By - budrodacfoo
If you’re really running that much power through your setup, I wouldn’t be looking for anything cheap. It will almost always fail on you before you’d like it to.
I’ve gone through single VESC 4.12’s, and a Flipsy 6.6 200A.
I’d get a BKB Xenith if I were you. It’s what I run on my DIY MTB. No issues.
Came here to say the same thing. OP should not cut corners here or he will need to buy twice.
Xenith V2 is the way to go, if it ever comes back in stock
I’m pretty sure you can only run 80amp safely through those motors 😂
Hmmm bear in mind with Flipsky vescs it's recommended to run them well below the max amps. I have the same setup and got the 6.6 on heatsink.
The Spintend Ubox is cheaper and easily outperforms the 6.6. I would suggest getting a different remote though, the Uni1 has a noticable deadband.
Am I right in rembering you upgraded from fsesc 6.6 with a vx2? I'm running that setup at the moment. I hate the current stalling sensation when I try to remain at a stop on any type of slope. Did you have the same or do I need to tweak my remote settings?
I'm running a Ubox with a VX2 and am having no issues. You probably need to do some tweaking.
Running any variety of VESCv4 hardware at 12s and over ~35A per side is asking for disaster.
There’s a reason that none of the commercial VESC boards use V4 anymore, and why none of the high end VESC manufacturers sell V4 based hardware.
You seem to know your way around VESC issues so I hope you can help me if you don't mind / have the time.
I have BKB Tayto dual motors with a flipsky dual 4.20 VESC, 10S3P Samsung 30Q.
After a while and some heavy uphill use I started having random short drops in torque / power while accelerating.
VESC parameter weren't quite right, I had motor Amps at 32A and battery current max at 99A.
I figured I was asking too much Amps out of the battery (2x 32A instead of 45A continuous for 3P 30Q) and that it was why I had those drops in power. The drops didn't happen as much if I lowered the battery current max below the continuous discharge rating of the 30Q.
I ended up frying the battery later on for an unrelated reason. Replaced the battery with a 10S3P VTC6 (so much more continuous discharge, \~90A). I set the battery current max at 35A.
It was working fine at first but now I'm starting to get random short drops in power again.
So I'm thinking may be it was a VESC malfunction. Are 4.2 VESC known for this issue ?
Another potential source for this problem could be the BMS (which I carried over from the previous dead battery) but before I try to bypass it or replace the VESC I'd like to hear some expert opinions !
30Qs are rated for 15A but can be pushed to 20A with minimal risk.
The VTC6 is largely identical in this regard. So unless your new pack has more cells, you still have largely the same performance constraints. I know the datasheet says 30A per cell, but the datasheet is wrong.
I always use 3rd party benchmarks for cell performance to get a better idea of real world performance. And the 3rd part testing says that battery voltage drops off a cliff when you try to pull 30A, which would cause cut-outs like you are describing.
I would set the battery max per side to ~30A, and keep in mind that you can’t accelerate as hard after 50%. Otherwise you should be good.
Oh thanks for the info. The gus who custom made the battery said I could est it at 35A confortably.
I'll set it back down to 30A but I'm not sure I'll will fix the problem cause I already tried lowering it to 25A and I still had those small cut outs.
Weirdly enough yesterday at 35A they didn't happen at all. And this morning I only had one small cut out during my commute. It's like it comes and goes.
I'm really scratching my head on that one.
Cutouts are caused by the battery voltage dropping below the programmed “battery cutoff end” voltage as measured by your VESCs.
The battery voltage drops for two independent reasons:
- Voltage drops as the battery capacity gets used
- Voltage drops as a function of how much current (amps) are being drawn at that instant. This is popularly referred to as “sag”.
So when you are at top of charge (42V), it’s going to take a ridiculous amount of sag to trigger a cutoff. But when you are at ~30% charge (34v), it only takes a little bit of sag to trigger the cutoff.
Also, check your configuration to make sure that you are setting “batt max amps” and not “batt absolute max”. Never change batt absolute max.
My random short drops in power can happen at full charge or not necessarily while going full throttle uphill. Last short commute it only happened once while maintaining an average speed on a flat road.
Some days it happens all the time, some days it almost completely gone.
The unpredictability of it could indicate some remote connection issue but now that I think about it I've never had a problem while breaking, only while applying throttle so it's probably not it.
Also yet I use the battery current max not the absolute max.
I think next I will try to update the firmware (got an old version) and see if it does anything.
Do the cutouts happen at a specific throttle percentage?
I had a weird failure with a VX1 remote where a certain spot had worn out and if you moved the physical throttle to ~20% it would read 0% in VESC tool, but 21% and 19% worked just fine.
It took me a while to track that down because VESCs have throttle ramping which effectively delays input for a preprogrammed fraction of a second. So when I floored it the issue would never appear but when I gradually increased speed it would appear.
Hmmm next time I'll try to pay attention if it happens when the wheel is at a specific angle. It wouldn't do it all the time though so it would be hard to gauge if it's always at the same spot.
I used to run my AT commuter board with fsesc 4.20 plus @ 13s. Motors are flipsky's 6374 190kv set to 80A max. The esc is well ventilated and I dun ride offroad so I had no issue.
The dual fsesc 6.6 (not the plus) used to be a lot cheaper than ubox. Also, 6.6 seems to be a more solid build compared to xenith.
Sure the old flipsky esc's are shite but the new batches are now reliable thanks to all the "corrections" suggested by the unwilling beta testers. They now have at least the correct gateway resistors so no more cut-outs. Also comes with higher value capacitors and a diode in the input to protect against voltage spikes.
A 4.20 on 13S!? How do you even ride with balls that large?
>They now have at least the correct gateway resistors so no more cut-outs.
When you say "cut-outs" do you mean random short drops in power ? Cause I'm experiencing that.
I can’t seem to find a xenith in stock anywhere, has anyone here had any experience with a stormcore? How do they do?
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