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Is Having No Battery a Problem?

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Grandcheapskate

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Oct 9, 2014
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I'm sure many of us have computers which we do not use on a regular basis. Maybe months (or years) go by between times we boot them up. So I am wondering...is it harmful to motherboards if they have no battery and you have to set the BIOS parameters every time you start the machine?

I have a couple of 386 and 486 boards where I needed to unsolder the battery because it has either started to leak or was on the verge of leaking. If I was going to use these boards on a frequent basis, I would use external AA batteries as replacements. But if I am only going to use the machine infrequently (or frequently for a short time), am I causing damage by writing the BIOS EPROM every time I start the machine?

Thanks...Joe
 
The BIOS is stored in ROM but the BIOS Setup configuration data is stored in a battery backed RAM called CMOS. Hence the need for a battery. :) So, it's perfectly safe to not have a battery.
 
My question is really about any potential damage or "wearing out" of the CMOS by having to update and save it every time I started the computer. It's easy enough on most boards to enter a few CMOS settings (date, time, disk types, etc.) each time you start the machine, especially if you go long periods of time between using the machine.

I was just worried that the CMOS was not designed to be written/saved potentially hundreds of times.

Thanks...Joe
 
Grandcheapskate said:
So I am wondering...is it harmful to motherboards if they have no battery and you have to set the BIOS parameters every time you start the machine? [...] But if I am only going to use the machine infrequently (or frequently for a short time), am I causing damage by writing the BIOS EPROM every time I start the machine?
Click to expand...
The CMOS memory is fortunately not an EEPROM, but battery-powered SRAM. You can save the settings as often as you want, it won't cause any damage/wear.

However, not only a couple of Macs, but also many PCs won't boot without a battery. They will power up, let you enter the BIOS - but once you saved the settings and restart, the settings are already lost again (incl. the fixed disk parameters, so no boot).
 
You will not live long enough to "wear out" CMOS SRAM in a clock chip--which is really what everyone should be calling this beast. If this is a machine that you will power up infrequently, you might consider replacing a rechargeable battery with a supercap--indeed, there are supercaps whose marketed purpose is as an SRAM "keep alive" power source.

Has anyone done this to a legacy PC?
 
Thanks guys. Seems like it is not an issue at all, which is great. I'll just keep machines battery free until/unless they are used frequently.

Thanks...Joe
 
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