Hi everyone, grateful for any help with this one. The screenshot chart at the end shows the exact point when the 240v sockets circuit on a 12v boat stopped working.
The strange thing is the RCD for the circuit did not blow and nor did the boat-side or shore-side trips.
The Multiplus 2 is not showing any warning lights and the only symptom (other than inoperative sockets) is the inverter side of the Multiplus defaults to charger only whenever I connect shore power.
My question is where to start? Is this likely a Multiplus configuration issue or should I be looking at the boat’s wiring loom?
I should say that 24 hours before this happened I added (as advised) a second set of cables from the Multiplus to a Lynx distributor. The single set of cables had a 250 amp fuse and I put a 200 amp fuse in each of the doubled up cables. Not sure if this contributed to/ caused but worked ok for 24 hours.
That looks like a short circuit in the wiring on the AC-out of your inverter. What you see in the graph is the overload protection of the MP2; it retries 3 times and then shuts down.
You first need to uncouple the AC-out from the network and find the fault. After that restart the MP2 by unhooking and reconnecting the DC.
The reason the breaker for the circuit didn’t trip was because of the maximum output current that is not high enough to reach the magnetic trip current of a household breaker. The overload protection of the PM2 makes sure the overload does not hold long enough to melt wires or cause a fire.
Thank you so much for the response and the insight. Especially valuable to learn how to read the graph, so thanks for the education. I will follow the instructions when down on the boat next week.
If I may prevail upon your knowledge further can I just completely rule out the fact that I doubled up the AC cables as being in any way connected? It does not seem logical, and it had worked fine for 24 hours before this happened, but I have learnt to always look at the last thing I’ve done as a start point of any error!
Also if we are narrowing down the short to the AC sockets circuit, at the time it ‘blew’ I had two fan heaters and then flipped on the kettle, which seemed to cause the issue. No chance it could just be an ‘overload’ as opposed to a ‘short’?
Many thanks for the support - it really helps build confidence to get better.
Oh! Well that changes things indeed. A kettle will usually run at 1500 to 2000W, and fan heaters at 1000W each easily. That means your well over the powerbudget the MPII can supply (2400W). Were you on a shore line? Or unplugged?
I was on 16Amp shore power. I clearly did not think about this very much but may have thought as MP2 can handle 32amp @230v I’d have been ok - obviously not!
Do you think if I just unplug things and follow your reset sequence all should be OK?
Only one of the ac out circuits is affected - the other has the water heater on it and seems ok.
The behavior from the graph meant the shore power was off, either on the dock, or on your vessel. It could also be, that there WAS a short, but on the shore line.
Best way forward would be tu switch off both the shore power and the ships AC-outlets (simply turn off the breakers) restart the MPII and work from there. First establish there is no fault aboard, then check the shore connection.
Thanks David for this extra info. I will go to boat next week and work through it, much encouraged by advice. I’ll report back for the benefit of others who are also keen to learn! Thanks again. Peter
