Charging NiMH with different levels of discharge

[spencer]

For a build I'm thinking of using 3 of these batteries in a 2D maglite. The only problem with using these cells is that runtime would be reduced over other options. The main reason I'm using them is because they are cheap. I'm thinking buy up 9 or so and then have 3 sets. I'm thinking of getting this charger and would be able to charge them all at the same time. I would need to charge at least six at a time and that's not really an issue for me (I don't think). Lets say I completely discharge one set of 3 batteries. I'll want to charge them up again. Can I charge the 3 that are dead and 3 or 6 more that have a little bit of discharge on them? Is that going to be bad for the batteries that haven't been used but have some discharge on them? Any other charger recommendations would also be appreciated.

Thanks,
Spencer

 

[AlexLED]

Hi Spencer, you should always charge (and also discharge) a battery pack with batteries in an equal state. Otherwise, the batteries become more and more unbalanced over time.
I would strongly suggest charging only 3 batteries at a time.

 

[spencer]

Thanks

 

[spencer]

What about a couple of these chargers?

 

[spencer]

Scratch the last idea. What about this charger with the batteries in 3S3P, 3S2P, 3S1P depending on how many batteries I need to charge? Would that work or would the batteries become unbalanced?

 

[AlexLED]

What about a couple of these chargers?

Hi Spencer, not a good idea ! That's a timer controller charger that will either over- or undercharge your batteries.

I'd suggest the Accupower Accumanager 20:
http://www.accupower-usa.com/User/featuredproduct.aspx?PSCID=10&PCID=4

 

[AlexLED]

Scratch the last idea. What about this charger with the batteries in 3S3P, 3S2P, 3S1P depending on how many batteries I need to charge? Would that work or would the batteries become unbalanced?

Well, that charger is ok, but you should not charge in parallel configurations.

The best results you would get with the charger I suggested above. It can charge up to 4 of your cells at the same time. Charging current is about 700 mA, so it will take about 3 hrs to load.