10.4.8 & Belkin UPS

I've searched the discussions and found some info but nothing that matches what I'm about to ask here. I believe this is OS related rather than hardware hence I've posted here....

I have used a Belkin 650VA Battery Backup UPS for about 8 months now. This device used to work perfectly until I noticed a few weeks back that it was not providing any UPS functionality.

Within Energy Saver, the UPS is seen by the OS but registered between being 261% full and 4% full within a few seconds of switching between the preferences.

I contacted Belkin and they have sent a replacement unit saying that the battery has probably died.

Problem is, the brand new unit has arrived and is showing the same issue - 261% full or 4% charge.

This and some other searching has lead me to believe this could now be an OS issue rather than hardware.

I have shortlisted the things that have changed since I first started using the UPS:

1. I added a RAID card and 2 extra HDD to the case.
2. I have upgraded to 10.4.8, previously running 10.4.6.

I have tonight completely removed the RAID from the computer and this has made no difference so I think this is an OS issue.

I've tried installing the Belkin Bulldog software but that constantly reports a UPS disconnect.

I've also installed SlimBatteryMonitor and have no joy - that reports "Charging with 0% capacity"

Please can anyone here help. Can this be resolved easily or do I have to reinstall the OS and avoid the 10.4.7/10.4.8 updates?

Any ideas?