Arthur_

B1 doesn't show a voltage when the engine is running it just says 'FAULT' . It turns out that B1 refers to the leisure batteries and B2 to the engine battery. With the engine off the voltage at the battery terminals under the bonnet was 13.4V and B2 on the solar display also showed 13.4V. With the engine running the voltage at the terminals was 14.5V. I can't remember what B2 showed but I expect it was the same. My theory is that the solar output to the leisure batteries goes through the habitation electrics and not directly to the batteries like in onecals diagram above. When the engine starts the habitation electrics are isolated and the Sunstor thinks its a fault because it can no longer find the leisure batteries - just my theory mind. I did find that the 2 leisure batteries were showing different voltages where they hadn't been wired correctly but that's another story.

It means that the solar is supplying charge. When the display shows 0.0 amps the * disappears.

Thanks for trying Derek. I didn't get any joy from them either. In the course of checking the wiring to the leisure batteries and on-board charger I have managed to puzzle out what most of the Sunworks display refers to so I'm probable OK with that now thank you. It is a pity that their technical support appears to be non-existent as the controller itself is a compact and tidy little unit.

Thanks Derek, You did a lot better than me.

No reply to my email to the manufacturer and they not answering calls. I left a message but no call returned either. Another thing that I've noticed is that when the vehicle is on hook-up and the on-board charger is set to either hab or vehicle the Sunworks display cycles through 'N', 'B' & 'P' for B1 which is the vehicle battery. All very mysterious. Still the main thing is that the solar is keeping the 2 lead-acid leisure batteries and the vehicle battery topped up and I'm happy with that. The Autosleeper is 2003 so I expect that the solar was installed a long time ago.

Thanks Derek, Yes, it looks to be the DB1C. I did send an email off to Sunworks before posting here but as yet have not had a reply. As I said, it seems to be charging the batteries fine but the FAULT message is a little worrying. I'll wait to see if I get any response from Sunworks.

Hello, We have a solar panel on our Autosleeper motorhome with a Sunworks solar controller that helps to keep both cab and leisure batteries topped up. Unfortunately we don't have a user guide so I'm not sure what everything means. Mainly it's the letter or symbol that's displayed after the battery voltage - 'P' and a '*' in the photo. When the engine is running the display shows 'B1 FAULT P'. The controller keeps the batteries topped up nicely but it would be good to know the meaning of everything displayed. I think it has 3 stage charging so perhaps it's something to do with that? I've search for a user manual online without success - can anyone advise? Thanks