FMAdirect.com, Cellpro Revolutions Lithium Polymer Batttery (test at 25 cycles)
As I reported just recently these two packs are still very fast in the car. I estimate they both have about 25 cycles now. I tested one and capacity was 4844 mAh for a 2.5 % loss. This is great; still over the listed specs. Voltage at a 20 Amp discharge was still 7.30!!. Discharge temp is super at 105F. I atribute these good numbers and good number retention to a superior brand and also a modest charge rate of 6 amperes as suggested by Linger. This brand has the best numbers and the best feel in the car than all the others that I have tested. I am averaging about 45 amp discharge in the touring car, so it is getting very hard use. It is being tested with a stock motor also. Maybe we can get another report. I have reposted the following information so you can compare the brands. Note that this particular pack at 150 mm is a bit long to fit most cars. It will fit a 7 cell car fine or my TC5 with some modifications. A clever enthusiast can shorten the leads to fit most cars. This requires removal of the small circuit board, I believe. Note that two of us have received 150 mm packs. The 135 mm on The FMA web site must be in error.
I had an oportunity to test my two new LiPo's from FMA direct. I also looked at some photographs and pack construction details which lead us to believe the original source is Saehan Enertech. Data on cycle life and performance of this cell is reported to me to be good.
Generally a LiPo pack will have the best numbers on the second or third cycle. I had one cell with a couple of cycles which tested:
Cell Pro Revolution
7.35 V at a 20 A discharge. Pack temp was reasonable at 110 F rising from 70F. Capacity was 4977 mA-h. I am extremely pleased. Track performance mirrored these good numbers. This is the best average voltage I have measure for a LiPo. Certainly a larger capacity battery tends to measure better, but these are not that much bigger than max amps which were about 4200 mA-h when new. Here are some numbers on some other packs I have tested for comparison. Now if you run softsided packs and can squeeze in this very long 150 mm long pack then I would recommend this pack so far. It does have a hard plastic and fiberglass thin protective plate on the top and the bottom to give a little protection to the edges.
I have tested a NiMH pack that had this same average voltage with powerful mod motors vs a LiPo ballasted to the same weight that only had 7.25 V average. The LiPo had a lot more punch. It just delivers the big amps better. This cellpro pack has the most punch that I have ever seen in the touring car.
Thunder Power Battery Tests at 20 hard, hot, high drain cycles
ThunderPower Battery at 20 cycles 3688 mA-h 7.17 V at a 20A discharge
ThunderPower Battery new 3950 mA-h 7.18 V at a 20A discharge
This is a 7% loss in runtime
which is about the same for MaxAmp Packs after this many cycles and very little loss in voltage.
MaxAmps New 7.21V at a 20A discharge, 4238 mA-h capacity
MaxAmps after about 25 cycles 3905 7.14 This is a 7.8% loss in runtime (estimated 6% loss at 20 cycles
The batteries are behaving very similarly at this point. A 1 % difference is less than the error in the treatment of the two brands.
Max Amp Packs
AmpMax Pack A
746 seconds at 20 Amps, 4144 mA-h, 7.16 V average
AmpMax Pack B
735 seconds at 20 Amps, 4083 mA-h, 7.19 V average
mA-h 2S1p Avionics LiPo when new
20A discharge, 574 seconds, 3194 mA-h, 6.87 V average
The guts of this pack are identical to the graphite edition 3200 mA-h pack.
Apogee Magnum 3800
Lithium Manganese LiPo
Pack C 20 Amp discharge, 6.94 V average , 3744 mA-h tested when new. This was my most recently purchased pack.
Pack A and B tested better when new but deteriorated to about this voltage fairly rapidly with only a few months of age and use. The capacity deteriorated to about 3100 mA-h at present after a few months of hard use.
Lithium Cobalt Dioxide Pack 3200 mA-h
20 A discharge, 612s, 3400 mA-h, 7.19 V
This pack maintained voltage and capacity extremely well with use and time.
An improvement to the very long leads on the original pack improved this voltage to 7.25 V
This previously posted Pic shows how I am running the Cellpro Revolution Battery. There is a Lexan guard now on the outside edge because I have had to move it right to balance the low speed control position. The battery strap is long. I have not compared it to a TC3 strap. If you have a TC3 strap, give me the length from bolt to bolt for the 7 cell strap. We can compare. My custom strap is 158 mm from bolt center to bolt center. I just reversed the stock battery support posts to use it.