Got a broken Network (looks like German brand…) brand P3 laptop. I take out its battery pack. its say 10.8V 4500mAH.
Inside pack, there are 9 MOLI ICR-18650E batteries in 3S3P method. I guess it each cell 1500mAH. And cells made in canada
Its around 12 years old… and there are cosmetic marks show laptop hardly used.
I checked each cells. every cells had reading 3.69V - 3.74V :bigsmile:
The man who give me laptop say its worked until last year.
I did a Capacity test with My IMax B6 (not a original Imax b6)
Cell charged to 4.2V @ 0.5A and rested 1 hour.
Discharge current : 1A, cutoff voltage 2.8V
1180mAH over original capacity of 1500mAH = 78% :bigsmile: capacity after 12 years
Those batteries seem to be doing pretty well after all this time. Maybe it has to do with how often they are used, it’ll be nice to have a well used old laptop to see how well they hold up.
First I used USB to RS232 cable (actually it USB to RS232 port adapter that came with CDMA land phone)
I connect Imax’s serial output to RX pin of RS232 port. but logview show wrong data. output of Imax data pin is very high impedance
So I had to put transistor with high value resistor to boost / level convert signal.
However you don’t need any mod if you’re use correct RS232 convertor
Yeah, older, lower-capacity batteries are generally more robust than newer, higher-capacity batteries (one of the trade-offs for higher capacity, plus cost-cutting is often a factor). I did a capacity test on a set of NiMH AAs a few months ago: 1005 / 1064 / 1080 / 1087 mAh. They’re Olympus-branded 1300mAh cells purchased in November 1998! And they have been through perhaps 200 cycles and have not been given best-practice treatment, having spent years between charges (and thus years completely self-discharged) more than once.
I just harvested 6 Panasonic CGR18650CG cells from a three year old Lenovo pack that had sat unused for more than a year. Four were at 2.5v and two were at 2.74v. I’ve been slowly charging them at 50mA to bring up the voltage a bit and then let them sit for a few hours. I have yet to fully charge them, let alone discharge them, but during the rest periods the cell voltage has not dropped appreciably, so I’m hopeful! :bigsmile:
