I have a PowerBook G4 17", which gets lots of daily use in various capacities. This includes 7 hours sitting idly waiting for calls to come in to a BBS.

Because of this regular and perhaps comparatively heavy use, I've become worried about whether I'm using the battery optimally. Until recently, I would mainly run the computer on the battery, and when the charge dropped to about 20%, plug it back in to charge it back to capacity. And then repeat.

But then I read that a computer battery (or at least, a "modern" computer battery) has a limited number of recharge cycles, and to maximise its life you should run it from a PSU whenever you can. So I've now adopted this practise.

Is this indeed the right thing to be doing? 17" PowerBook batteries aren't cheap, unfortunately!

Many thanks in advance

You are/were almost right with the way you handle(d) this. Usually common batteries are advised to get charged to around 95%, and discharged down to maybe 15%. At least that is what i have read before.
And i remember some clarification from Apple that only a full charge counts as a cycle and wears out the battery.

As an example:
my Macbook Pro's batteries are 92 months old (if i use the model's age), have 2008 charge cycles and still hold 4570 out of 6900 (66%) charge capacity.

Leaving the power connected all the time might work with modern machines, i don't know. But you will certainly kill older systems' batteries, as the charging electronics is not that advanced i assume.

[ Edited by amifrog 13.06.2020 - 16:16 ]

The cycle duty of lithium batteries is stated in full discharge-recharge cycles. Technically you should get 1000 until it drops to 75-85% capacity, but my iPhone went for around 7 years before I had to change its battery - which if I was fully cycling it would have been over 2500 cycles.

No matter how you treat batteries, they will age slowly and tend to sink slowly to 80% original capacity for a long time. They will hover there for most of their service life before suddenly losing much of the rest.

If you leave it charging all the time, it's almost as bad as constantly deep-cycling it. Dendrites form in the battery and can form shorts. You really don't want to be doing this. (Some modern laptops can control charging and you can set it to sit at 40% capacity for maximum longevity).

If you really want to keep it as long as possible, discharge the battery to around 40%, remove it, and store it in a cool dry place. If you need it in the machine then leave it plugged in, but "exercise" the battery by running it down to 40% at least once a week, and running it down to near 0% once every 1-2 months. This evens out the chemistry happening in the cells and prevents formation of life-reducing nasties.

[ Edited by KennyR 13.06.2020 - 20:03 ]

> Usually common batteries are advised to get charged to around 95%,
> and discharged down to maybe 15%.

AFAIK, best way to prolong service life of lithium-ion batteries is keeping the charge level between 30% and 70%.

OT - you run a BBS on your PowerBook? In MorphOS? Which software? Can we talk more about this? :)

> you run a BBS on your PowerBook? In MorphOS?
> Which software? Can we talk more about this?

Dedicated thread:
https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=12795&forum=3

Quote:

Sure :) I’m using Max’s which seems to run faultlessly. Th only snag is getting past not having serial.device. I installed an instance in EUAE and updated the config to use the pl2303 device, then copied the config across to MorphOS so it can then start (once you’ve got your pl2303 adaptor plugged in). This is for dial up, but you’d do the same thing to use it with telser.device. By the way, that works with MorphOS too, but not using it currently.

Thank you for all the replies. Damn - glad I checked and wish I hadn’t changed my practice! Gong to implement this as of immediately.