Do you know how to bypass the bms for discharge?
But his bms took it for a while, thatâs why im thinking itâs the cells
@willpark16 mentioned that he had a problem with his bms on a similar pack I think if the cells check out ok, then I would try bypassing the bms next
so the tabs that the balance leads go to looks like they go down roughly like 4 volts as I go down to the bottom of bat 34.00, 30.00 and the next one says only 3.4 and then it goes back to 26.00 and then 22.00 then 7.4 are they supposed to be in order or is this normal
They are in order but the best way is to isolate each parallel group with the volt meter each parallel group of 4 cells represents 1s so as you go down the line in series the voltages of each group adds in
group 1 will be the end of the battery that supplies the negative (black wire) output group 10 will be the end of the battery that supplies the positive (red wire) output
1 Like
If you can unplug the balance harness from the bms, you can check voltage of each group at the balance connector.
Ask him before U open!!! He will not replace no matter weather it was faulty before or not
too late, its already been opened and modified
Here is a chart I whipped up showing how to check individual cell group voltages at the balance connector. This is for bmsâs with 10 pin connectors. If your bms has 11 pin connector, you can still use this method or use the ground wire on the balance connector for the neg side of cell group 1.
Ok. I just got to read the whole thread. It looks like you killed your cells. HE2s are okay cells but if you had duals drawing up to 60A each, that means 120A total on a 4P, comes out to 30A per cell. If you ran it like that for a while, you definitely stressed out your cells and I wouldnât be surprised if their internal resistance has gone up significantly.
What this all means is that your cells will sag A LOT so that whenever you throttle hard, they hit the voltage cutoffs you have set. Once you let go, the voltage rises and you can ride again. Until you hit the throttle hard and the voltage sags again.
Try this, set your cutoff start at 30V and your cutoff end at 28V. If that doesnât work, try 28V as start and 26V as end. If either fixes it, then itâs your battery and youâll have to consider replacing it soon.
E: I would also suggest bringing your max batt current down to 20A on each ESC and upping the motor max current if torque is an issue at low speeds. Also Min batt current to -10A and -60A motor min. The big ones though are the cutoffs I stated above.
2 Likes
so I took it all apart and found that under the switch it was massively arcing and chared where it was shorting out on a piece of exposed metal so I re soldedrd and put back to gether and still cuts out at lunch today I will lower the cutoffs to 28 and 26 and hope that works if so I know battery wont last much longer so which one should I get I like the tb 6355 motors and I have 3 of them so something that would work with them they are 190 kv
No offense but I honestly suggest you have someone more experienced look at it. This thread screams fire hazard to me⌠youâre lucky that short didnât fry your battery.
really? thatâs not very nice. its not like you were born with all this knowledge in complex motor controllers . you had to start somewhere and ive been building hotrods and vintage custom cars my whole life and it is called diy is it not? im not the guy that brings his car to the mechanic for a blown head gasket or engine swap thatâs not how I was raised sorry and everyone on this forum has been very helpful thank you. and btw everyone problem has been solved and now I have the experience in troubleshooting a good amount on the vesc and battery pack and I can share it with others sorry didnât mean to get all puffed up that shouldnât have offended me but it kinda did
1 Like
Good stuff man!
What was the root cause?
(I go to the mechanicâs for a blown head gasket haha)
ď¤ Vesc x keeps cutting out during acceleration please help ive tried everything PROBLEM SOLVED you guys were right my settings have overstressed my cells and I just had to set my voltage cutoffs really low to accommodate, good learning experience im in the market for a new pack soon I guess
1 Like
Not trying to be a douchebag! Donât take it the wrong way. Itâs just that your life is at stake here. A short like the one you described could easily cause your batteries to explode and catch fire. Iâve seen these batteries blow and burn, itâs not a pretty sight and it also isnât something you can kill with a regular fire extinguisher. Having that happen under your feet could be deadlyâŚ
I am curious. Whats your motor kv and how many teeth does your motor and wheel pulley have.
Also, your voltage cutoff should never go below 25V, that is the limit for your batteries. The reason I suggested 26V is because your cells could also be out of balance which means one of the 10 packs could dip under 2.5V.
I still recommend that you check the individual voltages and make sure that they are still in balance. If not, leave it plugged in overnight and see if they get balanced. If that doesnât work youâll have to buy an rc charger and balance them manually.
1 Like
I Think im just gunna call this pack doomed and done for maybye ill dissect it later on and get rid of the stupid usb chargeports and all the hot glue and ductape crap and make a spare pack out if it . btw I am running 6355 tb motors 190 kv and 36/18 gearing (I like to go as fast as possible I always have 40 is borderline fast enough anymore I would be content with 45 on flat I think . lol
And what is your wheelsize? But in your case with that high gearing I would recommend lipo batterys. They can stand the higher current. When you go 40 mph on flat you need more than 3000 watts to keep that speed. There you are already above 80A. And with your settings you can draw more. When you have a new battery then it would be awesome if you can connect my app via Bluetooth module and make a video with the app at top speed. I think everybody would like to see that.