Running a Powabyke Mk1 on 48V

[ace_bridger]

A few months ago I fitted a Powabyke Mk1 wheel to my mountain bike and recieved some great help here from many people as I stumbled through the initial install.

Since then I have used it daily and love it....but, of course, my mind drifts to more power and speed (for my 'off-road' exploits!). It's a heavy beast so I'm likely to transfer the kit to a donor full suspension moutain bike when I find a suitable one.

Does anyone know whether the 36v Mk1 motor would take 48v? I can get it on the bench at work and gradually wind it up from 36v towards 48v but if anyone has any experience of increasing voltage on any bike then I'd welcome your experience and expertise!!

Love me, love my Frankenbike!!!

 

[oigoi]

I have some experience of over volting motors but not on an e-bike. Its hard to say as it really depends how robustly the motor was made and how much it is over engineered. I used a 12v motor once in an electric scooter and ran it on 24v to get more speed out of it and that worked fine.

If it is going to ruin the motor it would most likely be if you used full throttle on 48v going up a hill, the increased power usage would quite possibly overheat it.

You could try it and see how hot the motor gets - if the motor shows no signs of overheating you could be okay

 

[ace_bridger]

Hi there, thanks for the response.

I'm inclined to just try it as I have a few spae batteries from building the original pack.

It's running with a 36V controller from eBay, Chinese, and I wonder how much more voltage that than take too. I think I'll do one of two things...a) take the wheel off and take it to work and use a pwer supply to increase V over 36v and see or b) just plug it in to 48v and see what I have left afterwards!!

Any other experiences would be welcomed.

 

[Deleted member 4366]

You can apply as many volts you want to the motor. The only thing that happens with more volts is that it goes faster and gets hotter. Most 36v motors can easily do 48v - probably 72v is the limit before it starts smoking, but only under load. If you add extra cooling fins or water cooling, you can go a lot higher. Hall sensors don't like to get to hot so run sensor-less if you can. It's the controllers that have a maximum, and the limit usually depends on the ratings of the big capacitors that are inside the controller, so you only have to open it up and have a look on them. The max. volts is written on them. They are easy to replace with higher rated ones that you can get from Maplin, Farnell or RS, or maybe you can nick some out of your plasma TV or wherever, as they should be rated above 250v. If you go over the max. volts, they tend to go with a nice bang as the outer casing bursts off. Don't stand too close if you want to watch one explode -they go like bullets.

 

[theskip1]

i have run a powabike on 48v for approx 6 months as i had to cart my tools to work. worked fine until eventually, because of the motor running hot most of the time, the solder joints inside the motor dried out and parted.but I'm sure if you wish to keep stripping the wheel down and re soldering these joints it could last indefinitely

 

[ace_bridger]

d8veh: that's all good info, I'll do some investigation regarding the capacitors and if they look like they're rated below 48v I'll swap the controller for a 48V one but I bet they'll be fine. I stripped down the wheel when I first got it and took off the hall sensors and drum brake to fit it between my drop-outs so there are no hall sensors on there.

My commute is embarrassingly short, I built the bike to do a 12 mile commute but then changed jobs and it's now more like 1 mile (!), so I think I stand a good chance of keeping the motor cool. SOme trials are in order.

The skip1: that's really good info and gives me much more confidence to try it on 48V. What difference did it make on your bike? I imagine a higher top speed but was acceleration improved? Regarding the solder joints if they lasted 6 months then that's good enough for me. I work in aerospace engineering and have access to high temp solders so could always use these if my joints dry out. Also, I haven't stripped my wheel down yet and am looking for an excuse!!

Did you use the existing leads and wiring or uprate them? More volts means lower current for a given power but...if the motor is moving the bike at a higher speed then it is generating more power and hence drawing more current? Umm. My motor cable is actually 4 wire with 2 used in parallel for +ve and two for -ve.

Thanks for the responses and the great info and enjoy the rest of the weekend.

 

[NRG]

Checking the capacitor voltage alone may not be sufficient, you should also check the voltage rating of the FETs as well. The VDss of many FETs can be around 55v and a fully charged nominal 48v battery will exceed this.

Also, depending on the controller, the 5v / 3.3v power for the logic circuit may be supplied from a linear regulator and upping the controller voltage will exceed its input to output voltage rating.

Keywin (E-Crazyman on Ebay) can now supply 'universal voltage' controllers I understand so maybe you would be better off getting a new one anyhow.

 

[theskip1]

yes much more accelaration and speed around 25mph but you must remember to uprate your fuse ,I used a 40amp which worked ok. dont be tempted to give it a handfull of throttle or you will need to replace the fuse every time you pull away.after I resoldered the terminals once I never needed the extra power again so did not bother to fit the extra battery. also the powabyke hub motor is not the easiest motor to work on so resoldering can be a bit time consuming

 

[ace_bridger]

Thank you for the info and advice and I'll do some investigations and check the MOSFET supply voltage et al.

If I run a 40A fuse I'll be very careful to check the rest of the wiring to ensure that that will all be happy carrying 40A too....or fire may result!! I might have to up-rate the battery cables and associated wiring.

But nothing ventured and all that!!

Thanks again for the input...since getting the Mk1 wheel it was clear that it is running well below it's maximum so perhaps I can get it running somewhere towrad sth etop end. Fun, fun, fun!!