Worksman Pav-3

[woodyvt]

I just got a used Worksman Cycles PAV-3 for $100 off craigslist. The charger is junk from being left out in the weather but have ordered a replacement.
It has an AOTEMA hub-motor that I was told by Worksman Cycles is 36v @ 600 watts. It's not a very powerful motor and can barely get up any grade. Also, it's on a small 20 inch rim so speed is also pretty poor.
Questions: Can I over-volt this motor to 48 volts? If so, do I need to replace the whole controller or can it be modded?

I'd like to just replace the old motor but the way the bike is designed/geometry, installing anything larger than a 20 inch wheel/hubmotor will make the frame unlevel and make it unstable in turns... the bike geometry is very odd to begin with and the steering is obnoxious. http://worksmancycles.com/shopsite_sc/store/html/pav3.html

Any thoughts on increasing speed and power on this trike?
If I can't get it configured to have more power and speed, I'm just going to sell it on Ebay.

 

[amberwolf]

The Aotema if it's a brushed motor will likely run a lot hotter at the higher voltage, and would probably fail earlier, especially at high loads on hills and such.

If it's brushless it will probably work ok at the higher voltage, but it will run hotter if it is running at slower speeds while still pushing the throttle to the max. Most brushless hubs seem to work well enough at much higher voltages than they are "rated" at.


However: A danger exists (at least with geared hub motors because of their poor thermal path) that the motor's inefficiency at lower speeds will create heat faster than it can dissipate, even though it's only at partial throttle with not a lot of load, cruisng on the flats at lower than normal speeds. This has happened at least twice on my Fusin, at much less than half of full speed--once under a heavy load and once not only without such a load, but also with me pedalling. This only happened after using it with the lithium 48V packs capable of handling higher power levels, and not with the lower power NiMH packs either 48V or 36V.

If it is a geared hub, the heat can be helped by filling it partially with oil or ATF; there are at least a couple of current ongoing threads about this.

 

[wesnewell]

http://goldenmotor.com/ makes spokeless hub motors from 16-20" that would be perfect for this imo.

 

[dogman dan]

I'm going to take a wild guess that that motor is the lousy brushed model. The indicator would be only two wires into the hub. If it's three wires, or more, that's the brushless. Either one should tolerate 48v no problem. If it doesn't, you arent out much cash. Grab a cheap front wheel, and sell it off as a pedaler.

Faster motors can be bought for sure. Grin cyclery has 20" hubs in the right windings to go above 20 mph. But my experience with a schwinn delta trike is that above 15 mph things get pretty sketchy. Steering around obstacles gets harder and harder the faster you go. By 20 mph it's all but impossible to jink around a broken bottle or pothole.

I'd have to say, if fast is what you want, you are on the wrong path. Recumbent tadpole trikes are another story. They haul ass very nice.

 

[woodyvt]

Sold the trike. Not enough power for me. Didn't do too bad on it. Bought for $100, three batteries I had @ $20 each and a battery charger @ $30 = $160. Sold on Craigslist for $600 plus $50 for gas to deliver to a guy 20 miles from where I bought it. Not a bad profit for the weekend.

Thank you all for your thoughts and advice.

Give it some juice!