Balmer voltage regulator vs battery isolator

[Gypsy Diver]

I am installing a new Balmer 100 amp alternator with their MC-618 external regulator on my Ford Lehman engine. The alternator is supposed to charge the two battery banks on my single engine trawler.

It is all wired up but I haven’t started the engine yet because I need to modify the belt tension arm. But I thought this would be a good time to set the new external regulator to my battery type. Then I noted that there is NO VOLTAGE at the main positive cable attached to the alternator, and the regulator won’t turn on. The other end of that positive (red) cable goes to a battery isolator which serves the two battery banks. There is no voltage at that point either. There IS voltage at the two battery cables attached to the battery isolator.

I understand that the purpose of a battery isolator is to provide a “one way valve” so that current will only pass from the alternator to the batteries, but not the other way. That would explain why there is no current at the alternator with the engine turned off. BUT IS THIS CORRECT? The trouble shooting guide in the Balmer manual says there SHOULD be voltage at the regulator, even with the ignition turned off. But the troubleshooting guide makes no mention of the possible existance of a battery isolator.

If this is correct, then must I run the engine before the voltage regulator can be adjusted?

 

[Bmarler]

I am installing a new Balmer 100 amp alternator with their MC-618 external regulator on my Ford Lehman engine. The alternator is supposed to charge the two battery banks on my single engine trawler.

It is all wired up but I haven’t started the engine yet because I need to modify the belt tension arm. But I thought this would be a good time to set the new external regulator to my battery type. Then I noted that there is NO VOLTAGE at the main positive cable attached to the alternator, and the regulator won’t turn on. The other end of that positive (red) cable goes to a battery isolator which serves the two battery banks. There is no voltage at that point either. There IS voltage at the two battery cables attached to the battery isolator.

I understand that the purpose of a battery isolator is to provide a “one way valve” so that current will only pass from the alternator to the batteries, but not the other way. That would explain why there is no current at the alternator with the engine turned off. BUT IS THIS CORRECT? The trouble shooting guide in the Balmer manual says there SHOULD be voltage at the regulator, even with the ignition turned off. But the troubleshooting guide makes no mention of the possible existance of a battery isolator.

If this is correct, then must I run the engine before the voltage regulator can be adjusted?

I’m not sure if the isolator is going to cause issues or not, but I do know you need power to the ignition terminal to wake up the regulator so you can program it. I rigged up a jumper from the battery bank so I could do it without having the oil pressure buzzer going off.

 

[tpbrady]

Isolators are for isolating two battery banks from each other not the alternator from the batteries. Without having the isolator manual, it seems that the isolator is for separating two banks of batteries from another bank. In this case the alternator output would go to the start battery, the start battery to one side of the isolator, and the other battery to the other side of the isolator.

Tom

 

[CharlieJ]

What is the make and model of the battery isolator? If the isolator is an FET based unit, it must be turned on for it to operate but I don't think that is the problem.

You must supply a constant B+ (red wire) to the MC618 and a switched B+ (brown) wire that is energized when the engine is operating. The constant supply is supplied from the battery side of the isolator. The switched supply is often accomplished by tapping into the oil pressure sender output.

 

[SteveK]

What is the make and model of the battery isolator? If the isolator is an FET based unit, it must be turned on for it to operate but I don't think that is the problem.

You must supply a constant B+ (red wire) to the MC618 and a switched B+ (brown) wire that is energized when the engine is operating. The constant supply is supplied from the battery side of the isolator. The switched supply is often accomplished by tapping into the oil pressure sender output.

How do you get B+ from an oil sender, I thought it was a wire looking for ground?

 

[CharlieJ]

@SteveK #5
I mis-spoke: I meant oil pressure switch, not the oil pressure sender.

From the Balmar Operation Manual:

Install BROWN 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 cases, 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.

 

[Bmarler]

If using the isolator is problematic, consider changing to an ACR. Then you aim the alternator at one battery, use the ACR to connect the other battery when charging.
Really though, the isolator shouldn’t be a problem as the constant b+ at the regulator should be connected as close the the battery as possible.
Just curious, when you bought the 618 did you get the smart shunt and Bluetooth adapter? It really opens up the 618 for programming and monitoring.