Puffed my Lipo today - RC-Monster Forums

standard_63 · **Puffed my Lipo today -** 03.20.2006, 12:10 AM

Would too low of gearing draw too many amps thru my batteries? I've been messing with my Maxx for awhile now, and thought I had everything worked out until I pulled my batteries off today and one smelled terrible, puffy, and 185f!!! Only one pack got that hot, the other was only 140f and no puffy. This was after 20 minutes running on a track.

I'm running 2 x 2s2p 6000mah TPs, 9920 and 7XL. I have UE diffs, Gmaxx single speed, big tires and 12/51 gearing. I was trying this gearing because I was having problems overheating the ESC, but since I put a fan on the ESC runs cool. Motor temp seemed ok at 150f after 20 minutes, I was going to try 14t pinion next, but batteries are gone. :(

So, now I'm wondering if 2 x 8000 2s2ps would work ok? Since one pack seemed to draw down more than the other, I figure I should run a Li-saver on each battery?
Since I have a 9920 with dual deans plugs, would I just run one off each deans plug? Or would I hook the Li-saver right to each battery?

nitrostarter · 03.20.2006, 09:21 AM

I run 16/51 on my 7XL with 16 cells and get good temps. You need to up the gearing.

squeeforever · 03.20.2006, 04:40 PM

exactly, your gearing was WAY to low. thats your problem. actually, to low or high of gearing will make it run hot. so you should have went with a 16 tooth.

coolhandcountry · 03.20.2006, 07:18 PM

Quote:

Originally Posted by squeeforever

exactly, your gearing was WAY to low. thats your problem. actually, to low or high of gearing will make it run hot. so you should have went with a 16 tooth.

that works for motor squee. He is having lipo problems. The 7xl can draw some pretty good amount of current. You may consider falling back to a 8xl. It would help runtime and heat on esc.

squeeforever · 03.20.2006, 07:51 PM

he said that his esc was running hot but was ok after he added a fan. it was probably running hot because of the low gearing. and if im not mistaken the low gearing sucked to many amps that the batteries couldnt handle so the one puffed up.

standard_63 · 03.20.2006, 09:33 PM

My ESC ran way too hot when I ran a 6XL, but not as bad with the 7XL. It would thermal after about 10 minutes, that's why I added the fan. Now it doesn't really even get warm. The motor was running way hot though with a 14t, that's why I tried the 12t. It didn't run as hot with the 12t, so I thought I was on the right track.

I'll try a 16t with my GP3300s and see how that goes.

MetalMan · 03.20.2006, 09:29 PM

Low gearing will not affect anything except the motor. When you gear down, the amp draw naturally decreases. These brushless motors have efficiency points, and if they aren't putting out much power (low gearing), then their efficiency goes down.

squeeforever · 03.20.2006, 09:54 PM

with ue diffs that sounds about right. i run 20/51 with stock diffs on a 10xl and 16 cells. so i think thats about right.