12v systems intermittent shutdown

Corinium Duo 2017. All worked just fine until I had HPC and SemiAir fitted. Afterward, the GasIt LPG gauge lost its perm 12v supply and the below problem manifested.

Problem

On occasion, the 12v circuit will switch off entirely; there is a noticeable click from the oven/sink area, and everything goes off but the fridge lights on Gas. I cannot see anything that has "tripped". Switching the EC480 back on, it does so for about a second then it trips out. I can see briefly (as you can with EC480 "off") the various levels and disturbingly I can see the vehicle battery range up and down from 0v to 16v! Disconnecting the vehicle battery at the ignition makes no difference other than at some point it settles and correctly reads 0v from the vehicle battery.

It will do this consistently for ages until I physically turn off the EC500, wait a few mins, then turn it back on again. Then it might all be good again for hours or days even, but at some point, it switches off and we go round in circles again.

I've tried the above with EHU connected and not connected and I've tried it with just the 12v on, no pump or lights and get the same issue.

Solution?

I wonder if you good folks have seen this before? I'm tempted to think it's the charger unit because I can't see what else might trip out and couple that with the odd vehicle battery behavior. Of course, it could be something to do with how the wiring was done for the HPC and air compressor but I'm at a loss to explain what or where the 12v "trip" is...

Your thoughts in helping me troubleshoot are welcomed - thank you...


ETA: Hmmm further research suggests there is indeed a battery protect cut off, that seems likely as to why it turns off but why...?

Roopert wrote:I had to do an internet search to figure out what an HPC is, but anyway...

How long ago was the compressor fitted? If it was only recently then it would be worth contacting the fitting company to establish where they took 12V power from? I would expect this to have been from the vehicle battery, so it should, if that is true, be unrelated.

The EC500 does indeed have battery protection cutoff, but I don't believe it should manifest itself in the way that you describe. As I understand the feature, it should auto switch the habitation loads from vehicle to leisure battery at 10.9V, and should only turn off the power to habitation loads if the leisure battery drops below 9V. This is described in section 3.5 of the EC500 User Manual.

Unfortunately I don't know the Corinium Duo layout well enough to know what equipment is below the sink area, and how that relates to the location of the EC500. But I would want to investigate any electrical equipment located there.

One thing that would be worth checking: Make sure that all of the wiring looms that connect to the underside of the EC500 are securely plugged in. They have latches to prevent the multi-way plugs from working their way out, but it's not unknown for them to be not fully plugged in from the factory (or by someone else working on that area subsequently), which can allow them to work out under the weight of the wiring. You can get very unpredictable behaviour when those plugs are part in and part out!

Thanks, that's a good set of things to look at 

Spoken to Sargent and on further research; I have a few things to test but things are pointing to a failing Sargent solar controller...