I’ve got 8 NIMH cells from a Dell 2200 laptop pack that are all currently standing at 1.28v.
These are 17.8mm D and 66.5mm L with no embossing or printing on them. The negative end has the letters HR. Dark green cover with dark blue almost purple ring around the positive end.
The pack was 8 cells in series wiring. Pack said 9.6v nominal and 4500mAh capacity, so nominal is 1.2v.
What voltage do these charge up to?
An 8S NiMH pack should charge up to 11.6-12V.
Pack no more. So 1.45v - 1.5v each . . thanks!
Might search for 4/3A cells to find one that matches the wrapping.
They aren't going to charge up to a certain voltage, they are nimh cells. Simply use a good (-dv/dt termination) nimh charger to fully charge them.
This.
I based 11.6-12V on the fact that most of my cells charge up to 1.46-1.5V with a 9mV dV/dt setting—though I charge mine to 1.6C at about 1/10C, so YMMV slightly.
There is no such thing as a good -dv/dt termination nimh charger! Nimh cell voltage drop at full charge is WAY to iffy to depend upon. The best way to charge nimh cells is with a healthy current (1C) and dependable temperature monitoring that shuts down the charge when the cell starts to get hot.
Those are great cells. I got some from an old laptop. Almost threw them away thinking they were bad Li-ion’s, but checked them out because they were narrower. I charge mine in a AA 700ma Ni-mh charger and it appears to terminate properly every time. I made some “S”s with bare copper wire to adapt them to the cradle.
I use anywhere from 3 to 5 of them in my TR-3T6. Just as bright and seems to have good runtime. With 2 extensions (5 of the 4/3AF), the light is a serious club. I like to carry it jogging on nights I feel like having a little more security.
Thanks. I looked at a few links and threads via Google, but virtually nothing on the wrapper to match to. The diameter seems to be a little smaller than some of the 4/3 specs I read.
I very slightly nicked one of the wrappers, so I may pull it to see if the bare cell underneath has any markings if the cells charge OK and hold capacity. I don’t have a hobby charger so I will have to get some magnets and build some leads to try one of our NIMH chargers.
I would imagine our cells might be similar. I get a ton of Google matches on mine. My wrapper have the following on them:
“HR-4/3FAU 4.5Ah
SANYO JAPAN 11H”
I wrapped electrical tape on both ends of my cells to prevent rattle.
Here’s a pic of the inside. The writing on the inside of the wrapper is a mirror image of the printing on the bare cell. Dell pack was made in China with no info on battery source.
I couldn’t find any info on your cells either. Good news is the you already know the important stuff. From the laptop casing label and the serial wiring, you know they are 4,500ma (when they were new). You know they are Ni-mh. So they are safe to use in series. I imagine they will have similar characteristics to mine.
Curious but what lights do you nimh 18650’s in?
Read up post 7 for one example.