Electrical Gremlins -HELP!

Oct 26, 2010
2,155
Hunter 40.5 Beaufort, SC
I discovered something very strange that leads me to believe I have something wrong connected. It is kind of hard to explain but bear with me.

Hunter 40.5
AC Shore Power connected
Separate House Bank and Starting Bank, each with an ON/OFF Selector Switch (Not 1/2/Both)
Starting Bank is charged by a Bue Sea ACR
Battery Charger is a ProMariner50


My AC electrical was powered by Shore Power with the Battery Charger (a ProMariner) turned on. The DC Battery Selector Switch for the House Bank was turned ON (It is an ON/Off not a 1/2/Both switch) The DC Main switch on the DC control panel was also turned with several DC loads energized.

I switched the DC Battery Selector Switch for the house bank to OFF but the DC Main switch on the DC control panel was still ON. This should have killed all power to the DC Panel (I think) However, the DC panel was still powered and the equipment was running, even though the House Battery Selector Switch was in OFF. The AC power was still being supplied by Shore Power and the Battery Charger was on. When I turned the Battery Charger breaker off on the AC panel, the power was then turned off to the DC Panel.

My conclusion is that the AC powered ProMariner Battery charger is not hooked up correctly and is somehow providing DC power directly to the DC panel in some way. this is not a new hookup and I've had the Promariner installed for about 5 years so I don't know what has changed

I intend to go back to the boat tomorrow and attempt to trace the power and see if I can figure it out. Any help or ideas on why this is happening
 

DArcy

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Feb 11, 2017
1,770
Islander Freeport 36 Ottawa
The only way I can see that happening is if the battery charger is downstream from the ON/OFF switch, which doesn't seem right. Are you sure this is a new behavior? I don't see how this could have changed if you haven't moved anything around.
 
May 17, 2004
5,714
Beneteau Oceanis 37 Havre de Grace
It sounds to me like the charger output is connected to the Load side of the DC switch, not the battery side. That would allow the charger to keep powering your DC panel (but not charging the battery) even when the main DC switch was off. I don’t know that I would really call that a problem, just a particular layout to be aware of. You can trace the wire from the charger to the DC circuitry to verify.
 
Jan 11, 2014
13,043
Sabre 362 113 Fair Haven, NY
The ProMariner charger will serve as a 12v DC power supply in addition to being a charger. If the charger is connected to the system after the switch then it will supply power to the DC circuits.

If you disconnect the AC, does this still happen?

This will happen on my boat because all the charging sources are connected to bus bar which is connected to the main DC switch. The batteries (start/reserve and house) have their own switches before they connect to the busbar.
 
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Likes: LloydB
Oct 26, 2010
2,155
Hunter 40.5 Beaufort, SC
I don't know if it is actually new or it is the first time I've ever shut off the Battery Selector switch with the Battery Charger still on and the DC main switch on? I normally shut off all DC Breakers, then shut off the DC Main switch on the DC panel, then turn the Battery Selector Switch to Off.
 
Nov 21, 2012
749
Yamaha 33 Port Ludlow, WA
I concur with David and Dave. The charger is powering your DC circuits. An MPPT controller can do the same thing if it's wired on the load side of the switch.
 
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Likes: LloydB
Oct 26, 2010
2,155
Hunter 40.5 Beaufort, SC
Kind of figured that to be the case but I didn't intend to install it that way. My MPPT controller for the solar panel is wired directly to the house battery bank. Your suggestions have helped me narrow it down. In fact, I may just leave it the way it is. It does mean that I will want to make sure I leave the House DC Battery Switch is in the ON position when I want to charge the batteries from the ProMariner. However, I will still track down where the ProMariner is connecting and may decide to make sure I move it to the upstream side of the Battery Disconnect so it will charge without having to have the DC battery isolation switch closed.

Thanks for the input.
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,335
CAL 35 Cruiser #21 moored EVERETT WA
:plus:
Pro Mariner is supplying DC power. Definitely track down the wiring.
Easy confirmation. Switch off the Pro Mariner do the Gremlins disappear.

Do you have DC to all circuits or just some?

That may help to decide to leave it connected in the current structure or modify it.
 
Oct 26, 2010
2,155
Hunter 40.5 Beaufort, SC
:plus:
Pro Mariner is supplying DC power. Definitely track down the wiring.
Easy confirmation. Switch off the Pro Mariner do the Gremlins disappear.

Do you have DC to all circuits or just some?

That may help to decide to leave it connected in the current structure or modify it.
1 When I switch off the Pro Mariner (with Shore Power ON, DC Main ON, Battery Selector OFF, Engine not running) Gremlins disappear
2. DC is to all circuits on the DC panel (in the above configuration) until the Pro Mariner is switched off.
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,335
CAL 35 Cruiser #21 moored EVERETT WA
What happens when DC Main is off in the above configuration.
ProMariner on.
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,335
CAL 35 Cruiser #21 moored EVERETT WA
It sounds to me that the feature of the Pro Mariner to supply DC power to the boat when batteries are removed as In being replaced or serviced ashore was considered and activated at install of the charger.

That is the way I chose to install my charger.

I read about this option on MaineSails website while exploring the Sterling/ProMariner chargers.