. I think this would be a good feature to add to the C9000 if it ever evolves.

Tom


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## Bones (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> Marduke, I understand (I think), but are you also thinking that the figures don't conclusively suggest that termination was missed?



Your numbers are puzzling.

While they suggest that your charger failed to terminate when your cells initially reached a fully charged state, it still managed to terminate the charge well before time or temperature limits should have come into play.

Can anyone suggest a criteria the charger could have used to terminate the charge when it did?

Regardless, in this case, better late than never really does apply...


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## Muse (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*

I should add that while the declared capacity measured of my Rayovac Hybrid AAA batteries has been going up (Wow!) in recent charges (as shown above for one of those cells), I have been confounded in the last few weeks that my Sandisk Sansa m250 MP3 player (which uses one AAA cell) has been shutting down from insufficient battery power fairly soon after inserting a new battery. It has been getting 2-3 hours out of a battery, and used to do much better. I was wondering if this was indicative of a problem with the player but based on posts in this thread I have to think that the actual capacity of the cells has fallen off dramatically. I suppose I should do a Refresh or at the very least a Test cycle with the BC-900 with these cells in an effort to recover lost capacity. Or, maybe it's too late. oo:


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## TakeTheActive (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> I figure the not infrequent failure of the unit to initiate termination when using the low charge rate is indicative of inadequate engineering. *How else can this be explained?*



Cell quality (due to manufacture).
.
Operator error.
.
Cell quality (due to operator error; see *SilverFox's* Sig Line  ).


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## Marduke (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*

Muse,
Just remember that the values you have to date are NOT capacities. Run the "Test" cycle to get actual capacities.


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## TakeTheActive (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*



Marduke said:


> I've never really heard of any issues of missed termination with the BC-900...


You need to mistreat some cells. 



Marduke said:


> ...It uses several methods, so unless all 3 fail...


Four:
-DeltaV
Max Voltage
Max Temp
Max Time
If, by charging at a low (less than 0.5 - 1.0C) charge rate, a cell misses -DeltaV (because it's too small to detect), it could also easily not reach Max Voltage or Max Temp, leaving it to stop at Max Time, which will allow 3000mAh to be pushed into it.

*Reference: **La Crosse BC-900*


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## Mr Happy (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> I should add that while the declared capacity measured of my Rayovac Hybrid AAA batteries has been going up (Wow!) in recent charges (as shown above for one of those cells), I have been confounded in the last few weeks that my Sandisk Sansa m250 MP3 player (which uses one AAA cell) has been shutting down from insufficient battery power fairly soon after inserting a new battery. It has been getting 2-3 hours out of a battery, and used to do much better. I was wondering if this was indicative of a problem with the player but based on posts in this thread I have to think that the actual capacity of the cells has fallen off dramatically. I suppose I should do a Refresh or at the very least a Test cycle with the BC-900 with these cells in an effort to recover lost capacity. Or, maybe it's too late. oo:


Be careful to note what Marduke said: those increasing numbers are not "Measured Capacities", they are the amount of charge pushed into the cell. In this case, higher numbers are *bad*, not good. The more those numbers increase, the more they are telling you your cells are being damaged.

A refresh may help, and is worth trying.

However, remember to increase the charge current from 200 mA to 500 mA for future charges, and use the Test mode to get actual capacities. Also keep an eye on the charge progress when you can, and manually stop charging if the charge gets above 110% of the measured cell capacity.


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## Muse (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*



Mr Happy said:


> Be careful to note what Marduke said: those increasing numbers are not "Measured Capacities", they are the amount of charge pushed into the cell. In this case, higher numbers are *bad*, not good. The more those numbers increase, the more they are telling you your cells are being damaged.
> 
> A refresh may help, and is worth trying.
> 
> However, remember to increase the charge current from 200 mA to 500 mA for future charges, and use the Test mode to get actual capacities. Also keep an eye on the charge progress when you can, and manually stop charging if the charge gets above 110% of the measured cell capacity.


OK, a Test cycle will give me actual capacity. Will I get actual capacity when running the Refresh mode as well? To do so the BC-900 would have to present the energy dissipated during the last discharge part of the mode, I presume.


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## TakeTheActive (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> *I had one of the 4 La Crosse AAA cells that came with the charger die on me early on.* My records indicate (not certain this is correct) that I'd only charged the cell once in the charger, a Refresh cycle using the lowest dis/charge rate...


I had TWO La Crosse 700mAh AAA cells, STILL wrapped in their 4-pack shrinkwrap, LEAK on me (bottom cell in 2 packs). Bought Dec 2006 and let sit at ~45° in a Plano Storage Box until a couple of weeks ago.  IIRC, each pack was ~$3 @ Amazon so no great loss.

```
La Crosse 700mAh AAA             |  #5    #6    #7    #8
---------------------------------+---------------------------
mm/dd/yy C9000 Break-In          |
02/06/09 BC900 Cycle3:   200/ 100|  n/a   505   503   n/a mAh
02/05/09 BC900 Cycle2:   200/ 100|  487   503   492   441 mAh  
02/04/09 BC900 Cycle1:   200/ 100|  459   489   478   359 mAh
02/03/09 PS1   Charge:           |
02/03/09 BC900 Cycle3:   700/ 350|  392   435   n/a   202 mAh
02/03/09 BC900 Cycle2:   700/ 350|  205   407   437   132 mAh
02/03/09 BC900 Cycle1:   700/ 350|  119    94   152   103 mAh
[Bought: 12/22/06 - UNUSED; #8 leaking at top under wrapper]
```



Muse said:


> ...Not sure at this point but *figure I'll use Charge cycle 2/3 of the time, Test cycle every 3rd time* to keep tabs on each individual cell...


IMO, you can't just set one rule to cover all conditions. How are these cells being used? If the device they're in is:
Discharging them down to 0.9V and automatically shutting off, they could go LONGER between 'forced' discharges.
Sitting most of the time and the discharge is mostly SELF discharge, they will need 'forced' discharges.
CLICK on my Sig Line LINK and read about Charge Rates, 'Storage Box Queens' and Crystalline Formations.



Muse said:


> ...*I'm no longer going to use the lowest rates but the 250/500 rate*...


The '100mA Discharge' has it's uses (see the chart above).


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## TakeTheActive (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*



Mr Happy said:


> I think it matters how much charge was fed into the cell before the charger switched to full. *You would not normally want to see more than a 10% overcharge.* If it were an 800 mAh cell for instance, you would hope to see a charge less than 900 mAh. If you get numbers over 1000 mAh on charging, it probably is not doing much good to the cell.


Qualified by Charge Rate...

You can safely pump 160% into a cell at 0.1C. (3200mA into a 2000mAh cell @ 200mA for 16 hours)


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## TakeTheActive (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> ...are you also thinking that the figures don't conclusively suggest that *termination was missed?*


When folks are saying 'termination was missed', what they're REALLY saying is *-DeltaV* termination was missed.

When one of the "Backup Termination / Shutoff Mechanisms" is forced to intervene, excess charge can possibly occur (like in the early models of the MH-C9000 and BC-900). Maha addressed this by lowering Max Voltage and La Crosse chose to lower Max Temp.

CLICK on my Sig Line LINK and read the multitude of topics in the *Rechargeable Battery* section. Good stuff in them there CPF Archives! :twothumbs


----------



## TakeTheActive (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> OK, a Test cycle will give me actual capacity. *Will I get actual capacity when running the Refresh mode as well?*


It's all in your MANUAL.  (Pages 24-27)


----------



## Mr Happy (Feb 17, 2009)

*Re: Initial charge on Eneloops (AAA)*



TakeTheActive said:


> Qualified by Charge Rate...
> 
> You can safely pump 160% into a cell at 0.1C. (3200mA into a 2000mAh cell @ 200mA for 16 hours)


Indeed that might be so, but note that I used the word "normally". A 0.1C charge for 16 hours is a conditioning charge, and you would not normally want to do that. It is only for occasional use. If you charged your batteries that way every time, it would still reduce their working life.


----------



## Muse (Feb 18, 2009)

*Re: Initial charge on Eneloops (AAA)*



TakeTheActive said:


> It's all in your MANUAL.  (Pages 24-27)



Are we talking about the same manual? I haven't gone looking for the one that came with my BC-900 but just downloaded the manual and it has 8 pages. 
It does not indicate how capacity is determined in the Refresh mode. On page 4 it says:
- - - -
REFRESH MODE

Old rechargeable batteries and those that have not been used for a long time require refreshing. This process will recover the optimum capacity of the rechargeable batteries. By pressing the MODE key within 8 seconds after inserting the rechargeable batteries, the Refresh mode can be selected.
Refresh mode will start with discharging the rechargeable battery, then charging it. The repeated discharging and charging cycles will be launched until
no further increase in the measured capacities is estimated.
Note:

By pressing the MODE key within 8 seconds after inserting the rechargeable batteries, the Refresh mode can be selected. (The mode key shall first
be pressed and held for 1 second to activate the mode change. The subsequent pressing of the mode key will toggle between the “Charge”,
“Discharge”, “Test” and “Refresh” mode.)

Then the user may also select different discharging current by pressing the CURRENT key (see “Note” in Discharge mode and Table 2), within 8
seconds after inserting the batteries. (Or the display will blink once to indicate the end of setting and the current cannot be changed afterward.).

It may take up to several days to finish the refreshing process, depending on the selected discharging current.

The maximum refresh current is 1000 mA and is not affected by the number of rechargeable batteries inserted.


----------



## Marduke (Feb 18, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> Are we talking about the same manual? I haven't gone looking for the one that came with my BC-900 but just downloaded the manual and it has 8 pages.
> It does not indicate how capacity is determined in the Refresh mode. On page 4 it says:
> - - - -
> REFRESH MODE
> ...



page 5/8 table 5 vs table 6 or 7

It states that it is displaying "accumulated capacity" rather than "discharge capacity" in "discharge mode"

http://www.lacrossetechnology.com/900/manual.pdf


----------



## Muse (Feb 18, 2009)

*Re: Initial charge on Eneloops (AAA)*



Marduke said:


> page 5/8 table 5 vs table 6 or 7
> 
> It states that it is displaying "accumulated capacity" rather than "discharge capacity" in "discharge mode"
> 
> http://www.lacrossetechnology.com/900/manual.pdf


OK, then to get a *_capacity_* that's meaningful I evidently have to do the *Test *cycle *OR* the *Refresh *cycle.

My capacities shown for the batteries I was worried about (Rayovac Hybrid AAA) after the Test cycle at 250/500 dis/charge rate today are:
828
774
761
799

Maybe this means they are in good shape. How does one determine if his batteries *are *in good shape?

I think that in my case I may have fared relatively well while using the low 100/200 dis/charge rate in Discharge cycles on the BC-900 because I have a unique situation. My charger sits in a custom made charging stand complete with a fan blowing down directly over the cells. 





Assuming that damage to the cells has something to do with their temperature, they would not have suffered as much as otherwise. If the damage isn't so related to temperature but more to the fact of being force-fed 200ma in a full state, they still may have suffered damage. Is there a way for me to tell?


----------



## PeAK (Feb 18, 2009)

*Re: Initial charge on Eneloops (AAA)*



Marduke said:


> page 5/8 table 5 vs table 6 or 7
> 
> It states that it is displaying "accumulated capacity" rather than "discharge capacity" in "discharge mode"
> .
> ...



Given that purpose of the *DISCHARGE mode's* role is to deplete the battery (from any charged state), it only makes sense for the designers to display the "accumulated capacity" (i.e. charge put out by the charger) when it restores the battery to the FULL charged state. 

While discharging is used in the T*EST mode*, the additional pre-step of charging is needed due to the requirement of having the battery topped up to FULL before discharging to EMPTY...clear as mud but until the terminology because standardized for these high-end charger/analyzers, we can expect that the terms will be different things for different manufacturers. For the next 5 minutes, it makes perfect sense....I'll see how I fee tomorrow 

PeAK


----------



## Mr Happy (Feb 18, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*

Just use an MH-C9000 instead. Then all confusion will be avoided


----------



## Mr Happy (Feb 18, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> I think that in my case I may have fared relatively well while using the low 100/200 dis/charge rate in Discharge cycles on the BC-900 because I have a unique situation. My charger sits in a custom made charging stand complete with a fan blowing down directly over the cells.


You know, this actually could present a problem. The charger detects when to stop charging by an increase in the temperature of the cells (the increase in temperature is what produces the drop in voltage for the -delta V signal). If you forcibly cool the cells you may reduce the required temperature rise and thus fool the charger into overcharging the batteries.

Sometimes the best of intentions can lead you astray...


----------



## Russel (Feb 18, 2009)

*Re: Initial charge on Eneloops (AAA)*



Mr Happy said:


> You know, this actually could present a problem. The charger detects when to stop charging by an increase in the temperature of the cells (the increase in temperature is what produces the drop in voltage for the -delta V signal). If you forcibly cool the cells you may reduce the required temperature rise and thus fool the charger into overcharging the batteries.
> 
> Sometimes the best of intentions can lead you astray...


 
At a 200ma charge rate, what kind of temp rise can you expect during overcharge if Delta V termination is missed?


----------



## Mr Happy (Feb 18, 2009)

*Re: Initial charge on Eneloops (AAA)*



Russel said:


> At a 200ma charge rate, what kind of temp rise can you expect during overcharge if Delta V termination is missed?


Well, not a lot of course, but it isn't just temperature that does the damage. If you have 800 mAh AAA cells being charged at 200 mA that is a 0.25C charge rate, and if they get an applied charge of 1300 mAh that is a 500 mAh or 60% overcharge. A 60% overcharge at a 0.25C rate is not healthy for NiMH cells no matter how cool you keep them.


----------



## Russel (Feb 18, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*

So...

AAA 800mah NiMH batteries.

Charge at 400ma to 800ma to insure proper BC-900 charge termination. (Especially with less the perfect batteries.)

Use the TEST CYCLE to measure battery capacity because test cycle measure and display the amount of energy actually drained from the battery. (As opposed to Discharge cycle, which will display the amount of energy used to charge the battery.)

Use the DISCHARGE CYCLE to simply discharge and recharge (fully cycle) the battery.



Am I missing anything else?

Russ


----------



## Russel (Feb 18, 2009)

*Re: Initial charge on Eneloops (AAA)*



Mr Happy said:


> Well, not a lot of course, but it isn't just temperature that does the damage. If you have 800 mAh AAA cells being charged at 200 mA that is a 0.25C charge rate, and if they get an applied charge of 1300 mAh that is a 500 mAh or 60% overcharge. A 60% overcharge at a 0.25C rate is not healthy for NiMH cells no matter how cool you keep them.


 
True. The overcharge is bad, even with the extra cooling. I just doubt the charger would terminate on temp at that charge rate even overcharging. Does anyone know the charge termination temp for the BC-900?

I was leary of charging at higher rates until I tested some eneloops at 700ma. Still below the .5C to 1C recommended charge rate [edit: for AA 2000mah cells], but high enough to get an idea of temperature. Here is the highest reading I got. Note the room ambient temperature.


----------



## Muse (Feb 18, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*



Russel said:


> So...
> 
> AAA 800mah NiMH batteries.
> 
> ...


The Refresh cycle gives capacity based on the last discharge portion of the process, and so also gives a meaningful reading of capacity.

Of course you can always just charge the cell, no discharge involved. I do this sometimes when I'm in a hurry such as I need to use my camera soon and want well charged AA's.

If the BC-900 doesn't see enough voltage on the cell it will refuse to charge it at all. Instead of a voltage the charger shows the cell as Null. In that event you have to put the cell(s) in another charger, one that will supply a current to the cell and charge it for a couple of minutes. Then the BC-900 won't refuse to charge it. This has happened to me a few times.


----------



## Muse (Feb 18, 2009)

*Re: Initial charge on Eneloops (AAA)*



Mr Happy said:


> You know, this actually could present a problem. The charger detects when to stop charging by an increase in the temperature of the cells (the increase in temperature is what produces the drop in voltage for the -delta V signal). If you forcibly cool the cells you may reduce the required temperature rise and thus fool the charger into overcharging the batteries.
> 
> Sometimes the best of intentions can lead you astray...


Should I stop providing ventilation to the cells? :sigh: Part of the reason I did this was to put the charger in a position where if it did "melt down" it wouldn't damage anything. :thinking: The BC-900 actually senses the temperature of the cells in determining -delta V termination? How does it do that? Separate temperature sensors under each cell?


----------



## Russel (Feb 18, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*



Muse said:


> The Refresh cycle gives capacity based on the last discharge portion of the process, and so also gives a meaningful reading of capacity.
> 
> Of course you can always just charge the cell, no discharge involved. I do this sometimes when I'm in a hurry such as I need to use my camera soon and want well charged AA's.
> 
> If the BC-900 doesn't see enough voltage on the cell it will refuse to charge it at all. Instead of a voltage the charger shows the cell as Null. In that event you have to put the cell(s) in another charger, one that will supply a current to the cell and charge it for a couple of minutes. Then the BC-900 won't refuse to charge it. This has happened to me a few times.


 
Refresh cycle - thanks, I missed that one.

I gave my Sister a set of 4 Eneloop AAs after seeing the old and mismatched set of batteries She was using in her digital camera. A couple wouldn't start the charge due to low voltage as you describe. With the charger unpluged I just set a charged cell in the bay next to the dead one with the negitive terminal touching the charger negitive terminal, but with the positive terminal of both cells exposed (before you push the battery in place) and shorted the positive terminals together with a paper clip. (Connecting the two cells in parallel.) After about 30 seconds, I remove the paperclip, plug in the charger and push the cell into place to begin charging. That allows the charged cell to charge the dead one enough for the charger to begin charging it. If that doesn't work, I consider the "null" cell a lost cause.

Russ


----------



## Russel (Feb 18, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> Should I stop providing ventilation to the cells? :sigh: Part of the reason I did this was to put the charger in a position where if it did "melt down" it wouldn't damage anything. :thinking: The BC-900 actually senses the temperature of the cells in determining -delta V termination? How does it do that? Separate temperature sensors under each cell?


 
The BC-900 measures voltage for Delta V termination. Delta V is where the battery voltage drops slightly when the battery is fully charged. At least that is a very basic explanation. Temperature termination is a different method of terminating, or at least pausing the charge cycle If the battery is too hot. If you look between the cell ports of the charger, near the top of the port, you can see flat metal strips. I think that is where the BC-900 measures the battery temperature. I think it measures temperature of the cells in pairs.

Edit: As long as you charge at the recommended rate of .5C to 1C or 400ma to 800ma with the BC-900 and your 800mah [edit: AAA] cells, using your cooling fan shouldn't be a problem. 

Russ


----------



## Mr Happy (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> Should I stop providing ventilation to the cells? :sigh: Part of the reason I did this was to put the charger in a position where if it did "melt down" it wouldn't damage anything. :thinking: The BC-900 actually senses the temperature of the cells in determining -delta V termination? How does it do that? Separate temperature sensors under each cell?


The cause of the -delta V signal is the rise in temperature of the cell. It is the way the chemistry works; the voltage decreases as the temperature increases. What happens is that when the cell is full and can no longer absorb much charge, the excess current gets converted to heat, and this heat raises the temperature and produces a small drop in voltage. The charger senses this drop and stops charging.

There is no need to use a fan for cooling unless you notice the cells getting uncomfortably hot at the end of charging. Slightly warm or even mildly hot is not a problem.


----------



## Russel (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



TakeTheActive said:


> CLICK on my Sig Line LINK and read the multitude of topics in the *Rechargeable Battery* section. Good stuff in them there CPF Archives! :twothumbs


 
That is one impressive collection of links! Thanks for providing it, saves lots of time searching!


----------



## Mr Happy (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



Russel said:


> I was leary of charging at higher rates until I tested some eneloops at 700ma. Still below the .5C to 1C recommended charge rate [edit: for AA 2000mah cells], but high enough to get an idea of temperature. Here is the highest reading I got. Note the room ambient temperature.


112 F is about 45 C. That feels just warm to the touch and is not too hot at all where charging is concerned.


----------



## Russel (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



Mr Happy said:


> The cause of the -delta V signal is the rise in temperature of the cell. It is the way the chemistry works; the voltage decreases as the temperature increases. What happens is that when the cell is full and can no longer absorb much charge, the excess current gets converted to heat, and this heat raises the temperature and produces a small drop in voltage. The charger senses this drop and stops charging.
> 
> There is no need to use a fan for cooling unless you notice the cells getting uncomfortably hot at the end of charging. Slightly warm or even mildly hot is not a problem.


 
I stand corrected. I wasn't aware of the interrelation between temp and voltage at full charge. I recommend you listen to Mr. Happy. :thumbsup:

Russ

(Still unenlighted at >20 posts)


----------



## Russel (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



Mr Happy said:


> 112 F is about 45 C. That feels just warm to the touch and is not too hot at all where charging is concerned.


 
I agree completely, I charge my Eneloop AAs at 1000ma now.

Russ


----------



## Marduke (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> Should I stop providing ventilation to the cells? :sigh: Part of the reason I did this was to put the charger in a position where if it did "melt down" it wouldn't damage anything. :thinking: The BC-900 actually senses the temperature of the cells in determining -delta V termination? How does it do that? Separate temperature sensors under each cell?



The BC-900 has 3 methods to monitor charge:
1) -delta V
2) max temp (It will just pause, not end for high temp)
3) max V

The third one is the reason you cannot put a full cell on the charger and charge it again. It will immediately show "full"

There are two temp probes, between slots 1/2 and 3/4. The temperature is in the manual as 127F, which pauses charging until the cells cool.


----------



## TakeTheActive (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



Russel said:


> That is one impressive collection of links! Thanks for providing it, saves lots of time searching!



:thanks: :thanks: :thanks: :thanks: :thanks:
Many thanks...​


----------



## Muse (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



Russel said:


> The BC-900 measures voltage for Delta V termination. Delta V is where the battery voltage drops slightly when the battery is fully charged. At least that is a very basic explanation. Temperature termination is a different method of terminating, or at least pausing the charge cycle If the battery is too hot. If you look between the cell ports of the charger, near the top of the port, you can see flat metal strips. I think that is where the BC-900 measures the battery temperature. I think it measures temperature of the cells in pairs.
> 
> Edit:* As long as you charge at the recommended rate of .5C to 1C or 400ma to 800ma with the BC-900 and your 800mah AA cells, using your cooling fan shouldn't be a problem. *
> 
> Russ


If not a problem for AA cells, I'd think it wouldn't be a problem for AAA cells either at those charge rates with the cooling fan on. I've many times put a finger to a cell wondering if it might be hot but have never felt anything I'd call even a warm cell. Not sure there's a reason to have that fan going. :thinking: As long as it doesn't induce missed terminations, I guess it doesn't hurt and might help.


----------



## was.lost.but.now.found (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> If not a problem for AA cells, I'd think it wouldn't be a problem for AAA cells either at those charge rates with the cooling fan on. I've many times put a finger to a cell wondering if it might be hot but have never felt anything I'd call even a warm cell. Not sure there's a reason to have that fan going. :thinking: As long as it doesn't induce missed terminations, I guess it doesn't hurt and might help.


 
I've only had my BC900 for a couple months now, but I worry about the temperature as well when charging above the neighborhood of .3C. For example last night I charged a pair of newly discharged eneloops at 1000 mA. They got warm by 1 hour into charging, and continued to get hotter throughout the remainder of the charge. The were not so hot that I could not touch them, but it was kind of like cupping your mug of fresh hot cocoa. They are warmer than my cells get on the 15 minute charger.


----------



## rhymemaze (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



was.lost.but.now.found said:


> I've only had my BC900 for a couple months now...



Do you have version 35?


----------



## was.lost.but.now.found (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



rhymemaze said:


> Do you have version 35?


 
is there a v36? It's either 35 or 36 I can't recall, but it's not 32 if that's what you were getting at.


----------



## rhymemaze (Feb 19, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*

No, I don't think there is a v36. I was just wondering because I keep staring at this charger over at the ThomasDist. website


----------



## Mr Happy (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



was.lost.but.now.found said:


> I've only had my BC900 for a couple months now, but I worry about the temperature as well when charging above the neighborhood of .3C. For example last night I charged a pair of newly discharged eneloops at 1000 mA. They got warm by 1 hour into charging, and continued to get hotter throughout the remainder of the charge. The were not so hot that I could not touch them, but it was kind of like cupping your mug of fresh hot cocoa. They are warmer than my cells get on the 15 minute charger.


There seems to be something not right there. I have several times charged eneloops at 1600 or 1800 mA (not on the LaCrosse) and they do not get even slightly warm until the last few minutes of the charge. (See this post, and note how when charging at 1600 mA the eneloop did not get above 37°C until right at the end.) Could it be the charger itself that is getting hot and heating up the batteries that way?


----------



## was.lost.but.now.found (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



Mr Happy said:


> There seems to be something not right there. I have several times charged eneloops at 1600 or 1800 mA (not on the LaCrosse) and they do not get even slightly warm until the last few minutes of the charge. (See this post, and note how when charging at 1600 mA the eneloop did not get above 37°C until right at the end.) Could it be the charger itself that is getting hot and heating up the batteries that way?


 
The bottom of the charger did also get very warm, but I would not say so much that it was sole heat source for the warm batteries.


----------



## Cemoi (Feb 19, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*



rhymemaze said:


> No, I don't think there is a v36



I do have a v36, but it is the RS700 = BC700.


----------



## PeAK (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



was.lost.but.now.found said:


> .
> .
> .For example last night I charged a pair of newly discharged eneloops at 1000 mA. They got warm by 1 hour into charging, and continued to get hotter throughout the remainder of the charge. The were not so hot that I could not touch them, but it was kind of like cupping your mug of fresh hot cocoa. They are warmer than my cells get on the 15 minute charger.


New batteries that behave as they were designed to will have a distinct negative delta-V signal and have been termed "vibrant". Batteries that have gone through even a single overcharge/overheat cycle will be forever cursed. The best way to use them is to put them in low power electronics (i.e. wireless mouse) and then charge them using a timer and charge rate that does not exceed their original capacity. 

Even for new batteries, I not the charge rate and calculated the expected charge time. I then set a timer to have me check on the temperature and charge status at that set time. I'll reset the timer for 20% more of that "calculated time" and if they are still charging, I set these batteries aside for "refreshing" and more thorough monitoring during the charge cycle.

At higher charge rates, "less than vibrant" batteries can still generate a healthier termination signal to the battery charger if charged at higher currents. Have a look at some ongoing experiments that I have put in a different thread. Not especially the Sanyo AAA battery results that terminated at the higher current (no overheating) to the lower charge rate results that resulted in significant heating due to the lack of a detectable termination signal (for that particular charger).


PeAK


----------



## rhymemaze (Feb 19, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*



Cemoi said:


> I do have a v36, but it is the RS700 = BC700.



Do you have any similar heat issues (as discussed above) when charging @ 700ma?

...maybe I missed this in another thread, but why would LaCrosse come out with such a similar charger that has lower charge rates compared to the BC900? To deal with a heat issue in the BC900 when charging at higher rates?


----------



## SilverFox (Feb 19, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*

Hello Rhymemaze,

LaCrosse actually came out with the BC-700 first. It seems that they cleaned out their warehouses and all of the sudden we have had a "new" introduction of that unit. The BC-900 came out after the BC-700.

Isn't marketing wonderful...  

Tom


----------



## Russel (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> If not a problem for AA cells, I'd think it wouldn't be a problem for AAA cells either at those charge rates with the cooling fan on. I've many times put a finger to a cell wondering if it might be hot but have never felt anything I'd call even a warm cell. Not sure there's a reason to have that fan going. :thinking: As long as it doesn't induce missed terminations, I guess it doesn't hurt and might help.


 
After reading post #61 by Ms Happy, I think you are better off leaving the fan turned off. 

What I do, if I am worried about heat, is monitor the temp with a cheap indoor outdoor thermometer. I'm sure you saw the photo I posted in one of my earlier messages. That way you know what the temp is and don't have to worry about it.

Russ


----------



## rhymemaze (Feb 19, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*



SilverFox said:


> Hello Rhymemaze,
> 
> LaCrosse actually came out with the BC-700 first. It seems that they cleaned out their warehouses and all of the sudden we have had a "new" introduction of that unit. The BC-900 came out after the BC-700.
> 
> ...



SilverFox, 
Thanks for setting me straight with the models. This "heat" thing with the BC900 has me a bit concerned.


----------



## Muse (Feb 19, 2009)

was.lost.but.now.found said:


> is there a v36? It's either 35 or 36 I can't recall, but it's not 32 if that's what you were getting at.


How can you tell which version you have?


----------



## TakeTheActive (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



Russel said:


> ...Edit: *As long as you charge at the recommended rate of .5C to 1C or 400ma to 800ma with the BC-900 and your 800mah AA cells, using your cooling fan shouldn't be a problem.*


​


Muse said:


> *If not a problem for AA cells, I'd think it wouldn't be a problem for AAA cells either at those charge rates with the cooling fan on...*


I'm fairly confident that '*AA*' was just a typo and *Russel* meant '*AAA*' - I'm not aware of any 'recent production' 800mAh NiMH AA cells.


----------



## TakeTheActive (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



Marduke said:


> *The BC-900 has 3 methods to monitor charge*:
> 1) -delta V
> 2) max temp (It will just pause, not end for high temp)
> 3) max V...



*4 Methods:* 

-DeltaV - Terminate
Max Voltage - Terminate
Max Temp - Pause
Max Time - Terminate


----------



## TakeTheActive (Feb 19, 2009)

*Re: Initial charge on Eneloops (AAA)*



was.lost.but.now.found said:


> I've only had my BC900 for a couple months now, but *I worry about the temperature* as well when charging above the *neighborhood of .3C*...


IMHO, you're hanging out in a BAD NEIGHBORHOOD.  Move to 0.5 - 1.0C and you'll feel MUCH safer... :grouphug:


was.lost.but.now.found said:


> ...For example last night I charged a pair of newly discharged eneloops at 1000 mA. They got warm by 1 hour into charging, and continued to get hotter throughout the remainder of the charge. *The were not so hot that I could not touch them*, but it was kind of like cupping your mug of fresh hot cocoa...


Buy yourself an inexpensive digital thermometer with a remote probe like the RadioShack one *Russel* shows in his photo. I have an older RS model and you'll be surprised how HOT  a STILL safe 120ºF :wave: feels to the touch.


----------



## TakeTheActive (Feb 19, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*



rhymemaze said:


> ...I was just wondering because *I keep staring at this charger* over at the ThomasDist. website


*[OPINION]*
If you've been using rechargeable cells for YEARS and *already have a stockpile of (possibly / most likely) CRAP cells, buy the BC-900 first* and then get the MH-C9000 when funds allow (and you can also buy new LSD cells).
.
If you're a "Rechargeable Cell Newbie", just starting out, *with a stockpile of NEW 'vibrant' LSD cells, buy the MH-C9000 first* and then get the BC-900 when funds allow (and your original new LSD cells are approaching CRAP).
*[/OPINION]*


----------



## Russel (Feb 20, 2009)

*Re: Initial charge on Eneloops (AAA)*



TakeTheActive said:


> ​
> I'm fairly confident that '*AA*' was just a typo and *Russel* meant '*AAA*' - I'm not aware of any 'recent production' 800mAh NiMH AA cells.


 
You are correct! Thanks for pointing that out: 800mah *AAA *cells.


----------



## TakeTheActive (Feb 20, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> How can you tell which version you have?


Just out of curiosity, you understand, have you ever considered SEARCHing the CPF Archives and/or READing the (already assembled for you) FAQs? 

:welcome: [Join Date: Mar 2007] 

* CPF Post #97 (12-31-2005, 04:59 AM):*


> ...How can I find out what version I have?
> right after you plug in the charger, it displays the version number on the far right lcd cell...


[This thread is starting to remind me of the 'mV = Cell Capacity' thread...  I should log off and go to bed... :sleepy: ]


----------



## Russel (Feb 20, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*



TakeTheActive said:


> *[OPINION]*
> 
> If you've been using rechargeable cells for YEARS and *already have a stockpile of (possibly / most likely) CRAP cells, buy the BC-900 first* and then get the MH-C9000 when funds allow (and you can also buy new LSD cells).
> .
> ...


 
That's interesting. I've got the BC-900 with a MH-C808 on the way and a MH-C9000 planned for the near future.

I wonder how many of us have both the BC-900 and the MH-C9000?

Anyway, would you use the BC-900 for charging the 'vibrant' LSD cells and the MH-C9000 for the older, delapitated cells? Or, maybe I should just ask you: How would you use the two chargers with a combination of new LSD cells and older, more questionable cells?

Russ


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## TakeTheActive (Feb 20, 2009)

*Re: Initial charge on Eneloops (AAA)*



555BUK said:


> ...The charger used is a MH-C9000. *During normal charging it restricts max voltage to 1.47v before terminating cycle. During the manual (Break-in) mode, voltage is not terminated at 1.47v and the cells were charged to a fuller capacity*...


Are you sure about this?

I'm an 'old' (12/06) BC-900 owner and 'new' (01/09) MH-C9000 owner. I ran a NEW / NEVER USED set of 4 Rayovac I-C3s through 'Break-In' on the C9000 and they finished just fine (which I was planning to communicate to *SilverFox*). I recently ran a USED set of 4 Rayovac I-C3s through 'Break-In' on the C9000 and they cancelled out and dropped into 'Charge' (for just a few mAh). I re-started them and watched the display (quite often) and they were at 1.47VDC just before the switch. I 'Discharged' them at 100mA (to break down any large crystals) and repeated the 'Break-In' and had the same problem - they dropped back out into 'Charge'.

I'm aware of the "*Rayovac IC3 Cells Terminate Charge via Internal 'Pressure Switch'*", and I can't see this being involved at 0.1C. I tried 'Break-In' three times on the C9000 before I switched over to the BC-900 (I have a 'Refresh 200/100' and 'Refresh 700/350' currently in progress; First 700/350 just finished at 1925mAh).


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## Mr Happy (Feb 20, 2009)

*Re: Initial charge on Eneloops (AAA)*



TakeTheActive said:


> I'm an 'old' (12/06) BC-900 owner and 'new' (01/09) MH-C9000 owner. I ran a NEW / NEVER USED set of 4 Rayovac I-C3s through 'Break-In' on the C9000 and they finished just fine (which I was planning to communicate to *SilverFox*). I recently ran a USED set of 4 Rayovac I-C3s through 'Break-In' on the C9000 and they cancelled out and dropped into 'Charge' (for just a few mAh). I re-started them and watched the display (quite often) and they were at 1.47VDC just before the switch. I 'Discharged' them at 100mA (to break down any large crystals) and repeated the 'Break-In' and had the same problem - they dropped back out into 'Charge'.


I think what you are finding is that I-C3 cells are not "normal" cells. They contain some internal magic that cuts off the charger when they think they are fully charged. On the C9000 this confuses it, since it will think the battery has been removed and reinserted. On reinsertion the C9000 will forget the break-in cycle and default to charge mode.

Short answer: do not use I-C3 cells other than on the Rayovac charger. They are specially designed and will not behave like normal NiMH cells in every case.


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## NiOOH (Feb 20, 2009)

*Re: Initial charge on Eneloops (AAA)*



Mr Happy said:


> The cause of the -delta V signal is the rise in temperature of the cell. It is the way the chemistry works; the voltage decreases as the temperature increases. What happens is that when the cell is full and can no longer absorb much charge, the excess current gets converted to heat, and this heat raises the temperature and produces a small drop in voltage. The charger senses this drop and stops charging.
> 
> There is no need to use a fan for cooling unless you notice the cells getting uncomfortably hot at the end of charging. Slightly warm or even mildly hot is not a problem.


 
The direct cause of the voltage drop is the increase of the internal resistance of the cell, which in turn, is caused by the increase of temperature.
That is why, I usually do not recommend adding active cooling to chargers (fan). Although cells may be cooler at the end of charge, overcharge may occur.


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## Mr Happy (Feb 20, 2009)

*Re: Initial charge on Eneloops (AAA)*



NiOOH said:


> The direct cause of the voltage drop is the increase of the internal resistance of the cell, which in turn, is caused by the increase of temperature.


I think maybe you mean decrease of internal resistance on increasing temperature?


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## TakeTheActive (Feb 20, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*



Russel said:


> That's interesting...
> 
> ...I wonder how many of us have both the BC-900 and the MH-C9000?
> 
> *Anyway, would you use the BC-900 for charging the 'vibrant' LSD cells and the MH-C9000 for the older, delapitated cells?*


The REVERSE! 

With *a stockpile of (possibly / most likely) CRAP cells*, ~8-20+ years old, while I'm trying to run every one of them through a C9000 'Break-In', I'm getting a few 'HIGH' and 'MODE' errors (don't tell *SilverFox* - he'll just say *RECYCLE!*). My 'old' BC-900, on the other hand, will accept them (i.e. no NULL!).



Russel said:


> ...Or, maybe I should just ask you: How would you use the two chargers with a combination of new LSD cells and older, more questionable cells?


My 'NEW' C9000 has been running 'Break-Ins' on my existing inventory, 24x7, for 6+ weeks now. And just recently, I got the 'Bright Idea' :tinfoil: to also track Internal Resistance via the C9000's initial voltage reading. Cells that register 'HIGH' on the C9000 go to a 'Refresh 200/100' on the BC-900, hoping to break down the large crystals that formed from my neglect (read about 'Storage Box Queens' in my Sig Line LINK). Due to the different design of measuring discharge 'Under Load' (C9000) vs 'Off Load' (BC-900), the BC-900 can drain 'neglected' / high resistance cells lower (closer to 0.9VDC) than the C9000.

My 'NEW' LSDs (Eneloops, Duraloops, and Kodak) are still sitting SEALED in their packages, patiently awaiting their turn on the C9000, while the poor, aged, loyal, often-neglected Rayovac 1600s are slowly, but surely, hitting the RECYCLE bin... :candle: :mecry:


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## NiOOH (Feb 20, 2009)

*Re: Initial charge on Eneloops (AAA)*



TakeTheActive said:


> IMHO, you're hanging out in a BAD NEIGHBORHOOD.  Move to 0.5 - 1.0C and you'll feel MUCH safer... :grouphug:
> 
> Buy yourself an inexpensive digital thermometer with a remote probe like the RadioShack one *Russel* shows in his photo. I have an older RS model and you'll be surprised how HOT  a STILL safe 120ºF :wave: feels to the touch.


 
Actually, 120ºF (48.9 ºC) should not feel that hot to the touch. At work, I have an incubator that I frequently set to run at 50 ºC +/- 0.1 ºC (122 ºF). At that temperature I can touch and hold my hands on the internal metal surfaces without any problem. Then again, peoples sensitivity to heat may vary. IMO however, the temperature measured by these probe termometers is quite a bit lower than the actual cell skin temperature. This is manly due to the poor contact between the probe and the cells. Looking at the picture, you'll see that only half of the probe surface is in contact with the cells (and this trough the poorly heat-conducting plastic sleeve), the other half is cooled by ambient air. So, for me this is not a proper method to measure cell temperature. However, it could be used to measure dT/dt. Although absolute values will be lower the rate of temperature increase will be accurate. If you have a time to run such experiments (writing down time and temperature towards the end of quick charge say, every 20 seconds) it will be great.


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## Muse (Feb 20, 2009)

*Re: Initial charge on Eneloops (AAA)*



TakeTheActive said:


> Just out of curiosity, you understand, have you ever considered SEARCHing the CPF Archives and/or READing the (already assembled for you) FAQs?
> 
> :welcome: [Join Date: Mar 2007]
> 
> ...


Thanks for your relenting, and speaking your mind. Yeah, I joined a while ago but took a sabbatical. I haven't hung out here steadily. I'll try to be a better citizen. :wave:


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## Turbo DV8 (Feb 21, 2009)

*Re: Initial charge on Eneloops (AAA)*

Deleted due to erroneous information presented.


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## Mr Happy (Feb 21, 2009)

*Re: Initial charge on Eneloops (AAA)*



Turbo DV8 said:


> Sorry if this has been mentioned, because I haven't read the next two pages of posts. "Test" on the LaCrosse will only dispay discharge capacity while discharging. As soon as it begins the next charge cycle, the discharge capacity is erased and "accumulated" capacity is displayed. So unless you are right there at the charger observing the discharge current as the voltage hits 0.9 volts, the displayed "capacity" of the cell at end of test is not the discharge current, but the accumulated capacity. The only mode on the LaCrosse which retains the discharge capacity in the display during the subsequent charge is refresh mode. Just wait for it to go to charge, note the discharge capacity, then if you don't want another refresh cycle, simply unplug and plug back in the wall wart and set your charge rate.


This does not sound logical, though. What use would the "Test" mode be if it did not test the capacity of the battery and display it to you on completion?

In Table 7 of the BC-900 user guide at the foot of page 5, it says that the mAh shown on the display after the 2nd charge has finished is "_Capacity of the battery determined in discharging_".

According to the user guide, both "Test" and "Refresh" mode show you the measured discharge capacity after the cycle ends.

Are you saying this is not what actually is displayed in reality?

Reference: BC-900 user guide


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## Turbo DV8 (Feb 21, 2009)

*Re: Initial charge on Eneloops (AAA)*



Mr Happy said:


> This does not sound logical, though...
> Are you saying this is not what actually is displayed in reality?


 
Let me get home after work tonight and revisit my manual and charger. That is my recollection, but I will say that now owning two C-9000's has certainly turned more than one BC-900 feature on it's head, so I may be getting confused. I will check and edit post if I stand corrected. Thanks.


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## Russel (Feb 21, 2009)

*Re: Initial charge on Eneloops (AAA)*



Turbo DV8 said:


> Sorry if this has been mentioned, because I haven't read the next two pages of posts. "Test" on the LaCrosse will only dispay discharge capacity while discharging. As soon as it begins the next charge cycle, the discharge capacity is erased and "accumulated" capacity is displayed. So unless you are right there at the charger observing the discharge current as the voltage hits 0.9 volts, the displayed "capacity" of the cell at end of test is not the discharge current, but the accumulated capacity. The only mode on the LaCrosse which retains the discharge capacity in the display during the subsequent charge is refresh mode. Just wait for it to go to charge, note the discharge capacity, then if you don't want another refresh cycle, simply unplug and plug back in the wall wart and set your charge rate.


 
That is interesting, because the BC-900 that I am using, when in test mode, will display the --- at first while it charges the cell and while discharging the cell after that. After the (top off) charge and discharge are complete it will display the capacity discharged while the cell is recharged in the third and final part of the test cycle.

I know that when the display shows capacity and test and charge, I have the tested capacity of the cell and the unit is now recharging the cell. The capacity remains the same number throughout the final charge. I have one right next to me that is displaying 1079mah for an old radioshack 1500mah cell in test mode charging after discharge. It has been like that with the same number for the last few hours.

Russ


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## Russel (Feb 21, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*

The old radioshack 1500mah cell just finished charging, completeing the test cycle. The BC-900 now displays:

Flashing back and forth between these two:

1079mah
charge
test

and

FULL


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## Marduke (Feb 21, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*



Turbo DV8 said:


> Sorry if this has been mentioned, because I haven't read the next two pages of posts. "Test" on the LaCrosse will only dispay discharge capacity while discharging. As soon as it begins the next charge cycle, the discharge capacity is erased and "accumulated" capacity is displayed. So unless you are right there at the charger observing the discharge current as the voltage hits 0.9 volts, the displayed "capacity" of the cell at end of test is not the discharge current, but the accumulated capacity. The only mode on the LaCrosse which retains the discharge capacity in the display during the subsequent charge is refresh mode. Just wait for it to go to charge, note the discharge capacity, then if you don't want another refresh cycle, simply unplug and plug back in the wall wart and set your charge rate.



That is NOT correct. Both "test" and "refresh" show discharge capacities. Only the discharge mode shows "accumulated" capacity.


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## Turbo DV8 (Feb 22, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*



Marduke said:


> That is NOT correct. Both "test" and "refresh" show discharge capacities. Only the discharge mode shows "accumulated" capacity.


 
I stand corrected. My recollection is getting fuzzy over the LaCrosse workings since my attention has been focused on my C-9000's, in use non-stop since Christmas! Now I am left scratching my head over what it was about the TEST mode on the LaCrosse which caused me to dislike using it to obtain capacity. I thought it was because it didn't display the discharge capacity, but obviously not. Ah, now I think I remember. I did not like being saddled with the default current pairings (discharge current = 1/2 charge current). So I would charge first at the current I preferred, then run the discharge portion of the refresh at the drain I preferred to obtain capacity. Sorry for the misinformation I spewed.


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## Mr Happy (Feb 22, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*



Turbo DV8 said:


> I did not like being saddled with the default current pairings (discharge current = 1/2 charge current). So I would charge first at the current I preferred, then run the discharge portion of the refresh at the drain I preferred to obtain capacity.


Although the 2:1 ratio is fixed, I think a pairing of 1000 mA charge/500 mA discharge would give you very reasonable results.


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## Muse (Feb 22, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*



Mr Happy said:


> Although the 2:1 ratio is fixed, I think a pairing of 1000 mA charge/500 mA discharge would give you very reasonable results.


I presume you're thinking of AA's, not AAA's, correct?


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## Mr Happy (Feb 22, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*



Muse said:


> I presume you're thinking of AA's, not AAA's, correct?


Yes, I am. I tend to forget AAA's exist as I have so few devices that require them.

Edit: ...and then I notice this thread says "AAA" in the title 

For AAA cells I would pick something like 400 mA charge/200 mA discharge.


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## Muse (Feb 22, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*



Mr Happy said:


> Yes, I am. I tend to forget AAA's exist as I have so few devices that require them.
> 
> Edit: ...and *then I notice this thread says "AAA" in the title*
> 
> For AAA cells I would pick something like *400 mA charge/200 mA* discharge.


I was thinking of deleting that part of the title ("AAA"), and will do so now. I have both AA and AAA and in fairly equal quantities and needs. My BC-900 doesn't offer 200/400 but does have 250/500 and I will evidently be using those rates in the future, for my AAA's and probably the AA's too. As well, I have unplugged the 12v fan above the cells (it was being supplied by a 7.2v transformer).


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## Hoggy (Feb 22, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*



Muse said:


> I was thinking of deleting that part of the title ("AAA"), and will do so now. I have both AA and AAA and in fairly equal quantities and needs. My BC-900 doesn't offer 200/400 but does have 250/500 and I will evidently be using those rates in the future, for my AAA's and probably the AA's too. As well, I have unplugged the 12v fan above the cells (it was being supplied by a 7.2v transformer).



Unless someone says otherwise, I think 250/500 should be just fine.
Glad to hear that you unplugged that fan!


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## Turbo DV8 (Feb 22, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*



Mr Happy said:


> Although the 2:1 ratio is fixed, I think a pairing of 1000 mA charge/500 mA discharge would give you very reasonable results.


 
I am not yet a converted disciple of the "First Church of 0.5C to 1.0C Charge Rate." :duck:So for LSD AA cells, 700 mA is tops for me for non-rushed charging. Yet, 500 mA is the minimum drain I would want to use, so you see the default settings don't suit me. Now that it's all coming back to me now, the other reason I never used TEST mode on the LaCrosse is I am not certain it is healthy to charge a cell at a high rate then immediately begin to discharge it, as the TEST function on the LaCrosse does. Not to mention, it gives an artificially inflated discharge capacity by measuring charge one is not likely to ever recoup in real-world use. By charging manually, I can let it rest for an hour or so before starting the discharge portion of the REFRESH mode.


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## SilverFox (Feb 24, 2009)

*Re: Initial charge on Eneloops, charging strategies. (AAA)*

This thread split off and was discussing the reason of the temperature rise at the end of the charge. This deserves its own thread, so I split it off and you can find the discussion continuing here.

Tom


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## bob_ninja (Feb 26, 2009)

Here is an attempt at summary:

The prevailing wisdom as promoted by Tom is to use:
0.5C-1C charge rate until cell drops to 80% of original capacity when it was new (actual measured, not nominal printed on it)

This approach minimizes danger of missed termination and overcharging to almost nil.

That being said:
1) one can still charge at rates below 0.5C
2) one can still keep using cells after they drop below 80% capacity

Clearly in this case risk of missed termination and overcharging is higher. The key point is this:

When doing both (1) and (2) then the risk of missed termination is *VERY HIGH*

So the rule is not to do both. You can charge new/vibrant/fresh cells below 0.5C (1) or older/tired cells at/above 0.5C but don't do both!!!!
Even so you should keep an eye on charge process for either (1) or (2)

For instance, I still charge my AAAs at 200 mA on BC900 as they are all in a good shape (about .2C)
However, I charge my old crap AAs on BC900 at minimum 500 mA (although to be honest even that is too low) and keep an eye on it from time to time (about 0.3C - so I am breaking the rule already 

This should help you avoid overcharging.

Notice I keep talking about BC900. It is ideal for tired/older cells because it is more tolerant of them; Maha charger is more sensitive and will simply refuse them. So clearly BC900 is better suited for older cells.

However because of its small size and tight space it tends to generate more heat, hence a lot of us keep using lower rates on BC-900. As Tom pointed out it is not a good idea, so you have to be careful. If you get missed terminations then move up charge rate.

MH-C9000 has a better spacing, is generally cooler and has a gentler charge algorithm (earlier maxV termination). So it is ideal for newer/vibrant cells and higher charge rates. I have no problems using 1A on it. Most of the time I am around 800 mA, 0.3C (seems 0.3C is the magic number for me 

So it is ideal for newer cells and all sorts of analysis, break-in, etc. BC900 modes are bit odd sometimes (as this thread points out).

So use both chargers and be careful with older cells and lower charge rates.


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## Russel (Feb 26, 2009)

bob_ninja said:


> However because of its small size and tight space it tends to generate more heat, hence a lot of us keep using lower rates on BC-900. As Tom pointed out it is not a good idea, so you have to be careful. If you get missed terminations then move up charge rate.


 
I find that when I charge Eneloops AA cells at 1000ma with the BC-900, if I only put batteries in the first and last cell bay, the battery temp max is much lower.


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## was.lost.but.now.found (Feb 26, 2009)

Russel said:


> I find that when I charge Eneloops AA cells at 1000ma with the BC-900, if I only put batteries in the first and last cell bay, the battery temp max is much lower.


 
All of a sudder this seems like common knowledge. I was involved in a recent thread and after mentioning my high temps on BC900 for .5C and above people thought something was wrong with my charger. Good to know this is just normal. Now back to the discussion of adding a cooling fan.


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## bob_ninja (Feb 26, 2009)

Russel said:


> I find that when I charge Eneloops AA cells at 1000ma with the BC-900, if I only put batteries in the first and last cell bay, the battery temp max is much lower.



Yes, good point. I also do this all the time when not in a hurry, simply use the 2 slots at the ends, so plenty of cooling. I find you can work around BC-900 shortcomings like heat using simple methods like this.

I think many/most problems occur when all slots are used at well over 1A charge rates. Then heat can build up much more. That is why I like Maha charger for 1A+ rates as there is plenty of spacing and cells are easy to reach, insert and remove.


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## Russel (Feb 26, 2009)

bob_ninja said:


> Yes, good point. I also do this all the time when not in a hurry, simply use the 2 slots at the ends, so plenty of cooling. I find you can work around BC-900 shortcomings like heat using simple methods like this.
> 
> I think many/most problems occur when all slots are used at well over 1A charge rates. Then heat can build up much more. That is why I like Maha charger for 1A+ rates as there is plenty of spacing and cells are easy to reach, insert and remove.


 
The BC-900 will charge at 1500 and 1800ma with only the first and last of the four battery bays occupied. I'll bet that cell temp at these higher charge rates and the close proximity of the cells being charged is the reason that the BC-900 is configured this way. 

Just received a MH-C9000 today. Time to play with my toys! It appears to me that having at both a BC-900 and a MH-C9000 is advantageous, the features of the two chargers seem to complement each other. I have to admit I am going enjoy the battery spacing of the MH-C9000. I end up needing a tool to pry out the middle batteries with the BC-900, if I don't want to disturb the outer cell bays.

Russ


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## Russel (Feb 26, 2009)

*Re: Initial charge on Eneloops (AAA)*



NiOOH said:


> ...IMO however, the temperature measured by these probe termometers is quite a bit lower than the actual cell skin temperature. This is manly due to the poor contact between the probe and the cells. Looking at the picture, you'll see that only half of the probe surface is in contact with the cells (and this trough the poorly heat-conducting plastic sleeve), the other half is cooled by ambient air. So, for me this is not a proper method to measure cell temperature. However, it could be used to measure dT/dt. Although absolute values will be lower the rate of temperature increase will be accurate. If you have a time to run such experiments (writing down time and temperature towards the end of quick charge say, every 20 seconds) it will be great.


 
Very true! And you didn't even mention the fact that these thermometers are probably very inaccurate in general. My jury rigged temp test (JRTT) does however give you some kind of idea of the maximum temp the batteries reach. Being a NiMH charging novice, I had no real idea what temp the batteries would reach when charging, that is why I would always charge at 200ma. Fortunately for me, new Eneloops seem to provide the charger with an adequate delta V for the charge to terminate. I never recorded any overcharges. The reason that I would charge at such a low rate was to keep the batteries cooler, knowing that heat is bad for NiMH. So, I hook up the goofy JRTT to get some kind of idea how hot they get at higher charge rates. The test served it's purpose well enough, though it was not very accurate. I now charge all of my Eneloops AA cells with a BC-900 at 1000ma with confidence that they are not getting excessively hot. I do however charge only two batteries at a time using the first a last battery bays to help keep the max temp lower.

Russ


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## geek4christ (Mar 2, 2009)

*Re: Initial charge on Eneloops (AAA)*



Muse said:


> Should I stop providing ventilation to the cells? :sigh: Part of the reason I did this was to put the charger in a position where if it did "melt down" it wouldn't damage anything. :thinking: The BC-900 actually senses the temperature of the cells in determining -delta V termination? How does it do that? Separate temperature sensors under each cell?





Muse said:


> If not a problem for AA cells, I'd think it wouldn't be a problem for AAA cells either at those charge rates with the cooling fan on. I've many times put a finger to a cell wondering if it might be hot but have never felt anything I'd call even a warm cell. Not sure there's a reason to have that fan going. :thinking: As long as it doesn't induce missed terminations, I guess it doesn't hurt and might help.



I still keep a fan on my BC-900. I am fully aware of the fact that I'm tricking the cells into being cooler and am preventing the Max Temperature check from ever happening. All of the cells I've run through the charger (you may call them vibrant I guess, they're mostly well cared-for Eneloops) have generated a strong enough -deltaV to terminate.

I too, wondered if the fan was overkill. I accidentally charged one of my Eneloop AAs at 1000mA one time and forgot to turn on the fan. It got hot. I have been assured by some well respected members, Mr. Happy in particular, that the fact that I was able to hold them meant they weren't overheated, so I'm fairly confident I didn't damage them. However, they were too hot for me to feel good about. So I leave my fan going when charging.

Why?



Mr Happy said:


> There seems to be something not right there. I have several times charged eneloops at 1600 or 1800 mA (not on the LaCrosse) and they do not get even slightly warm until the last few minutes of the charge. (See this post, and note how when charging at 1600 mA the eneloop did not get above 37°C until right at the end.) Could it be the charger itself that is getting hot and heating up the batteries that way?



Because as Mr Happy says, I think the charger is contributing a lot of the heat I feel on my cells when charging without the fan. When I introduce active cooling, I feel much better about the lower operating temperature of my charger. In looking into the reports of BC-900 meltdowns, I'm pretty sure all the ones I've seen were caused by charger itself overheating the cells to the point of them venting. The NiMH cells seem to be innocent victims to undue heat inside the charger.

It's not, then, that I'm worried about long-term damage to my cells so much as I'm worried about damage to my charger due to components inside running too hot. In later firmware revisions, LaCrosse has bumped the Max Temp cutoff down to a safer level, so even this is probably overkill, though.

So if you want to keep the fan on them, by all means do so. If you know the possible risk of missing termination and also missing the max temp failsafe due to active cooling, and subsequently monitor your charges (which we should all be doing anyway) you should be just fine.


----------



## NiOOH (Mar 2, 2009)

*Re: Initial charge on Eneloops (AAA)*



geek4christ said:


> So if you want to keep the fan on them, by all means do so. If you know the possible risk of missing termination and also missing the max temp failsafe due to active cooling, and subsequently monitor your charges (which we should all be doing anyway) you should be just fine.


 
If you, like me, run on average 1-2 charges each day, watching them becomes more like full time job :green:

I recommend passive cooling that only dissipates the heat generated by the charger. Placing the charger on a large heatsink helps quite a lot. If a charger heats my cells to uncomfortable levels, I'd rather change the charger. That said, my BC900 (RIP) worked well in this respect with charging currents up to 700 mA.


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## Turbo DV8 (Mar 2, 2009)

*Re: Initial charge on Eneloops (AAA)*



NiOOH said:


> I recommend passive cooling that only dissipates the heat generated by the charger. Placing the charger on a large heatsink helps quite a lot.


 
And definitely supplement those pitiful mosquito bites on the bottom with stick-on feet to raise the charger for better convection. Two pencils placed underneath is about the right height, too.


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## Beacon of Light (Mar 3, 2009)

*Re: Initial charge on Eneloops (AAA)*



SilverFox said:


> I wear out 40 - 50 NiMh cells in about 2 years. Prior to following the manufacturers recommendations, I would go through that many cells in under a year. I am very pleased with this. Not only do I save some money, but I am also seeing much better performance from my cells during the time they are in use.



You only get 2 years out of cells? Wow I guess I shouldn't complain that some of the cells I have been using since the late 90s (like the first Ray O Vac NiMH cells that I bought which were before Maha or Eneloops existed) are still working, albeit not at optimal levels but still useable in remotes, wireless mice/keyboards, and LED flashlights. I'm the kind of guy that wants to get every last drop out of something before throwing it away.


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## was.lost.but.now.found (Mar 3, 2009)

*Re: Initial charge on Eneloops (AAA)*



Beacon of Light said:


> You only get 2 years out of cells? Wow I guess I shouldn't complain that some of the cells I have been using since the late 90s (like the first Ray O Vac NiMH cells that I bought which were before Maha or Eneloops existed) are still working, albeit not at optimal levels but still useable in remotes, wireless mice/keyboards, and LED flashlights. I'm the kind of guy that wants to get every last drop out of something before throwing it away.


 
If I recall, SilverFox's general rule of thumb is to recycle them after a drop to 80% of original capacity. To each their own I guess. I'm with you - I'd like to squeeze the last bit of life out of them as long as they are consistent in their capacity that is.


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## SilverFox (Mar 3, 2009)

*Re: Initial charge on Eneloops (AAA)*

Hello Beacon of Light,

There are times when I recharge cells 2 - 3 times a night. At this rate of usage the number of cycles adds up quickly.

A lot of the equipment I use my batteries in is what I call "mission critical." It has to work, and work well, when I use it. I have zero tolerance for crap cells.

For example, let's take a look at your car battery. After it wears out, it will still be able to run the car, it just can't start it. In my case, when it gets to the point that it won't start the car, I call it crap and recycle it.

Tom


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## SilverFox (Mar 3, 2009)

*Re: Initial charge on Eneloops (AAA)*

Hello Was.lost.but.now.found,

That is the whole problem. Once a cell drops below 80% of its initial capacity, it no longer gives consistent performance. Also, cell to cell differences are amplified, so if you grab a couple of cells for a multi cell application, you end up with poor performance as well as damaging the cells during discharge.

On top of that, the cells internal resistance goes up and this accelerates the degradation of the cell during use and charging due to the extra heat. 

If your needs are less critical, you may be satisfied using crap cells, but for mission critical applications, they are not tolerated.

Tom


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## Beacon of Light (Mar 3, 2009)

*Re: Initial charge on Eneloops (AAA)*



was.lost.but.now.found said:


> If I recall, SilverFox's general rule of thumb is to recycle them after a drop to 80% of original capacity. To each their own I guess. I'm with you - I'd like to squeeze the last bit of life out of them as long as they are consistent in their capacity that is.



Exactly, anything less than that is wasteful. I am just csalling out those that will throw away a 2700 mAh battery just because it now maxxes out at say 1200 mAh. Wasteful...


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## Beacon of Light (Mar 3, 2009)

*Re: Initial charge on Eneloops (AAA)*



SilverFox said:


> Hello Was.lost.but.now.found,
> 
> That is the whole problem. Once a cell drops below 80% of its initial capacity, it no longer gives consistent performance. Also, cell to cell differences are amplified, so if you grab a couple of cells for a multi cell application, you end up with poor performance as well as damaging the cells during discharge.
> 
> ...



That makes even less sense that you would recycle batteries once they reach the 80% mark. If you are using your charger 2-3 A DAY, then all the more reason to use the old batteries, since you are already using the charger a lot, what a few extra charges for the old batteries. I could see if you were lazy and only used a charger once a week or once a month, since you'd just want batteries that last the full capacity and don't have time for cells that will only hold 800 mAh-1200mAh, but since you do use the charger a lot I don't see the reason you'd throw them away.


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## Hoggy (Mar 3, 2009)

*Re: Initial charge on Eneloops (AAA)*



was.lost.but.now.found said:


> If I recall, SilverFox's general rule of thumb is to recycle them after a drop to 80% of original capacity. To each their own I guess. I'm with you - I'd like to squeeze the last bit of life out of them as long as they are consistent in their capacity that is.



Yeah...
Every time I hear Silverfox say that, I want to bop him on the noggin with a whiffle ball bat. 

I have some old 700mah rated cells that, after reviving, still only show as 314mah with heavy internal resistance.. What even *I* call some truly crap cells! Yet they don't seem to be doing so bad in one of my air-conditioner remotes. I may change my mind later - but so far, so good.

I've read some people saying that they have a hard time recycling batteries at the 80% marker. And I always want to chime in with "then DON'T" - if one doesn't mind putting up with their various batteries' quirks, then by all means USE them. 

:sigh:... Silverfox ... Gotta love him though.. He's done so much testing for all us.


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## SilverFox (Mar 4, 2009)

*Re: Initial charge on Eneloops (AAA)*

Hello Beacon of Light,

I was recently working with some people that had your attitude toward rechargeable cells.

We had to inspect a section of buried pipe. The pipe was 48" in diameter and the section we were inspecting was about 1/2 mile long. In spite of efforts to clean it out, there was a lot of sludge and water left in the pipe. Our only source of light was our flashlights.

My light lasted the whole way, and was much brighter than the others.

The other people, who were thinking along your lines, actually had to stop twice and replace batteries. Both times, they dropped end caps and batteries in the sludge and mumbled something about not liking to use rechargeable batteries in their lights. After the second time they changed batteries, their lights were almost as bright as mine was, and mine had been on the whole time.

You may prefer to "play" in the sludge and carry lots of extra batteries, but I just want my light to work, to work well, and not to be left in the dark. 

Tom


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## NiOOH (Mar 4, 2009)

*Re: Initial charge on Eneloops (AAA)*



Beacon of Light said:


> That makes even less sense that you would recycle batteries once they reach the 80% mark. If you are using your charger 2-3 A DAY, then all the more reason to use the old batteries, since you are already using the charger a lot, what a few extra charges for the old batteries. I could see if you were lazy and only used a charger once a week or once a month, since you'd just want batteries that last the full capacity and don't have time for cells that will only hold 800 mAh-1200mAh, but since you do use the charger a lot I don't see the reason you'd throw them away.


 
I use the same criteria as Tom does. Do not forget that capacity reading is only part of the equation. High internal resistance and high self-discharge (with non-LSD cells of high capacity mainly) also mark the turning of a good cell into crap one. The price of a good quality NiMH AA cell is 3-5 times higher than the price of an alkaline cell. After recharging it 200-400 times it has paid for itself 100 times. I see no reason to compromise performance of expensive electronics or to risk the life of my expensive chargers (missed terminations) just to save couple of cents.


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## Hoggy (Mar 4, 2009)

NiOOH, (you and Silverfox now)


Not every application needs high-performance top notch cells, nor is every electronic device expensive. As far as the charger, my C9000 has a 3 year warranty.
:duck:

And with known bad cells, I NEVER put them on any charger without watching them like a hawk. 
As I say, it all depends on how much someone wants to put up with their various cells' quirks.


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## Mach1 (Mar 4, 2009)

*Re: Initial charge on Eneloops (AAA)*



Beacon of Light said:


> Exactly, anything less than that is wasteful. I am just csalling out those that will throw away a 2700 mAh battery just because it now maxxes out at say 1200 mAh. Wasteful...



That's just silly. If your time is worth 32 cents per hour, go ahead and track each of your AA batteries on a spreadsheet as the cycles pile up. Then, calculate the run time for your flashlights as mAH goes down....

If my flashlight runs for 60 minutes on new batteries and I notice shorter times, I'll do a run time test. If it runs for less than 50 minutes, I toss the batteries. Oh, my! How wasteful!

Golly gee. I figure it's better to have light when I need it than to save $10.95 on a 4 pack of new NiMH AAs.

$90 Maha 808M, check!

Plenty of worn out 2700 NiMH AAs, Check!

Blackout that lasts 4 hours longer than the run time of my now crap 1500 mAH capacity batteries, D'oh!




P.S.: I toss them. I don't recycle. I don't drive a Pious, I mean Prius.


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## Hoggy (Mar 4, 2009)

*Re: Initial charge on Eneloops (AAA)*



Mach1 said:


> P.S.: I toss them. I don't recycle. I don't drive a Pious, I mean Prius.



No matter which end of the spectrum you fall on, you really should RECYCLE them.

It doesn't take much effort at all to put them in a 'recycling' bag and give it to Radio Shack every once in a while. Just use one of the plastic bags they give you at any grocery store or any other store in the US. EDIT: I'm sure other countries often use plastic bags too, but I can't be certain about it.

I'd bet 1 Billion dollars that you have kids.
Am I a Billionaire? 
:tsk:


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## Mach1 (Mar 4, 2009)

*Re: Initial charge on Eneloops (AAA)*



Hoggy said:


> No matter which end of the spectrum you fall on, you really should RECYCLE them.
> 
> It doesn't take much effort at all to put them in a 'recycling' bag and give it to Radio Shack every once in a while. Just use one of the plastic bags they give you at any grocery store or any other store in the US. EDIT: I'm sure other countries often use plastic bags too, but I can't be certain about it.
> 
> ...



I do not have children. I used to live in California where cities like Manhattan Beach have outlawed plastic shopping bags and every home had four separate trash cans for recycling. I now live Wyoming. :nana:



Hoggy said:


> NiOOH, (you and Silverfox now)
> 
> And with known bad cells, I NEVER put them on any charger without watching them like a hawk.
> As I say, it all depends on how much someone wants to put up with their various cells' quirks.



What's more ecologically sound? Tossing my bad cells away or watching them start a fire and burning my house to the ground because I can't monitor charging? How can you afford to spend the time watching bad cells like a hawk for hours and hours? Do you collect social security ?


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## Turbo Guy (Mar 4, 2009)

Like Silver Fox I have mission critical applications ( I fly R/C airplanes) and will not risk an expensive aircraft or place myself and others in harms way by trying to get by using questional batteries. 

I also can not stand a camera or flash that does not more than 50 photos without a battery change and I most especially can not stand a flashlight or GPS that decides to stop working at the worst possible moment.

I also happen to be a Ham and a HT that your or others life may depend on needs dependable long lasting batteries. 

All of these above applications of mine can be covered with AA NiMH cells with the exception of deciated LiIons in my Cannon Digital Rebel.

Sanyo Eneloop and Rayovac Hybrids have proven to be reliable and provide good service life. They can set for months and be good to go with no topping off required. A few extra sets of AAs are very easy to carry and should be part of everyones go bag.

Now for other uses around the house I often use far less than prime cells. After being used in the above application my NiMH AAs get cycled down to use in personal CD / MP3 players,a LED 2AA Mini Mag-Lite that I wear daily and other misc. application such as TV/entertainment devices remotes.

When to toss a cell? Tom uses the 80% rule which has been an industry standard for a very long time. For mission critical I use that rule also but I first cycle(condition) the cells and find the true capacity, no some manufacture's should be about number.

My non mission critical uses I will tolerate a cell down to 60% if it shows no signs of developing extremely high IR or very high self discharge. Cells that get overly warm during a normal charge or that lose 20% or more of their charge in a week are a waste of time as well as being boarder line dangerious at best.

Long post for a new member so please excuse me.


Charles


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## NiOOH (Mar 4, 2009)

Turbo Guy said:


> I also can not stand a camera or flash that does not more than 50 photos without a battery change and I most especially can not stand a flashlight or GPS that decides to stop working at the worst possible moment.
> 
> Charles


 
Hello Charles.
I agree with you 100%. I have a camera flash that costs as much as a small second hand car. What's the point of stuffing it with marginal cells, just to watch it recharging for 15 seconds and the bad cells heating up the expensive electronics inside to unacceptable levels.
I have nothing against my tired cells to spend the last year of their lives in some remote control around the house or in the mouse I clicked to get to this forum right now, but for critical applications, I always have 3-4 sets of vibrant cells in top condition.


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## bob_ninja (Mar 4, 2009)

Both Tom and Charles make perfect sense.

Tom may choose to stop using them after 80% or ...

I simply mark weaker sub-80% cells with a dot. Then at any point in time I can choose appropriate cell for appropriate application. In my case I have a bunch of toys (for my kids, children toys) that are perfect for weak cells - not mission critical, so I keep a bunch of weak cells. Others pointed out devices that tolerate weaker cells like wireless mice. Again, I just keep a bunch of extra cells, all weaker type, so at any time I have a backup.

Then again if I were in tough places, mud or at 0F, then the last thing I want is to mess with are cells. Then I'll use my best cells.

The context of cell use is important when talking about old/weak vs new/strong cells.


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## Beacon of Light (Mar 4, 2009)

*Re: Initial charge on Eneloops (AAA)*

Not trying you how to do your job, but in your situation new Eneloops are probably standard or lithium rechargeables since it is the only light source. I guess if you are using your light a lot at work I would also think you'd carry at the least a 8 cell case full of charged batteries. 

For those of us (probably 75% or higher) that aren't plumbers or building a subway at 2am, I still say using worn cells are still worthy.



SilverFox said:


> Hello Beacon of Light,
> 
> I was recently working with some people that had your attitude toward rechargeable cells.
> 
> ...


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## Beacon of Light (Mar 4, 2009)

*Re: Initial charge on Eneloops (AAA)*

Please send me your old NiMH batteries then, I will give them a second life. 



Mach1 said:


> That's just silly. If your time is worth 32 cents per hour, go ahead and track each of your AA batteries on a spreadsheet as the cycles pile up. Then, calculate the run time for your flashlights as mAH goes down....
> 
> If my flashlight runs for 60 minutes on new batteries and I notice shorter times, I'll do a run time test. If it runs for less than 50 minutes, I toss the batteries. Oh, my! How wasteful!
> 
> ...


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## Beacon of Light (Mar 4, 2009)

*Re: Initial charge on Eneloops (AAA)*



> What's more ecologically sound? Tossing my bad cells away or watching them start a fire and burning my house to the ground because I can't monitor charging? How can you afford to spend the time watching bad cells like a hawk for hours and hours? Do you collect social security ?



You can't set your charger next to your monitor? You probably spend at least an hour or so online surfing this forum at least. You'd at least see if the battery is sparking or leaking without having to passively watch a charger (less exciting than watching grass grow or paint dry).


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## Beacon of Light (Mar 4, 2009)

*Re: Initial charge on Eneloops (AAA)*

I guess I am in the minority, but most of my battery usage wouldn't be mission critical unless you call a digital camera mission critical. Even with that as the case, I rarely ever use but the most recent and high capacity cells I own for camera work or Eneloops without having to worry if they were sitting in the camera for 3 or 4 weeks between uses. The older cells go into lights, wireless mice, keyboards, remotes, mp3 players, etc. 

I can still get at least 5-6 hours (which is basically a weeks worth of use for me) worth of runtime out of my CMG Infinity with the old Nicad Eveready from 1991 and most capacitry it takes on my Lacross is just shy of 350 mAh. That to me is 5-6 hours of time that would never have occured had that cell been dropped off at Radio Shack.


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## Hoggy (Mar 4, 2009)

*Re: Initial charge on Eneloops (AAA)*



Mach1 said:


> I do not have children. I used to live in California where cities like Manhattan Beach have outlawed plastic shopping bags and every home had four separate trash cans for recycling. I now live Wyoming. :nana:



Sorry if it sounded like I was getting too personal, but I always find it incredibly ironic that so many people that don't care about the environment also happen to have kids. 
I never understand why some places have 4 separate bins. It seems like they want to make recycling as inconvenient as possible. I hate going to throw something out and having to decipher which bin is for what. It would make it much more convenient to just have 2 - one for garbage and one for all recyclables, then the recycling company separates them later. Not to mention that some people will mix them up anyways.
So I guess I can understand your newfound freedom, then. 



Mach1 said:


> What's more ecologically sound? Tossing my bad cells away or watching them start a fire and burning my house to the ground because I can't monitor charging? How can you afford to spend the time watching bad cells like a hawk for hours and hours? Do you collect social security ?



I moved my charging 'station' next to my computer.. So I don't _really_ watch them like a hawk, but that way if I ever smell or see something I can do something about it. Plus I don't have all that many batteries that I'm charging them every day, unlike some other people here.

For things like my camera or EDC light (i.e. mission-critical), I of course only use the top-notch LSD's, but for things like my air-conditioner remote.. I'll just use some crap ones in there - now that I have the ability to determine what actually *is* crap.


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