Does anyone know how to use an electric motor to charge a DC battery? I read on ehow.com that all you need to do is find a way to spin the shaft and it produces electricity that will charge the battery? Is that true, is it that simple?
Here is why I ask the question. I am building an electric bike from random parts and I have 2 permanent magnet motors. So I was thinking if I were to hook up the second motor as part of the gear system I could use it as a trickle charger. Does that make sence? It would be spinning around 900 rpm would that be fast enough to do anything?
Im not planning on using charging the battery solely with the generator. Im thinking that since I have the extra motor and the space I could probably use it to be a trickel charger. Not as the permanent charging device but just to extend the battery life while riding.
I don't know what a "trickle charge" is, but however much extra you will charge the battery, that's at least how much extra the battery will drain in order to charge itself.
Runnign this proposed process:
Battery chemical energy > electrical energy > mechanical energy > electrical energy > battery chemical energy
is clearly not as efficient as just leaving the battery chemical energy alone.
I used to ride a bike with, for its time, the standard dynamo friction-driven against the side of the rear tyre. 6vac 1.2amp it was rated, and on callow fingers would give a fair tickle.But let me tell you, there's nothing that sucks more than trying to ride a bike that has a generator attached. It is hard work. The bike will not coast; it will slow to a stop rapidly unless you work to keep it moving - and that's tiring.
The Dynohub was a bit better than that. Not much friction loss - pretty well perfect for a cycle lamp. There days, they could be a lot better, with the posh magnets that are available. You would need to find a way of making it into a motor but the gearing (1:1) would make it pretty unsuitable.
I disagree. Each time it is brought up in this thread, it is not mentioned that they mean regenerative braking only. It certainly seems that the posters are hoping to literally recharge the battery while using it to power the bike.Nobody is talking about perpetual motion. This technique is standard in electric and in hybrid cars.
You know, after reading so many instances of people wanting to do this type of thing (OP), I think there should be some sort of mandatory science experiment that all students are required to do before they even let them out of elementary school.
Something like cranking a hand generator for 3 minutes at no load and then repeating it with a 12 watt light globe connected and describing the differences encountered.