Make your own Variable eBike Battery Charger!


New member
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9:17 PM
Jun 21, 2018
I managed to make my own variable eBike battery charger using a Boost Voltage Converter:

boost voltage controller.jpg

I am powering it with a 19.5V 13A laptop power supply to create a electric bike charger. It can charge any battery from 20V to 100V. This thing is not capable of outputs smaller than the input so if you want less output voltage at higher amps you must input less voltage. It works wonderfully as a bike charger but you must set the voltage and current every time you want to charge a different battery. With all that said, this setup is hundreds of dollars more economical than buying an adjustable electric bike charger. Do your homework and understand basic Ohms law before setting it up and you will be a happy person.

boost voltage controller ebike charger.jpg

This converter does retain settings when power is turned off. I left it disconnected for an entire week, and it went back to the last settings when i plugged it back in. Also it does not get hot at all when charging my 20Ah eBike battery to 58V at 3 Amps.

And here's the Digital Display I'm using to show the charge Voltage & Current. It makes it much easier to dial in the Boost Voltage Converter since there are no digital readouts on the unit.

voltage amperage digital display.jpg
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Thanks for the idea - hopefully it doesn't catch on fire although it sounds like you know what you are doing! Just keep it away from anything flammable when charging.
Pretty sure I’d want it in a vented box. I’ve seen some thing similar that uses a pc power supply.
Love to hear alot more about this idea and get some details.