lipo batteries
 

how do you find the continuos amp rating and the max amp rating for lipo cells? i found a good deal on some lipos. its 6 loose 2100 mah cells for 60 bucks. there rated at 10C. also, to make a 3s 6300 mah pack i would only need 3 cells correct?

To find the continuous amp rating, take the "C" rating and multiply it by the capacity in amp-hours. So, in your case, a 2100mah 10C Lipo can do 21amps continuous (10 x 2.1). To make a 3s 6300mah pack from 2100mah cells, you need 9 cells (3s3p). BTW, that's a good deal, assuming that they aren't just some cheap Chinese cells. Would you care to share your source?

sure. http://cgi.ebay.com/ws/eBayISAPI.dll...e=STRK:MEWA:IT

9 cells?!?!?!?! for one pack!

I think 10C may be their max burst rate. So that means that they are more like 6C cells, or 12.6amps continuous.

For the pack configuration, let's put it this way:

You make 3 groups of 3 cells in parallel. Each group is 6300mah and 3.7v. You put each group in series, to give 11.1v, while still maintaining 6300mah.

i didnt see were it said "max output" :o

If they are truely 10c continous cells the max output would be 63 amps. Depending on the rating burst for a couple of seconds could be higher.

If the other post that said 6c is more accurate then the max rating would be about 38 amps.

Total power is watts. at 10c it would be 693 watts
at 6c it would be 418 watts

Just one word of advice. Lipo's are great... but stay within specs. Mistakes can be costly and dangerous


Highflier

Gunna need lots of wires!! tell me how it works out!! if it works good, then ima get some!! thats like a 6000mah pack that is less then 100 bux!!! :) ANd they made in china from my cousins, so i know its good stuff! lol

no, nbcaz, it requires 9 cells to make a 3s pack using those cells. unless you wanted to make a 2s pack.

EDIT: i found these cells. it would only require 6 to make a 3s2p 6000 mah pack and the continuous amp draw would be 81 amps and a max of 117. i think these would do pretty good.

http://cgi.ebay.com/ws/eBayISAPI.dll...MakeTrack=true

they be okay if you have a place to mount them the 3 x 2 5/8

They are 9c constant for a 3000 mah pack which is only good for 27 amp in 2p for is 54 amp

Those might work, but i would stick with proven avenues like Thunder Power and Kokam/FMA because they have done all of the trial and error and probably blown up a few too to find the right combo.

While on the subject of lipos. How hard is it to make your own packs for loose lipo cells. Is it dangerous or something.

That would be 54 amps constant,78 amps max,6000mah.

3s3p would give you 81 amps constant,117 max,9000mah.That's similar weight to NiMh for the voltage though but with HUGE capacity.

There's only 6 available though.lol.

MetalMan built his packs i think, i think it would be safe enough if MetalMan talked you through it.I think the only danger would be if you got it wrong and shorted them,which is why i wouldn't trust myself to do it.

I have built up 3 Lipo packs. Shorting is definately a hard thing to avoid, but as long as it is very quick, no damage will be done. Also, you have to make sure that the tabs stay as cool as possible, otherwise you can damage the seal, which would damage the pack. As long as there is a nickel strip welded to the positive tab, then you can use only regular solder. If there is no nickel strip on the positive side, then you have to get the aluminum solder and flux which is difficult to work with, shortens soldering iron tips' lives, and makes a lot of smoke. I can give more info. if it is desired.

crazyjr, there are lots of other good companies out there besides TP and Kokam. In fact, Kokam tends to almost severely overrate their cells (for some cells). I personally like Maxamps, and 2 of my packs are from them - one was built by them (but later modified by me), and the other I bought as loose cells. These were their older generation cells, though. Their newer cells are quite good, and will hold up to their ratings (at least the 2100mah does). If you email Maxamps, you can get loose cells for $13.50 for a 2100mah cell, which is a VERY good price for a 15C cell. I am very tempted to buy some, but I may need to buy a new controller soon.

There is where I was thinking about metalman. They are on site now. little more than you posted. do they have the metal on them like talking about.

Maxamps will also make packs for you right now. I want to buy 2 3s packs and stick them in parallel - all for the cost of $95 shipped! To get that from Thunder Power, I would spend $150!

I was thinking in the neighbor hood of 2s 3p for 2 pack in series for 3p4s. Unless i got with 2p 4s 2 packs in parrellal for 4p 4s. I amy go with more i just so confused. :C:

I would suggest you go with 2 2s4p, and then put them in parrallel. It would make balancing/charging easier.

If I go with the 2s 4p they would be in series for a 4s 4p combo.I was thinking of a 3s 4p in series as well for 6s 4p. I need to stick with in a 4s pack for the simple fact of my charger.

I am familiar with others like Apogee, Maxamps and Cheapbatterypacks.com and others. Those two were the ones that were on the top of my head at the time i wrote that post. I was just meaning that it might be better to leave it to the experts due to the volatile nature of lipo's if mishandled or overheated.

Maxamps has an excellent guarantee/warranty on their packs. Also, the cells that they use come from the top Lipo manufacturer in China, so they are of good quality. Believe it or not, but the TP batteries would be more likely to get too hot than the Maxamps ones would - but that comes at the price of the extra weight of the Maxamps over the TPs. Kokam on the other hand, is expensive and heavy. I find Maxamps to be the inexpensive middle :L:.

I have made both 2s and 3s packs. A few comments on that
1) I will not make 3s packs myself again. Just a pain to do. Plus they don't look as nice as a profesional job.

2) 2s packs are not that bad to make. For a good savings I would make those packs. I had to use the the special soldier to boot.

If I needed 4s packs I would make 2 2s packs and use a deans plug harness to make those packs into 4s or a 2P pack.

Guess to make a long post shorter. buy if you need 11.1 volts consider building if you need 7.4 volts

Highflier