How much can a 1500w motor be overvolted?

[500w_Of_Power]

Hello everyone!

Awhile back, you wonderful people helped me build my first "real" ebike, a 1500w 48v machine. However, as you all were right, now I want more speed. I am wondering what your estimation of how many watts/volts this motor could take. I have heard about them taking 5000w, but I don't want to melt the motor. I am going to get a better rims/spokes and re spoke it because I have not had a really good experience with the Voilamart rims.

The motor is a "1500w" Voilamart standart from what you buy from the kit.

Thanks!

 

[fill]

#1 What speeds are you comfortably reaching atm.
#2 What speeds do you want to hit.

work out what percentage increase in speed your target is. lets call it X%

Start off by looking at an X% increase in Battery Voltage, it should get you close..
(if you hit 30mph but want 60 mph thats 100% increase so look at doubling voltage if voltage alone is tweaked..)

However priority #1 imho should be installing a reliable way to accurately monitor the motor temperature That way you can ensure any tests remain within 'safe' margins.

 

[500w_Of_Power]

Comfortably, I am reaching 33 on flat ground. I would like to hit at least 50.

 

[Chalo]

Power required to maintain a given speed rises with the cube of velocity. Remember that's not only power that you have to provide to get to that speed, but power in all those surface bumps as they punch you silly. So don't get too greedy for speed you can't use, or won't want to.

You'll need 3-1/2 times as much power to hold 50 mph as to hold 33mph. That's not necessarily 3.5X as much maximum power, but 3.5X as much at 50 mph as it takes to hold 33. In your case, it's probably 1500-2000W to go 33 mph vs 5000-7000W to go 50.

The easiest way to raise top speed is to increase battery voltage (using a different controller if necessary). But if you don't have enough amps/torque to support the implied resistance at your target speed, you won't get there.

I suggest messing with the Grin motor simulator to see what you're up against.

 

[E-HP]

Power necessary for 50 mph is around 4500W depending on seating position (wind resistance) and rolling resistance (fat tires take a lot more). So you need around 6kW from the battery, due to losses/efficiency. So the battery needs be capable of outputtng 80V and at least 70A, so a fully charged 72V battery could get you there.

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[neptronix]

Comfortably, I am reaching 33 on flat ground. I would like to hit at least 50.

On an upright bike, a 1500w rated motor will sustain 35-40mph and do 50mph for very short periods of time.

52v would take you into the mid / upper 30mph zone & this would be well suited to the motor's capabilities.
60v would get you up to ~40mph, which the motor would overheat after maybe 5-10 miles.

You probably need 72v or higher to hit your target speed. But this motor can do that speed for some minutes. You probably want a larger motor for that. 2.5-3kw rated is what's needed to sustain that speed for a good period of time.

You will also want a more powerful battery once you get into the higher voltages because the motor is going to need more amps.

 

[wturber]

If you do decide to push this motor you may want to put some Statorade in there as well as monitor the motor temp. The Statorade should give you a bit more time before you overheat.

 

[500w_Of_Power]

Man you guys are AWESOME! Thank you so much for all the information. I plan to make a 72v pack out of 6 R5 36v "Shorty" Packs on Jag 35. Probably cant push that lil' Voilamart 1.5kW to 50mph without drastic consequences.

Currently looking at a 3000w motor off Amazon with a matching controller to go with it. Still, I have to save again, probably wont get it built for another month, but currently selling my old hard tail MTB, and a nitro RC car, so that should give me just enough for the kit and batteries.