Author Options:

Do i need to regulate the amps when wiring something into my car accessories plug? Answered

Hello! Excuse my ignorance if this is obvious, just like to be sure (and hopefully learn something!)

I have a universal battery charger that came with an adapter to use it with car accessory plugs. That was lost long ago... I thought i would try to make a new one. I have soldered a plug that fits into the car ciggarete lighter on one end of wire, and a plug that fits into the universal battery charger on the other end. But now i wanted to make sure i don't blow up my battery charger by trying to use it :)

The bottom of the battery charger says "input:   DC 12V    1 Amp". The real question is, how do i control how much amperage is going into the circuit? Or will the universal battery charger just 'pull' as many amps as it needs?

I put my multi metre in the end of the cable for the universal battery charger that plugs into the wall, and it read 2.3 amps or so. When i pocked it in the ends of the cord i wired for the car, it was reading around 9.5. Don't know if i'm doing that right any way, all help an knowledge appreciated.

Thank you in advance!


The forums are retiring in 2021 and are now closed for new topics and comments.

9 years ago

To measure amps you have to put your amp meter in series with the socket. Your amp meter must be capable of carrying that amount of power though or you put a resistor in series and measure the current across that. I wouldn't bother measuring either.

If the charger is working properly it will only draw the amount of power it is supposed to.

but since you lost the original plug, you MUST check that there is a fuse built into the unit.  Very often the fuse is built into the adaper socket that you have lost.  If the unit has no fuse and should fail for some reason, your car could catch on fire.  The last fire I went as a volunteer fireman was caused by an aftermarket radio installed without a fuse.  Funny thing was it was installed by an electrician who should have known better.

So find that fuse.

The Skinnerz
The Skinnerz

9 years ago

Where did you solder on the 12V plug?

If you put it on in place of a normal 120/230V wall plug, it will not work, and will pull a high current. If it has replaced mains plug with a built in transformer, it will be fine, as long as it is wired the right way round.

Seeing as the currents you measured are significantly above the 1A rating, it is likely that there is an issue.

Does the charger still work with the new 12V plug on it?

What did you put the 12V plug in place of?