Electrical Back Feed

[hatchmick]

We have well kept 2014 Hunter 426 with a strange electrical issue. The boat has a Freedom 25 batt charger, and a separate inverter, a Panda Genset, and two AC units. As far as I can tell no changes or alterations have been made or added since it left the factory. The issue is when I turn off the two master battery (start and house) switches and have a 110 volt AC power on # 1 line coming into the boat I have some 12 volt power at the 12 volt panel. If I turn off # 1 and use only # 2 incoming A/C power it does bring power into the 12 volt panel.
I am speculating that the batt charge must feed off of the #1 A/C 110 volt power before the battery switch and this accounts for the back feed. There is no battery charger circuit breaker on the 110 volt panel which I also find odd. The back feed amperage seems low as I can hear the 12 volt fans increase speed when I turn the battery switch back on.
Is this normal to have this back feed? Has anyone else seen this and it an issue to be concerned?

Also, some of the wiring Hunter apparently used looks more like welding cable instead of heavy duty marine 12 volt battery cables. Does anyone else have a similar issue/concern?

 

[centerline]

it sounds like there is a problem somewhere, however slight it may or may not be.

one way to tell is to get a 12V short circuit tester like this, and use the meter to trace/find the wire where the power is coming from....

there are much more sophisticated devices that can do so much more in short circuit testing such as this one that I have, and some much more complicated, but for a simple and dependable device, the first one is good to have on board.

it is used simply by holding the meter near the wire loom and then when you get a signal, hold it near each wire individually until you find the one carrying the current.... then follow the wire... or if the wires are all the same color, use the meter to find the right one on the other side of the bulkhead or compartment so you can continue to follow it.... until you find the source/connection or the termination end...

the device with the alligator clips is a power sender that can be connected at either end or in between, to power up a circuit, weather its an open circuit or a shorted circuit, so that you can trace the wire to its connection or termination... and find the problem

the problem you seem to have will be a simple test, as when all circuits are dead except the one in question, there will be no confusion as to what wire it is and where it goes...

 

[Don Lucas]

If your 426 is like my 410 only #1 AC shore power line feeds to the the inverter/charger. There is no inverter/charger breaker because the inverter selector switch determines which battery is either on for supply to the inverter or from charger (and on my boat the engine alternator). The house battery breakers next to the inverter selector switch determines which battery feeds the main DC panel, these are independent from whatever is going on with the inverter/charger circuit.

 

[ice breaker]

on my 2004 41 the battery switch does not isolate or shut off anything. It appears to be part of a legacy wiring system. The main breaker does shut off all of the power, except bilage pumps. I believe much of this does have to do with the inverters being added to most of the boats at the time.

Take a look at the electrical diagram for your boat that came with the manual. It is a puzzle, but should have some notes on inverter vs no inverter.

 

[hatchmick]

Thanks all for the inputs- Will try and match the multiple wiring schematics to the actual-as built boat wiring. We get some noise on the VHF when it is on shore power #1 - I assumed the backfeed was the problem. It appears that it may have been wired that way from Alachua factory.