li-poly cells

HACHI-RYOKU · Post by **HACHI-RYOKU** » Tue Nov 16, 2004 6:19 am

I found some good li-poly cells.

http://www.eflightdesigns.com/cgi-bin/p ... cgi?CAT=19

Notice the 20mah li-poly cell at the bottom.

ph2t · Post by **ph2t** » Sun Nov 21, 2004 5:17 pm

excellent find man!

look how small this bastard is:

great site! gonna add it too my list.

ph2t.

HACHI-RYOKU · Post by **HACHI-RYOKU** » Mon Nov 22, 2004 6:57 am

Yeah, I've been looking for some info on how to recharge that one though. If it's like most li-poly batts, and it takes a 1C charge rate with a li-poly or li-ion recharger, than I'd have to say I'm having difficulties finding a charger for it that charges at 20ma or less. Otherwise I'd be all over that already. The lowest rated charger I've found so far goes down to 80ma and that's it. Do you know of another one?

gnubee · Post by **gnubee** » Mon Nov 22, 2004 9:13 am

not a good idea to charge lipos in parallel either. cant just charge 4 at a time at 80 ma unless they were used together also.

HACHI-RYOKU · Post by **HACHI-RYOKU** » Mon Nov 22, 2004 12:04 pm

Well, I hadn't thought of that yet. I would put them in series anyways.

I haven't found any literature that says I can't charge cells in parrallel like I would charge them in series. Newb, are you just saying it wrong?

gnubee · Post by **gnubee** » Mon Nov 22, 2004 3:42 pm

lipos explode when overcharged. if the batts were used individually they would have differing amounts of charging needed to get back to 100%

the only safe way to charge in parallel is if you make a pack out of it and use it parallel also. this helps keep the batts at the same level.

this would allow you to charge at 80 ma - 4 20 ma cells together would be 80 ma. if you charge them that way and then separate them and use them separately it is difficult to match their discharge levels for charging together again.

codesuidae · Post by **codesuidae** » Mon Nov 22, 2004 5:48 pm

gnubee wrote:it is difficult to match their discharge levels for charging together again.

Can they be discharged seperately, then paralleled up again before charging and allowed to settle for awhile before being placed on the charger?

ph2t · Post by **ph2t** » Mon Nov 22, 2004 6:12 pm

ye, but you need to be able to monitor the voltage levels pretty accurately beteen the cells......

gnubee · Post by **gnubee** » Mon Nov 22, 2004 9:21 pm

Can they be discharged seperately, then paralleled up again before charging and allowed to settle for awhile before being placed on the charger?[/quote]

this is the very thing i am warning not to do. hooking them together in parallel does not "even them out".

lipoly also does not show much voltage drop during discharge. that makes it difficult to match the discharge amount between cels for recharging.

not impossible, but difficult. guess wrong and one of the cells will overcharge while the rest are still trying to charge. best to wire them together and use them that way.

HACHI-RYOKU · Post by **HACHI-RYOKU** » Tue Nov 23, 2004 9:10 am

Cool. Thanx for the info. I hadn't figured that one. But I follow you.