Is there any point in Over Volting a mid-drive motor?

Running a 36v hub motor with a 48v battery is a proven way to increase top speed (subject of course to legal restrictions, controller limitations etc).

With a 36v mid-drive motor wound to be at peak efficiency at (say) 100rpm, what benefits does running with a 48v battery give? Presumably max speed of the crank potentially goes up by up to 33%. My legs don't like to spin at 133rpm!

I understand that for the same power, you will be using a lower current which potentially has benefits if you are close to the design limit for current with a 36v battery.

But are there any benefits if using a high quality large capacity 36V battery which is capable of supplying all the power you need as a rider?

But are there any benefits if using a high quality large capacity 36V battery which is capable of supplying all the power you need as a rider?

Think you pretty much answered the questions yourself.

Overvolting, say a Bafang, would require a new controller. Plus, there could be heat issues, affecting reliability.

Best way to get the maximum performance out of a crank drive, is to use a high continuous C rating battery pack. Samsung 30Q's are a good choice. Then make sure your chainring and cogset ratios are suitable for the type of riding you do.

Edited February 13, 20179 yr by Fordulike

Think you pretty much answered the questions yourself.

 

Overvolting, say a Bafang, would require a new controller. Plus, there could be heat issues, affecting reliability.

 

Best way to get the maximum performance out of a crank drive, is to use a high continuous C rating battery pack. Samsung 30Q's are a good choice. Then make sure your chainring and cogset ratios are suitable for the type of riding you do.

Thanks - just wanted to make sure I wasn't missing something.

Just need to save a few pennies now to get a 30Q pack from Eclipsebikes (they seem to be well regarded and not outrageously priced).

Thanks - just wanted to make sure I wasn't missing something.

 

Just need to save a few pennies now to get a 30Q pack from Eclipsebikes (they seem to be well regarded and not outrageously priced).

Yep, got a 30Q planned for the end of the month from Eclipse myself.

Edited February 13, 20179 yr by Fordulike

I second gearing and a battery capable of 20 Amps continuous "without" sag (mine sags 0.6 V on highest assist, about 0.1 V or less otherwise). You have a 104 BCD spider so you can play around with various chainwheels to find the one that is right for your riding style and terrain. Spinning faster with the small 32 tooth chainwheel and in a higher gear the other day actually got me up my local hill at 23 km/h instead of the usual 19 km/h with the 42 tooth. So even after 1000 km on the GSM I am still learning the ropes with a mid-drive.

That said I am looking at a 44.4 V battery but mostly for the commodity of having identical LiPo packs. That is a 23% increase in speed.