Computer battery

[#1]

it depends what task it is doing, by almost always yes it would need to know the time.

[#2]

In that case I don't think it would matter too much but if you were reliant on the journal log time or had cron jobs needing to be executed on schedule then knowing the time would be helpful!

[#3]

Actually got around to changing the battery this morning, on starting up there was a message about the BIOS being reset but everything is working ok, having changed batteries in the past I do not recall getting any messages, or perhaps I did and don't remember as it was years ago.

[#4]

Not all boards drop the bios memory when replacing the battery. That's probably why you don't remember having that message previously.

[#5]

I'm no expert, but it is hard to tell.

You don't know if it is a dead battery (could be), or if the time is correct and your internet is fine the OS could be syncing it from there. If you've made other customisations to your BIOS it could cause a problem. Main thing is the BIOS knows the boot drive so your computer works I guess.

Not far from where I live there are a few pound shops, which sell a pack of loads of watch-ish batteries for a £1 (surprisingly), and they include CR2032's. 

If you suspect that, and you have a similar shop nearby you could try that.

[#6]

I just bought a 10-pack of these the other day (although they were only £1-25 at the time) - the seller also offers packs of 5 and 20. They seem to be genuine and are labelled 'Made in Japan'. Please note I have no connection with the seller other than as a satisfied customer.