Thread: Batteries

Hi shack, seeing as you want to play with charging older batteries, if you have a lithium battery, anything of 50Ah or bigger, full charge the lithium battery then disconnect the charger.

Now get a set of jumper leads and connect the lithium battery in parallel ( + to + and - to - ) to any type of lead acid battery ( AGM or Wet Cell ) in any state of discharge and leave them like that for a week.

Before connecting the lithium battery, do a load test of the lead acid battery you are going to charge.

After the week, disconnect the lithium battery and load test the lead acid battery again.

You might be in for a big surprise.

Originally Posted by RANDLOVER

More power to you, but I thought desulfation would need a higher voltage as IIRC my battery puts out 16 volts in ''repair'' mode.

Hi RANDLOVER, 16v is fine for Wet Cell batteries but is a No-No for many AGMs.

Using a lithium battery connected in parallel supplies a constant 13.3v.

This constant voltage will desulphate the battery and charge it VERY SLOWLY.

This is good for any lead acid battery and does not harm the lithium battery.

I had this setup in my Tiguan for 2.5 years and it not only recovered a stuffed Lead Acid cranking battery but maintained it in a fully charged state.

After removing the lithium battery, the stuffed lead acid cranking battery lasted another 6 months before finally needing to be replaced.