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HPI Savage Flux XS Overheating Problem

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HPI Savage Flux XS Overheating Problem

Old 07-11-2015, 04:32 PM
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boomgreen87
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Default HPI Savage Flux XS Overheating Problem

My HPI Savage Flux XS keeps overheating shortly after i begin running it, usually around 5 minutes or less. However, it seems as if it is the battery that is overheating, not the motor. What could be the problem?
Old 07-12-2015, 05:43 AM
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NachoRTR
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If you are using a nimh battery it will overheat as it can barely keep up giving power the motor. If its a lipo, it may have a low C rating for this car. I would recommend one with 30+ just to be sure.
Old 07-12-2015, 07:21 AM
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boomgreen87
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Originally Posted by NachoRTR View Post
If you are using a nimh battery it will overheat as it can barely keep up giving power the motor. If its a lipo, it may have a low C rating for this car. I would recommend one with 30+ just to be sure.
Both of my batteries are lipo and they both used to run fine with the truck until the last, I don't know, 4 or 5 runs. One is an older battery that has been used quite a bit and the other is a newer battery that hasn't even been used 10 times yet.
Old 07-13-2015, 06:43 AM
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EXT2Rob
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Hey Boomer, welcome. Based on your number of posts, can we assume your Savage is fairly new? And, maybe you are too?

Electric trucks are great, and have little maintenance compared to nitro. BUT they still DO need some maintenance. If your truck was running fine, then the motor started getting overheated, and nothing else changed, chances are you have one or more bearings that need attention. One bearing that has locked up can cause enough drag to heat up the motor. The easiest ones to check first are the wheel bearings. They're the ones that get the dirtiest. Take each bearing out and test it for smoothness. If it is gritty or locked up it needs attention.

Using a hobby knife, carefully pry up the inner edge of the rubber bearing shield on both sides of the bearing. Clean out the bearing with motor spray or WD-40 and blow it out with compressed air. Check the bearing for smoothness. If it's still gritty, clean it again. If it was locked up, you may need to take a toothbrush to it. Once clean, replace one shield and add bearing lube to the open side, then reinstall the shield. The bearing should be nice and smooth now. If not, replace it.

Get out the tools and start takin' the truck apart. You've got bearings on the diffs too. Take the diffs out and check all of them, and service any that require it,

If you don't have one, get yourself an infra-red thermometer for monitoring your motor temps. Brushless motors shouldn't get over 170F. Beyond that, you run the risk of the magnets loosing power and or the wire insulation can melt and short.
Old 07-13-2015, 08:03 AM
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boomgreen87
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Originally Posted by EXT2Rob View Post
Hey Boomer, welcome. Based on your number of posts, can we assume your Savage is fairly new? And, maybe you are too?

Electric trucks are great, and have little maintenance compared to nitro. BUT they still DO need some maintenance. If your truck was running fine, then the motor started getting overheated, and nothing else changed, chances are you have one or more bearings that need attention. One bearing that has locked up can cause enough drag to heat up the motor. The easiest ones to check first are the wheel bearings. They're the ones that get the dirtiest. Take each bearing out and test it for smoothness. If it is gritty or locked up it needs attention.

Using a hobby knife, carefully pry up the inner edge of the rubber bearing shield on both sides of the bearing. Clean out the bearing with motor spray or WD-40 and blow it out with compressed air. Check the bearing for smoothness. If it's still gritty, clean it again. If it was locked up, you may need to take a toothbrush to it. Once clean, replace one shield and add bearing lube to the open side, then reinstall the shield. The bearing should be nice and smooth now. If not, replace it.

Get out the tools and start takin' the truck apart. You've got bearings on the diffs too. Take the diffs out and check all of them, and service any that require it,

If you don't have one, get yourself an infra-red thermometer for monitoring your motor temps. Brushless motors shouldn't get over 170F. Beyond that, you run the risk of the magnets loosing power and or the wire insulation can melt and short.
Thanks, you were a lot of help! You are correct that I am fairly new to RC still (got my truck in March) but I bought the truck used. A lot of maintenance has been done to it since, however. I will check the bearings, those haven't been cleaned yet so that could fairly well be the problem. Thanks again for your help and if I have any questions, I'll come back and ask.
Old 07-13-2015, 07:28 PM
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Hate to be a pickle, but I don't think it's that. Sorry.

if the batteries are getting hot it's generally because they are not up to the task.

what are the specifications of the lipos and how old are they?

what do u mean by hot? How hot are they
Old 07-14-2015, 07:27 AM
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Originally Posted by boomgreen87 View Post
Both of my batteries are lipo and they both used to run fine with the truck until the last, I don't know, 4 or 5 runs. One is an older battery that has been used quite a bit and the other is a newer battery that hasn't even been used 10 times yet.
I hear ya, Max, but he also made this statement, which implies everything was hunky-dory until a few runs ago when things started getting hot. That tells me that something changed. And usually, that something is DRAG, no? I agree that NiMh packs tend to overheat with brushless systems. I've melted shrink-wrap on NiMhs, which is why I went to Lipo. Lipos can heat up too, if they are too low of a C-rating, or, the pack is getting old. I've got a Gens Ace 40C pack that is getting old, and I use it only for my daily fun run, since it's capacity has decreased such that it's not worth using on a race day. I ran it the other day in my SCT with the big Novak 550, and that battery got REALLY hot (110F) and even puffed the case a little. That never happens when I run it in my Hyper TT. So the power the motor system is trying to pull also affects how hot the battery gets. But I'll still bet ya a donut the OP has one or more bearings that need replacing.
Old 07-14-2015, 08:26 AM
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Originally Posted by EXT2Rob View Post
I hear ya, Max, but he also made this statement, which implies everything was hunky-dory until a few runs ago when things started getting hot. That tells me that something changed. And usually, that something is DRAG, no? I agree that NiMh packs tend to overheat with brushless systems. I've melted shrink-wrap on NiMhs, which is why I went to Lipo. Lipos can heat up too, if they are too low of a C-rating, or, the pack is getting old. I've got a Gens Ace 40C pack that is getting old, and I use it only for my daily fun run, since it's capacity has decreased such that it's not worth using on a race day. I ran it the other day in my SCT with the big Novak 550, and that battery got REALLY hot (110F) and even puffed the case a little. That never happens when I run it in my Hyper TT. So the power the motor system is trying to pull also affects how hot the battery gets. But I'll still bet ya a donut the OP has one or more bearings that need replacing.
I agree that it isn't that the batteries aren't up to the task because as you pointed out, I said that they were running fine before. So there has to be something wrong with the truck or maybe one of the connections. I am going to test out my older battery again to make sure that it is in fact not a problem with the batteries. Once I'm done that, I will start looking into what may be wrong, check the bearings, etc.
Old 07-16-2015, 03:14 AM
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Sorry I still disagree... Here I'll explaine more.

Im under the impression that the batteries are getting hot and the motor is not...

So in saying that it's very unlikely that there is a load issue... If it was something causing excessive drag the motor would be the first thing to overheat. But if the first thing is the battery it's clear that it's not up to the task

even if it's something like a bearing. There is no way it could overheat the battery before the motor and ESC unless there is a serious mismatch to the actual current draw and what the battery can provide...

also... If I'm right it's extremely dangerous pushing a lipo to the limit... If it gets hot it will rupture.... And I don't know if u guys have seen some of the videos I've done but it could potentially destroy the car.... Also another thing that's been discussed before. If he is pushing the battery that hard, there is also a real chance of a massive voltage spike when u go from fully loaded to no load and that spike could potentially destroy the ESC

it doesent matter if the batteries worked before... That's irevelant and not very logical. What that logic u could say there is nothing wrong with it because it worked last time. But the fact is, things fail... And yes they can happen over night.

I think u will find if a battery is getting hot it's because it's either been charged or is been discharged to fast
But we shouldn't guess..... As soon as we find out what the batteries are and there specs it should paint a bigger picture.

so to really get to the bottom of this we need to know
Is it running the factory flux motor and ESC?
Whats the voltage, mah and c rating of the batteries that are overheating?
Are there anyother modifications to the savage?
how hot is hot?
Does it cut out/brown out?
how long lave u had it? And has it been used much since?
Old 07-16-2015, 03:20 AM
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phmaximus
 
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As a minimum They need a battery that can spit out at least 80a something like a 2s 4000mah 20c

if ur running something like a 2s 2000mah 20c then that's the problem, something like that can only handle 40a
Old 07-16-2015, 07:48 PM
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EXT2Rob
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Wow, how did I miss that? Phweew. I muss lern too reed gooder.
Old 07-19-2015, 05:38 PM
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boomgreen87
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I understand what's being said about how it doesn't matter if the batteries worked before, just I figured that it would gradually show signs instead of being able to go out in grass going like 3/4 speed then the next run having the battery cut out after only a few minutes of going like 1/2 speed on gravel. And I have the battery specs here:

Battery 1 (Older One):
2s Lipo 4200 mah 25C 7.4v

Battery 2 (Newer One):
2s Lipo 6000 mah 60C 7.4v
Old 07-21-2015, 09:07 AM
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Hmmm...I could see the 4200 pack getting hot I suppose, but that 6000mah 60C pack should be more than up to the task. Mind you, the packs DO get warm when they are run. As much as 100F or even a little higher.

You say "...then the next run having the battery cut out after only a few minutes." So, you've put a fresh Lipo in the car, and it only runs for a couple minutes, then stops? No power to the motor? How 'bout power to the steering servo? Still active? Or is the whole car shut down?

You know what.....here's an idea: If the whole car shuts down, and you can get it going again by toggling the power switch, you could have a bad power switch. I've got one going bad on my SCT. Runs fine for a while, then all of a sudden it just stops. No power to anything. Toggle the power switch, and all's well again. The power switch is a cheapo that I've seen fail before on another car. I replaced it with a HobbyWing.
Old 07-21-2015, 09:14 AM
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Hmmm...I could see the 4200 pack getting hot I suppose, but that 6000mah 60C pack should be more than up to the task. Mind you, the packs DO get warm when they are run. As much as 100F or even a little higher.

You say "...then the next run having the battery cut out after only a few minutes." So, you've put a fresh Lipo in the car, and it only runs for a couple minutes, then stops? No power to the motor? How 'bout power to the steering servo? Still active? Or is the whole car shut down?

You know what.....here's an idea: If the whole car shuts down, and you can get it going again by toggling the power switch, you could have a bad power switch. I've got one going bad on my SCT. Runs fine for a while, then all of a sudden it just stops. No power to anything. Toggle the power switch, and all's well again. The power switch is a cheapo that I've seen fail before on another car. I replaced it with a HobbyWing.

Of course, this doesn't address the supposed hot battery issue.... I can't believe that a hot battery would cause the ESC to stop the car. A hot ESC, yes. Hot battery? No. The ESC doesn't care, nor even knows, if the battery is getting hot.
Old 07-21-2015, 11:27 AM
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boomgreen87
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The steering servo still works but I can't move at all. Then I will be able to move again after a couple minutes but then it just stops again after a minute or two of running.
Old 07-22-2015, 07:32 AM
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I have looked thru this whole thread, again, and nowhere in it is TEMPERATURE mentioned. An infra-red thermometer is an essential tool. Without temperature measurements, we are only guessing. But based on your last post, it's beginning to sound to me like you've got a bad ESC. Most ESCs have a thermal limiter that shuts it down if it gets too hot. But if that circuit is not working right, i.e. it THINKS the system is getting hot, it could shut down the ESC. The fact that it runs for a few minutes, then stops and after a few minutes goes again, but then stops again....something is faulty, and I'm guessing the ESC. Is the car still under warranty?
Old 07-22-2015, 02:36 PM
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Like I said, I bought it used. So I am assuming that it is no longer under warranty. Is there a way to check whether or not it IS the ESC that is the problem?
Old 07-22-2015, 05:35 PM
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Oh yeah, sorry, forgot. Used. I'm afraid the only way is to swap in another ESC. Cuz your batteries are certainly up to the task.

Hmm. Does the car sound like it's still on when it stops? A fan? Steering servo making any noise? Or just dead, no power? Maybe a continuity issue between ESC and receiver?
Old 07-22-2015, 05:37 PM
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boomgreen87
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Everything pretty much sounds the same except the fact that the vehicle won't move.
Old 07-23-2015, 06:45 AM
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Ok, so by that you mean there IS a fan running? When it is stopped, do the wheels turn? If so, pull the ESC wire out of the receiver ch2 then reseat it. If that doesn't do anything, it still runs then stalls, you could try swapping in another receiver, but I suspect your ESC is faulty.
Old 06-06-2021, 01:56 AM
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Originally Posted by boomgreen87 View Post
Both of my batteries are lipo and they both used to run fine with the truck until the last, I don't know, 4 or 5 runs. One is an older battery that has been used quite a bit and the other is a newer battery that hasn't even been used 10 times yet.
DO NOT use the older battery i have a flux hp and i put myy old batteries into it and after about 3 runs they were smoking and nearly caught the truck on fire

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