the barrel batteries are rechargeable, you can't just hook up a cr2032, it will REALLY not appreciate it (the board puts out charge current during operation).

If you want to use a non rechargeable battery as replacement, you need to put a diode on the positive lead for protection.

Personally, I will probably get a battery holder for either 3 AA or AAA cells and use eneloop rechargeable batteries. Eneloop are rechargeable nimh Batteries with especially low self discharge.

//Edit: I forgot, there are rechargeable CR2032 equivalent that come with soldering legs like the barrel batteries, however, they are Lithium-Ion cells. They are supposed to work fine, but I don't really like to use them in this case, because they don't come with protection and the board lacks proper charge circuitry for those cells.

Being in the US, you can also find triple cell NiMH or NiCd battery packs for cordless telephones. They work perfectly.

Okay so I can use something like this holder with an eneloop rechargeable battery ?

you need 3 AA/AAA rechargeable cells, a single cell won't do since you need to match the 3.6V of those "barrel batteries" (they are actually 3 nimh or nicad coin cells in series).

Does your motherboard have a connector for an external battery? Many of them do. Then you can just chop off the barrel battery and connect either 2x AA or 4x AA battery holder (depending on whether the motherboard needs 3V or 6V) and use normal AAs, as many motherboards don't try to charge batteries connected to the external battery connector. But before you do this it's a good idea to measure the voltage on the connector when the motherboard is powered on, to make sure there is no voltage measured on the connector pins. If there IS power on the external battery connector when the motherboard is operating then it does try to recharge the external battery and you can disregard this advice 😀

Intel486dx33 wrote:

What type of coin battery can I use to replace a Barrel Battery on a 486 motherboard ?

CR2032 ?

There is rechargeable version of it: LR2032

The charging profile of a Li-Ion battery is quite different than the original barrel pack. NiCd (what was probably originally installed) and NiMH batteries are generally not so sensitive and have fairly simple charging circuits. They also have similar voltages per cell, so you can generally use either type interchangeably.

In either case, it's preferable to locate the battery pack away from the motherboard where it can't damage anything if it fails.

Are these batteries okay ?
https://www.ebay.com/itm/10X-3-6V-LIR2032-Lit … V4AAOSwve1as0fn

Intel486dx33 wrote:

Are these batteries okay ?
https://www.ebay.com/itm/10X-3-6V-LIR2032-Lit … V4AAOSwve1as0fn

some people use them for this, however it is not a good idea. They are Lithium Ion cells and as such sensitive to incorrect charge curves. The charging circuit on a motherboard is not designed for lithium ion cells and the cells also lack protection circuitry. When they are charged incorrectly they can and do blow up. And that is not meant figuratively.

If you feel lucky, you technically can use them, but do so at your own peril. If something goes wrong, consider yourself warned. I strongly recommend against it.

Are these batteries okay ?

https://www.ebay.com/itm/Panasonic-Eneloop-AA … cAmzS:rk:8:pf:0

Yup, both NiMH and NiCd should work just fine.

These are not 3.6v is that okay ?
https://www.ebay.com/itm/Panasonic-Eneloop-AA … cAmzS:rk:8:pf:0

Intel486dx33 wrote:

These are not 3.6v is that okay ?
https://www.ebay.com/itm/Panasonic-Eneloop-AA … cAmzS:rk:8:pf:0

they are 1.2 V. 3 of them in series will work, there are battery holders for that.