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Registered Member #191
Joined: Fri Feb 17 2006, 02:01AM
Location: Esbjerg Denmark
Posts: 720
What kind of voltage, Ah and C rate are you looking at? For pouch type cells, i think Kokam is still the best, if not expensive. 18650 cells might be easier to manage thermally if you are looking into high C rate.
Registered Member #16
Joined: Thu Feb 02 2006, 02:22PM
Location: New Wilmington, PA
Posts: 554
Electroholic, I'm looking at 3 individual packs, 3 cells each, 5-6AH per pack, maximum discharge current of about 3-3.5A in bursts, with an average of less than 1.5A. Basically, I'm going to shove as much capacity as I can into 1kg.
I'd like to charge them fairly rapidly though, around .75C give or take, if at all possible. The protection circuit I have my eye on right now is also a charge controller, but can only swing about 1.3A max charging current. That's a bit on the low side, but having the charger complete with cell balancing built right in probably makes it worth the trade-off.
Registered Member #191
Joined: Fri Feb 17 2006, 02:01AM
Location: Esbjerg Denmark
Posts: 720
5 or 6AH RC packs should still be readily available from RC stores. And if you are not cycling at high C-rate, the useful life is more dependent upon the storage condition and manufacturing quality. What BMS are you looking at, can you bypass the charge controller but leave the balancing circuit functional and use an additional RC type charger?
Registered Member #618
Joined: Sat Mar 31 2007, 04:15AM
Location: Us-Great Lakes
Posts: 628
I if he gets a good charger or has a good charger, I don't think it will let him charge with out a balance, at least mine doesn't but then again I splurged on a $250 charger, a bit over kill but it is a Hyperion which are said to be one of the best, and I liked it because I could charge up to a 12s battery pack, as well as claiming to handle 100W per charge port (de-rated from 180W).
Registered Member #509
Joined: Sat Feb 10 2007, 07:02AM
Location:
Posts: 329
At work we've had luck with batteryspace lipo batteries, big 29.6v, 10AH packs feeding some vicor dc-dc converters for portable power for various equipment. A lot of their larger ones have built in balancing, which is nice, so even charging with a CC/CV power supply, or only somewhat smart charger is fine. Check out the next catagory up from the one I linked too, they have higher capacity Li-ion and Li-po packs.
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Big Li-Poly Battery Packs
