Automatic Power Selector... why?

[dhays]

So I have been doing more hunting around the boat recently trying to identify parts of the electrical system that I've been ignoring for the past 8 years. Here is an example that has me stumped.

This Automatic Power selector is installed on the boat and feeds the house circuit that, controls the power to the solenoids that connect the various high loads to their respective batteries. This device is really unknown to me but appears to be used primarily with ZF Microcommand controls. I can understand its application for that, as it helps to ensure that if you lose power in one battery bank, it will quickly switch to the secondary bank so that you still have control over your engine.
ZF Automatic Power Selector

The thing is, I don't have electronic controls on my engine. They are cable. The throttle is a cable control. So the only reason I can see for having this is to be able to power the solenoids that keep the engine connected to its battery, the thrusters to their bank, and the House bank to the house battery. It is setup with Source #1 as the House, and Source #2 is the start battery. I don't have a problem with this being there other than it takes up extra space on the DC bulkhead AND it looses about .6v. The output from the Load is about .6v less than the input.

So my question... is this normal behavior for these things? If so, that seem odd. If not, is it a sign that this thing is failing? I would be tempted to just get rid of it. However, I'm going to swap the house agms for lithium and I suppose there is the very small chance that their BMS could shut them down, then it would be nice to have that circuit fed by another bank.

 

[Delta Riverat]

I would get rid of it for 2 reasons;

1) It drops half a volt which is way too high for a switch.
2) The max load is 70 amps. Seventy amps? You must be joking. Probably another reason it drops half a volt.

 

[Portage_Bay]

So I have been doing more hunting around the boat recently trying to identify parts of the electrical system that I've been ignoring for the past 8 years. Here is an example that has me stumped.

This Automatic Power selector is installed on the boat and feeds the house circuit that, controls the power to the solenoids that connect the various high loads to their respective batteries. This device is really unknown to me but appears to be used primarily with ZF Microcommand controls. I can understand its application for that, as it helps to ensure that if you lose power in one battery bank, it will quickly switch to the secondary bank so that you still have control over your engine.
ZF Automatic Power Selector
View attachment 158691
The thing is, I don't have electronic controls on my engine. They are cable. The throttle is a cable control. So the only reason I can see for having this is to be able to power the solenoids that keep the engine connected to its battery, the thrusters to their bank, and the House bank to the house battery. It is setup with Source #1 as the House, and Source #2 is the start battery. I don't have a problem with this being there other than it takes up extra space on the DC bulkhead AND it looses about .6v. The output from the Load is about .6v less than the input.

So my question... is this normal behavior for these things? If so, that seem odd. If not, is it a sign that this thing is failing? I would be tempted to just get rid of it. However, I'm going to swap the house agms for lithium and I suppose there is the very small chance that their BMS could shut them down, then it would be nice to have that circuit fed by another bank.

Find out what it powers. Disconnect the load side and see what doesn't work.

What do your engines require to run? An electric fuel solenoid in an energize to run system? Any electronic engine controls, not throttle and shift.

 

[Delta Riverat]

If it drops half a volt at 70 amps it is dissipating 35 watts. Thirty five watts on some little contacts will get really hot.