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View Full Version : I Want to make a Lithium Ion Battery Charger



Cory
06-22-2017, 8:08 AM
After pricing out a battery charger made specifically for lithium batteries I thought maybe I could save a pile of money and use a cordless drill battery charger. I found this Hitatchi 14.4V/18V charger on clearance for $ 15 bucks! I can't see why I can't Macgyver it to work. I just don't have the wiring know how to make it work.

I plugged this in and took a voltmeter and this is what I found out:
black to red 0 volts
black to white 3.3 volts
black to brown 5.0 volts
black to yellow 5.0 volts

So it looks like 13 volts total, which is right where I want to be. I don't know why the red wire has 0 volts?

I'm thinking if I twist the white, brown and yellow wires together that would give me 13 volts of charging? Am I correct in this thinking or am I missing something?

This is the battery I'm using and this is the spec sheet from the cordless battery charger
77531

77532

I'm not sure what these letters mean
77533

Sky
06-28-2017, 5:12 AM
Honestly dont know
Im guessing that charger is for a banked battery. Or at least banked differently.
Most likely a different capacity and or load rating...

maybe lookup internal diagrams, compare the drill batt with the bike batt and go from there