Any use or value to dead T61 batteries?

[cadillacmike68]

I have a few dead T61 (and several T20 & 30 series) batteries.

Can anything be done to re-cell them or is there any residual value to them?

[ilakast]

The T20/T30 batteries are always useful even if dead cause they support the laptops, so people might be looking for them on ebay and would buy them for a reason.

Can't think of any use for the T61 ones though. Re-celling seems not to be worth it, given time and cost.

[TuuS]

If anyone does want some dead T60/61/500 batteries I have dozens, many surely have good cells in them as it's usually the controller that fails and I'd ship you a huge box of them for $20 (to cover postage).

The cells would probably be handy to a hobbiest even if you weren't going to rebuild the batteries, but if someone wanted to rebuild the, the best method would be to start with a battery that works but holds little charge and replace the worn cells with better ones from a battery with a failed controller, however you have to be very careful as there have been reports that simply opening the circuit will disable the controller and replacing a discharged cell with a fully charged one will cause a false "unsafe condition" and disable the controller. Once disabled there is no easy way to make it work again.What is recommended is to discharge the battery to a state of about 10% and splice the new cells in parallel before removing the old ones, swap them one at a time or all at once, but don't allow the controller to detect an open circuit. It's not as simple as removing and replacing cells.