i have a electric bike because of a bad knee. trouble is soon the four 12v batteries life will be spent. i would like to convert to a heavy duty 12v car battery which i could also charge with my 80watt bp solar panel. i couldnt get any specs on the motor in the rear hub. what do i need? help much appreciated.-if it is a convertor of 12v to 48 were would i get that and from who could i get advise.
2007-03-05 01:49:51 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Engineering
Chances are that suitable 12v motors are not available for the application today. Otherwise the bike maker would have chosen it. However, you never know.
The motor should have its power consumption displayed somewhere. That may be expressed in watts (like micro-wave), and/or current requirement in amperes (amps). Usually the current displayed is the steady state current. Startup current is usually much heavier. That is a start, how much power the motor needs to put out.
The second thing you need to know is the torque the motor generates. This is not necessarily displayed. The motor must overcome the inertial leverage of the large diameter of the wheels. This basically dictates the torque requirement. Of course if you find a replacement whose torque is a little low, it simply will accelerate slower, or you can help it with some pedalling. But you do want enough torque so that on level ground, it can at least keep pushing the bike along. If you can find the manufacturer of the motor, it is a way to track down the specs including the torque. With luck, the company has a website from which you may be able to pin down the motor specs.
Conversion of 12v DC to 48v DC with the likely current load you need for the motor is probably not too practical. The power requirement is likely to be too high for today's components. You will also lose a fair amount of power in the conversion. That is why I am assuming a motor replacement.
Good luck & have fun.
2007-03-05 02:11:05 · answer #1 · answered by kyq 2 · 1⤊ 0⤋
You have 4, 12 volt battery's, and you want to convert to (4) "heavy duty" car battery's, which also happen to be 12 V. Go ahead and make room and swap out the batteries. The difference between the batteries you have and the car batteries is that the car batteries can hold a charge longer (more Amp hours). You may want to research 48 V battery's which have the capacity(amp-hours) you are looking for instead of having 4 12V car batteries.
2007-03-05 02:02:38 · answer #2 · answered by BRUZER 4 · 0⤊ 0⤋
I'd suggest that you simply improve the four 12v batteries as they are. If you wish to charge them from a 12v source, you can connect them in parallel while they're being charged and in series while they're in the bike.
A 12v to 48v converter is presumably available, but although converter technologies have been greatly improved over the years anything that's capable of driving your bike is unlikely to be small or cheap or thoroughly efficient.
2007-03-05 02:04:00 · answer #3 · answered by 2n2222 6 · 0⤊ 0⤋
Why don't you attatch a permanent magnet alternator to your rim or motor and charge up your batteries that way. Your batteries will eventually run down, but they will last a lot longer and you don't have to worry about using bigger, heavier batteries. It will be as though you are using have the power from the battery.
2007-03-05 04:18:25 · answer #4 · answered by Anonymous · 0⤊ 0⤋