Electric Bikes - quick wiring question

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toasterburn
05-15-09, 08:26 PM
I'm bought a broken scooter from the thrift store, and I took it apart, rebuilt and rewired it.

I have it working now, but I need to be able to charge the batteries. Right now I have the batteries wired straight to the motor with an on/off switch on the handlebars. Where in the circuit do I wire the charger port? The one I have has two wires coming out of it. Do I wire it in series?

I also want to build a simple circuit to let me know when the batteries are charging and when they're full. Any ideas?

Thanks in advance for your help.

donob08
05-16-09, 08:46 AM
Toaster

The charger goes right across the battery (get polarity right). I've attached a crude schematic.

Be sure swith is off so that you aren't 'charging the motor. Usually the charger has LED's Red => Charging Green => Fully charged.

Don
toasterburn
05-16-09, 12:25 PM
thanks, that's just what I needed.

wernmax
05-16-09, 11:12 PM
Simple 4 Led visual voltage level for 12V battery from Radio Shack's "Getting Started in Electronics".

Nowadays you can usually get a digital volt meter for less than $5 so it's hardly worth the trouble of building this unless maybe you want it incorporated permanently into the bike as a voltage level indicator.

Lower 2 LED's could be red, 3rd yellow, 4th green, for full charge. You would have to calibrate it with a voltmeter to set off LED's at proper voltage points. Haven't checked lately but Digikey probably has this as a single "all-in-one" chip now.