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Charger efficiency

2355 Views 3 Replies 2 Participants Last post by  Coley
Can anyone tell me if some chargers are just a lot more effecient than others?

I was using a 36v/1.5amp cheapo charger to charge my electric cycle. I usually measured about .5 kilowatts to charge up.

A couple days ago, I added another battery to convert to a 48volt system. I rigged it up so that 3 batteries charged with the 36v charger and the other battery charged from a 12v 6amp charger I had around.

Now when I measure the power usage to charge all four batteries, I get about 1.25 to 1.5 kilowatts!!!

How does adding one battery double or triple the amound of power to charge?

All I can figure is that the plain 12V charger is just not as efficient as the little 36v one.

Does voltage or amperage effect efficiency?

I am planning on getting a 48V charger when I can afford it. "Battery Tender" makes both a 48V single output, and a 12v/4 output model that I think might work well.
I am looking for some sort of a 8 to 10 amp on-board, 48V charger. Any recommendations?

Also, I just put together a web page for my cycle.
Please take a look at:

This is the first time I have done anything "webby", so pardon the poor design and broken links. But really, please take a look and leave a comment.


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Discussion Starter · #3 ·
I found a 12V 1.5 amp charger around that I wired up in series with my 36v 1.5 amp charger. I tested it and it looks like it should charge a 48V system fine.

I think this 12V charger may be a little more efficient than the other one I had been using, but I can't tell because my Kilawatt got wrecked! With all the rain we have had in the Midwest, water ran under may garage floor and flooded the Kilawatt, which was laying there measuring the electric motorcycle charge.

Never thought about it before, but it's time to get a GFI in my garage!

Anyhoo, this does seem like a more economical solution that shelling out $200 for a 48V charger.

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