Trickle charging

azureblue · Post by **azureblue** » 24 Apr 2021, 10:26

Check to be certain - a friend with a P2 is back in town after 6 months gone - his battery is near dead. I have a smart trickle charger - is it safe to charge the battery while it is still hooked up, from the under hood terminal?

Post by **RickHaleParker** » 24 Apr 2021, 16:04

It is safe to charge with the battery hooked up but it would charge faster if the battery unhooked from the car. If it is flat dead it might take weeks to bring the battery back to life longer if you leave it hooked up to the car. It will also charge faster if you do the charging inside where it is warmer.

azureblue · Post by **azureblue** » 24 Apr 2021, 16:10

Thanks - I was going to loan him my charger, so I want to make sure he does it right...

Post by **abscate** » 24 Apr 2021, 18:46

If it sat for six months it’s likely the battery is dead beyond recovery. You need a fancier charger with the modulated voltage to revive a sulfated battery

Post by **RickHaleParker** » 24 Apr 2021, 18:56

abscate wrote: ↑24 Apr 2021, 18:46 If it sat for six months it’s likely the battery is dead beyond recovery. You need a fancier charger with the modulated voltage to revive a sulfated battery

He has a smart trickle charger. A smart trickle charger with a pulse mode is what I used to recover that Volvo junkyard battery from 150 mv.

Let him play god, bring the dead back to life.

Post by **jonesg** » 25 Apr 2021, 02:27

I'd jump start, then just go drive it.