which charging method

[exe]

Hey all,

I want to add 4S or 6S to my existing premade BMS 12S 13ah pack. Since HK doesn't sell 13ah packs, I will have to parallel 2 packs to get to 13ah, and then series that with my exiting 12S pack. My existing 12S pack is a Li-NMC, a form of Lipo, I believe it can do 60amp continuous draw. I assume any of the Lipo HK sells will be ok? What C rating should I stick with? Will there be an issue with mixing my 2.5 year old (only <2K miles) battery with the new cells? I will be using this on my 40amp Grinfinion controller.

There are two methods (or more) to charge. I can get dumb battery supplies and use a balance charger like these two setup:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=76184
http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=66718

Or maybe this power supply from Icecube:
http://lipoconnectionsolutions.com/HP-12v-750w-Power-Supply-4mm-Bullet-Vertical-127504MMBV.htm


Or I can get a smarter power supply, like a meanwell that has adjustable voltage and current (any recommendation and is Ebay safe to buy a genuine one from?) , and use a Battery Medic type device like so:
http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=26136

Once my main 12S pack dies, I plan to either replace them with more HK Lipo cells, or switch over to Adappto, so I hope whatever I buy I can also use later on. Could you all check my rough idea, thanks.

 

[dogman dan]

Series connecting your old nmc pack with lithium cobalt wont work so good. You'll have to stop the nmc early, because its empty voltage is lower than the lipos empty voltage. Or maybe your nmc is weaker than you think, and the nmc will die first. You'll have to run two voltmeters to know.

But you can do it,,just stop when the lipo is at 3.5v or higher. or when the nmc is empty, whichever comes first.

You'll have to charge them separately of course.

For 60 amps from 13 ah,, you could go with the 20c crap packs, but I'd recommend 30 c or better if you can afford it.

I'd also VERY strongly urge you to make up a lipo pack with all new cells, all the same age. Not some now, some later. Just get 18 or 20s,, whatever it is you wanted, and 10 ah of it now. Buy a stack of 5 or 6s 5 ah packs.