That gives me hope Because I’m not but I will be soon
Something to keep in mind is that the vesc feels like it has a mind of its own. Like I was max throttle going 30mph and I was about to stand up from a tuck motioning thats all you got because I wanted faster. Next thing you know the vesc kicks into to high gear (“turbo”) and all my weight gets shifted to my back foot and I almost ate shit but thankfully I didn’t. I put my hand on my chest the whole ride because I was so shaken up.
This might be due to mismatched motor and battery max. Could also be due to low voltage management, the vesc will throttle back if the voltage dips and it will come back once the voltage rises again after acceleration. Same goes for temp management.
Wouldn’t it be the RPM sweet spot where the motor accelerates a little on its own? But i do know I’m to heavy for a single because sometimes it doesn’t want to go any faster than around 15mph or climb a slight hill I think I hit the temp start cutoff.
That shouldn’t be so apparent as to knock you off the board. I really think it is a result of the various limiting functions within the vesc.
Batteries for sure. some of those laptop batteries probably only give 2-5A and starve your ESC of power.
I have those Zippy 4s 8Ah batteries - run them regularly on GF’s single motor Vanguard. Work great and get good mileage.
Mileage - best way to estimate is to figure out Watt Hours (Wh). Take your Voltage x Ah = Wh.
So your example Zippy cells - 4s (3.7v nominal = 14.8v) in series (x2) = 29.6v x 8Ah = 236.8Wh. You should roughly expect 1km per 10Wh. So approx 23.6km/14.6mi. On the flats - not racing, and not being a big rider. All those will decrease range, but it’s still a good estimate on paper when planning battery size.
1 Like
The problem was on my end in part because I was going to stand up and at the same time the boost kicked in. I’ve learned to always stay in tuck when using vesc and going fast.
Another thing that could be happening is the voltage will come back from sagging after accelerating and increase the top speed due to the relationship between kv and voltage.
Edit: More I think about this the more sure i am that this is what is happening. I distinctly remember looking down at my voltage display in a tuck and seeing my voltage rise and feeling the slight boost in top end.
I would be willing to guess that a pack with more voltage sag would result in a more apparent boost after leveling out at the top speed or cruising speed.
1 Like
I think that sounds about right two of my lipo packs aren’t in the greatest condition. I’m going to build a 18650 pack soon.
Is it possible that the vesc went over the set max erpm limit I set in bldc tool?
Multiply your kv by your nominal voltage and if you are under 8600rpm you should be fine. I like a little more buffer for the occasional dh session but it is only a real danger if you release the throttle and let the motor spin freely beyond the maximum voltage/rpm
The Zippy’s have a BMS already in each pack, right? So what charger do you use? What is your top speed?
I’m at a little under 190lbs and my build goals were 10-12 miles (check) and around 25mph top cruising speed (I calculate 24.94mph weighted-- check?).
I’m over the suggested limit. I have torqueboards motor that spins theoretically at 67k rpm at 12s which means 190-200kv? There is a bigger risk going downhill? I plan to get vesc v6 when it’s available
It can be problematic if you are not careful.
1 Like
Nope - no BMS. You need a regular Lipo charger. On a budget and want simple - i recommend a iMax B6ACv2 - has AC-DC Power supply inside for one plug simplicity. If you want ability to charge more than 5 Amps - and don’t mind some complexity (or can use for other RC hobbies) - check out the iCharger chargers (206b/306b). I have the 306b w/ dual dell server power supplies for 24v 1500w.
To charge multiple batteries - a simple parallel board. Helps to occasionally charge individually.
Speed is all in the gearing. Not having her board in front of me, i’m not positive of motor gear, but likely:
83mm wheels - 200kv motor - 8s - 14/36 = 21mph. She tops out at around 8mph realistically, but i do ride it every once in a while and it moves along fine w/ me on it (265lbs).
I usually gear for 25mph on my builds (single or dual motor). 8-10s usually and love running 97mm wheels for rough roads (or unattended small children). I gear as low as i can w/ the larger wheels and higher voltage on 190-200kv setups. Run some gear calculators and you should do fine. Don’t go below 13t on the motor on 9mm belts - it will skip. I might not go below 14t on a single, or go at least 12mm or 15mm wide belts.
GL!
So @sprocket12 did you get a new battery pack? I would concur and say this is your limitation. The peanut gallery is getting loud in here 
Oh yeah! I went with two Zippy 8000 mah 4s1p at 30c. I placed them together to make an 8s1p. Plenty of torque. Top speed around 27 mph and i get just under 12 real world miles!
Rebuilding now. We are at around 14" snow and in single digit temperature (F). So i needed something to do. 
@chaka @devin I keep my ERPM pretty low and my Real-world (and anecdotal) experience has been that if I approach or exceed that limit and apply throttle, I just continue to coast. I can hear VESC engaging but it never presents a “braking” effect if I’m beyond ERPM and apply more throttle. I forget which parameter it is in BLDC Tool, but I believe that this behavior is the default.
@treenutter Thats the parameter. When it is disabled then it simply shuts off the VESC. When it is enabled it brakes when it exceeds the MAX ERPM.
2 Likes