I recently built a battery with the help of a friend using HG2 cells and I noticed I lose quite some power after about 5 minutes of moderate to high throttle use. Everything stills runs fine, I just go a lot slower.
Could the HG2s be the culprit or is it the ESC and/or motor overheating? What’s the general performance of the HG2s? Hindsight, I probably should’ve gone with the 30Qs.
My pack is a 10S4P config, bypassed BMS for discharge.
New or salvaged cells?
Balanced?
Where did you buy them from?
Also, 1 or 2 motors?
Do you have any means of measuring temperatures? (metr module or similar)
HG2 are good cells if you got legit ones. Unfortunately there are a lot of HG2 fake cells outside.
There are some different reasons why that is happening and not so easy to say as outsider with the information you gave.
It can be a problem of the cells or the battery pack itself but it also can be an issue of your esc or motor.
Maybe start with posting some pictures of your build and battery.
Did you check the temp of your esc and motors at the time you lose power?
I was supposed to give a little more info you guys just mentioned, but I forgot.
I got the cells from liionwholesale.com, all came balanced. I’m running a single motor and I don’t currently have a way of monitoring temps or voltage while riding. (I made another post asking if anyone had a Metr in the US)
Since I’m running Ackmaniacs firmware, I’ll probably dig up my HC-05 module for now.
The reason the built a new pack is because my old one (using 25Rs) was slowly dying. The range dramatically decreased at some point. I still have it and was planning on trying that out as well to see if I lose any power. I just hope my HG2s are legit.
Liionwarehouse generally sells legit cells. You deffinetly need some way to check temprature of the pack. Also you should check your cut off settings in the vesc tool. Sometimes those are set alot higher then they should be.
I already re-did my VESC setup and set the cutoff to the recommended for 10S (30V start cutoff, 28V cutoff).
I have a battery meter set to percentages on the board and generally on my old battery I could actually see the sag pretty clearly after getting off and looking at it. The sag on the new pack is very small.
I found my BT module and installed it to use Ackmaniac’s app. The battery pack is fine. I now believe it’s just the ESC heating up as the pack has minimal voltage sag, especially compared to my old pack which I tested out and would only last about 4-6 miles. I was testing it at night and the temp hit 75C after about 2.2 miles, 15C under my max limit, and I still had my expected power. During the day, I could imagine it getting hot a lot faster. This is just the ESC temp though. I don’t have a way to check the battery temp.
Don’t bother with the battery temperature.
Do you have any means of checking motor temperature?
In any case, as you said, if your vesc reaches 75C during the night it will get hotter during the day and throttle.
I don’t have a way to check motor temps.
I’m planning on designing and printing a shroud that holds a fan to suck up fresh air and blow it out the back. I also think I need to open up the esc (it’s a focbox) and replace the thermal pads.
Seems like I have thermal issues on all of my things, PC included lol.