I’m trying to make a quick single drive setup–weight reduction is the goal of this so I want to use 10s to keep the motor efficient as it’s peak efficiency is at 10s. Also does the vesc still have a high rpm max?
I believe the VESC’s V4.12 have the 60k ERPM limit. I think the FOCBOX can go higher, though not sure if it’s as high as the VESC 6, which is 100k ERPM.
Is that in bldc?
yes it is char
I have a vescX whats the rpm limit on that?
That’s a FOCBOX from before they renamed it, so 60k.
F i feel like I’m gonna go over that at 10s.
You will probably hit around 67k which may just be okay on a FOCBOX. 3.7V * 10S * 260kV * 7 pole pairs = 67,340 ERPM.
Umm you have to use a fully charged battery in that equation. so I will hit 76440 ERPM
You’ll be doing 68796 erpm at 90% efficiency, 64974 at 85%, which I believe a lot of people assume.
Honestly you can probably just set your limit at 60k and chop off a little bit of your top speed.
My last build was 280kv at 10S. Even with that I only reached 60k when I was REALLY pushing it (checked logs) and testing my speed capability. Over 20mph is uncomfortable for me.
EDIT: also that was on a stock vesc 4.12, I’m sure you’ll be fine on a focbox as they are a little more robust.
Your loaded voltage will not be 4.2V. The only time your voltage will be 4.2V per cell is fresh off the charger with no load. Practically you will never see even close to that.
True but its always better to account for that. I think I’m just gonna run it and set the rpm limit at 60k. I’v fallen on this same setup before so I’m a bit apprehensive. Although I was using a cheap maytech vesc at that time.
You are not going to get anywhere near the max erpm while riding unless you are going down a steep hill 10 miles long with the wind behind you. Just don’t spin it on a bench and you will be fine.
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I have hit max rpm before with these but I was using a 8p pack back then so there was no sag at all. But now that I’m using a 2p pack I should have tons of sag so I’m probably never hitting max rpm. Its reassuring to hear from other people using this type of setup.
what was your top speed when you hit 60k?
23mph was what I peaked at. This was on a track around a football field and I could barely make the turns at that speed.
In the area I’ll be using this the roads are narrow and there are lots of frequent intersections, so there’s really nowhere else I’d be comfortable going that speed.
Current build with 270kv on 8s instead of 10s is projected to have a similar top end, with better acceleration due to a much larger stator and different gearing.
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Oh don’t test speed on a track that’s a really bad idea find a straightaway and just let em rip. @TowerCrisis Oh your going to have less torque at 8s not more but if your using gearing its probably gonna be the same.
Got higher wattage motors, rated only up to 8S, so I will be pulling significantly more amps. But as I’ve seen so far, they’re very high efficiency motors, and the board could have a fairly “eco” friendly group of settings.