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?
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.