# How to charge Eneloops in La Crosse BC-700?



## Russelljohnson (Mar 17, 2010)

Well I've checked out the other threads but there isn't a general consensus of how to actually charge eneloops.

I just picked up 8 pieces and threw then in my new La Crosse BC-700. I am using the refresh mode so that it discharges and charges it a few times until it detects maximum capacity.

In other threads, people say 0.1C or 0.5C. What does C stand for? I only current in units of Amps or mA...

The BC-700 defaults charging at 200mA. It can also do 500mA and 700mA. It seems like people on the forum like to charge at a higher current? One last question I had was I didn't really understand what you guys mean by termination. How do I know the charger terminated at the right time?

NiMH is at 1.2V right?


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## SilverFox (Mar 18, 2010)

Hello Russelljohnson,

Welcome to CPF.

NiMh chemistry is a nominal 1.2 volts. That means that it holds 1.2 volts for most of its discharge. The actual voltage runs from 1.45 volts right off the charger down to 0.9 volts when they are completely discharged. It is pretty much a useless value just like Alkaline cells that are rated at 1.5 volts. Alkaline cells start out at 1.5 volts (or actually a little higher) then drop in voltage from there.

A cell with 2000 mAh of capacity that is subjected to a 2000 mA load will drain the cell in about 1 hour. This is a 1C load. A 0.5C load would drain the cell in 2 hours.

Charging is similar. To charge a 2000 mAh cell at 1C, you would charge at 2000 mA. If you want to charge at 0.5C, you would charge at 1000 mA.

Look up Battery University and you should be able to find a graph on what happens during charging. Basically the cells voltage will continue to rise until the cell is fully charged, then it will drop a little. The charger is set up to recognize this drop in voltage as the time to end or terminate the charge. If the charge continues, the cell can be damaged due to overcharging.

When charging NiMh cells, the strongest termination signal occurs when the cell is charged in the 0.5C - 1.0C range. It is possible to use lower charge rates, but they are not as reliable throughout the life of the cell.

There is a special case when charging at 0.1C. The cell can handle a fair amount of overcharge when charging at this low rate. With a 2000 mAh cell, 0.1C is 200 mA. Since there is not as strong of a termination signal at this low rate, the charge is usually terminated on time. I believe your charger allows you to see how much charge has been put into the cell. If you charge a 2000 mAh cell that is fully discharged and end up putting 3000 mAh back into it, your charger has missed the termination signal and has timed out. The cell has been overcharged.

Tom


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## Russelljohnson (Mar 18, 2010)

Thanks for the clear info Tom.

My charger shows the current mAh of each battery. So to manually know when the battery is finished charging, it should be very close to the rated capacity of 2000mAh correct?

Should I charge at the highest available current from now on? It would only be .35C at the highest. Why do some people say to charge at a lower rate to prolong the battery life? This has got me all confused.


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## Mr Happy (Mar 18, 2010)

Russelljohnson said:


> Should I charge at the highest available current from now on? It would only be .35C at the highest. Why do some people say to charge at a lower rate to prolong the battery life? This has got me all confused.


There's a lot of debate about this, and there is no absolute certainty about the answer.

This thread of mine might give you some insight. Look at the two charging graphs at 2000 mA and 400 mA. You can see how the dip at the end with 2000 mA is very pronounced (easy for the charger to see), whereas the dip at 400 mA is nearly absent (easy for the charger to miss).

Therefore charging faster makes it easier for the charger to stop when it is supposed to.

Now take a look at this page from Battery University. What is shown on that charging graph and not shown on mine is the internal cell pressure. Notice how the pressure inside the cell goes skywards towards the end of high rate charging, and also how the temperature shoots up steeply.

These changes in pressure and temperature are going to put thermal and mechanical stresses on the cell that over repeated cycles will cause slowly accumulating damage to the internal structures.

Therefore to prolong the life of the cell it would be preferable to use lower charging rates, as long as the charger can detect the end of charge signal and avoid going into over charge. However, in some applications lower charging rates might reduce the ability of the cell to perform at maximum efficiency.

As you can see this is not a simple picture, and there is no perfect answer for every situation. Taking everything together though, the best advice would be to use the 700 mA charge rate for Eneloops on your BC-700.


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## Russelljohnson (Mar 18, 2010)

Thanks Mr. Happy & Tom. Sincerely appreciate the assistance.


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## guggie (Mar 18, 2010)

Just some personal experience:

I charge my Duracell low discharge cells (like Eneloops) in a LaCrosse BC-9009 at both 200ma and 500ma. They consistently take about 1700-1800maH and terminate perfectly fine. I just charged 2 cells that were showing low in my GPS and each cell took 1790 exactly. Pretty impressive.


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## Russelljohnson (Mar 18, 2010)

How can you manually tell that the battery charge is full? When it's at 1.5V and 2000mAh?


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## N162E (Mar 18, 2010)

Russelljohnson said:


> How can you manually tell that the battery charge is full? When it's at 1.5V and 2000mAh?


When charging is complete "FULL" will appear on the corresponding slot. The LaCrosse chargers tend to sense end of charge at much lower current than the Maha charger. I routinely use 500 ma rate for my Eneloops.


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## Russelljohnson (Mar 18, 2010)

N162E said:


> When charging is complete "FULL" will appear on the corresponding slot. The LaCrosse chargers tend to sense end of charge at much lower current than the Maha charger. I routinely use 500 ma rate for my Eneloops.



What's the mAh on your full charged cells? One of them have been stuck at 1400mAh for like the past 4 hours. 1.46 volts currently. Is the current mAh reading representative of how much juice is in them?


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## guggie (Mar 18, 2010)

Russelljohnson said:


> What's the mAh on your full charged cells? One of them have been stuck at 1400mAh for like the past 4 hours. 1.46 volts currently. Is the current mAh reading representative of how much juice is in them?



Fully charged AA sized Eneloops are at 2000mah. If you charged one that has not been fully discharged, then only the amount you used will be put back in, less some waste for inefficiency of the charge process. The current maH reading is how much you have put in the cell, not the capacity of the cell.


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## Russelljohnson (Mar 18, 2010)

guggie said:


> Fully charged AA sized Eneloops are at 2000mah. If you charged one that has not been fully discharged, then only the amount you used will be put back in, less some waste for inefficiency of the charge process. The current maH reading is how much you have put in the cell, not the capacity of the cell.



Hmm... that's weird since I put them on "refresh" which is supposed to discharge them and charge them back up. Wonder if I have bad eneloops.


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## guggie (Mar 18, 2010)

Russelljohnson said:


> Hmm... that's weird since I put them on "refresh" which is supposed to discharge them and charge them back up. Wonder if I have bad eneloops.



The interpretation of the screen readout depends on the mode you are using. Check your operating manual for your charger.


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## Russelljohnson (Mar 18, 2010)

guggie said:


> The interpretation of the screen readout depends on the mode you are using. Check your operating manual for your charger.



Thanks for tip. Checking the manual once again revealed that the displays have different meanings for different modes. Definitely a good idea to RTFM.


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## Russel (Mar 19, 2010)

The BC-700, in refresh mode, when displaying capacity:

Shows the capacity discharged while discharging

The capacity of the last discharge while charging,

Then, when finished refreshing, the maximum capacity recorded from the discharge cycles during refresh.


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## TakeTheActive (Mar 19, 2010)

Russelljohnson said:


> ...*One of them have been stuck at 1400mAh for like the past 4 hours. 1.46 volts currently*...





Russelljohnson said:


> ...that's weird since *I put them on "refresh"* which is supposed to discharge them and charge them back up. Wonder if I have bad eneloops.


Reading the manual and understanding how a device works is always a good idea.

Your cell(s) have finished at least one DISCHARGE and the measured CAPACITY was 1400mAh. It's currently in the CHARGE stage, almost complete at 1.46VDC. Healthy Eneloops will terminate at ~1.53VDC on a La Crosse.

The next alphanumeric that you should see on your display will either be 'FULL' or a number greater than 1400. Let's say the next number you see is 1414mAh. It 'beat' 1400mAh, so, it will try again (and again and again), as long as it 'beats' the last number. If the next number is 1400 or less, it will display 'FULL' and stop cycling.


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## bltkmt (Apr 23, 2010)

I have a BC-700 question - I did read the manual but am not clear on one point. I am going through my Eneloops and doing the "Discharge/Refresh" cycle on each of them. Some batteries finish ("Full") their cycle ealier. I would like to be able to take those finished cells out and start some new cells on their cycle without interfering with the cells on the charger that had not yet finished. I can't figure out how to program the charger for certain charging bays while not effecting bays that are already in use? Any help is appreciated.


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## NutSAK (Apr 23, 2010)

I don't think the charger will let you change modes after a cycle has been selected for a particular cell, so changing the mode or current should only affect the cell you just inserted (within 8 seconds of insertion) and not those that are currently in use. However, I don't have my charger in front of me, so I'm not 100% sure of that. 

So, you can ensure single-cell selection only by pressing the compartment key of the cell you insert so that any subsequent mode or current changes only affect that compartment. The compartment key is mentioned on page 6 of the manual, but it doesn't have a clear description of its use.


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## Mr Happy (Apr 23, 2010)

bltkmt said:


> I would like to be able to take those finished cells out and start some new cells on their cycle without interfering with the cells on the charger that had not yet finished. I can't figure out how to program the charger for certain charging bays while not effecting bays that are already in use? Any help is appreciated.


I think you will need a Maha C9000 to do this. I don't believe the BC-700 has the capability to run independent cycles and modes in each slot.


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## 45/70 (Apr 23, 2010)

It works like NutSAK said. You just press the number key for the cell you just inserted, then the display for that cell will start flashing. You can then adjust to whatever mode, current etc. that you desire. The 8 second rule still applies though, and once it commences, you can't change it again without removing the cell and starting over.

*Edit:* Once you do this, the displays will likely be out of sync. To correct this, you just need to step through the "Display" key to get them all on the same page, so to speak.

Dave


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## Lite_me (Apr 23, 2010)

bltkmt said:


> I have a BC-700 question - I did read the manual but am not clear on one point. I am going through my Eneloops and doing the "Discharge/Refresh" cycle on each of them. Some batteries finish ("Full") their cycle ealier. I would like to be able to take those finished cells out and start some new cells on their cycle without interfering with the cells on the charger that had not yet finished. I can't figure out how to program the charger for certain charging bays while not effecting bays that are already in use? Any help is appreciated.


I believe that this post from TTA just a couple days ago covers what you are trying to do. Option 2


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## Turbo DV8 (Apr 23, 2010)

TakeTheActive said:


> The next alphanumeric that you should see on your display will either be 'FULL' or a number greater than 1400. Let's say the next number you see is 1414mAh. It 'beat' 1400mAh, so, it will try again (and again and again), as long as it 'beats' the last number. If the next number is 1400 or less, it will display 'FULL' and stop cycling.


 
I haven't found the above to entirely reflect my experiences with the BC-900. I never use Refresh on my BC-900's ... I prefer to use TEST and DISCHARGE and keep my eye on the time. One thing I noticed when I first got my BC-900's and did play with the refresh function, was that it seemed not always to make sense when the unit decided to advance to the next cycle or terminate. Don't take these as actual numbers, but they serve for my example. In one case a cycle might render 1850 mAh, and the next 1870 mAh, and it will continue to the next cycle due to a difference of 20 mAH between those two cycles. Yet, another cell might render 1850 mAh one cycle, and the next cycle renders 1890 mAh, for a difference of 40 mAh, but it will decide to halt any further cycles. Perhaps the decision to continue or halt is based upon something other than just change in mAh? Has anybody else noticed this?


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## strawbale (Jun 28, 2012)

After this thread http://www.candlepowerforums.com/vb/showthread.php?339877-Advice-sought-for-new-AA-AAA-charger I got myself the BC-700 and some Eneloops AA & AAA.
On putting the first set of 4 new Eneloop AAAs through the TEST cycle (@200/100mA) it seems that 1 cell missed termination at the end of the first charge (they all measured 1.30V out of the packaging): after it stayed an hour longer than the others @ 1.52V and still hadn't gone into discharge, I pulled it out.
On my second set of 4 new AAAs in TEST cycle (@200/100mA) two cells seem to have missed termination and the end of the second charge.
What shall I do with my 3rd set of 4 AAAs - TEST at 500/250mA? Should I conclude that charging at 200mA is too risky? Should I return the charger (which is a hassle, as bought abroad)?
Thanks in advance for any advice!
Peter


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## SilverFox (Jun 28, 2012)

Hello Peter,

Welcome to CPF.

In order to successfully charge a cell, there needs to be a method to terminate the charge. A common method of charge termination involves looking at a drop in voltage as the cell passes through full charge.

The higher the charge rate, the larger the termination signal. Conversely, the lower the charge rate, the smaller the charge termination signal. 

As cells age (and also with brand new cells) the charge termination signal can trigger early, or not show up at all at lower charge rates. 

With all of this to consider, it is usually best from a charge termination perspective to charge at a rate that completes the charge in 1 - 2 hours. This is referred to as a 0.5C - 1.0C charge, with C = capacity of the cell.

Eneloop cells have a capacity of around 2000 mAh, so a 0.5C charge would involve charging at 1000 mA. A 1.0C charge would be charging at 2000 mA.

When you charge at a rate below 0.5C, you run a risk of missing the charge termination signal. You have experienced this. The issue is that overcharging wears out the cell. Most cells can stand an overcharge at a very low charge rate for a limited amount of time. The standard for determining capacity of the cells involves charging at 0.1C for 16 hours. This involves some overcharge, but the rate is low enough and the time is limited to the point where it does not damage the cell. On the other hand if you leave a cell charging at 0.1C constantly, it will be used up in about a year.

Many people observe that their new cells that are in good condition will terminate properly at lower charge rates, but over time they stop looking at what the charger is doing and after the cell ages missed termination is common. To guard against this, chargers have a timer that limits the charge time. Depending on what the timer is set to, this limits the amount of overcharge the cell can receive.

Low self discharge cells may be more prone to overcharge damage than normal NiMh cells. This hasn't been looked at in depth, but the few cases of Eneloop cell failure have involved leaving the cells on a charger for an extended period of time. I have also seen this with an Eneloop battery pack that was being topped off to balance the cells in the pack. A cell actually started to vent even though the charge current was low. 

We tell people to attend to their charging operation. Keep an eye on things and know when to step in and stop a charge when termination is missed. Your charger will have less problems determining the termination signal if you charge in the 0.5 - 1.0C range. With the BC-700 and Eneloop cells you don't have the capability to charge at 1000 mA, so you will just have to keep an eye on things. Set a timer. If the charge hasn't terminated when the timer goes off, manually stop the charge.

You can play with this by setting the charge rate to 0.1C. With Eneloop cells that would be 200 mA. Put the cells in and set a timer to 16 hours maximum. I am not sure what the upper limit for the BC-700 is, but you can get an idea of how well things are going by looking at the mAh put into each cell. Some cells should terminate properly, others won't. While this also happens at higher charge rates, it is much less frequent. Looking at the amount of charge put into a cell will give you an idea if the termination was proper. You may have to do a discharge followed by a charge to find a target number, but then you can compare how much you are trying to put back in. There is some variation in this depending upon charge rate, but it should give you and idea of what is going on.

Tom


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## strawbale (Jun 28, 2012)

SilverFox said:


> Welcome to CPF.
> .....
> 
> Eneloop cells have a capacity of around 2000 mAh, so a 0.5C charge would involve charging at 1000 mA. A 1.0C charge would be charging at 2000 mA.
> ...



Thank you!
So for my Eneloop AAAs (800mAh) charging at 500mA (= 0.6C) should be fine?
For the AAs (2000mAh) I'll use 700mA, as it's the maximum, and will keep an eye on it ànd use a timer.
Peter


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## Nielsen (May 15, 2013)

Hello everyone.

This is my first post on this forum.

Could it be possible that the real capacity on the cells are higher than the specified capacity? I wonder because I usually charge my AAA cells at 200mA on my BC-700 and the charge is terminated at around 850mAh. But after I came across this thread I tried to charge the cells at 500mA and then the charge terminated at 1050mAh. So the question is could the actual capacity be higher than the specified capacity or do my cells overcharge when I'm charging them at 500mA? What do you think?

Kind regards,
Martin


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## HKJ (May 15, 2013)

Nielsen said:


> Hello everyone.
> 
> This is my first post on this forum.
> 
> ...



NiMH cells are always overcharged, you have to measure the capacity with a discharge.


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## LAM09 (Oct 23, 2013)

I recently bought the Lacrosse BC-700 charger, but I wanted to know how can you tell when your batteries are charged on the Discharge/Refresh mode?

Thanks


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## LlF (Dec 20, 2013)

Never mind


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## tomandjerry00 (Feb 18, 2014)

Resurrecting a few month old thread here, but I just bought 16 AA eneloops and a LaCrosse BC-700. I am running all of the batteries through a discharge-refresh cycle @ 700 mA before I leave Sunday for their first charge. 

I've left them for over 24 hours and they are still going, should I pull them or just keep letting them do their thing? Other thoughts? 

As always, thanks for the help!


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## ChrisGarrett (Feb 18, 2014)

tomandjerry00 said:


> Resurrecting a few month old thread here, but I just bought 16 AA eneloops and a LaCrosse BC-700. I am running all of the batteries through a discharge-refresh cycle @ 700 mA before I leave Sunday for their first charge.
> 
> I've left them for over 24 hours and they are still going, should I pull them or just keep letting them do their thing? Other thoughts?
> 
> As always, thanks for the help!



The 'refresh' function can take many cycles, I think my instructions state and it's up to the charger to determine when 'enough' is 'enough.'

As per the instructions for REFRESH:

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

When no increase is found, between cycles, the BC-700 will call it a day.

FWIW, the Maha C-9000 takes approximately 40-44 hours to complete its 'Break In' function on ~2000mAh AAs.

Chris


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## Lite_me (Feb 18, 2014)

tomandjerry00 said:


> Resurrecting a few month old thread here, but I just bought 16 AA eneloops and a LaCrosse BC-700. I am running all of the batteries through a discharge-refresh cycle @ 700 mA before I leave Sunday for their first charge.
> 
> I've left them for over 24 hours and they are still going, should I pull them or just keep letting them do their thing? Other thoughts?
> 
> As always, thanks for the help!


There is no need to do a refresh on a new set of Eneloops. You can top them off with a charge if you like, or just start using them. It really doesn't matter.


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## tomandjerry00 (Feb 18, 2014)

ChrisGarrett said:


> The 'refresh' function can take many cycles, I think my instructions state and it's up to the charger to determine when 'enough' is 'enough.'
> 
> As per the instructions for REFRESH:
> 
> ...




Perfect, that's what I was hoping to hear! 

Thanks!


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## LAM09 (Feb 18, 2014)

What is the best current setting for charging 3rd gen Eneloops?


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## ChrisGarrett (Feb 18, 2014)

LAM09 said:


> What is the best current setting for charging 3rd gen Eneloops?



Most of us like to charge Eneloops at 1A. I have some Sanyo 2700s and some Accupower 2900s, that I've charged at 1.2A, but 1A is a nice sweet spot.

On the BC-700, 700mA is the max, so that's what I use. It's about .37C for the ~1900mAh Eneloop Gen. 2s/3s/4s, so at the lower end of the charging rate scale, but it has to do.

Chris


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## LAM09 (Feb 19, 2014)

ChrisGarrett said:


> Most of us like to charge Eneloops at 1A. I have some Sanyo 2700s and some Accupower 2900s, that I've charged at 1.2A, but 1A is a nice sweet spot.
> 
> On the BC-700, 700mA is the max, so that's what I use. It's about .37C for the ~1900mAh Eneloop Gen. 2s/3s/4s, so at the lower end of the charging rate scale, but it has to do.
> 
> Chris



Cheers Chris. Will it not shorten the battery life by charging them on 700mA?


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## markr6 (Feb 19, 2014)

I like 700mA. I've been using that since 2008 and never had an issue with my 2000mAh Eneloops. Never get hot, or even warm actually while terminating perfectly every time.


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## LAM09 (Feb 19, 2014)

markr6 said:


> I like 700mA. I've been using that since 2008 and never had an issue with my 2000mAh Eneloops. Never get hot, or even warm actually while terminating perfectly every time.



Thanks then. I have been using the lowest current rate, but it takes so long. I will start using 700mA instead.


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## ChrisGarrett (Feb 19, 2014)

LAM09 said:


> Cheers Chris. Will it not shorten the battery life by charging them on 700mA?



1A for Eneloop Gen. 2s, 3s and 4s is .5C and that's fine, but I don't know if any of us here, have hard, fast data on longevity based on any typical charge rates, so don't sweat the minor stuff.

If I get 1000 cycles charging at 1A, out of my Gen. 2s, vs. 1500 cycles at 700mA, that's still nine years at one cycle per week, so is that really such a big deal? 

They're $2.50 a battery, so you can buy a Subway sandwich, chips and a drink for almost that much, the way I have things figured out and it's not a huge deal breaker for me.

700mA vs. 1A is 3 hours vs. 2 hours and I'm good with that trade off.

Chris


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## markr6 (Feb 20, 2014)

ChrisGarrett said:


> They're $2.50 a battery, so you can buy a Subway sandwich, chips and a drink for almost that much, the way I have things figured out and it's not a huge deal breaker for me.



LOL I love that!

Sometimes you really need to stop, step back and think like this. Not just in this example but in life in general. Don't sweat the small stuff!

But of course, we still like to ask the questions and think "what if..." for the sake of discussion


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## mdixon (Feb 20, 2014)

I have the same charger, charge gen2/3 aaa eneloops at 500mah and have noticed from time to time that the bc700's readout says one (or more) has taken way over 800mah, like 895mah the last time I saw this. does that mean it's being overcharged?

they're all newish batts, 2013 date stamp, have run them down and recharged a number of times, etc. the recharge voltage was in the 1.5x range but took it out of the charger instead of waiting for "full" because I was afraid it was being damaged.

also given the battery is considered dead when voltage gets down around 1v, there must still be mah left in it at that point correct? so the battery 800 mah rating in effect means "800 mah above and beyond what's in it when considered 'dead'" so maybe seeing ~900 mah going into it isn't anything to worry about?


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## ChrisGarrett (Feb 21, 2014)

mdixon said:


> I have the same charger, charge gen2/3 aaa eneloops at 500mah and have noticed from time to time that the bc700's readout says one (or more) has taken way over 800mah, like 895mah the last time I saw this. does that mean it's being overcharged?
> 
> they're all newish batts, 2013 date stamp, have run them down and recharged a number of times, etc. the recharge voltage was in the 1.5x range but took it out of the charger instead of waiting for "full" because I was afraid it was being damaged.
> 
> also given the battery is considered dead when voltage gets down around 1v, there must still be mah left in it at that point correct? so the battery 800 mah rating in effect means "800 mah above and beyond what's in it when considered 'dead'" so maybe seeing ~900 mah going into it isn't anything to worry about?



I was fiddling with some AccuPower 1200 AAAs in my BC-700 the other day, that are two years old and not doing so well. I.R. in the 1.80v range on my Maha C-9000 and some of them missed termination and seemed to keep charging for 20 extra minutes, before I terminated them.

I like my BC-700, but you need to watch it with batteries that might be 'hitting the wall.'

I remember early on, with some older batteries, I would miss a termination, here and there, but I was ignorant at the time and didn't put two and two together.

Chris


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## Dimt (Feb 21, 2014)

I'm lazy so I usually charge my Eneloop's at the default 200ma. Most of the time they are FULL within 24 hours. If I'm in a hurry I will pump it up to 700ma.
I have been using the same batteries for at least four years without a problem.


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## LAM09 (Feb 24, 2014)

I know this is might be a stupid question, but is their any difference in charging batteries on different currents on a BC-700 other than the time it takes to charge the batteries?


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## ChrisGarrett (Feb 24, 2014)

LAM09 said:


> I know this is might be a stupid question, but is their any difference in charging batteries on different currents on a BC-700 other than the time it takes to charge the batteries?



You'll get heat build up charging at the higher rate, which can momentarily stop the charger from charging for a bit, until the temps come down. I think that bays 1&3 and 2&4 (don't quote me on the exact pairings) are connected, so when things shut down due to temps (140*F?) those two bays affected, will stop charging.

This is generally an issue with older batteries, with higher internal resistances and not new ones, but the BC-700 is a smaller charger and the batteries are crammed in there, close to each other, unlike the Maha C-9000, which offers some 'breathing room' around the bays.

Chris


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## SilverFox (Feb 24, 2014)

Hello LAM90,

Welcome to CPF.

In addition to the heat issue that Chris mentioned you also need to be aware of how the charger terminates the charge.

Many chargers terminate on a change in voltage (-dV). As the cell reaches full charge and goes into overcharging the voltage of the cell will drop a little. Studies have shown that the -dV signal is stronger when the charge rate is such that the cell is fully charged in about 1 - 2 hours. This is also called charging at 0.5 - 1.0C. To determine the charge rate you look at the capacity of the cell. A cell with 2000 mAh would have a 0.5C charge rate of 1000 mA and a 1.0C charge rate of 2000 mA.

Charging at lower rates can still produce a end of charge termination signal with newer cells, but as a cell ages the signal becomes weaker and weaker. This results in a missed termination and that results in overcharging damage to the cell. Most chargers have a maximum charge amount termination as a back up so you may not notice that the termination signal has been missed.

If you need to charge at a lower charge rate do your best to estimate that amount of time a charge should take and set a timer. When the timer goes off check to see if the charge has terminated. If it hasn't give it a little while longer then if it still hasn't terminated take the cells out and manually terminate the charge.

Tom


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## markr6 (Feb 24, 2014)

That's good info. Charging my 2500mAh Eneloops is a problem even at 700mA. They get up to about 1.44v and sit there getting pretty hot. Regular Eneloops get into 1.45-1.50, then very quickly hit 1.52v or so then terminate.

If I had more than just a few Eneloop XX, I would get a better charger just for them.


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## LAM09 (Feb 24, 2014)

Thanks Silver Fox and Chris for the info. I am going to check how long they charge for in the future, and keep an eye on the batteries whilst charging.


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## LAM09 (Feb 24, 2014)

One other thing guys, what is the best charged on the market ATM? 

I currently have a BC-700 ATM as mentioned previously.


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## ChrisGarrett (Feb 24, 2014)

LAM09 said:


> One other thing guys, what is the best charged on the market ATM?
> 
> I currently have a BC-700 ATM as mentioned previously.



The BC-700 is a very good charger and if you travel a lot, it's small enough and sophisticated enough, to be quite useful on the road. Plus, it does 12v, even though it doesn't have a true 12v input.

It has quirks, like any other man made device and if you learn and watch out for those quirks, you'll be well served.

I bought both the BC-700 and Maha C-9000 because I figured that I'd try a few different batteries and a couple of chargers, for sense of variety. I was already committed to spending some money, so the $40 BC-700 wasn't breaking the bank.

That being said and repeating myself once again, if I could go back and do it all over again, I would buy another Maha C-9000 in lieu of the BC-700 and then pick up something like the Sanyo Eneloop NC MQR-06 for traveling. Also, I won't be buying any AccuPower 2900/1200s, nor the PowerEx Imedion AA LSD batteries, going forward.

Live and learn.

Chris


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## LAM09 (Feb 24, 2014)

ChrisGarrett said:


> The BC-700 is a very good charger and if you travel a lot, it's small enough and sophisticated enough, to be quite useful on the road. Plus, it does 12v, even though it doesn't have a true 12v input.
> 
> It has quirks, like any other man made device and if you learn and watch out for those quirks, you'll be well served.
> 
> ...



Cheers for the reply mate. Thanks for giving me an insight as to what I should look out for in general.


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## LAM09 (Feb 25, 2014)

Has anyone tried Varta rechargeable batteries, and if so; what are they like?


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## markr6 (Feb 25, 2014)

ChrisGarrett said:


> That being said and repeating myself once again, if I could go back and do it all over again, I would buy another Maha C-9000 in lieu of the BC-700...



I'd jump in that time machine with you there Chris!


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## pinoy (Aug 25, 2017)

LAM09 said:


> Thanks Silver Fox and Chris for the info. I am going to check how long they charge for in the future, and keep an eye on the batteries whilst charging.



Keep in mind. If a battery has significant internal resistance that will cause the charging time to increase.


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## Cekid (Aug 25, 2017)

LAM09 said:


> Has anyone tried Varta rechargeable batteries, and if so; what are they like?



not happy at all...avoid if you can...they are not reliable, have short shelf life, and gone for good after not so much use...i throw already i think 12 of them AA 2100 while i still have eneloops older than them...varta was big name back in the day here in europe, but now it's only a name...


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