rcgldr Posted November 8, 2021 Share Posted November 8, 2021 What is the maximum safe power and current for the V8F? I’ve been keeping mine under 1300 watts and 15 amps, but someone mentioned they had peaks of 1500 watts and 21 amps with no beeps. Quote Link to comment Share on other sites More sharing options...
Chriull Posted November 8, 2021 Share Posted November 8, 2021 5 hours ago, rcgldr said: What is the maximum safe power and current for the V8F? I’ve been keeping mine under 1300 watts and 15 amps, but someone mentioned they had peaks of 1500 watts and 21 amps with no beeps. The maximum possible motor output power is available at half no load (lift cut off) speed. To both sides it decreases to 0 at stand still and no load speed in the form of a parabola. Your reported power value is power supplied by the battery, which also includes the losses (quite significant at lower speeds + higher burdens). So this value is very speed and battery charge state dependend. Not really usable. Quite similar for current - inmotion reports battery current, which does not really work for some sane warning. One could just find by trial and error/finetuning some limits for ones specific driving behaviour. Could be dangerous as driving behaviour changes can render the warning useless... Begode/Veteran report motor current, which is a nice measure for mosfet/wire burden. V11 reports since some later firmware update pmw duty cycle % (called safety margin in Euc World, ? In wheellog,darknessbot) which is a "real" value as safety warning. Don't know if the V8F got the same upgrade? Some apps estimate pwm duty % and/or currents? But i have no idea how accurate/usable this is. Quote Link to comment Share on other sites More sharing options...
rcgldr Posted November 8, 2021 Author Share Posted November 8, 2021 (edited) 52 minutes ago, Chriull said: The maximum possible motor output power is available at half no load (lift cut off) speed. To both sides it decreases to 0 at stand still and no load speed in the form of a parabola. Your reported power value is power supplied by the battery, which also includes the losses (quite significant at lower speeds + higher burdens). So this value is very speed and battery charge state dependent. Not really usable. Quite similar for current - inmotion reports battery current, which does not really work for some sane warning. ... pwm % For V8F, lift cut off speed is probably 50 kph. I got a peak of 49.6 kph on a 70% charged battery, by carefully tilting the V8F. However, the power and acceleration are limited by the firmware in a lift test, as it didn't take much effort to hold the V8F in place during a lift test. A parabolic power curve is typical for DC motors. V8F motor is stated as 1000 w nominal, 2000 w peak, but I don't know what the peak power of the battery is. However, the main concern is peak current. In this comparison video, the V8F cuts out on the second acceleration test, apparently due to a blown fuse (video only notes it would never turn on again), but I don't know what current fuse is used on the V8F. There were 2 beeps just before the cutout. https://www.youtube.com/watch?v=hAEOnvDNaYw&t=724s I've tested tilt back at 15, 20, and 25 kph, but don't want to try it at higher speeds, so I set tilt back to it's max setting of 35 kph, keep my actual peak speed below 30 kph, and only use moderate acceleration. Most of the time I'm running at 20 to 25 kph, a bit less than 20 kph for mild declines and inclines on a local paved bike path and around 15 kph or less for a 6 degree slope on a private street near my home. EUC World can display PWM %, but apparently the V8F doesn't report it. I weigh 86 kg, so I'm being cautious on the V8F. A rider will acclimate to speed and acceleration over time on any vehicle (I've got 225 miles on the V8F now), so I have EUC call out stats every 30 seconds to keep track of speed. Still, it would be nice to know if I'm unknowingly pushing the V8F close to some limit that doesn't trigger beeps. Edited November 8, 2021 by rcgldr Quote Link to comment Share on other sites More sharing options...
Chriull Posted November 8, 2021 Share Posted November 8, 2021 32 minutes ago, rcgldr said: For V8F, lift cut off speed is probably 50 kph. I got a peak of 49.6 kph on a 70% charged battery, by carefully tilting the V8F. Lift cut off speed is proportional to battery voltage - so at 100% with 84V one has higher lift cut off speed as at 70% with ~((4.2-3.3)*0.7+3.3)*2~79V 32 minutes ago, rcgldr said: However, the power and acceleration are limited by the firmware in a lift test, as it didn't take much effort to hold the V8F in place during a lift test. A parabolic power curve is typical for DC motors. V8F motor is stated as 1000 w nominal, 2000 w peak, but I don't know what the peak power of the battery is. Motor specified wattage is just a nummer. 32 minutes ago, rcgldr said: Still, it would be nice to know if I'm unknowingly pushing the V8F close to some limit that doesn't trigger beeps. Maybe a way could be to draw some speed over current diagram like in Correctly one would have to use motor current, but as only battery current is reported and at the limit (overlean, pwm duty cycle == 100%) both current values are the same, one could maybe see ones driving behaviour. From the limit lines only the point with the lift cut off speed is known ... Quote Link to comment Share on other sites More sharing options...
Kutvis Posted November 8, 2021 Share Posted November 8, 2021 (edited) 80kg dude. All time maximum speed against pedal tilt, constant beeping. Overpowering every now and then. As it was my 1st wheel I didn't know it is at all dangerous. Died walking it on yard, after hard ride. Luckily I was not riding it. Didn't realise to get any records of powers. Lasted me 130km. My next wheel was.. Inmotion V10F, same thing. On this one I had power pads. I recorded constant draw under 800W and peaking over 3000W. Died when I arrived to friends home, 250km. Edited November 9, 2021 by Kutvelo Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.