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.

 

[luna]

The Automatic Power Selector likely does not feed the house circuit, nor are the thrusters likely connected to it as a load.

It does what its name implies, selects the higher of any two connected power sources (they don't have to be batteries) to power whatever you connect to it as a load. The load is often just the ZF Microcommander controls, nothing else, unless you also deem it critical (your VHF?) by connecting it as a load.

The controls for shift and throttle are what most people would consider critical. As a result, it would be nice if they had a back up power supply. This device does that by selecting the highest voltage of either of the two power supplies (batteries) that are connected to it, thats it. Nothing more. The batteries themselves are never connected together.
This way the engine controls hopefully have a separate, secondary, workable voltage source.

Even though your engine's throttle and your gear's shift selection is done by cable at the engine/gears, the fact that you have this device tells me that these cables only go to a box about 10" square and 8" thick, likely in the ER, which is only wired to your controls at the helm(s). Inside the box are the motors, cable connection hardware and controls that actually pull/push the cable. You are almost "fly by wire" as your actions at the helm only produce an electrical signal. No control cable is pushed by the helm levers.

This device is a diode based selector and as a result the voltage drop through the device is said to be 0.35 to 0.45 Volts depending on load. If you are measuring 0.6 volts, make sure no voltage drop from the conductors is included.

The device, although branded ZF is likely made by Newmar out of Newport Beach CA. which uses as a motto "A Mission Critical Electronics Brand." How fitting!

Here is a link to their info. on the product. Doesn't it look similar? Stickers are easy to make.
Newmar generally mades good stuff, albeit you won't find it on your phone.

Automatic Power Selector | 12V DC | 24V DC | 48V DC | 70 Amps to 160 Amps | Mobile Mount | Newmar Powering the Network

Automatic Power Selector by Newmar Powering the Network: 12V DC, 24V DC and 48V DC, 70 Amps to 160 Amps. The Automatic Power Selector (APS) is a solid state device which enables installation of a seamless, redundant power system for critical electronic loads. It selects the higher voltage of two...

www.poweringthenetwork.com

If it was me, I would confirm what powers it (both feeds) and what are the loads. Once I'm happy with that, I would keep it as it provides a useful service.

 

[DDW]

It may also be powering the engine electronics. I assume you have a common rail engine, it will stop instantly without 12V power.