I am in the process of using one of my old laptops for a specific task. Of course, due to age, one of the issues I've come across is battery life. Under any stress, the battery lasts maybe 20 min. If I do nothing, it may go on for 45 min. Recently, I came across a few videos where folks rebuilt their laptop battery packs and I'm wondering if it's worth it for this old machine. Without too much effort, I managed to disassemble the Lithium Ion pack and it is made up of 9 cells labelled as Sony Energytec US17670 which, according to my research, are 3.6 V cells and, as luck would have it, here is the same pack disassembled:
formatting link
Now the big question is: 1) Is it worth it to replace these cells? Some quick searching is showing them being quite expensive even for "generic" cells which I understand probably wouldn't last any longer than the time I'm getting now. The next question would be 2) If worth it, what would be a suggested source for obtaining the replacements? Finally (3) is there any way simple way to increase power on time of these current cells? I have read of people putting them in the freezer, etc, but I don't think that's for this type of battery.
If all else fails, I'll just continue using the AC adapter.
Depending on how much your time is worth to you, there are all sorts of outfits that refurb laptop batteries. Last time I used one it was about $50 for a 9-cell Thinkpad pack, iirc.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics
160 North State Road #203
Briarcliff Manor NY 10510
hobbs at electrooptical dot net
http://electrooptical.net
Apparently - some types have configuration data in volatile memory; if you remove the old cells without providing a sustaining voltage, the onboard controller chip becomes *VERY* dumb.
Presumably this can also happen if the battery gets completely dead - but all the books are telling me that writes off the cells anyway.
That's been my experience. Only had one successful rebuild. That pack had a PIC processor and resetting it restored functionality.
There are other issues. You can't solder to the cells. If you get tabbed cells and try to solder those together, the cells probably won't fit back into the plastic. I used a tab welder for all my experiments.
If you buy a "new" battery, it has probably been sitting in a container in Arizona for a decade or two. If it works at all, it probably won't be much better than what you have.
If you have it professionally rebuilt, make sure to verify that they can reset the chip so it will work in your computer.
For that vintage laptop battery, there are likely tools that let you reprogram the protection chip after a rebuild. Last I looked into it, the cost of the software was several times the cost of a new battery.
If you can tolerate the AC adapter, just keep using it.
But, back to the question. There are some things you can try. If you have the test equipment, you can take the lid off the pack and rebalance the cells. That's safest for the cells, but very much more dangerous for you if you don't know what you're doing.
There are calibration procedures that discharge the cells flat by running the computer until it quits, then recharge to full without interruption one or more times. Problem with that is that if the cells are badly imbalanced, you can cause the pack to shut down completely and refuse to recharge.
The primary failure of laptop batteries is increased internal series resistance.
The electrons are in the battery, but the protection circuits won't let you have them. The symptom is that the battery gauge says 100%, and seems to be discharging normally, but at some point drops abruptly to zero. If you turn off the battery features that sleep or shutdown the system at some battery level, the laptop may run for very much longer. Problem is that it shuts down abruptly and you lose whatever you're doing and may have to chkdsk the drive to clean it up. Once you become accustomed to how long it will run, you can often manage that process manually.
The other problem is the same as the calibration issue. Discharged to flat, the pack may permanently disable itself.
There are applications that can read the pack registers and tell you what the battery thinks its condition is. It's very dependent on the battery and the sensors in the laptop and the software. You have to try several to see if any work on your system. I've had some success with PC Wizard. Versions 2008 thru 2012 were most helpful. Newer is not necessarily better for this function. May have to try them all.
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