Ok further to the above post I have recieved a reply from the manufacturer and I have replaced the battery to accurately determine how long it takes to get the low battery warning so I have a good record of where i stand now.

The hub reported a low battery after 5 hours use with a brand new battery. I did a 1 hour ride the day i replaced the battery and a 4 hour ride the following day, the next day I caliberated using the garmin and got the low battery warning before setting off. As I say I know the battery will keep going for 3 weeks but at least this way I can quickly determine if any service actions have had an effect.

According to the reply I got, a firmware issue has been identified which is causing this problem and new firmware is being tested as I type, assuming the testing goes well it should be available in the next few weeks. Apparently I will be able to carry out this update myself using the USB port on the hub and will not need to send the unit back.

Result! I thought this thing was just super power hungry and wondered why they didnt design it with 2 batteries in the first place. As I say it works perfectly so I assumed all was ok.

Anyway I'll let ya know how the update goes. If it does indeed result in me getting 100s of hours out of a battery instead of 10s then I wont be able to fault the hub at all. Its an excellent piece of kit!