SpudFiles

Is it possible to use a battery charger as a DC transformer? I just replaced one, and I'm wondering if I could use the old one as a step-up transformer, instead of a step-down like it's designed.

Do you have any more specific information on the charger? By step up transformer do you mean an inverter? (low volt dc to 120v ac) Typically most battery chargers are a regulated ac power supply with a recifier at the outgoing to change to dc. Maybe with some modification this could be arranged but would be likely unreliable at best.

The charger is in two parts. There's the plug-in wall attachment that converts 120V AC to 12V DC 1.6A current. Then that unit plugs into the actual batter charger, that converts that current to 1.4V 4A DC. I'm interested in the DC-DC part. Can I use it backwards to step up voltage?

Probably not, the dc-dc part is likley a solid state voltage regulator similar to the lm317 ic chip. Some poking around on the web should yield plans for a step-up transformer and radio shack might have the parts. Good luck, let us know how it works out as I've never made a step-up transformer before! If ya don't mind, what's it for?

I've honestly no idea what most of the parts are. I think I see two capacitors, three diodes, an induction coil, and a transistor.

I was just thinking it might be an easy way to increase DC voltage and put more charge on a capacitor if I could adapt it. Cellular phone picture:

DC to DC converters do exist that converts from low voltage to a higher voltage. The charging circuit for a disposable camera flash is a good example.

A normal DC power supply for charging batteries can not be simply used backwards. It was never built to discharge a battery and feed the power back to the source.

Okay. Thanks for the info.

What tech said. The big problem is that the voltage step down function is an AC function. The stepped down AC is then rectified and smoothed to create the DC.

Going backwards wont work since the rectifier bridge can't convert DC back into AC.

DC-DC converters (like a photoflash board) are actually DC-AC-AC-DC converters. The DC-AC conversion is done via an oscillator since a rectifier bridge is a one way device.

Ahhhhhhh thanks, that helps a lot.