Charge a 12v battery with a laptop charger

Jul 27, 2018
I have a laptop charger that supplies 19v. Can I charge a 12v battery if I lower the laptop charger voltage to 14.5 volts using potentiometer?
Not really, I presume you are talking about a car battery? The charger PSU will not be outputting enough current (amps) Even if it does work without over heating, it would take a long time to fully charge it.
Jul 27, 2018

What can i do to use it? Thanks?

i also have a 12v 4 amp psu. would it be better to use it?


Jan 27, 2006
A lead-acid battery actually requires at least 13.2V to charge, and an "intelligent" charger may use up to 14.5V during some parts of the charging cycle. The laptop charger is a bad idea not just because it will be very slow, but because it doesn't know when to stop charging, which will damage the battery. The PSU probably doesn't output enough voltage to charge, regardless of the current.
Jul 27, 2018

I really need to charge a 12v car battery urgently. Is there a temporary way to do it without buying a charger? Thanks :)



A set of jumper cables and a running vehicle would do it.
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