How to make a 24v source power a 96v motor.

I made a thread in the Introduction section but was told to come here for better info! Here's a copy/paste of the thread:

I just bought a new car and am moving to Norfolk Virginia in a few months to attend Old Dominion University. I don't want to drive my car too much around this terrible place due to me terrified of people dinging, scratching, etc. my car. Also don't want to skateboard or anything that requires me to sweat. So I want to make an electric bike, also kinda want to do it just for fun.

I will be picking up a mountain bike from my uncle in about a week, so no bike as of yet, but I do have some other things.

I have 2 x 12v 145ah batteries and a treadmill electric motor - peak 2.25hp, 1.3hp continuous @ 95V 18amps.

Now clearly you see the issue haha, I'm having trouble finding a GOOD way to convert the 24v to 95/96v for the motor.

Any suggestions? Also, will this treadmill motor work?

If I'm not relaying enough info for a solution etc, please tell me, I'm very new to electronics of this kind.

Thanks in advance!

Well, let's see. I'm no authority on this, but I have a thought or two.

That treadmill motor is probably designed to work with alternating current. I think it's not likely to work on direct current. (by the way, I wonder why it's not rated at 110 volts?)
But this is just guesswork and might be nonsense.

A 145 amp-hour battery would have to be about as big as a small beer cooler and weigh 50 lbs or so. Maybe you meant 14 1/2 amp-hr? that would make sense.

All you'd need is 8 of those, wired in series, and you'd have 96 volts. But that would be a lot of weight.

You might be better off clicking on some of the vendors here and finding a 24 volt hub motor. If you didn't buy batteries (since you have your own), then you'd get it pretty inexpensive.

good luck.

bluegoatwoods said:

Well, let's see. I'm no authority on this, but I have a thought or two.

That treadmill motor is probably designed to work with alternating current. I think it's not likely to work on direct current. (by the way, I wonder why it's not rated at 110 volts?)
But this is just guesswork and might be nonsense.

A 145 amp-hour battery would have to be about as big as a small beer cooler and weigh 50 lbs or so. Maybe you meant 14 1/2 amp-hr? that would make sense.

All you'd need is 8 of those, wired in series, and you'd have 96 volts. But that would be a lot of weight.

You might be better off clicking on some of the vendors here and finding a 24 volt hub motor. If you didn't buy batteries (since you have your own), then you'd get it pretty inexpensive.

good luck.

Click to expand...

I used my camera phone, which is the worst camera ever haha.

But I'm pretty sure my info is right :/

Pictures are too fuzzy to make out. Take the stuff outside and take a pics in the daylight.

Still, on the motor I think I read "DC motor" on the label.

But you'd still need an awful lot of batteries. And you'll likely need some sort of gear reduction.

That's not to say that it can't be done. But I have a feeling that it won't be done quick or cheap.

I'm not worried about gearing, I just need the batteries to juice the motor enough to make me go haha. I dunno how to make a converter to quadruple voltage.

No, I don't think there's any "converter" that'll do that for you.

I'm pretty sure that your only choice on that is to hook up 8 12v batteries in series.

You already have two. So you need six more. Figure on about $250.00 for those.

Then you gotta figure out how to mount them on your bike.

And I might as well not even go on with that. This just isn't a very workable option.



I wonder if merely applying your 24 volts to the 95 volt motor would work for you. It might not be the most efficient use of that particular motor. But if it moved your bike, then that wouldn't matter. It might be worth a try.

I say sell the motor and use the proceeds to buy (like bluegoatwoods said) a 24v hub motor. Even if you could get a dc-dc converter, it would just add weight and complexity.

Could use a step-up transformer, Might be difficult to find the exact input and output voltage though. Plus transformers are kinda huge battery drainers. Unless you know of someone who is able to make them. Of course this will add more complexity and weight as mentioned before. Then there's the problem of some sort of controller. I don't know of any 96v controllers out there. The last i checked 48v was the highest i saw. Could be more available but i don't know for sure. Anyway it is a much better option to purchase an electric kit. Hub motor seems to be the best way to go(as bluegoatwoods said). Put it on, hook up some wires and battery, turn on the power, twist the throttle, and go.

Well shucks. I just got the bike I'll be using today, it's a typical mongoose mountain bike, but it does have some nifty places to hook up a rack behind the seat, which makes things a tad easier

I also plan on relocating the rear brakes to where the kick-stand is.

I also am not really interesting buying a kit, I want to make this, hence the whole reason for doing it.

I'm thinking with your inputs I'm gonna start searching for a 1500watt+ 24v motor.