Upgrading a 2-bank charger to a 1-bank charger/inverter

[RodrigoDC]

Originally Posted by Dsanduril

The difficulty you are running into is that the cables that connect the "charger" portion to the battery are the same as the ones that power the "inverter" portion from the battery. With that configuration there is no easy way to connect the charger to two batteries. There is no separate "charger output" that you can connect to a your Promariner isolator. So, you have two options:

a) just connect the inverter/charger to the house bank and call it done. Why do you need to charge the start battery from the inverter/charger? The alternator will take care of this when you run the engine. Unless you leave the boat sitting for long periods of time there is likely little need to charge the start battery from the charger - although it could be desirable/necessary if the boat sits for long enough that self-discharge is a problem.

b)use any one of the methods above (echo charger, ACR, DC-DC, ....) to combine the batteries when the charger is active. You might even be able to make the Promariner handle this function if it genuinely switches state when the ignition stud has voltage and it will work in "reverse", but the manual is silent on this subject so it would require testing. The simplest in this case would be as smac says:

Right, great points Dsanduril. The more I learn about my electrical system, the more I see how complicated it was set up by the previous owner.


What if I connect an ACR to a manual switch on the negative wire to turn it on only to top off the stater bank, then shut it off? Yes, this defeats the purpose of automation, and you're right that the starter should not be used much and will be recharged in a matter of minutes/hours from the alt. But I'm just paranoid to start my engine only to find out there is not enough juice on it.



Furthermore, the house batteries will be taxed because I keep my boat on a mooring ball during weekends. So My concern is that some clueless guest may run the AC or something and kill the house bank while tied up to the ball. At least I will make sure to be able to start the engine to take the boat back to shore.


Let me know what you think of an ACR with a switch to negative.

[Stu Jackson]

Originally Posted by RodrigoDC

Right, great points Dsanduril. The more I learn about my electrical system, the more I see how complicated it was set up by the previous owner.

What if I connect an ACR to a manual switch on the negative wire to turn it on only to top off the stater bank, then shut it off? Yes, this defeats the purpose of automation, and you're right that the starter should not be used much and will be recharged in a matter of minutes/hours from the alt. But I'm just paranoid to start my engine only to find out there is not enough juice on it.

Furthermore, the house batteries will be taxed because I keep my boat on a mooring ball during weekends. So My concern is that some clueless guest may run the AC or something and kill the house bank while tied up to the ball. At least I will make sure to be able to start the engine to take the boat back to shore.

Let me know what you think of an ACR with a switch to negative.

Why complicate things even more? Dsanduril is right, KISS. The ACR will ONLY work when shorepower or alternator output is available. Why switch it at all (UNLESS you plan to be motoring for really, really long periods)? I do have a switch in the negative of my Yandina combiner, but hardly ever use it and I motor a lot here in BC.


"What if I connect an ACR to a manual switch on the negative wire to turn it on only to top off the stater bank, then shut it off?" The battery acceptance of the start bank will take care of that, you never have to switch an ACR off. That's the whole purpose of an ACR.



"Some clueless guest?" You need to choose your friends more carefully or remove the fuse to the AC if you're not there. This is a bassackwards way of dealing with a charging issue for which you do have solutions.

[RodrigoDC]

Thank you all who assisted me. This is what I decided to do in case my configuration is helpful to anyone:

Originally Posted by Dsanduril

b)use any one of the methods above (echo charger, ACR, DC-DC, ....) to combine the batteries when the charger is active. You might even be able to make the Promariner handle this function if it genuinely switches state when the ignition stud has voltage and it will work in "reverse", but the manual is silent on this subject so it would require testing. The simplest in this case would be as smac says:

I'm using the Xantrax Freedom XC to charge the House Bank directly (via a fuse). From the alternator, the Promariner connects to both banks directly, giving it priority to the Starter Bank. In between, I connected a Blue Sea Systems ACR 7610 that so far is charging both banks via the Xantrex or the Promariner without overcharging any one bank.


I feel that I'm set. Time will tell if this configuration may damage any of the batteries, but according to my voltmeter, both banks oscillate between 13 and 13.4 volts, even when my wind turbine is charging the house bank.


Thank you again and fair winds.