Car batt charger for electronics testing

[YY1]

Can I use an automotive battery charger as a 12v power source for testing/building electronics projects like car stereos?

I have three chargers, a 20 amp charger/starter, a 6/2 amp and a 2 amp "maintaner".

I have been using a model train transformer for several decades, but my most recent car stereo is 50w per channel, and it will barely power on.

Would I need to add a regulator for protection?
If so, can I use one from a car?

 

[Meep-Meep]

A car batt charger is basically a step down transformer with a full wave bridge (or I suppose a cheap one can be a half wave). I don't think they have any filtering caps inside so there will most likely be a lot of ripple and that will show up in the power line as noise. If you get the biggest electrolytic capacitor from Radio Shack (like 1500 mFd or more / 35-50V) you can just hook it up across the charger leads - paying attention to the capacitor polarity of course. Before hooking it up I would check the output with a volt meter to make sure you are in the 12-14 V range.

 

[YY1]

A filter cap is a good idea. I think I might even have a 1000uF laying around.

 

[Meep-Meep]

Unlike carburetors when it comes to filter caps bigger is usually better.