Tips on balancing Eneloops before charging?

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Hi guys I have the generic eneloop slow charger which works fine but the problem is I don’t use AAA’s in pairs & the charger only works in pairs so there not balanced before charging. I know there not expensive but I like to look after my gear so any input would be great : )
At the moment when there low I put them in my fenix E05 until it starts to flicker then I repeat the process with another cell until I have a pair to charge which is a bit of a pain and I’m not sure how good it is to keep running the cells down to nothing? ? ?

The only thing I came up with was to buy a Maha C9000 but this seems bit overkill? Although it’s a lifelong bit of kit so maybe not? Any ideas cheap options 1st​ please lol.
 
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The cheap option is to buy a AAA battery holder, and connect a 20 ohm resistor between the battery contacts. Just put the battery in the holder, and wait a few hours, and it will be fully discharged. That way all cells will start at the same point in the charge cycle. 20 ohms will result in a drain that is low enough that the battery will be able to fully discharge, and will not even get warm. The damage in most NiCD or NiMh batteries comes from reverse charging (running current through them in the wrong direction after being fully discharged). I wish I could claim to have discovered this method, but the credit goes to an EE Professor from my University days....
 
mattheww50 said:
The cheap option is to buy a AAA battery holder, and connect a 20 ohm resistor between the battery contacts. Just put the battery in the holder, and wait a few hours, and it will be fully discharged. That way all cells will start at the same point in the charge cycle. 20 ohms will result in a drain that is low enough that the battery will be able to fully discharge, and will not even get warm. The damage in most NiCD or NiMh batteries comes from reverse charging (running current through them in the wrong direction after being fully discharged). I wish I could claim to have discovered this method, but the credit goes to an EE Professor from my University days....
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Very bad idea. :shakehead
 
I agree with entercpf - Of course reverse charging is battery-killer but discharging it down to 0V is killing the battery too! This technique can be time to time used only on Ni-CDs to destroy dendrites or something like it - i don't know exactly but there is a thread about it.
 
you dont need C9000 but any other cheap charger with multiple outputs, i.e. independent channels. Sanyo sells maybe 10 different NiMH-chargers for AA/AAA and some of them have 4 independent channels (for 4 cells).

yes, if you have cells have a different charge level, then charging them in a dual channel is not good.

and yes, if you stick with your system with no major investments, then the 20 ohm resistor method is as cheap as it can get. Works but the idea is not good.

A cheaper method than C9000 would be a generic hobby charger (also called balance charger) or a Sanyo charger with independent channels good luck
 
I have use for AA 1 Ohm resistor + diode. End voltage is 0.6V. For AAA maybe 4.7 Ohm + diode.
 
LFP11 said:
I have use for AA 1 Ohm resistor + diode. End voltage is 0.6V. For AAA maybe 4.7 Ohm + diode.
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end voltage at rest, or end voltage at discharge load?
i cant maintain Eneloops at lower than 1.10V. The point is: when i totally(!) discharge an Eneloop cell in a flashlight, the cell comes out at < 0.84V, and then quickly recovers to, for example 1.12V.
 
shelm said:
end voltage at rest, or end voltage at discharge load?
Click to expand...
Discharge time was overnight. End current was very small less than 1mA so 0.6V was end and rest voltage. I have use this just old cells before I bought C9000.
 
Hello Andy,

I think your best bet without buying a new charger is simply to keep track of your discharged cells and charge them in pairs. Kind of a pain, but it doesn't cost anything.

Of course the C9000 charger, or any other independent channel charger would be better, but chargers cost money.

Discharging a NiMh cell to 0 V using a resistor or by direct shorting, and then storing it in a shorted condition is controversial. Quality cells seen to handle it without problems, but it can age the cell a little faster. The other side of this is the damage done by over charging.

Actually, now that I think about this a little, what you need to do is pick up more flashlights. This will push your needs over the edge where a quality charger will be viewed as an investment and not as a cost.

Tom
 
I picked up the "Sony Cycle Energy BCG34HRE4KN" on Amazon which includes 4 AA batteries. It's got 4 independent channels and also has a refresh function. I think it's one of the better values out there.
 
Fully discharging an independent Eneloop AAA or AA is not going to significantly damage it. But as Tom pointed out, it will most likely add extra wear to it over time. Unlike NiCds, I personally would not leave them dead shorted.

Independently discharging them in a flashlight until the flashlight starts to dim is not a problem at all, and the cells should recover to a little over 1V.

But yes, get the C9000 (and more flashlights and Eneloops). ;)
 
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I hate buying stuff I dont need as I always feel a bit greedy but I like what your saying : )

Next time I chat with the wife I'll just explain "Tom said it was an investment honey & Tom is a very clever man"

Hi Wrend when I said running them down to zero it was just a figure of speech not an actual measurment as soon as the light starts to flash / flicker and turn it off and it still has enough juice to power up an E01 (tried this once) so dont think there damaged in any way : )

I agree with you I'd never run anything down & leave until its dead shorted.


Cheers for the imput.



Cheers
 
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A simple charger I use is the Tenergy V-9688. Paid $28 shipped off ebay, nothing fancy. It charges the batteries one at a time in it's 4 bays, AAA-D. I had one off those cheap compact wall chargers that only worked in pairs, never liked it. I have too many little devices that run off one battery.
 
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