# Charger comparison (Part 2)



## SilverFox (Oct 11, 2007)

...continued from here.



Charger Comparison

Edit: I will be adding results from various chargers to this post as I test them.

I have heard several people express that rechargeable batteries just don’t hold up as well as other types. Others complain at the poor run time they experience when using rechargeable cells in their lights.

Many people have rechargeable lights (TigerLight, Streamlight Stinger and Ultra Stinger, MagCharger, SureFire 8NX and 8AX, SureFire 10X Dominator, SureFire L7, and the list goes on) and complain that they don’t get decent run time from them. 

When looking at rechargeable batteries, the charger my play a more important role than the cells themselves when it comes to performance. I decided to take a look at this from the charger perspective. Could it be that our charging methodology is flawed? 

I picked up a new travel battery charger and have been getting acquainted with it. 

The *Titanium TG-700* (from www.AmondoTech.com ) is a compact independent channel charger for AA or AAA NiMh or NiCd cells. You can charge up to 4 cells at a time and it plugs into AC (110V-240V) and also comes with a DC (12V-24V) adapter. Charging current is about 450 mA. It then goes into a trickle charge mode of 30 mA. It does not have a discharge circuit.

Dimensions are 4 ¾” long x 3” wide x 1 ¼” thick. It weighs 4.5 ounces and the DC adapter adds another 2 ounces for a total of 6.5 ounces. AA cells fit right in and a flip of a lever reduces the length of two slots (two levers total) to accommodate the shorter AAA cells.

I decided to test a group of cells charged in this charger and compare the results to the same cells charged in my *Vanson BC-1HU.* The Vanson charge rate is 500 mA and the trickle rate is 50 mA. It is also an independent channel charger and unlike the TG-700 it has a discharge function.

I also picked up some Titanium AA 2400 mAh cells to check out. 

*Please note that these procedures do not apply to Li-Ion or Li-Poly cells. *

The first procedure with new cells is to go through a few cycles on them. I started by discharging the cells, then charging them up again on my Vanson. I repeated this cycle 4 times, then proceeded to discharge them again.

I would assume that when the charger green light comes on, the cells are fully charged.

I put the cells on the Titanium charger and let them charge until the indicator lights turned from red to green. I then took them off the charger and let them cool down. The cells got up to about 130 F during the charge cycle. After an hour of cool down, I ran the discharge tests.

I then waited an hour and put the same cells in the Vanson charger and once again pulled them out when the lights turned green. The temperature was only about 110 F, but I followed the same cool down cycle. After an hour of cool down, I once again ran the same discharge tests.

Here is a graph of one of the tests, however the other cells behaved in a similar fashion.

EDIT: As you can see, the following graph has the data from all of the chargers. It is getting a little messy, so I am adding a table with the chargers ranked according to Watt Hours. The reason I choose Watt Hours is because it represents a combination of capacity and voltage retention under load. Capacity is important, but it is my humble opinion that Watt Hours is more important.

Here is the charger ranking according to Watt Hours







As you can see, both chargers ended the charge early, but the Vanson was able to get more charge into the cells before the green light came on. I later found that if I left the cells trickle charging for an additional 2 hours on the Vanson and 4 hours on the Titanium, the capacity of the cell went up and there was little difference between the chargers. I finally ended up with a rating of 1.94 Ah, 2.35 Wh, and 116 M at this 1 amp discharge rate.

The next time you go to grab the cells off the charger when the light turns green, remember you might be able to get an additional 10-20 minutes of run time (at a 1 amp load) by letting them trickle charge for a while.

I would suggest that for AA cells of around 1800-2500 mAh capacity, you can leave the cells on a Vanson charger for an additional 3 hours after the green light comes on (or 5 hours for the Titanium charger) to get that extra capacity.

I am quite pleased with the Titanium TG-700 and will be replacing my Radio Shack 13 hour charger with it while traveling. 

Edit: 1/23/05 added *Maha C-401FS* charger results. Thanks Brock for letting me borrow this unit.

The slow charge rate on the Maha C-401FS does a very good job of getting the most capacity into the batteries. The price is that it takes a bit longer to charge.

The fast charge rate on the Maha C-401FS is scary. Not only do the batteries heat up, but it appears that the slots charge unevenly. I will terminate the charge when the cells reach 130 degrees F. The cells on the Maha charger shot past 130 rapidly and as I was reaching to shut the charger down, the green light came on. The temperature continued to climb to 135 and was still going up when I pulled the cells from the charger and held them in my hand to cool them down. This is not new information, it has been reported several times before. I just want to confirm that it does happen and I believe constant use of this setting will reduce the life of your batteries.

On the other hand, if you need a quick "top off" to get a bit more capacity from partially used cells, the fast charge would give you extra capacity quickly. For example if you are out using your lights and run the batteries part way down. You could come in, take a short break, put the batteries on fast charge, pull them off the charger before they heat up, and go back out and have more fun. The "balanced charge" of the cells may be thrown off by this, but it might be worth a try to get some additional run time.

Brock sent me his charger and this observation is based on a sample of one. I did do two runs to verify the trend, and it appears that the C-401FS on fast charge delivers different charge rates to the different slots. I ran my first test and was surprised to see the scatter. I mixed up the batteries so they were charging in different slots, and got very similar results. The performance followed the slots, not the batteries. On this charger, slot 1 does the best, and slot 3 the worst.

Here is a graph of the results from the fast charge.






This is another reason not to use the fast charge option on the C-401FS. 

To sum up, the Maha C-401FS on slow does a great job of charging AA and AAA cells. It does not have a discharge function. On fast charge, cells get too hot and there is some inconsistency between the amount of charge for each slot. Overall a good charger, just be careful when using the fast charge option.

1/25/05 added results from the *Ccrane KC-983 Quick Charger.* Thanks Brock for letting me borrow this unit.

It did a good job charging. I noticed a slight reduction in capacity from slots 3 and 4, but it was not enough to worry about. With this charger you put a single cell in and check the condition of the cell with the lid open. To start charging, you need to close the lid. The charger first goes through a discharge cycle down to 1.0 volts, then a “soft start,” then a “fast charge,” ending up with a “trickle charge.” I believe it has independent channels, however, if you put another cell in to be charged in the middle of the charge cycle, it will start discharging the cell that was already in there. I guess it resets every time you open the lid. The batteries only got warm during charging.

1/28/05 added some results from the *Triton* charger/analyzer. Thanks Bwaites for letting me borrow this unit.

The Triton has so many features it would take some time to check them all out. I focused on the charging side. I have to say that it is one of the most versatile chargers out there. The Triton user manual states that you can do a better job of charging if you set the parameters rather than use the Auto settings. That is an understatement! The Triton on Auto mode is close to, if not THE, worst performer so far. If you get a Triton, take the time to figure out the settings. You will enjoy better performance from your batteries as a result.

I set the Triton for a 400 mA charge rate to get a good comparison with the other chargers in this test. It did almost as good as the full 24 hour charge on the Vanson. I ran additional tests at 1 amp and 2 amps and was surprised. There was very little reduction in the total capacity and the cells stayed below 100 degrees F. After testing the Maha on fast mode, I was expecting the cells to get hot at 2 amps, but they didn’t. The charging algorithm used in the Triton does a great job.

Some brief comments on the Triton’s other capabilities. I did several discharge tests and got results similar to what I am seeing with my CBA. I check the NiCd charging and discharging function and found it similar to the NiMh. I charged up my lead acid battery from my Pelican Big D without problems. People using the Triton report that it is a very good charger, but also it has a few minor quirks. That did not stop them from highly recommending it, but it will take a while to get used to it.

The Triton will also charge Li-Ion and Li-Poly cells and packs. There is some debate over the termination of the charge. To get a “full” charge on a Li-Ion cell, you need to charge to 4.2 volts and hold it there until the current drops way down. You do not trickle charge Li-Ion, but the last part of the charge is at a rate below most trickle charge rates. The price you pay for utilizing a “full” charge is reduced cycles. Charging to 4.2 volts gives you about 500 cycles. The Triton charges to 4.1 volts and does not seem to hold the final part of the charge long enough. Pulling a cell from the Triton saw the voltage drop from 4.1 volts to 3.9+ volts in about a half hour. My experience with other chargers is that a cell “fully” charged to 4.2 volts will drop to 4.185 volts in a week. The Triton does charge faster than my other chargers, but you end up with less capacity in the cell. 

There are a couple of advantages in terminating the charge early. You will heat the cell up more with you hand than with the Triton charging it, so I would suggest that it is safer. The other advantage is increased cycle life. A cell charged to 4.1 volts is estimated to give you around 1500 cycles.

I have only touched the surface of what the Triton is capable of, but my brief exposure to it has me planning to get one. Please understand that the Triton is designed for the RC community to field charge their battery packs. You hook it up to your car battery and away you go. To use the Triton in the workshop, you will need a separate power supply. Radio Shack sells an excellent 13.8 volt 15 amp unit that works well with the Triton.

1/29/05 I have added the results from the *Energizer 1 hour* charger. Thanks Brody.

This charger is pretty straight forward. Put the cells in, plug it in and go. I observed that with my Titanium 2400 AA test batteries it took 1 hr 17 minutes to charge. That is close to an hour. The temperature topped out at 110 degrees. It did a pretty respectable job of charging the batteries.

1/30/05 I have added the results from the *Lightning 4000N* charger. Thanks Brody.

This charger is very impressive. It is smaller than the Titan TG-700 and does a better job of indicating full charge. It has a discharge function and the cells stayed cool during charging. At the completion of charging it switches to a trickle charge mode. The trickle charge mode is different than others in that it does a high current pulse at a low cycle rate. Most chargers give a low current constant rate. You are cautioned not to “store” batteries on the charger for an extended period of time. Overcharging damage may result.

The down side is that it only runs on AC power. It is interesting that the manufacturer ( www.RipVan100.com ) has a bold headline that reads “No Car Adaptor Needed.” Another down side item is that it only does pairs of cells. It has two independent channels and each one hold two cells. You have to charge two batteries at a time. 

The publicized advantage of charging two cells at a time is that it tends to equalize them. I can see that this would be an advantage in devices that use pairs of batteries, but if you only use one at a time, the advantage is lost.

This is an excellent charger if you have no need for the ability to charge from your car, and don’t mind doing pairs at a time.

2/1/05 I have added the results from the *Ray O Vac IC3* charger. Thanks Underdog for letting me borrow your charger and batteries.

For the purpose of this evaluation, I am only including the results from charging my test Titanium 2400 mAh AA cells on the IC3 charger. In this application, the IC3 charger is simply at timed charger. You put the battery in, and in about 12 hours it is charged up and ready to go. I was very pleased with the “overnight” performance. It did a good job on non-IC3 cells. I would not purchase this system to charge normal NiMh batteries, but in a pinch it works quite well. This system is better utilized with the IC3 batteries.

The IC3 system testing (with the IC3 batteries) will be covered in a separate thread. It seems to work very well. If you need batteries in a hurry, this is the system for you.

2/6/05 *La Crosse Technology BC-900* Charger (available from Jon Burly)

It has modes that range from simple to complex.

In simple mode, just plug the cells in and come back the next day and they are ready to go. The charge rate of 200 mA is great for AAA cells and is OK for AA’s also. When the charge is complete, the LCD display shows FULL. In a perfect circuit a 2400 mAh AA battery should be fully charged in 12 hours, but figuring in losses, 14 hours is more realistic.

I could stop there and say this is a great charger… but there is more.

I will not go into all the details because there is another thread that pretty much spells out all the features. Suffice it to say that it offers: 
6 charge rates (from 200 mA to 1800 mA) and
6 discharge rates (from 100 mA to 900 mA) for AA cells.
3 charge rates (from 200 mA to 700 mA) and 
3 discharge rates (from 100 mA to 350 mA) for AAA cells.
A test mode.
A refresh mode.
And a display that gives you lot of information about the cell you are working with.

It has 4 independent slots and you can mix AAA and AA cells, NiCd and NiMh chemistries next to each other. You can even pick (with minor limitations) different charge and discharge rates for different slots. You can match cells for use in multi cell lights and check for weak cells. The refresh mode lets you break in new cells and revive old ones.

This charger is a true workhorse. 

I have issues with the absolute numbers it gives for capacities, but it is consistent from slot to slot and from cycle to cycle. I find it gives more uniform capacities if you start the test mode with a fully charged cell. 

It is too bad they don’t have one for C and D cells…

All of this and there is more. The charger comes in a handy carry bag along with 4 adapters. You can use your AA batteries in C and D cell applications. I have a 3 D Mag Mod by 3rd Shift (great light Stephen) and I have been using 9000 mAh D cells in it. The D cells weigh about 6 ounces each. The Titanium 2400 mAh AA cell along with the AA to D adapter weighs about 2 ounces. I pop 3 of these in and safe about 12 ounces when using the light. Granted the run time is less, but it still goes for a couple of hours and that is enough time for a lot of projects.

Not only does this charger have lots of features, it also does a good job of charging. I show that it came in very close to the best of all those tested.

What more can I say. I am very impressed.

2/15/05 I have added data from the AccuPower *AccuManager 20* Charger. Thanks Lureleven for letting me check this charger (and a number of cells) out.

We have a new winner. The Vanson BC-1HU (charging for 24 hours) held the lead for the most charged cells until now. The AccuManager 20 has done a better job in a shorter time. 

This charger has independent channels for 4 bays of round cells and two 9V bays. It will charge NiCd and NiMh chemistry in AAA, AA, C, D, and 9V sizes. It shares the same housing as the Vanson, but has a distinctive blue and yellow color. AccuPower claims they do not need a discharge function because the algorithm they use for charging will take care of any memory effect that is forming in NiCd or NiMh cells. 

The most significant claim is that the AccuManager 20 will charge up any capacity battery in one setting. The Vanson is only good to about 8000 mAh batteries. My 9000 mAh cells require a reset half way through the charge cycle. There is a shut off timer for safety, but it is set for something like 35 hours. This gives a theoretical charge limit of 24500 mAh. I tried 9000 mAh, 11000 mAh, and 12000 mAh cells and the AccuManager 20 had no problems charging them up.

Cells get warm while charging but do not get hot, and this charger seems to be able to get a full charge into the cells quite well. When the green light comes on, the cells are ready to go. You can leave them on for a maintenance trickle charge, but they are good to go when the light comes on (it actually goes from blinking while charging to steady on when finished). This may be a good replacement for the Vanson, especially when using high capacity batteries. 

4/12/05 Wayne at www.amondotech.com sent me some chargers to check out. The first one I pulled out was the *V4000.* This charger looks and performs exactly like the Lightning4000N. It does pairs of AA or AAA cells NiCd or NiMh chemistry. The test results were exactly the same as the Lightning4000N so I will not post the graphs. All in all a pretty nice charger if you use pairs of cells.

4/12/05 The Amondotech Titanium *TG1000* is a 4 channel charger for AA or AAA cells and NiMh or NiCd chemistry. It did a pretty good job of charging. It uses a cord to plug into the wall and is a little more bulky because of that.

4/12/05 The Amondotech Titanium *TG2800* is a great charger. It has 4 channels for AA or AAA cells, does NiMh and NiCd cells, and has a discharge function. It also has an LCD display that gives a graphic of a cell and an indication of the charge state. When you are discharging, the graphic goes down. When you are charging, the graphic goes up and shows the charge level in 4 segments. The LCD display is back lighted. This charger did almost as good as my Vanson after 24 hours. Very impressive. The plastic door comes off easily, but the charger works with out it just fine. Cells come off the charger at about 95 degrees F, then the charger goes into a trickle charge mode. Charging current is 2.0 amps max. This charger has replaced the TG700 as my travel charger, even though it is not designed to run on 12 volts. I’ll find a place to plug it in…

4/12/05 The reign of the AccuManager 20 has just been toppled. I just picked up a *Schulze isl 6-330d-RS.* It has a lot of the similar functions as the Triton. It is able to charge any type of battery or battery packs up to 30 cells NiCd or NiMh, up to 19 lead acid or gel cells (38 volts), up to 11 Li-Ion or Li-Po cells, up to 13 Lithium Manganese Oxide cells (whatever they are), and that is about it for the Battery 1 output. It also has a Battery 2 output that will do up to 6 NiMh or NiCd cells, 4 gel cell or lead acid cells (8 volts), and up to 3 of the Li-Ion, Li-Po, and Li-MO cells. This is quite the charger.

Like the Triton, the 330d requires a separate 13.8 volt battery or power supply. The manual suggests to not use a power supply, but there are a lot of people using them without problems (including me). I believe you need to make sure the power is clean and has a good capacity. I believe a 30 amp unit would be adequate. It works fine on a car battery and will even warn you if your battery voltage falls below 11.25 volts. The charger draws about 50 mA when idle.

Charge rates for Battery 1 output are up to 5.5 amps and 332 mA for the Battery 2 output. It also has a bunch of automatic programs including auto charge, auto discharge, auto CD, auto DC, and a cell former that does 3 cycles of charge discharge. Discharge rate is up to 1.0 amps in 8 steps. You can run both Battery 1 and Battery 2 outputs at the same time.

Like the Triton, the 330d has an auto program. The nice thing is that the Schulze algorithm actually works and does a good job of charging cells. The auto program starts off at a low charge, then ramps up to a higher charge, then ramps back down to finish. All the time it is shutting off for a moment to check the battery condition. I find the Auto program to be a bit slow, but it works well. On a single cell it spent a lot of time charging at 500-600 mA. 

This charger is designed for battery packs and the RC crowd. I can charge a single cell on it, but it takes some extra work. 2 cells and up are fine. You can not discharge a single NiMh or NiCd cell.

It does a great job on Li-Ion. The cells come off at 4.205 volts.

The instruction manual is a bit obtuse, but after a few times using the charger it starts to make sense. After that, it’s easy. I would say that if you just want to drop a cell in and have it charged up, the Schulze is not for you. If you are willing to spend a little time getting to know how it works, it is excellent.

There are many more features, but that covers some of the highlights. More information is available at www.schulze-elektronik-gmbh.com/index_uk.htm . They also have several big brothers to this unit.

The Triton is easier to figure out “right out of the box,” but the Schulze does a better job of charging. I also have a link to connect it to my computer for some data analysis (right up my alley  ). 

I do have one objection… The box it came in was a loud pink color, as is the labeling on the unit, as is the battery hook up leads. I am not sure what the Germans have in mind, but when I think of a “Manly Tool,” pink is not the first color that comes to mind… :nana: 

Check the graph out, we now have a new leader. This charger was able to push a little more in to my test cells (about 3.3% more). I am very impressed.

2/1/06 It has been my pleasure to check out the *Maha C808M* charger. This is a fantastic charger and I am very pleased with the way it performs. Please refer to my review of this charger in the reviews section. 

This charger is a very good performer. It charges AA, C, and D cells at 2 amps and keeps them cool while doing that. It also can charge at 1 amp by hitting the soft charge button. In addition, it has a discharge/conditioning cycle. 

I don’t recommend leaving cells on the charger, but if you want to do that, this is the charger to do it with. The trickle charge rate is low enough that I believe your cells would be safe left on it indefinitely. 

This charger utilizes an advanced charging algorithm that does a very good job of charging while also considering how to get the most cycles from your cells. As you can see from the results, it does not push the most capacity into the cells, but it is right up there with the top contenders. 

I will gladly trade a little capacity for the knowledge that my cells will last longer. This charger also does a good job of charging the high capacity D and C cells. At the other end of the size spectrum, it does a good job on AAA cells as well. 

Thank you William at Maha for providing this charger for evaluation. You have a real winner with it.

4/5/07 I have added the results for the *Duracell 15 Minute * charger. This charger is very similar to the Energizer 15 minute charger, and the results are also very similar. It is my opinion that because the Duracell 15 minute charger actually takes about 18 minutes to charge, it may be a little bit easier on your cells. I have not tested this, but the cells seem to end up a little cooler. 

The back of the Duracell unit is slightly arched, and the feet are longer than then Energizer unit. This allows for better air flow, and I think it is a design improvement.

If you need your cells in a hurry, the Duracell 15 minute charger joins up with the Energizer 15 minute charger to provide you with charged cells in a very short time. This charger, like the Energizer unit, is picky about cells that have developed higher internal resistance. If your cells are "crap," this charger will refuse to charge them.

4/5/07 I have also added the results for the * Maha C9000 Wizard One * charger/analyzer. The original version had some issues with termination and has been superseded by the improved version. This unit is giving the BC-900 a lot of competition, and offers a lot more flexibility.

You have to program each slot independently, and have charge rates ranging from 200 mA to 2000 ma in 100 mA steps, and discharge rates ranging from 100 mA to 1000 mA in 100 mA steps. You can use the Refresh/Analyze function to charge/discharge/charge your cells with a read out of the capacity on a large back-lit display. You can run up to 15 cycles selecting the charge and discharge rates you want. You can do a discharge only. This function even works with Alkaline cells, but is not recommended. 

One of the most beneficial features is the Break-In function. This function allows you to program in the capacity of the cell, then the C9000 will do a 0.1C charge for 16 hours, rest for 1 hour, a 0.2C discharge, followed by another 0.1C charge for 16 hours. This takes a long time, but your cells will perform better with this "forming" charge. Since the function starts with a charge, it is best to do a discharge first, but it is not totally necessary.

This is refereed to as a Standard Charge, and is the industry standard for determining the capacity of cells. This capacity is supposed to be what is labeled on the cell, but there seems to be some liberty taken with the current cells. Most of the current labels are "optimistic." This function will allow you to evaluate if the good deal you got on some high capacity labeled cells was really a good deal.

There is one caution. If your cells have higher internal resistance and you charge 4 cells at 2 amps, the charger, and your cells, will heat up. Even with cells in excellent condition, they will get hotter charging at these higher rates.

Another plus for the C9000 is that it can be powered from a 12 volt source. This makes it a good choice for remote and emergency situations.

Excellent charger/analyzer and I highly recommend it.


Tom


----------



## LuxLuthor (Oct 11, 2007)

I like it so much, I just bought my second Hyperion 1210i from CheapBatteryPacks.com which now has the A123 3.3V Saphion charging algorhythm. There are many times I need another charger for long conditioning 0.1C runs.

I highly recommend it.


----------



## Handlobraesing (May 31, 2008)

My Duracell 15 minute just caused a Duracell 1800mAh cell to vent even though it didn't refuse to charge it.


----------



## SilverFox (May 31, 2008)

Hello Handlobraesing,

Most NiMh cells will vent when you charge them at 4C or above. 

Tom


----------



## Handlobraesing (May 31, 2008)

In other words... the 15min charger is quite hazardous to batteries..?


----------



## SilverFox (May 31, 2008)

Hello Handlobraesing,

No, I would say that it is possible that 15 minute charging can shorten the cycle life of NiMh cells.

So, what is the story on your 1800 mAh cell? Did only one cell vent, or did you have more cells vent? How old are these cells? What kind of use have they been in? 

I had several of the CBP 1650 mAh cells vent during 0.1C charging. In this case it was a quality control issue. Other of the same cells had no problems at all.

Roughly, how many cells have you charged on a 15 minute charger, and how many have vented?

Tom


----------



## Marduke (May 31, 2008)

Handlobraesing said:


> In other words... the 15min charger is quite hazardous to batteries..?



That's fairly common sense. 4C will kill cells in quick order. Instead of measuring cycle life in hundreds of cycles, you're down in low double digits at best with increasing high self discharge, internal resistance, and lowering capacity all along the way.

Guess the designers should have thought about that and warned you, huh? Might need to call their legal dept and straighten things out....


----------



## GQGeek81 (Jul 7, 2008)

After 14+ pages we finally get to the info I'm looking for

I just got my BC900 but I've been thinking one of these super fast chargers for the vehicle would be nice for 'out there' when I'm in a hurry for more power. 

Now the documentation with the BC900 suggests that using higher power to charge the batteries will negatively effect them while speeding charge times but by how much?

Do we have any quantitative data on the Duracell or Energizer 15 min chargers (or other brands) in terms of their effects on total cycles possible on a battery? 

I'm also not clear on what they do to the battery. If I torture a battery in a 15 min charger regularly till it seems to stop working as well can I rejuvenate it with the BC900 or is it knocking on the grave at that point?


----------



## Mr Happy (Jul 7, 2008)

GQGeek81 said:


> After 14+ pages we finally get to the info I'm looking for
> 
> I just got my BC900 but I've been thinking one of these super fast chargers for the vehicle would be nice for 'out there' when I'm in a hurry for more power.
> 
> Now the documentation with the BC900 suggests that using higher power to charge the batteries will negatively effect them while speeding charge times but by how much?


It depends on the charger. NiMH cells can be charged at rates up to 1C, but any negative effects depend on how well the charger handles the end-of-charge situation. A typical cell can handle charge currents up to 2 A at the beginning of charge without any problems -- almost all the charge is absorbed successfully by the cell. But towards the end of charging, some of the charge cannot be absorbed and is rejected as heat. If this situation is allowed to go on for too long, the cell will start to suffer excessive wear and shortening of life. The typical "-ΔV" algorithm used by most chargers is somewhat aggressive in this regard, and does allow cells to be a little overcharged before charging stops.

However, if lower charging currents are used there is a danger the charger will not detect the end of charge at all, and then the cell could suffer even more excessive overcharging and wear.

A good rule of thumb is to see how hot the cells get at the point the charger stops charging. If they are warm to the touch, perhaps very warm, then everything is OK. However, if they get hot or very hot, especially if they are uncomfortable to touch, then you should dial back the charging current and charge them more slowly.



> Do we have any quantitative data on the Duracell or Energizer 15 min chargers (or other brands) in terms of their effects on total cycles possible on a battery?


Indeed we do. As a result of some excellent testing by Silverfox, we have this thread: https://www.candlepowerforums.com/threads/114943



> I'm also not clear on what they do to the battery. If I torture a battery in a 15 min charger regularly till it seems to stop working as well can I rejuvenate it with the BC900 or is it knocking on the grave at that point?


After you torture a battery to death with a 15 minute charger, it is dead. You can't rejuvenate it after that kind of treatment.


----------



## DualMonitors (Sep 22, 2008)

thx Silverfox et al for such a useful thread! i get a sinking feeling in me that says the La Crosse BC-900 must be replaced soon by a newer model, which is why they are selling them for around $39 including 4AA and 4AAA La Crosse branded NiMH's. that puts the charger at around $30, which is pretty low. or, the abovementioned 8 NiMH PLUS 8 Sanyo Eneloop AA's and the BC-900 for $58 (not so special a price as it is merely selling you 8 Sanyo Eneloop's for $19).

that said, i believe Silverfox said that one must be very careful with La Crosse's as there is one component internally that is used at its maximum capability, and it CAN melt or plain malfunction and fry both your batteries and the charger - which he recommends putting on a non-flammable surface.

is the La Crosse BC-900 that "iffy"? is the quality as well as quality control that mediocre? one would think that after all these years of making this model, and after new firmwares/versions (now i believe onto V. 33), they would upgrade that ONE single component in order to eliminate the Achilles' heel!! As Silverfox's review was a couple of years back and with an earlier version, we wouldn't really know if the currently sold version has any improved/upgraded hardware components to upgrade that some-time overloaded component.

I wonder if, considering the popularity of the BC-900, there's a chance that someone might have done a more recent "re-visit" review of it and see what changes might have taken place?

thx so much in advance!


----------



## geek4christ (Sep 22, 2008)

I have a BC-900 that I purchased earlier this year from ThomasDistributing.

Based on the research I did here before buying, I only use the charger with a small fan blowing on it. This has worked wonderfully for me as it keeps both the charger and cells nice and cool throughout a charge (at the 1000 mA rate) with a very slight cell warm-up right before termination.

Well, the other day I carelessly stuck an eneloop on to charge at the 1000 mA rate and didn't remember to switch the fan on. When the cell finished charging I pulled it and it was very hot to the touch. Not too hot to hold onto, but way hotter than I prefer (I know, very subjective and unscientific of me). I was amazed at the difference in temps when the external desktop fan wasn't used.

So I realize this may be unwieldy for some, but I would recommend using a fan with this charger if you plan to charge at a rate higher than 700 mA. It is a big enough deal to me that I won't recommend this charger to friends and family, even though I love it. I feel that it is still a great value and does an excellent job of getting electrons into those NiMHs, but unfortunately does seem to have thermal management issues.


----------



## Codeman (Sep 22, 2008)

FYI - if the cell wasn't too hot to hold, then it didn't heat up enough to cause any damage.


----------



## DualMonitors (Sep 22, 2008)

may i ask what "C" means when folks say: charge at the rate of 1C or 2C?

what is the unit of measurement?

i understand mAh, etc, but i don't follow what everyone means by saying 1C this and 2C that...

thanks. sorry for such a basic question.


----------



## Marduke (Sep 22, 2008)

C as it's being used in terms of batteries is a normalized unitless term related to charge and discharge rates with respect to capacity.

If you have a 2000mAh cell, and discharge it as a rate of 2A, the rate is 1C (1 hour to discharge). If you were to discharge it at 1A, the rate is .5C (2 hours to discharge). Charging works the same. If you charge at 200mA, your charge rate is .1C, meaning it should take about 10 hours to charge.


----------



## geek4christ (Sep 23, 2008)

Codeman said:


> FYI - if the cell wasn't too hot to hold, then it didn't heat up enough to cause any damage.



Agreed, Codeman. Well, almost...I'm sure no short-term damage was done.

I do know that high temperatures have a negative effect on cycle life for NiMH batteries, however. Whether or not that effect is seen when the cells only stay hot for a short period of time, I'm not sure.

But the thing that concerns me is the rise in cell temperature is only supposed to happen towards the very end of the charge. In my case, I believe much of the heat was being contributed by the charger itself. Maybe one of these days, I'll get the proper equipment to perform an empirical test to verify that.


----------



## Mr Happy (Sep 23, 2008)

geek4christ said:


> In my case, I believe much of the heat was being contributed by the charger itself. Maybe one of these days, I'll get the proper equipment to perform an empirical test to verify that.


A compact charger will always be liable to this problem. The internal current regulating circuitry will generate heat, and this must be dissipated somewhere. I believe the Maha C9000 has a large case with big air gaps around the cells partly to alleviate this issue. Even so, when you charge cells at 2000 mA it still warms them up a little, though not enough to really worry about.


----------



## LuxLuthor (Sep 24, 2008)

Tom, I just got a Competition Electronics Turbo GFX 35, as was not at all happy with the inaccurate CBA-II results. Going through the 70 page manual (pdf on above link) now. 

Even their adjustable "simple" battery holder with separate center voltage detection spring loaded pin in middle of charger terminal is a work of genius...and I don't say that casually.


----------



## SilverFox (Sep 24, 2008)

Hello LuxLuthor,

I have looked at that unit and it seems to be very good.

I have run comparison tests between the CBA II and the Turbo GFX 35 and ended up with very close results.

Their cell holder is very nice.

Tom


----------



## LowBat (Jan 4, 2009)

Just found an improved version of the Amondotech TG-2800. I was at Target and noticed they had a Targus TG-LCD2700 which is identical to the TG-2800 except it also comes with a 12v cord. I don't have a picture of it, but found it online here.


----------



## Dave_5280 (Jan 4, 2009)

I've got the same Schulze charger as above from my RC days and was wondering if anyone found a good battery holder to use with it?


----------



## SilverFox (Jan 4, 2009)

Hello Dave,

You may find this thread informative...

Tom


----------



## chewy78 (Jan 7, 2009)

.


----------



## Dave_5280 (Jan 10, 2009)

SilverFox said:


> Hello Dave,
> 
> You may find this thread informative...
> 
> Tom




Thanks, I had seen the thread in the past but I had not seen the more recent posts which are a little more what I had in mind.

You would think some of the charger companies are already selling some holders.


----------



## NW Hiker (Feb 12, 2009)

Greetings to all,

I approach this forum humbly, recognizing I lack the deep technical sophistication displayed by the major of posters. A friend of mine who buys products for an outdoor shop approached me with a request: "If I wanted to offer mainstream customers a high-quality battery charger (more advanced than the models bundled with Rayovac and Duracell rechargeables), what would be a good choice?" (Particularly, he adds, one that can handle more than four cells at a time.) He asked me because I'm a minor hobbyist who is familiar with brands such as Maha and LaCrosse. Based on the advice I'll culled from reading through pages of posts, I'm included to think that recommending those two brands is credible advice. Would any of you resident wizards care to agree or disagree? I salute you all, and thank you.


----------



## Mr Happy (Feb 12, 2009)

You might also consider some of the AccuPower and Titanium branded chargers.


----------



## filibuster (Feb 16, 2009)

Silverfox, were these tests done with all bays filled with AA cells in the various chargers? 

The graph above says "cells" (plural) so I'm assuming you had at least two cells but if you would clarify if the results were all based on charging a full compliment of batteries supported by the chargers. I've always assumed this was the case but wanted to make sure.


----------



## SilverFox (Feb 16, 2009)

Hello Filibuster,

My test cells include 4 cells that are closely matched. If the charger is capable of charging 4 cells, I use all of them. Some of the chargers are capable of charging more than 4 cells, and in this case the test is done with only 4 cells. However, in these cases I will do multiple runs to compare the consistency of charging from slot to slot.

Tom


----------



## travelinman (Feb 16, 2009)

I love my maha 401. It's so light even with the little international voltage switching power supply that it's a treat to pack. I always (except for 1 brief occasion) use it on low! I also never use it with the cover closed.

As at least one other as already mentioned I have a rig built for my lacross 700 on a big heat sink with a computer power suppply fan blowing across the charger and batteries when used. I also use it on either 200 or 500 ma, never more.

Hasn't anybody done a test on the Delkin single rcr 123A charger?


----------



## ODatsBright (May 22, 2009)

After having read through all the threads I've purchased both the Maha C9000 and the Accumanager 20 and I have to say that I'm quite happy with both. The Accumanager isn't quite as well built as the C9000 but seems to give very good results, especially with C size cells. 

I have a question for Silverfox. With the other chargers "beating out" the Vanson, what is the reasoning for still using it? Is it for consistency? I have a boat load of Tenergy 2600's that seem to only get about 70% of the 2600 mah rating and I'm wondering if several 14-24 hour charges on a timed type charger would revive them. I've done several refresh and analyze cycles and 2 break in cycles and still can't seem to get them above 70% of the labeled rating. Would these cells be deemed "dead"?

Thanks.


----------



## SilverFox (May 22, 2009)

Hello ODatsBright,

Actually the Vanson is mostly retired... Its duties have been taken over by the C9000 and the CM808. 

Tenergy cells seem to suffer from overinflated capacity ratings, so your cells may be just fine. I would check the mid point voltage under load to see if it is holding up. If it is still acceptable, the cells are good, but if it is suffering, you may need to try to do some reviving of the cells.

Tom


----------



## SpideRMaN (Jun 19, 2009)

Maybe This can help to determine NiMH charge rates (taken from triton2 charger manual)


----------



## thedeske (Jun 19, 2009)

Silverfox - thank you sir for the time and knowledge.
Very Generous


----------



## oldtimer (Oct 3, 2009)

Best thread ever! Thanks! Are there any updates? I'm using a 15 minute charger but didn't know it was so bad for the batteries. I was going to get a Lacrosse but didn't know it was rated so low.


----------



## asmith (Dec 30, 2009)

Like someone mentioned in the original thread, I'd like to see the Sanyo Eneloop charger tested. May just go with the Targus version of a TG2800 though.


----------



## Mr Happy (Dec 30, 2009)

asmith said:


> May just go with the Targus version of a TG2800 though.


I found this makes the batteries very hot during charging. I therefore don't like it.


----------



## Lurveleven (Apr 26, 2013)

Schulze just went out of business, so that is no longer an option.


----------

