jmcvicker

iTrader: (2)

Anyone try the A123 batteries in a 12th? You could do 2S1P and get a 6.6v setup with 2 cells at 2300mAh. That may or may not be great for a 8-minute race but may work for 5-6min. They have a nice flat voltage profile. A123 are a larger cell so they'd need to be fit properly or they'd not workout. They're LiFePo and not prone to the fires and other stuff that could accidentally happen. And, they're 30-60C draw - good potential for the mod classes. Not sure if the draw potential is there for stock motors.

trailranger

I have a 6.4V LiFePO4 pack made from FOUR Sub-C sized batteries. 1900Mah

Yes they worked but were faster then crapped out becuase of the limited capacity. Would work for 5min races, but still they were faster so you had to motor down one class.

Buggy Brad

I run 2s3p 18650(1100mah) A-123 cells and they are working great, with my 27 single run times are about 15 minutes. The pack weight is 9.25oz. I gear so I'm no faster than anyone else running 4 cells and that keeps everyone happy. One of my racing buddys is running 2s1p 26650(2300mah) and runtimes are a shade over 9 minutes with a 17.5 and the pack is 6.5oz. I plan to run A-123's for good now and a few others that we race with are fed up with NIMH and asked a lot of questions so I wouldn't be surprised to see a few more 123 powered cars at next weeks race.. The 18650 cells can be found at wal-mart online if they have any left and were selling for 12.00 to 17.00 for a 2s pack, you would look for a Black&Decker VPX cordless tool pack......BB

Fred_B

iTrader: (1)

I have similar cells to try (probably the same cells). If you wire them as a 1 cell pack the runtime is a lot better (3800 mAh). It's still not perfect but it is an option for the guys running t-bar cars. I would assume that you could just motor up to 13.5 and run in the stock class like the LiPo guys have been trying. Or just run mod if they want to go "fast".

Fred_B

iTrader: (1)

Trying to control the gearing to keep the cars the same isn't going to work for a foam tire class. That's one of the biggest problems with running 2 cell voltage. But, if it works at a club level then go for it.

jmcvicker

iTrader: (2)

Fred - can you go into more details? I don't understand your 2 last posts.

1-cell pack for LiFePo would end up with 3.3v - not great for 12th scale. Sure, it has higher Amp draw - so maybe you could get a 19T to run similar to a 27T in terms of performance. I'd like to get A123's setup with 6.6v in either a 2S1P setup or 2S3P setup with the smaller cells. That would be interesting in terms of quick charge time and good cell draw performance.

John St.Amant

iTrader: (1)

I dont need a new charger ,,, again,.,, i dont like baby sitting Ni-Mh cells nor would i want to buy even more crap to shove in my box or set up at the track.. Cant we just use 1 cell lipos and a flight pack,, the infra structure is already set up to go.. and im getting pissed waiting for everyone to figure out what they want to run.

1/12, 1 cell lipo 4000 no higher, 13.5 I bet would be fun and fast enough with little or no B.S.!

FraBe

hi all,

following this tread eagerly interested. In Germany are several peoples, testing new configurations for using LiXX in a 1:12 pancar.

Some use Lipoly as stick or saddle 2p1s with 13,5T or 9,5T brushless, others use LiFepo4 as 2p1s with the same brushles motors or a 19T brushed.

Best result, I think, is the configuration from "mineralwasser". Itīs a LRP-Lipo, 1800mAh, 2s1p, beetween the links of his CRX-Genx placed transverse, powered with a GM Dr. Speed 13,5T. Runtime is over 8 min. race trim and speed (insignificantly slower than 4 cells NimH with 19,5T brushed).

Good as well is to use a LifePo4, 2s1p, loaded with Lipo-Program (up to 4,1/4,2V each cell). This people use a 19T brushed (alternatively a 13,5 or 9,5T brushless.

See some pics:
http://www.moosi-masters.de/forum/vi...=quote&p=16403

Frank
English?. Sorry, but I do my best

Fred_B

iTrader: (1)

As far as I'm concerned the only way to get higher voltage packs to work in 12th is to TOTALLY change the motors, batteries, and likely speed controls. A complete tear-up will be resisted by a major portion of the 12th racers. I'd bet that most in the midwest would tell anyone wanting to change the entire class rules (batteries, motors, and weight) to get bent.

You can't have some "gentleman's agreement" to "gear to the same speed" in 12th. It's racing and we'll push to the limit every time.

On the A123 (any LiFePO4) you will have less voltage than a 4 cell and a little less than a LiPo but do not confuse the voltage here. 3.3 or 3.7 volts nominal means absolutely nothing compared to voltage under load. Will 3.3 or 3.7v be slower than 4 cell or 2 cell LiPo/LiFe? Yes. Is that a bad thing? No. Anyone that wants to go "fast" can simply run a faster ROAR approved motor including mod.

Buggy Brad

A A-123 26650(2300mah) cell is 2.8 volts with 35 amp load applied. So running A 2s setup your only 0.8 volts higher than a good 4 cell NIMH pack with the same load........BB

Buggy Brad

I didn't do anything but place the batterys on the chassis and begin running, it was pretty simple......Brad

Buggy Brad

I don't want to cheat, if I beat someone I want it to be because I am a better driver......BB

Fred_B

iTrader: (1)

Just .8 volts is over 10% higher voltage compared to a good NiMh pack. Yeah, it's plug and play but it's going to be faster if the IR of the cells is reasonable. Put into perspective, that's like having 1.4v NiMh cells under load.

As far as I'm concerned anything that's going to make the cars even faster than what they are now is a bad idea. New people are having problems running stock speeds and mod is pretty much out of control.

Buggy Brad

Yes, stock is pretty fast......BB

John St.Amant

iTrader: (1)

Lets all just run a 6 volt gel cell duct taped to a shoe box with square tires. then we can all buy new junk to throw away next year! SHEESH!