Hello,
I still love my 15" TiPBG4, and it works flawlessly, except for the lack of a functional battery. I do have a spot welder, so, in theory, I could rebuild a battery pack. But, I was thinking of going another direction, that will be easier to support, in the future.
My first idea is to use a power bank with 24vdc output, and power the machine via the barrel jack. I know that the "24v" banks vary between 21-29vdc, depending on state of charge, and I'm not sure what the specs on the regulator inside of the powerbook are.
My second idea is to build a 14.4vdc replacement battery module from LiPo pouch cells, and insert it into the battery compartment. That is actually pretty easy, especially since I'm not worried about maximum battery life. My concern, though, is that the PB might well not like being unable to communicate with the battery module.
Has anyone tried either way? I did some searching and didn't come up with a lot of results.
Thanks!- Alex
if you are adventurous, pop open the existing battery box and replace the old batteries with similar new ones. will probably not be lipo. most likely some kind of nickel battery, but since you are not worried about runtime this will not be an issue. By replacing the cells will equivalent technology cells, the charge circuits and Batt id circuit will remain compatible with the machine.
I don't know about those old PowerBook batteries but a lot of x86 laptop batteries of that era used a common 18650 type battery which you can easily buy. You can take apart most of those batteries and replace the cells. Sometimes only one or two of the cells actually fail too so the repair may be pretty cheap. If you google online you can find instructions on how to do it including how to test cells to determine if they are failed or not.
Are you speaking from experience, or just repeating things you heard or assumed? Combining cells of differing ages is extremely dangerous and greatly increases the risk of fire.
These packs are deliberately made difficult to rebuild because lithium-ion cells are unstable and can explode in a fireball if abused, or even if there were quality problems when they were manufactured. Most of the 18650s (for example) that you can "easily buy" are rewraps, which means that they are factory seconds that were scrapped and repackaged for sale by third parties. Rewraps often have lower capacity than advertised, and since they come from factory rejects, they have a higher risk of cathode overhang, a quality problem that can lead to an internal short-circuit and thermal runaway.
The pack contains a battery-management chip, usually a BenchmarQ product from Texas Instruments, that monitors the "health" of the cells and communicates via I2C with the computer. If the BMS detects low cell voltage, it often permanently locks the pack to prevent further failure. Special software tools (not publicly available) are needed to reset the pack if this happens.
It's also not safe to use a soldering iron to make connections to cells, as the heat can damage them internally. It requires spot welder equipment.