As the title says I'm having intermittent issues on 3s. The problem is once in a while I put a fully charged 3s lipo in the rally, I will run it for about 2 mins and it goes into stage 1 thermal protection. Its knocked down to 50% power so I shut it off unplug the lipo (cool to the touch) check the motor temp (maybe luke warm but barely) plug in the lipo turn it on and no problems. I run to low votlage cutoff and battery stil shows 3.86v per cell. Any thoughts or comments are welcome. My 4x slash didn't do this, did I get a bad esc in my rally?? Thanks in advance
I would run a smaller pinion and see if you have the same problem. Either that, or stick to 2S like I do. On 3S you're going to burn through stock parts like crazy...my $.02
Make it idiot-proof and along comes a better idiot
What is the c rating of your 3s battery, I suspect that under load you are hitting the LVC, (which traxxas LVC's sometimes have a high cutoff), your batteries may be the problem, at resting voltage they may say 3.86vpc, but under a load they may be dropping voltage to under the LVC cutoff point.
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I thought about it and its a 35c 4000mah 3s. I might need a 5k or larger 3s. But after it goes into limp mode and i shut down unplug it, ill throw it back in and get the 30min run out of it. Thats where im confused. All in all i figured its prolly the battery
Here's a little info on the VXL-3S ESC:
Stage 1: 3.6v it cuts 50% power
Stage 2: 3.3v cuts off all power
So if the truck is WOT and under load and close to LVD it will hit stage 1 first, then stage 2 if it reaches that threshold. Its all good for a reason though to save your LIPOs. They are known to LVD early at times though.
The good thing with Castle Speed Controls is you can control their LVC behaviour (voltage you want it to cut 50%) to start with.
You do NOT need a bigger or higher amp lipo. Its very likely your simply experiencing a slight glitch with the ESC. If things arent hot, your not thermaling the ESC. But it could be an early LVC issue like has been mentioned. That pack you have can deliver more than enough amps for the VXL3S system. (unless its a rediculously crappy lipo, which is possible).
But, I will say this, 3S in the rally with a stock VXL3S system is not a good idea. You will most certainly overheat the motor at some point. If your running for 30 minutes on a 3S, even geared down, your going to over heat it. The motor just cant take that kind of power in a 4X4 vehicle. If your not checking your temps OFTEN, you should be. If the motor goes over 200degrees, its permanently damaged. 180 is max safe temp and on a 3S, getting to that point does not take long at all. Sometimes only a few minutes if your running hard.
Completely agree here. I run 3s, and am running a mostly stock Rally. Only mods are an Integy Motor Heat Sink, and Traxxas ESC cooling fan. Everything, including gearing is stock out of the box. I cannot get 30 min runs on 3s, without hitting 170+ degrees F on the motor. Without the motor heat sink and ESC heat sink I experienced this problem described, but only once, and it was the first time I had the rally out, and I was completely abusing it on asphalt. It was loads of fun, and damage soon followed. Days later, stock without a heatsink and ESC fan still, I hit 200F on the motor. I shut it down, the ESC was also nearing 160F. Ordered the heatsink and esc fan, and temps have been down considerably on the esc, but the motor remains hot and seems to be getting hotter, faster. I know hitting 200F is the temp needed for demagnetization to begin and any further heat on the motor accelerates this problem, hence this is likely the reason why I am getting shorter run times due to motor heat. Also on 3s, I have already destroyed the rear diff, and slipper clutch. Also, to be considered, running 3s is going to ensure you eat through stock tires like no tomorrow. Pro-lines stick, and therefore my rally will wheelie nicely, but cause me to overheat fast because they are taller than the stock rally wheels and tires. I enjoy the four wheel burnouts provided by 3s, and the stock tires. Battery used is a Dynamite Gold 4200mah, 30c.
Last edited by SHIFTT IX MR; 06-18-2013 at 10:03 PM.
Are you sure it's in lipo mode? This sounds like a nimh-setting problem to me... or it's a brownout, but that's unlikely with all stock equipment.
Can you borrow your buddy's lipo and see how your truck runs? That can rule out the battery real fast.
My Black & Blue Rally is faster than your color...