A123 - Less Voltage = Less Power?

[Webbage]

I am setting up a AX-10 Crawler with a Sidewinder ESC, 55T Integy Lathe Motor, and a Castle BEC. I thought I;d post this in gerenal as it's more about principles of electric operation than specifically Crawling.

I am seriously considering using A123 rather than conventional LiPo because it's easier to manage. The problem is a 3S LiPo pack pushes out 11.1V, but a 3S A123 only pushes out 9.9V. Is this going to cause significant power loss in a crawler or is it not something to worry about?

My knowledge of Physics suggests that to get the same power at lower voltage you draw more Amps. Is the ESC or Motor capable of doing this or is it going to draw the same Amperage regardless of the Volts pushed down it? A123 is capable of throwing out the Amps big style so draw on the battery isn't a major issue

Is there any setup advice anyone can provide to get the best out of these packs with the setup I'm running? Primary concerns are torque and smooth throttle response.

 

[flm_savage]

i think you will be fine with the A123 cells. I only run a 2S lipo on my weak little goat setup and it does just fine.

 

[Webbage]

Yeh, I hammered this one out on another forum and the basic opinion is A123 falls somewhere between NiMH and LiPo overall. I'm gonna go with a A123 3S1P and see where it gets me.

 

[CharliesTheMan]

See if you can buy a charger that will charge A123 and LiPo, that way if you switch over to LiPo because of the weight and performance, you wont have wasted your money on the charger.

What motor are you going to be running with this setup? Also what ESC will you be using, because you may need to run a BEC.

 

[Lessen]

A123 batteries are Li-ion right? If so I know the Duratrax Ice and Great Planes Triton2 both can charge Lipo and Lion.

 

[Webbage]

Getting a bit short sighted in your old age eh Charlie (check my first post).

For a charger I, on your recommendation, was gonna get a Hyperion EOS6060i, which does all 4 battery types (NiCd, NiMH, LiPo, A123).

 

[SMaxxin]

For a charger I, on your recommendation, was gonna get a Hyperion EOS6060i, which does all 4 battery types (NiCd, NiMH, LiPo, A123).

I also have that charger and I love it BUT if I were running a123 batteries I would want a charger than is capable of charging at 10a.....The best thing about a123 is they can be fast charged at 10a which means a fully charged battery in around 15-20 minutes!

The bad thing is your going to really step up in price and you will need a power supply to run it.

If you have the money either one of these would be a nice choice but remember you still need a power supply.

http://www.maxamps.com/EOS0610i.htm

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXPYT8&P=ML

 

[Webbage]

The 6060i pushes out 6.0A max charge rate, although I am not sure as to the details of how you would set that on a A123, a brief look at the manual states you can set the rate 'Above 1C'. At 6.0A it will charge a 1100mAh pack in 11 mins, and a 2300 mAh in 23 mins. I think that's fast enough for me

 

[sweetdiesel]

A123 cells have a higher voltage drop under load than lithium polymer or lithium manganese. For crawlers which run lower rpms it may not be a big deal, but in a higher Kv rated brushless motor application, a 1 volt difference is a large loss in speed and power.

 

[Lessen]

off topic:

Wasn't it A123 batteries that were used in that 1:1 electric drag motorcyle. I saw that in a magazine quite a while back.. probably well over a year ago.

 

[Webbage]

A123 cells have a higher voltage drop under load than lithium polymer or lithium manganese. For crawlers which run lower rpms it may not be a big deal, but in a higher Kv rated brushless motor application, a 1 volt difference is a large loss in speed and power.

Yeh I found that out while discussing it on the 'other forum'. I don't think it's an issue on a crawler, as you say, I think the issue was on very high draw. There's some argument as to wether they actually live up to the 30C rating A123 give them and actually till perform respectably in high performance applications.