Well, I took the plunge. I flew my new AirWild Extra 260 with AR7000 receiver all powered by A123 cells. They worked great and NO REGULATORS. Resting voltage was 6.8 volts, 6.5 volts under 1 amp load, 6.3 volts under 2 amp load. After a 10 minutes of setup and range testing and 15 minute flight, still 6.5 volts under load. I could not be happier (well maybe if they were lighter, 5oz for 2300mAh pack). No worries of undervoltage to the AR7000.

Before doing this test, I had called Hitec and they said no problem with the higher voltage and they said they use them. I called DA and they did not know of A123 batteries but said don't run over 6.9 volts. Perfect. I used the nice Airwild 22AWG wire with three pin deans. The third pin tied to the center tap (between the two cells). This allows me to "balance" charge them through the external charge plug. I removed the third wire going to the receiver (didn't know if the receiver would like 3.4 volts going to the signal line). I used the FMA Cellpro to charge them. Thanks to the guy on this forum or the "other" for giving me this idea.

Hybris,

What is your source for the cells? I've heard of guys buying the Dewalt tool packs and removing the cells.

Bob R.

http://www.a123racing.com/

OK, how did I miss these? I thought A123's were NiMh batteries so previously ignored the posts on them. These sound very promising. I've questioned for a while whether regulators are truely necessary on our servos. I know the manufacturers say higher than 6 volts will shorten the life of servos but has anyone done any independent tests on this? I've always run regs on my Li-ions but I'd love to get rid of them.

Looks like Horizon is a dealer for these packs...anyone know what they say about using them as flight packs withiut regs???

Dick Hanson has been playing with these batteries for awhile now and really likes them. Perhaps he'll chime in or you might try getting a hold of him?

I got mine from a Dewalt pack. 10 cells for $100 from ebay. Check the new cells. Some have reported bad "new" cells (the batteries were sitting on the shelf for too long). Mine were all 3.3 volts out of the package. I believe Tanicpacks.com also is selling these cells/packs.

"50% more power (up to 60C burst) than competitive Li-poly batteries"

Hybris, how is your setup going? What charger do you use? I would not mind trying a setup with the a123s if charging and maintaining were easy. These cells are a bit heavier but without a regulator on each battery the gap quickly closes. I don't fly 2.4 right now but would like to get the best power to my servos possible. I'd like to know how your tests are going, specifically how the DA ignition is holding up.

Regards,

Joe

A local flyer has this 60 size heli running off of the "drill" A123 cells.

They were much lighter, smaller and CHEAPER than the thunder powers. I think he said that the TP's still have an edge in power.

The A123 are working great. I now have over an hour on them. I recharged them after 2 flights (30 minutes) and the receiver pack took 450mAh and the ignition pack took about 160mAh. Both charged in about 15 minutes (balanced), near full charge was in about 5 minutes. I used a FMA CellPro through the charging jack. I made an adapter with a cellpro pigtail to standard servo connector. Resting voltage seems to be about 6.8 volts. The DA ignition seems to be fine so far. They said just don't run it over 6.9 volts for very long.

As far as a TP Lipo giving more power, not really. Both packs are going to be limited by the 22AWG servo wire. Now if you have 12AWG wiring going into a power box and 10 JR 8711s stalled pulling 4 amps each. The 40 amp load is still within the specs of both plus if you had that many servos you probably be using two packs. I would be supprised if we pull much over 10 amps at any given time.

A123 benifits over lipos and Lions (as I understand them):
Cost
durabiltiy (metal can)
pressure relief valve (for bad failure)
can take some over charge (will kill lions and flame lipoys)
can be fully discharged without killing the battery (it is hard on them)
NO FIRE (does not catch fire if shorted or overcharged (the wires may burn though)
Fast charging (they can be fully chaged in 15 minutes) with the new FMA ballancepro but I like the cellpro more because it has a display.

wow

Wonder if they plan on making them higher than 11.1 volt?

2.68 hours of flight now clocked on them. No issues. I seem to pull less than 200 mAh out of them per 15 minute flight.

Tanic packs sells them: www.tanicpacks.com

I got mine from ebay. Dewalt DC9360 battery (36v) for about $110 delivered.

Instruction on taking apart a Dewalt pack: http://www.slkelectronics.com/DeWalt/packs.htm