Both are rechargeable.
First is three NiCd cells (1.2V each) in series (resulting in 3.6V), usually any NiCd pack with three cells in series is a suitable replacement. Second is a VL2020 (Vanadium-Lithium coin cell) with wires attached which you probably already knew. 😉 You can buy the cell with solder tabs, solder on the original leads and wrap it in electrical tape for isolation.

Doornkaat wrote on 2020-06-02, 04:59:

Both are rechargeable.
First is three NiCd cells (1.2V each) in series (resulting in 3.6V), usually any NiCd pack with three cells in series is a suitable replacement. Second is a VL2020 (Vanadium-Lithium coin cell) with wires attached which you probably already knew. 😉 You can buy the cell with solder tabs, solder on the original leads and wrap it in electrical tape for isolation.

Thanks for the information, very useful. Regarding the VL2020, I've read that soldering (heating, in general) a battery is dangerous because it can explode, is it true? or it can be done without much problem? any special care about it?

Just keep the iron on it for only a few seconds. If you have it on there for an extended period of time to try to melt the solder, your temperature is set too low and all you're doing is pumping heat into the battery

aha2940 wrote on 2020-06-02, 13:46:

Doornkaat wrote on 2020-06-02, 04:59:

Both are rechargeable.
First is three NiCd cells (1.2V each) in series (resulting in 3.6V), usually any NiCd pack with three cells in series is a suitable replacement. Second is a VL2020 (Vanadium-Lithium coin cell) with wires attached which you probably already knew. 😉 You can buy the cell with solder tabs, solder on the original leads and wrap it in electrical tape for isolation.

Thanks for the information, very useful. Regarding the VL2020, I've read that soldering (heating, in general) a battery is dangerous because it can explode, is it true? or it can be done without much problem? any special care about it?

What wiretap said plus I think the VL2020 always comes with solder tabs. They don#t transfer heat too quickly so if you pre-tin their ends and the wire's ends you only need to heat them very shortly to attach the wires. If you have a little bit of soldering experience this is a job you can 100% do! 😀

Hi again guys

Thanks a lot for the advice on soldering, really useful stuff. So, I've been doing some research and VL batteries are just expensive. So I looked for other options to get the 3.0V of the VL2020 and the 3.6V of the IBM battery and found several options:

3V:

3.6V:

However some of these have a huge difference in mAh capacity when compared to the original batteries. Would that be a problem? should I stick to batteries having the same mAh capacity? or it does not matter?

Thanks!

Just make sure they have the same or higher capacity not less. And for some of the bigger capacity batteries they tend to be larger as long as you have the space for them you can go for the higher capacity ones.

As far as I know batteries differ greatly depending on their chemical composition and will react badly to wrong loading currents. This may range from not accepting any charge at all over early failure to leaking or exploding.
Depending on the loading circuitry it may be fine but it may also overheat with high capacities or interpret wrong capacities as defective cells and outright refuse loading them.
The loading circuitry on that laptop is probably specific to a certain type of cell so it should be replaced with that type or it may cause damage.
What you want to look for for the VL2020 is a Lithium Vanadium Pentoxide (LiV2O5) cell. Doing a quick search I can find suitable batteries for ~5€. I don't know about the Colombian supply though.
The other one is a nickel–cadmium battery. The Beston pack you posted consists of Ni-MH cells that are much more sensitive to overcharging. They use similar loading voltages so you can probably get one and see how hot it gets.
I know of people who replaced them with supercapacitors but again I'm not an expert and I don't know what issues may arise from this solution.

Sorry I can't give you a more conclusive answer.

Lithium batteries are not rechargable so don't use that.

The barrel battery will leak onto the board so don't use that.

I have used that cordless phone pack with AT motherboards with great success in the past, go for it. Use dupont jumper wires to relocate it toa part of the case where it won't harm anything if/when ti leaks. NiMH is less prone to leaking anyway, and recharge characteristics are the same as NiCd.

Thanks for your insights guys, it seems choosing a replacement battery is not as simple as it seemed at first. I got confused by this though:

appiah4 wrote on 2020-06-05, 13:13:

Lithium batteries are not rechargable so don't use that.

However the listing for the Varta 3V battery says it is rechargeable, and the original VL2020 battery on the laptop is lithium (see pic in first post) and also rechargeable, so I do not understand, are some lithiums rechargeable and others not?

Both VL and CR coin cells are Lithium batteries, with the VL series being rechargeable. And every modern device also uses rechargeable Lithium batteries. It's not the Lithium that decides whether a battery is rechargeable or not, but the material used in conjunction with it.

The pictured Lithium battery is a CR 1/2AA, it's not a rechargeable Lithium battery.

I've got a 760E with a shattered screen that needs the same batteries to even boot. Thanks, IBM. I especially appreciate the sloppy soldering I found when disassembling the keyboard to get to them. Alas, I've never been able to locate a replacement for the triple cell pack myself at any price, and while $10 for the singular cell is a pain, without both, my busted laptop remains eternally inert.