Revive a dead Nimh battery

[wibblywobbly]

I had a battery that was down to 1.5v and the charger refused to acknowledge that it was connected. The current in the battery was so low that it would not charge.

A quick look on the web and I found this solution.

Get a fully charged battery and connect the + to the + on the dead battery, connect the - to the -.
Hold the wires in place for 30 seconds.
Job done.

How does this work? Inside the battery a chemical reaction takes place over time that causes a build up and creates a short circuit that prevents the battery charging. By shorting out the battery this way it causes a heat build up that melts the chemical residue, and allows the battery to take a charge again.

Just saved a £20 battery in 30 seconds. I love the internet!

[tomhugill]

Really good to know thanks Rob! I've got a few that would benefit from this.

[wibblywobbly]

It deffo works, the dead battery charged right back up to 8.9v.

[43rdRecceReg]

I had a battery that was down to 1.5v and the charger refused to acknowledge that it was connected. The current in the battery was so low that it would not charge.

A quick look on the web and I found this solution.

Get a fully charged battery and connect the + to the + on the dead battery, connect the - to the -.
Hold the wires in place for 30 seconds.
Job done.

How does this work? Inside the battery a chemical reaction takes place over time that causes a build up and creates a short circuit that prevents the battery charging. By shorting out the battery this way it causes a heat build up that melts the chemical residue, and allows the battery to take a charge again.

Just saved a £20 battery in 30 seconds. I love the internet!

I saw a charger once that claimed it could even re-charge alkaline batteries (by up to 90%), without causing an explosion, or burning your house down. That's a sort of Lazarus charger I didn't buy it, but I have a Swedish charger that can recondition buggered car batteries, and I believe it uses a similar principle to the one you've described. As I didn't want to reduce the house to a smoking ruin with the alkaline/ Lithium charger, I gave it a miss. The one I use for Lithium based battery packs is the Vapex VTE500P (with auto cut-off), and It seems to be very capable; even when dealing with pretty drained units. I like it's trickle feature too, as it helps it to revitalise units coming to the end of their recharge limits. Lithium based batteries rarely take more than a few hundred re-charges (but up to 1000 is often claimed).
An excellent tip, Rob, by the way

[Estnische]

I saw Herman with a Swedish battery reviver in his suitcase but he swore it wasn't his...

IMG_0779.JPG (29.23 KiB) Viewed 3825 times

[wibblywobbly]

Reviving car batteries works on the same principle, shove a huge shock of current through it to blow the sulphation off the plates. I've seen it done with a welding kit, by tapping the terminals with the welder clamps. I never cease to be amazed at some of the tricks and tips that exist on You Tube.

That said there are a few on there that are downright dangerous, but luckily people who know what they are talking about are quick to post comments pointing out the dangers, or the fact that the claimed result cannot possibly be true. Free energy machines spring to mind, though Coanda effect flying saucers are pretty cool.

[HERMAN BIX]

I saw Herman with a Swedish battery reviver in his suitcase but he swore it wasn't his...

IMG_0779.JPG

OHHHhhhh...........thaaat
Yeah, it was mine, but I wore it out
Thats when I discovered actual human Females..........(Hmm, should have quit while I was marginally behind!)

[siegfried]

Great tip, anyone know how to recharge a LIPO battery that has over discharged, I forgot to unplug it one night so it went completely flat. Any fix as it won't charge now?

[wibblywobbly]

Do this at your own risk.

phpBB [video]

[siegfried]

Clever idea, thanks