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Main Message Board / Re: ACR Wiring Revisited (again)
« on: August 03, 2022, 10:55:45 PM »
Wurl
GREAT as Stu says we need to understand what our wiring does -- then messing with it becomes less of a mystery!!
What most do not understand is that there are two sets of wiring -- the engine harness wiring that Universal installed (gummy bear plug at the engine end.) and Catalina boat wiring (the fuel pump power, the fuel tank sender, and the Alt AC wire to the tach -- all to the panel -- plus the tank negative/bond wire, deck fuel fill bond wire, and battery cables to the engine.) Universal had nothing to do with those CTY wires going to the panel so they never went thru the harness gummy bear plugs!! When CTY installed the harness extension to the cockpit panel it simply included "it's wiring" with the "engine wiring" as one bundle.
If you want a no-charge fuse set up for the panel feed wire I have about 50 here.
The fuel pump wire is redundant!! When I make a new harness for a customer I run ONE wire and split it at the engine end (to the pump and the Alt excite terminal.)
The terminal strips can be problematic -- it's best that you butt crimp the wires ad do away with the terminal strips. Per ABYC, every terminal MUST HAVE its wire supported within 6" of the terminal. That doesn't mean hanging in space with a spare wire wrapped around it as the Seaward "upgrade" instructs owners to do!!!
if your Alt has an external sense terminal could it be use to sense house battery voltage instead of AO voltage?
Yours must be a Motorola 8EM2017KA alternator.
No problem - so long as the excite terminal sees 12v, the alt excites. Same with the tach signal -- they both are referenced to your bonded-together negative battery terminals.
There's an argument that the most important V reading is what you have to start the engine. Of course I STILL maintain that a start battery should be an **EMERGENCY** battery and used only then but it's difficult to convince folks of that. With an ACR it doesn't matter much though. But the V meter in the cockpit is really to show whether the alternator is charging, not meant to give you an accurate battery V (hence why the OEM panel had an ammeter.) Just put a toggle switch on the panel and you can read either voltage source (or pull the voltage right off the AO terminal to show whether the Alt is charging, regardless of which battery.
GREAT as Stu says we need to understand what our wiring does -- then messing with it becomes less of a mystery!!
My wiring matches the diagram here, except I have an extra wire on the key switch 'I' terminal for the fuel pump.
https://www.catalinadirect.com/images/features/Z4644%20Wiring%20Diagram.pdf
The yellow wire pictured is a jumper from the AO to alternator sense.
What most do not understand is that there are two sets of wiring -- the engine harness wiring that Universal installed (gummy bear plug at the engine end.) and Catalina boat wiring (the fuel pump power, the fuel tank sender, and the Alt AC wire to the tach -- all to the panel -- plus the tank negative/bond wire, deck fuel fill bond wire, and battery cables to the engine.) Universal had nothing to do with those CTY wires going to the panel so they never went thru the harness gummy bear plugs!! When CTY installed the harness extension to the cockpit panel it simply included "it's wiring" with the "engine wiring" as one bundle.
If you want a no-charge fuse set up for the panel feed wire I have about 50 here.
The fuel pump wire is redundant!! When I make a new harness for a customer I run ONE wire and split it at the engine end (to the pump and the Alt excite terminal.)
The terminal strips can be problematic -- it's best that you butt crimp the wires ad do away with the terminal strips. Per ABYC, every terminal MUST HAVE its wire supported within 6" of the terminal. That doesn't mean hanging in space with a spare wire wrapped around it as the Seaward "upgrade" instructs owners to do!!!
if your Alt has an external sense terminal could it be use to sense house battery voltage instead of AO voltage?
Yours must be a Motorola 8EM2017KA alternator.
Quote
Assuming the panel feed is left on the start battery and the AO goes to the house battery, will there be issues with the alternator excite or AC output to the tach?
I'd see my starting battery voltage (when not combined) rather than monitoring the alternator, but maybe that's okay with me.
No problem - so long as the excite terminal sees 12v, the alt excites. Same with the tach signal -- they both are referenced to your bonded-together negative battery terminals.
There's an argument that the most important V reading is what you have to start the engine. Of course I STILL maintain that a start battery should be an **EMERGENCY** battery and used only then but it's difficult to convince folks of that. With an ACR it doesn't matter much though. But the V meter in the cockpit is really to show whether the alternator is charging, not meant to give you an accurate battery V (hence why the OEM panel had an ammeter.) Just put a toggle switch on the panel and you can read either voltage source (or pull the voltage right off the AO terminal to show whether the Alt is charging, regardless of which battery.
