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Relay for always on MC-614

Apr 1, 2019
22
Freedom 38 Boston, MA
I have a Balmar MC-614 voltage regulator, and since I re-wired my alternator so that it directly charges my batteries (i.e., not through the same cable that goes from the batteries to the starter), I realized that it’s powered on all the time. I did as MaineSail suggests and installed a Service Disconnect switch when I rewired everything, and the two wires (terminals #2 and #9) from the MC-614 are connected to the alternator side of that switch. From there, the positive cable goes to an “always on” positive bus, and then to the batteries.

Here’s my question: is there any reason not to wire the MC-614 to a relay, so that it’s only powered when I turn on the engine panel? I know it probably doesn’t consume a ton of current, but I still don’t like the idea of it being on 100% of the time. I already use a relay that’s powered by the engine panel accessory circuit to turn off/divert my wind generator when I’m running the engine, so I know it could do the job. Is there any reason not to do this for the voltage regulator?
 
Feb 26, 2004
21,710
Catalina 34 224 Maple Bay, BC, Canada
Here’s my question: is there any reason not to wire the MC-614 to a relay, so that it’s only powered when I turn on the engine panel?
When I installed my MC-612, predecessor to your MC-614, there was already a separate power feed to the regulator from the ignition switch itself, so no additional relay was needed. Did you do something different? Good on you for doing the service disconnect. :)
 
Apr 22, 2011
699
Hunter 27 Pecan Grove, Oriental, NC
My MC-614 will not turn on without the ignition key on. If I turn the ignition off while the engine is running, the alternator will stop charging. My alternator output is connected directly to the house batteries not to the starter.
 
Apr 1, 2019
22
Freedom 38 Boston, MA
My MC-614 will not turn on without the ignition key on. If I turn the ignition off while the engine is running, the alternator will stop charging. My alternator output is connected directly to the house batteries not to the starter.
Do you have a service disconnect between the alternator output and the battery bank?
 

Ward H

.
Nov 7, 2011
3,019
Catalina 30 Mk II Barnegat, NJ
Here’s the section from the manual on connecting the regulator’s ignition wire:

The BROWN Ignition Wire #3 in diagram at right provides ON/OFF voltage for the regulator. This wire is included in the Ford-style plug at the regulator end of the wiring harness. The other end of the wire is fitted with a butt connector.Typically, the ignition wire is connected to the ON side of the ignition switch.This may be at the actual switch, or to a wire in the existing engine wiring loom that delivers switched voltage from the ignition switch. In some an oil pressure switch may be used to activate the regulator. In either case, the regulator’s ignition wire must see zero volts when the engine ignition is switched off.
The #3 wire is 3rd up from the bottom on the right side of the regulator.

Sounds like this wire is somehow connected to an always on connection by mistake.

A service disconnect shouldn’t affect this at all unless it is not wired correctly.
 
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Apr 1, 2019
22
Freedom 38 Boston, MA
YES! Thank you, this is perfect! I’ll just re-connect the brown wire to the engine accessory circuit and I should be all set.
 
Apr 22, 2011
699
Hunter 27 Pecan Grove, Oriental, NC
No, I do not have a service disconnect switch. Am considering installing one though.
The ignition switch will turn off the alternator as MS stated. I misspoke in saying that I was considering installing a service disconnect switch. What I am thinking about installing is what Balmar calls a "small engine mode" switch. When the switch is on, it will short the neg a pos alternator temp. sensor cables. This tells the alternator to reduce its output by 50%.