volt meter wont show anything you need to load the battery and test the result, ie pull 2 or 3 Ampls of it and check it stays above 11.8v

or use a proper battery tester like most would on a service.

The regs for your system required the battery to be chnaged every 5 yrs wether it needed it or not, but they may have said its due.... and you declined etc.

I do have a battery tester, but it's rather Mickey mouse, so appreciate the tip about checking it with load.

Had that a few times on RM, but we ask customer to sign to accept responcibility ie if we get called out due to battury failure - call out becomes chargeable (

Just fitted the new battery.

The old one showed 13.2V on the meter, but when a 2A load was connected across it - light bulb - that fell to 9.3V. Which underlines your point about not relying on no-load readings.

Thanks again.