Can I charge a 12v battery using a 19v laptop charger?

[Electricwhizkid]

I have a 12v 7Ah battery and I was wondering if I could use a 19v laptop charger to charge it? Is that too much voltage? It'll only be for overnight because the vehicle doesn't have a charging system.

 

[mrmike_49]

it would most likely burn up the charger

 

[Electricwhizkid]

That's what I was thinking, but I found a 12v 3A adapter that went to an old cable box and it seems to be working. The block is kinda getting warm is that normal?

 

[mrmike_49]

warm, normal, hot = bad. If it gets too hot to hold in your hand, unplug it! Or if you smell smoke

 

[Electricwhizkid]

As of right now it's warm but too hot. You think it will be ok if I leave it plugged up all night?

 

[mrmike_49]

I really wouldn't leave it plugged in while asleep - just a little too risky. Charge it tomorrow while you're awake to keep an eye on it

 

[Electricwhizkid]

Ok, but I really need it in the morning. How long will it take to charge? I plugged it in to a GFCI plug, would it trip If the adapter burns up?

 

[mrmike_49]

time to charge = total charge needed by battery/3Amps per hour

GFCI "might" trip if charger catches on fire, likely would "eventually", but why risk an unmonitored charge until you know it will safely work at least once?

 

[Electricwhizkid]

Ok, I didn't leave it plugged up all night, but I did plugged it in during the day and it didn't get too hot and it charged the battery. I think I'll just buy a onboard charger from the parts store and just use it