FMA LiPos in an E-Maxx

[Papa]

Thanks Mac keep us posted!:cool:

[MetalMan]

One thing about Lipos is that you shouldn't use them when they are below room temperature (70 degrees). They need to be able to warm up so that they can provide maximum power. If you start them off at 50 degrees, then you would be likely to hit LVC because the cell isn't warm enough yet. This is very important for those of you that will be doing winter driving with Lipos where the outside air temp will be about 60 degrees or lower. To fix this, a simple hair dryer can be used.

EDIT:
You can see how this occurs when Lipos are graphed. Before the cells' temperature warms up, many brands of cells will make dip in their voltage even at 70 degrees. This is actually decreasing as newer and newer cells come out, though. Look at the purple (48C) line on the graph of this Kokam 3200mah cell:
http://img.photobucket.com/albums/v1...kokam-3200.jpg

Originally posted by MacII in another thread
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Only trouble, my E is still setup for 5 mins racing. Even if I had the battery capacity my motor and speedo a very hot after 5mins. Cooling it would take some effort and likely some gearing changes.
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Gearing is definately a huge factor and I don't see what your gearing is set at in this thread.

Your truck looks all aluminum, minus the CF battery plate. W/ the LiPo's installed what are you looking at for weight? I'm guessing 10-11 pounds.

A Feigao 10L has about 27 less oz-in torque than a Feigao 10XL when pulling 100amps. I think w/ the Kv and torque of the 10L, and the weight of your truck, this may be why you're running hot.

I don't know enough about Schulze to say how warm they generally run. I run a BK20120 because I wanted to make sure the speed control wasn't the weakest link...so it never even gets warm.

My Maxx, ready to race is 10.5 pds, I run 14 cells (gp3300 1.17, matched) w/ 18/64. My 2400XL will run 170 degrees w/o the heatsink, thermal grease, and 80mm fan. W/ the aforementioned stuff I run about 120-130 degrees. I get over 10 minutes+ runtime on a big fast track (http://globalservices.globalhobby.co...c.php?t=15061.). On WOT my truck will just barely pass a 1/8 buggy.

I think w/ a 9XL and proper gearing you'll easy run the 10 minutes w/ more than enough speed and a tough aluminum truck to boot.

Sweet pics and truck, btw.

Originally posted by C.H.U.D.
Gearing is definately a huge factor and I don't see what your gearing is set at in this thread.

I'm running 14/64 in 2nd gear (G-Maxx Single Speed).

Your truck looks all aluminum, minus the CF battery plate. W/ the LiPo's installed what are you looking at for weight? I'm guessing 10-11 pounds.

I'm buying a small digital scale any day now, I know the truck is heavy. I have tried to save weight were possible but I know it's heavy. The LiPo saved a LOT.

A Feigao 10L has about 27 less oz-in torque than a Feigao 10XL when pulling 100amps. I think w/ the Kv and torque of the 10L, and the weight of your truck, this may be why you're running hot.

Interesting...The 9L and 10L I've got really move the truck like nothing else on the track, they certainly don't seem to be taxxed at the gearing I run. I just switched to LiPo a few weeks ago and it's been cold on race days (50 degrees) so temping has not really been an issue. I can't tell if the weight saved translates into cooler motor temps. Hopefully it does. I know on some of those 95 degree + days this summer it was a contest to see who wouldn't thermal shut down. I still can't believe I didn't thermal at Madness in August.

My Maxx, ready to race is 10.5 pds, I run 14 cells (gp3300 1.17, matched) w/ 18/64. My 2400XL will run 170 degrees w/o the heatsink, thermal grease, and 80mm fan. W/ the aforementioned stuff I run about 120-130 degrees. I get over 10 minutes+ runtime on a big fast track (http://globalservices.globalhobby.co...c.php?t=15061.). On WOT my truck will just barely pass a 1/8 buggy.

I think w/ a 9XL and proper gearing you'll easy run the 10 minutes w/ more than enough speed and a tough aluminum truck to boot.

All sounds good. Switch to LiPo and your truck will be even lighter and quicker. As this season is over, I'm beginning a winter rebuild but I think when I hit the track next year, I'll be driving an all new E-MT...maybe the G2R or something else...