over power a hub motor...

16 posts / 0 new
Last post
deacon
Offline
Last seen: 12 years 1 month ago
Joined: Thursday, March 19, 2009 - 05:12
Points: 55
over power a hub motor...

does anybody know for sure what would happen if I got a larger controller and put 36 volts into a 24 volt hub motor.

reikiman
reikiman's picture
Offline
Last seen: 1 week 1 day ago
Joined: Sunday, November 19, 2006 - 17:52
Points: 8447
Re: over power a hub motor...

Depends on the motor.

Usually motors can be overvolted to some degree. But there's a risk of burning out part of the motor. Especially if the voltage goes too high.

antiscab
Offline
Last seen: 2 days 6 hours ago
Joined: Saturday, July 7, 2007 - 23:55
Points: 1686
Re: over power a hub motor...

if its a brushed motor you are limited by what the commutator can do.

if its a brushless, and you use a digital controller, with a motor side continuous current limit the same as or below motor rating, you wont run into any heat problems.

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km

garygid
Offline
Last seen: 12 years 3 months ago
Joined: Friday, December 19, 2008 - 23:25
Points: 441
Re: over power a hub motor...

You could burn up the motor (quite possible), destroy the controller (maybe), start a fire (less likely), ...

But, you never know for sure until you try it. Can you get somebody to tape the event?

We all enjoy a good chuckle, and you might make enough on a "funny-video" show to buy components that actually are designed to work together.

Please be careful.

Cheers, Gary
XM-5000Li, wired for cell voltage measuring and logging.

dogman
dogman's picture
Offline
Last seen: 13 years 3 weeks ago
Joined: Tuesday, April 29, 2008 - 15:41
Points: 830
Re: over power a hub motor...

Depends on the motor. I killed a heinzmann 24v in a few minuites that way. What motor is it? Sometimes it is the same motor that can take 48v or more, but they just make it legal to ride in Australia or somewhere by giving it a weak 24 v controller. Sometimes a motor like that will have smaller wires to the hub that might melt if really overpowered, but not likely at 36v. I'd say if it is a regular direct drive hubmotor it should be doable. If it is a gearmotor, then you need to be more carefull about the amperage of the controller. When I melted my heinzmann, I was running it on a 36v 35 amp controller instead of a 24v 20 amp. So designed for 480 watts, I was only putting 1260 through it! heh heh. Anyway, my point is the gearmotors, using a smaller motor and gears to get the power to the wheel, can be less tolerant of ovevolting. Direct drive motors tend to be able to run at a wide range of voltages. many dd motors can run 48v with no problems at all.

Be the pack leader.
36 volt sla schwinn beach cruiser
36 volt lifepo4 mongoose mtb
24 volt sla + nicad EV Global

deacon
Offline
Last seen: 12 years 1 month ago
Joined: Thursday, March 19, 2009 - 05:12
Points: 55
Re: over power a hub motor...

The motor is from an e z glide hub motor kit brushless type.

I planned to swap out the controller for a 36bolt if I give this a try. I will take a look at the motor wires to determine their size.

I might not jack it up but I was curious to know if it could stand it. I guess one day when I am tired of the toy I will give it a try. thanks guys

deacon
Offline
Last seen: 12 years 1 month ago
Joined: Thursday, March 19, 2009 - 05:12
Points: 55
Re: over power a hub motor...

couple of more questions please... how can I tell if the motor is direct drive or geared. do they both look the same or is there an appearance difference.

Also where can I get a larger controller I had no idea that it would be so hard to find a source for just a controller.

ps buying stuff designed to work together takes all the fun out of it.

antiscab
Offline
Last seen: 2 days 6 hours ago
Joined: Saturday, July 7, 2007 - 23:55
Points: 1686
Re: over power a hub motor...

you can buy controllers from
www.kellycontroller.com

they also sell replacement hub motors (i think their biggest is 72v 6kw continuous).

running a motor at a higher voltage does allow you to push the motor to make considerably more peak power.
it also increases continuous power, by achieving the same torque at higher speed.

at higher speeds you do unfortunately need more force to overcome air resistance.
so you almost always need more motor side amps to increase top speed.
as long as you keep motor side amps below rated, you wont run into any thermal issues.

so a 48v 1500w motor becomes a 60v 1870w motor (at 1.25x the speed) or a 72v 2250w motor (at 1.5x the speed).
these are all continuous ratings.

if at 1.25x the speed, 1.25x the continuous motor rating isn't enough, then you will run into thermal problems.
so it depends how oversized your motor is to start with.

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km

dogman
dogman's picture
Offline
Last seen: 13 years 3 weeks ago
Joined: Tuesday, April 29, 2008 - 15:41
Points: 830
Re: over power a hub motor...

e z glide is a new one for me. There is an eezee motor that is geared, and can take up to 48v. Generally a geared motor makes a lot more noise than a direct drive. Direct drive hubs may grunt a bit at low speeds but once up to full speed are pretty much silent. If the motor is geared, then the requirements for controllers get a bit technical due to the faster rpm of gearmotors. Direct drive motors use a more swappable controller. Ebay has a lot of controller options. One way to take some of the sting out of matiching up the wires is to go with a sensorless controller, which won't need the hall sensors in your motor to work right. Hightekbikes.com and ebikes-ca are good sources for a 36v-48v sensorless controller.

Be the pack leader.
36 volt sla schwinn beach cruiser
36 volt lifepo4 mongoose mtb
24 volt sla + nicad EV Global

deacon
Offline
Last seen: 12 years 1 month ago
Joined: Thursday, March 19, 2009 - 05:12
Points: 55
Re: over power a hub motor...

As you can tell hub motors are all new to me. So forgive the elementary questions please. I'm pretty sure it is a direct drive motor by the way.

So here are novice questions. How many wires actually go to a front hub motor.

Most of the controllers on ebay are for scooters. I assume they are brush type controllers. They won't work on a brushless motor will they.

So if my controller now is for a 250 watt motor using a 24 volt battery pack. Does that mean it is a 10amp draw. So if I go to a 36 volt controller I still want a ten amp draw controller. which would make the motor running at 350 watts. Is that about right or have I totally mucked it up.

antiscab
Offline
Last seen: 2 days 6 hours ago
Joined: Saturday, July 7, 2007 - 23:55
Points: 1686
Re: over power a hub motor...

if its BLDC, then you will have 3 thick wires (one for each phase).
you may also have 6 thinner wires (two to power the hall sensors, 3 for the hall sensor output, and one for the thermsistor).

as long as you stay at 10A, you should be fine. you got that part correct :)

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km

deacon
Offline
Last seen: 12 years 1 month ago
Joined: Thursday, March 19, 2009 - 05:12
Points: 55
Re: over power a hub motor...

One more question. Do you think the controller I have now could handle a 25% increase in power with burning up. I thought I might toss in a low reserve 6volt battery into the mix if there was better than a 50 50 chance that it wouldn't blow the controller. I even toyed with the idea of a switch to add the 6 additional volts only when needed for the big daddy hills.

A simple a/b switch would work just fine for that.

antiscab
Offline
Last seen: 2 days 6 hours ago
Joined: Saturday, July 7, 2007 - 23:55
Points: 1686
Re: over power a hub motor...

im not familiar with your specific controller.
it depends what the Fets on the powerstage are rated to.
without pulling it apart, and reading the part number you wont know.
perhaps someone else can tell you the limit of your controller?

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km

dogman
dogman's picture
Offline
Last seen: 13 years 3 weeks ago
Joined: Tuesday, April 29, 2008 - 15:41
Points: 830
Re: over power a hub motor...

If the capacitors inside the controller, (they look like little cans) are rated high enough, it is very likely that the controller can take more voltage, at least for awhile anyway. A 24v sla battery pack will actually put out 28v when fully charged, so look for about 40v or more on the lables on the capacitors. If the capacitors say 50v or more on them, then the controller has a good chance of being ok for 36v, which is actually 44v at full charge.

Chances are very good that the motor can handle 36v at 500 watts just fine. Direct drive motors tend to be made work at a wide range of voltages, typically from 24v to 48v. Figuring out the wiring sequence with 7 wires all mixed up can be pretty hard to do, so overvolting the controller you have will be very tempting to do. If the motor is going on a bicycle, then a pedal first, or sensorless controller will be much easier to figure out the wiring for, since it will only have the three power wires.

Be the pack leader.
36 volt sla schwinn beach cruiser
36 volt lifepo4 mongoose mtb
24 volt sla + nicad EV Global

deacon
Offline
Last seen: 12 years 1 month ago
Joined: Thursday, March 19, 2009 - 05:12
Points: 55
Re: over power a hub motor...

I think I have decided to hit it with a 6volt increase to the battery pack sight unseen. I might put in the a/b switch so that the power is only at the higher voltage for a few minutes then again if it's going to burn up I can replace it with a stronger controller so why not give it a shot.

I think I will kick it around in my head a couple of days then order a 6volt battery. Between me giving it a couple of cool down days and the arrival of a battery, I will have plenty of time to change my mind.

By the way I want to thank all of you for the help. I have muddled thinking these days so I really do appreciate the help.

deacon
Offline
Last seen: 12 years 1 month ago
Joined: Thursday, March 19, 2009 - 05:12
Points: 55
Re: over power a hub motor...

So I did it. I added six volts to the battery pack. Before I hooked it to the controller I read the pack at 33.8 volts. I hooked it up and it worked with the wheel off the ground. I was cautiously optimistic. I put it on my test track and immediately noticed that the power seemed to come and go. Then I started up a hill and near the top it shut down.

I stopped to check for connections and heat on the controller or motor. Nothing was amiss, so I started on a long downhill run. It didn't seem to be going any faster and when I hit the backside of the hill, it didn't seem to pull any better. Then out of the blue it shut down.

I unplugged the battery pack and removed the extra six volts. I took off again to see if I had damaged anything. The bike ran perfect.

When I got home I checked the pack without the extra battery and it read 27volts. The 6volt battery read 6.1 volt.

so there was either a bad connection or some kind of overload protector in the controller. I'm thinking that the extra voltage ran the amp pull over the max when it hit the hills. The controller shut down rather than self destruct. I have no idea if this is true, but I'm not going to try that again.

I will either get a stronger controller or get myself in better shape. Getting in better shape seems the safest plan of action.

Log in or register to post comments


Who's online

There are currently 0 users online.

Who's new

  • Nikson420
  • mhufnagl
  • Jamesato
  • VectrixPTLx
  • Schnabelwesen

Support V is for Voltage