I dont know, what is consensus - for me is solution CR2032 holder on external battery pins and desoldering leaked 3,6V Varta...

CR2032 is lower voltage and isn't a rechargeable - isn't there a risk damaging the battery?

Badscrew wrote on 2021-08-22, 12:52:

CR2032 is lower voltage and isn't a rechargeable - isn't there a risk damaging the battery?

External battery pins does not charge CR2032.but u r right some mobos doesnt like cr2032 so forget cmos settings.
You need 3.7 rechargeable lion batterry

How about using a pack of three low capacity Ni-MH AAA rechargeables? Will this work as an easy drop-in?

My MB doesn't have any dedicated "external battery" pins, only the ones where the Varta was soldered on.

there re varta style batteries around at 3.6v rechargeable varta is one of several brands but its the battery type you need search for.

LIR2032 is a drop in rechargeable replacement for a CR2032. So I’d go with one of those plus a holder.

LIR2032 is a drop in rechargeable replacement for a CR2032 but not for the 3.6V Varta ? 😁

Oh wait these LIR 2032 are 3.6 or 3.7 V, not 3.2 as I was thinking.

Worth a look then, interesting

You can still buy some NiMH 3,6V rechargeable battery, compatible with old NiCd 3,6V, if You don´t have external abttery pins on Your mobo https://uk.farnell.com/c/batteries-chargers/b … ry-voltage=3.6v
Of course, You can use pack of 3x1,2V in serial connection.

Badscrew wrote on 2021-08-22, 14:17:

LIR2032 is a drop in rechargeable replacement for a CR2032 but not for the 3.6V Varta ? 😁

Sorry, yes I meant a physical size replacement for a CR2032. So a CR2032 holder plus an LIR2032 would be a good varta replacement.

The fact LIR2032 use lithium ion compared to NiCD for original batteries isn't problematic ? I thought lithium needed more precautions to be charged.

Li-(Ion, Pol) batteries have different charging characteristics, so they can't simply be plugged into an existing circuit. NiMHs aren't the exact replacement for NiCd batteries either, but from rechargeable ones the closest.
Can also be used non-rechargeable, but with a protective diode, blocking recharging from the mobo. The 3V voltage of CR2032 is not a problem for most plates, the BIOS settings reliably hold.

I was warned against using NiMH rechargeables when I last looked this up in the following thread:

jaqie wrote on 2012-02-19, 15:16:

NiMH would be very dangerous to do that with - they are tempermental on how they are charged. not nearly as bad as lithium types though! NiCD would be perfect but remember they can leak like the originals, too.

Barrel style CMOS battery question

I ended up using the 3x alkalines with a 1N4002 diode in series suggestion - works a treat if a bit bulky with the 3 AAA holder.

This was for a direct replacement of the leaky Varta - if you have an external battery header you’ve got more options. Another idea I liked was to disable the charging circuit directly on the board (by removing resistors etc) and just fitting a CR2032 battery holder but obviously you have to know what you’re doing there.

Leaning towards 3 AAA in a holder and a diode myself. Cheap and effective, easy maintenance.

Badscrew wrote on 2021-08-22, 18:46:

Leaning towards 3 AAA in a holder and a diode myself. Cheap and effective, easy maintenance.

Use rechargeable AAAs instead. No diode required then.....

Regulars are cheaper 😁

Badscrew wrote on 2021-08-22, 18:46:

Leaning towards 3 AAA in a holder and a diode myself. Cheap and effective, easy maintenance.

I support this

Are you sure you don't have an external battery header to plug it into though? Can dispense with the diode if you do

It doesn't seam to - and it's also a weird off-brand 486 MB I can't find the docs to.
I have like dozens of diodes anyway, so not a big deal 😀

Also, using a diode with 3 alkalines will drop the voltage from 4.5 to about 3.8- 3.9V that will be closer to 3.6. Not that BIOS should care anyways but at least better on paper.

Badscrew wrote on 2021-08-23, 14:36:

It doesn't seam to - and it's also a weird off-brand 486 MB I can't find the docs to.
I have like dozens of diodes anyway, so not a big deal 😀

Also, using a diode with 3 alkalines will drop the voltage from 4.5 to about 3.8- 3.9V that will be closer to 3.6. Not that BIOS should care anyways but at least better on paper.

The RTC chips have a very wide range of acceptable standby voltage input, anything from 3-5V should be perfectly fine