charging a wee 8 cell (2S4P 240mAh) pack - RC Groups
Apr 08, 2008, 08:07 PM
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Discussion

# charging a wee 8 cell (2S4P 240mAh) pack

I've been looking at putting 8 60mAh cells into a DLG (using the small cells will let me 'shape' the overall pack into the nose of the sailplane). It will be semi-permanent install (ie it won't come out for charging, etc).

Couple questions:

1) will feeding 2S voltage at 240mAh into the pack from a charger equate to 10C per cell (per the math), or will cell differences result in significant imbalances?

2) can I get a good charge (not optimal), then use a balancer to bring the cells into balance? How often will I need to balance - each charge, or every few charges?

3) I've heard the 'wee' cells can take much more than a 10C charge - anyone have any input on this?

I'm guessing the answers are somewhat subjective, but let's hear from the experts...

Thanks,

Don
 May 08, 2008, 12:54 PM Registered User Don, 10C charge is way too much for a lipo Regardless of how may cells you have in series its still a 2S pack that should be charged at 7.4V (2S) Regardless of how may cells you have in parallel it still must be charged at 1C or 2C if manufacturer allows. in your case (1C)240mA or (2C)480mA Once you put 4 cells in parallel that will be 240mAh and 3.7V, do that agin with the other 4. Once this is done, connect the 2 sets of 4P cells in series as 2S. For balancing you will need a 3pin connector. THIS IS THE SIMPLEST WAY TO BALANCE. you do not want to tap into each individual cell on its own, ITS A PAIN to maintain and adds weight. If you dont have a balancer connect all 8 cells in parallel for a hour or so before you start assembly, this will balance them perfectly. Best Wishes, Dan TrueRC
May 08, 2008, 01:22 PM