killing batteries??

[3030hoyle]

One of my scx10ii is killing batteries. I put a fresh all charged up battery in it and go to crawling. It acts normal until you get in a spot that requires some torque or like a bind. When it gets in a difficult spot is kills the battery boom just like that. What is making this happen? All the electronics are still stock that come in a rtr deadbolt. I just went back to a stock 35T motor. Any Ideas? I was thinking short somewhere or esc troubles, so I ordered a new esc but haven't installed it yet. I figured I would ask the experts before I start fixing the wrong thing. I'm sure one of you guys that have been crawling way longer than I have has the answer. Thank You for the help.

[ferp420]

what battery are you using it sounds like a nimh battery on a lipo setting

[3030hoyle]

3s 7.4 Lipo's
it will do it to 3 of the same batteries over and over again. When I put the same batteries in other crawlers ill get an hour or two out of them.

[AC49]

Does your ESC or motor get hot when you get it into one of these "Battery killing" situations?

If you disconnect the mottor from the drivetrain does it feel like any binding is going on or does it spin smoothly?

Are you lifted at all? (could have a really bad pinion angle.)

[Sniper4370]

Originally Posted by 3030hoyle

3s 7.4 Lipo's
it will do it to 3 of the same batteries over and over again. When I put the same batteries in other crawlers ill get an hour or two out of them.

3s lipo is 11.4v are you sure you are charging correctly? explain "killing" the battery. Like instant drain to low voltage cutoff?

[OSRC]

Sounds like voltage sag. Does it kick off LVC under heavy loads?

I had a similar issue, turns out my batteries were shot. I'd be crawling and after a short while my truck would stop dead - way before it should have. When I got home, my charger showed I only used 20-40% or so of the battery. Stumped me for a while...one of the guys on here suggested volt sag, so I hooked up a voltage tester on while driving and boom - could see the volts drop under load which triggered the LVC.

[3030hoyle]

So I messed up I meant 2s not 3s. my bad. But to answer AC 49 no the motor does not get hot ever. and it rolls just fine without the motor connected I tried that this afternoon. But that voltage sag is very interesting and I would like to know how you fixed that problem. But I don't think that's it because I can take out the battery and put it in another truck and it will run forever after charging it. I have not tried to take the battery out after it happens and put it in another truck without charging it I will have to try that. I just changed the esc Ill have to keep you guys updated on what happens.

[3030hoyle]

Originally Posted by Sniper4370

3s lipo is 11.4v are you sure you are charging correctly? explain "killing" the battery. Like instant drain to low voltage cutoff?

yes like when you get in a position that requires a bunch of torque it does like a instant drain with no warning.

[3030hoyle]

Originally Posted by AC49

Does your ESC or motor get hot when you get it into one of these "Battery killing" situations?

If you disconnect the mottor from the drivetrain does it feel like any binding is going on or does it spin smoothly?

Are you lifted at all? (could have a really bad pinion angle.)

It always stays cool. Its not lifted It does have a lot of extra weight but my other trucks do too and I have not had a problem yet. Its just this rig. You get in a bind and it drains your battery instantly.

[AC49]

Yea it kinda sounds like voltage sag
(Which means the battery resistance should be getting a bit high, if you can test it) but that is fixed with a new battery. If that same battery works in a different truck under the same conditions then perhaps it’s just your ESC which means you should have no issue now that you’ve replaced that.


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[3030hoyle]

Originally Posted by AC49

Yea it kinda sounds like voltage sag
(Which means the battery resistance should be getting a bit high, if you can test it) but that is fixed with a new battery. If that same battery works in a different truck under the same conditions then perhaps it’s just your ESC which means you should have no issue now that you’ve replaced that.


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Yah the batts work fine in other rigs, I have not got to test my new esc yet I also have a snapped axle shaft that I'm waiting on parts for. But I have high hopes. Thank you all for the input.

[Kingmeow]

Find a friend who has a charger that can measure Internal Resistance (IR) as your pack is being charged. Sounds like your battery is getting towards its end of life. If it has high IR readings then that's an indication.

As to why that pack works in your other rigs, are the other rigs similar in gearing, size, usage, etc.? Those other rigs could be pulling less amps.

[3030hoyle]

Originally Posted by Kingmeow

Find a friend who has a charger that can measure Internal Resistance (IR) as your pack is being charged. Sounds like your battery is getting towards its end of life. If it has high IR readings then that's an indication.

As to why that pack works in your other rigs, are the other rigs similar in gearing, size, usage, etc.? Those other rigs could be pulling less amps.

The other trucks are the same. I have three scx10ii. The only difference is the truck that is doing it has a lot more axle weight.