Hi everyone, I often go to my local recycling center to get power tool batteries to salvage 18650 cells for building ebike battery packs. The other day I came across this old Macintosh Powerbook battery for series 3400 laptops circa 1996. For kicks I picked it up and found these Sony Energytec US26650 CL14 X cells inside. I looked online to no avail to find specs for them. I would like to do a capacity test on them but don't know what to charge them to, 3.7 or 3.2 nominal voltage or even something else. Is there anybody out there that could give me any information on them ? It would be appreciated as I would like to make a pack to power my lights etc.
26650 cell specifications
- Thread starter ebikeruss
- Start date
m3654 on battery label leads to
https://www.energyplusbatteries.com/PD8a58vf25b/M3654-Replacement-Battery-Pack
which says
Which means it's:
4s 2p
14.4 / 4 = 3.6v per cell nominal (thus probably 4.1v or 4.15v full charge)
2700 / 2 = 1350mAh per cell
No idea on C-rate, for either charge or discharge, so I'd recommend keeping it as low as possible. Especially given their age--well over two decades--the cells may not even be usable anymore. (even if they hold a voltage).
https://www.energyplusbatteries.com/PD8a58vf25b/M3654-Replacement-Battery-Pack
which says
Which means it's:
4s 2p
14.4 / 4 = 3.6v per cell nominal (thus probably 4.1v or 4.15v full charge)
2700 / 2 = 1350mAh per cell
No idea on C-rate, for either charge or discharge, so I'd recommend keeping it as low as possible. Especially given their age--well over two decades--the cells may not even be usable anymore. (even if they hold a voltage).
Thank you amberwolf for your research and reply. The battery pack you found is actually a replacement pack which must have used 18650 cells as this pack is an original pack using 26650 cells in a 4s1p configuration. Using the voltage of 14.4 would make each cell have a nominal voltage of 3.6 volts. They may be 23 years old but they still have voltages of 1.34v, 2.14v, 2.26v and 2.37v. I will charge them to 4.1 volts and check their capacity. I hope they have more than 675 mah, but won't hold my breath given their age. I will post my findings in a few days.
Those voltages mean they are dead, damaged because they have discharged below 2.8v (the typical minimum cutoff for this chemistry), and are no longer safe to use.
At the least, teh ones below 2.0v are physically damaged and shouldn't be recharged.
The kind of damage Li cells incur when overdischarged can potentially cause a fire, during any stage after they are recharged. Can happen during any recharge, or discharge, potentially even just sitting there.
I don't recommend using any of the cells from that pack.
At the least, teh ones below 2.0v are physically damaged and shouldn't be recharged.
The kind of damage Li cells incur when overdischarged can potentially cause a fire, during any stage after they are recharged. Can happen during any recharge, or discharge, potentially even just sitting there.
I don't recommend using any of the cells from that pack.
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