Faulty PMS3V and/or battery

[Steve Driver]

Hi all. I recently bought a campervan for the first time and have a challenge with the 12V power system. The van uses a PMS3V to manage the power as well as charging the battery when mains power is available. The battery is also (separately) charged from a solar panel. I have had the van connected to our mains supply since we got it home four weeks ago, but I've never seen the battery fully charged. If I disconnect the input from the solar panel the battery voltage falls quite swiftly, so I think that the battery needs replacing (it got to less than 10V in about 10mins before I chickened out and reconnected the solar panel). However I'm loath to put a new battery in until I'm happy it can be recharged. The lights on the front panel of the PMS3 look normal (the 'charging' light illuminates), however when I disconnect the battery from the PMS3 and put a DVM between the 'Van' terminal and the -ve rail, I see nothing whereas I would expect 13 volts (or over). This is why I assume that the PMS3 is faulty. Am I missing something? I've checked the circuit breakers and fuses at the front of the PMS3 as well as the 20A fuse at the back. I just thought I'd get a second opinion before I replace the PMS3. Thanks. Steve

 

[Reallyretired]

What voltage do you get on the battery when it is allegedly charging. If its around 13.6v and fallsto 10v when disconnected its the battery thats duff. If its only 12.7v or less when charging its the charger at fault though the battery has probably had it too by now.