Welder to restore car batteries?

JOEPRO · 2026-03-14T16:41:11+0000

Had anyone tried this? That is, to connect an arc inverter welder at low amps (50.or less) to a failing car battery to bring it back.

I tried it briefly today on a 14% health 4 year old exide battery (had 2x of those fail - bad brand) and it dropped to 12% health after 5 mins. So I stopped. I have several other near dead car batteries I can try it on if people seem to have success with this?

Kram · 2026-03-14T17:02:30+0000

Waste of time in my opinion, not going to try it, but I do have several low health batteries that need to be scrapped.
I dont see that any brand is really different to any other.

Letting batteries sit in a discharged state will quickly ruin any of them. Appears that German cars like to kill batteries, is that how you get so many? :laughing:

BrokenBiker · 2026-03-14T17:06:19+0000

I used to run the final testing department of a worldwide battery manufacturer, in our local factory...

I can 100% assure you it's not worth a sniff to try and restore a dead battery.

roofman · 2026-03-14T17:46:08+0000

plenty of good tips on youtube to bring batterys back to the living, its all about removing the build up of nasty deposits on the lead plates and with good results too.

Kram · 2026-03-14T18:41:34+0000

Or you can weigh in several scrap ones and buy a new one, keep it in good health by charging occasionaly, ideally in a road worthy and frequently driven, non german car!