House Battery Discharge When Running-Albin 35 Twin Cummins

[TD]

Has anyone ever tried getting the wiring diagram for their Albin? I sent email with no results. I was out in the Ocean [Pacific]fishing last week and after 9 hours all navigation instruments went dead. Checked the house battery voltage and it was 10 volts. Lucky no fog and I didn't have jumpers to connect to start battery. Haven't investigated yet but guess I need to trace a charge wire to the house battery. It charges to 13.5v on shore power. Any info is appreciated. TD

[Denis]

Over last winter I tried to get a wiring diagram from Albin but was told by their customer service guy that they do not have one. I got a little testy with him, knowing full well that they must have one for every boat they make. There can't be a manufacturing facility ridiculous enough to hard wire each boat without a diagram. But never the less I could not get a diagram. I had to trace the wires I was looking for.
Sorry I could not help. Denis

[Mariner]

I crawled around and made my own.

Do you have switches that allow you to combine the two batteries? Clearly for some reason your house and start battery are staying isolated. This is good when you're on the hook, but not when you're underway.

[TD]

I cannot use the battery switch to connect to one of the two start batteries even though the switch has a number 2 and all position. I haven't investigated yet but there might be an isolation device which does not let it do this. I am going to try and trace any charge wire back to the alternator charge plug wire. Thanks for the suggestion. TD

[Mariner]

TD, that doesn't really make sense. It seems unlikely that Albin would have built the boat without the ability to charge the house batteries off the engine.

On our boat, there are two of the Perko switches. When they are both switched to "all" the banks are combined. When they are both switched to "2" the banks are isolated. This allows you to protect your start battery when on the hook, and then start your engine without damaging the electronics. Once the engine is started, you combine them, and both batteries charge from the alternator. The only piece of documentation we got from Albin was a single piece of paper explaining this.

I've since modified it, but that is how it came from the factory. How many/what type of batteries is your boat equipped with?

[Mariner]

TD,

Just to clarify, Automatic Charging Relays are designed to allow current flow when charging, but not when drawing down. That is, when the voltage is above say 14 volts (indicating that the alternator is putting out power), it opens the connection allowing power to flow from the start bank to the house bank, charging both. But when the voltage drops back down to 13 volts (indicating that the alternator is not turning), it closes the connection and stops the flow of electricity, ensuring that the start battery is not drawn down by house loads.

You may have an ACR, but it would not cause the problem you describe unless it is improperly adjusted, or your alternator is not working properly (or is undersized).

Isolators, on the other hand, are designed to only allow the flow of electricity in one direction. These are used when a system has a dedicated battery for a single purpose, such as starting a generator, or running the bow thruster. Some boats have isolated batteries for the helm electronics. A battery isolator will allow power to flow to the dedicated battery from the main battery, but not back from the dedicated battery to the main battery. This ensures that it remains charged, even when the main battery has been drawn down. This is critical for things like a generator starter battery, upon which you may rely if your main battery becomes dead. It's unlikely that your boat is equipped with an isolator, based on what you've described. It's clear that your alternator is connected to the start side of your system (as it should be). An isolator would only ensure that your house battery stayed charged while your start battery was allowed to run dead, which is the exact opposite problem from what you're describing.

What you're describing is precisely what happens on our boat if I do not combine the batteries when running. Except on our boat, the problem usually becomes immediately evident as soon as I tap the bow thruster to push off the dock, and the engine shuts down, as it is electronically controlled!

[TD]

Mariner--Thanks for the reply. I have two 8D's and one 4D. I have four perko switches--one for the generator, one for the house and one for each engine. When I was out in the ocean fishing and found 10V on my house battery I tried switching to all or 2 with no results. I haven't actually tried turning all the batteries switches [house and two engine batteries] to all. I will try that. Thanks again for the reply. Terry

[TD]

Mariner--I should have also mentioned that I have a group 27 size battery for the generator and I have always left that switch off when running. Terry