'07 XC90 - Had battery changed, multiple warnings.

[SwissXC90]

Can only be a power problem or CEM corrosion problem:

POWER:
Check battery terminals are clean and tight
Check alternator connections are clean and tigh

CEM:
Check connectors to CEM are clean, and show no sign of water damage whatsoever (some dismantling required)
Inspect CEM (remove, open covers) and look for water damage. If any signs of corrosion exist, you must trace and fix the source of water damage, then fix (via specialist) the CEM or replace it, and replace any corroded wiring and connectors.
Cause of water damage is often leaking sunroof drain pipes, or windscreen leaks or leaks on wiring loom entry point to CEM.

Water damage in CEM is unfortunately not uncommon and can cause symptoms such as you are observing.

[Verbal]

Thanks for the advice.

Battery cables look pretty clean but going to go at them anyway. Will also play around with the alternator connections.

Those two are my prime suspects. CEM would be a miraculous coincidence unless a new battery could aggravate it.

I've all but eliminated anything actually mechanically wrong with the car, it is now working out why it is throwing these false error messages and why a new battery has brought it all on.

[SwissXC90]

Why did the old battery die?
Simply old age, or as a symptom of a problem with the charging circuits?

You need to verify that the alternator is doing it's job properly.
Bad alternator contacts, bad connections, loose terminals can all cause problems

I suggest running the alternator test in VIDA, make sure the results are OK
Consider graphing the battery voltage over time and make sure the charge voltage is as expected

[Verbal]

I had the battery changed as I noticed I was getting Low Battery warning when sitting with the radio on for 5 minutes with engine off at the services.

It also went flat after not being driven for only 4-5 days. To me that's nearly always been time to change the battery, it was the original, so well over 10 years old.

Halfords (only place open on a Sunday after being jumped) 'tested' the battery and alternator and told me both were fine. I said do the battery anyway as I was there and was still basing it on my experiences above.

Since then, nothing but problems.

I mentioned earlier that even when they had the tester clamped onto the battery, the Brake Failure - Stop Safely red exclamation showed. So whether this is something to do with voltage fluctuations I have no idea, just surmising as literally nothing else been done but a battery change.

[Verbal]

Cleaned the battery terminals thoroughly and no joy.

I'm going to try and get it into a local indy Volvo specialist tomorrow and see if they can diagnose it.

I'd be horrified if this turns out to be something major off the back of a battery change.

[XJSDriver]

As SwissXC90 suggests, it is likely there is something else going here that may or may not have been exacerbated by the battery change: on reading all your posts the evidence is pointing to an existing problem which is not battery related. However, I would ask your indie to test the battery and alternator first so you can be sure they are OK and move on to the next stage of diagnosis.
Good luck.

[Tannaton]

There is also the possibility - however small - that the replacement battery is faulty....