lithium batteries - longevity of them

[AlpineRaven]

Hey all, 
I have 3x PowerBook 3400 batteries and 3x Lombard/Pismo Batteries and all 6 batteries does hold good amount of charge in them. Since they are over 20 years old....

My question is - what is the best way to keep them active for longest as possible preventing from dying/dead?
Cheers

AP

 

[beachycove]

Half charged and cool is all I've seen. The trouble with that is that old cells don't seem to hold a charge for long, so long-term storage is a real problem. I'd probably try to rotate them in and out of the machines rather than just use two of them.

 

[FacnyFreddy]

I don't think I have ever seen a Pismo battery "bulge" from age/elements like I have the "flat" cells in more modern powerbooks/macbooks.

The round cell design tends to be more reliable, historically, but holds less power storage/in^3, which is why macs went away from the format years later.

I charge up and discharge my pismo batteries 2-3 times a year, but, never run them completely empty.