I recently added a Blue Sea M-ACR to the solar charging system I installed in Mariah back in 2021. I put it in mainly just for use with solar charging, but if you’re familiar with ACRs, you know that ACRs combine battery banks under any charging conditions (solar, alternator, shore power charger), and don’t discriminate between charging sources.
But I really only want the ACR for solar charging: With the engine alternator running, I prefer to manually select where the charge goes using the battery switch. With my shore power charger, three battery banks can be powered independently so I don’t need an ACR for that. It’s only under a solar charge, which day-in and day-out puts out more power than the usually-nearly-charged house bank needs, where I want to regularly combine another battery bank for charging. But even the second bank (a single starting battery or a single trolling motor battery, depending on which is selected) sits idle at a near-full-charge most of the time. So, I typically only run the ACR a few days every month just to keep everything topped off. A toggle switch, installed below the ACR, deactivates the ACR when not desired.
Here's the basic layout. 8ga wire connects each battery to a small, manual OFF-1-2-Both switch located in the lower cubby aft of the electrical panel. The common post of the switch connects to the solar controller’s output terminal. The Batt 2 connection comes off a 40A fuse in the house battery compartment. The Batt 1 connection comes from a 40A circuit breaker near battery #1 terminal on the Main Battery Switch.
The Blue Sea M-Series ACR is good up to 65A. My solar controllers only put out about 20A max. My Motorola alternator is rated at 50A. Eight-gauge wire can typically handle about 50A at the lengths I used.
The small OFF-1-2-Both switch below the ACR can be used to manually direct solar output to either bank (or both banks), or to disconnect solar output altogether. The ACR can be switched to ON to allow auto combining of battery banks (during charge conditions) unless the manual switch is selected OFF.
I also added a red LED to show when the toggle switch is activating the ACR. Without the red LED, the ACR only flashes its internal LED once every 15 seconds when the ACR is in STBY mode.
But I really only want the ACR for solar charging: With the engine alternator running, I prefer to manually select where the charge goes using the battery switch. With my shore power charger, three battery banks can be powered independently so I don’t need an ACR for that. It’s only under a solar charge, which day-in and day-out puts out more power than the usually-nearly-charged house bank needs, where I want to regularly combine another battery bank for charging. But even the second bank (a single starting battery or a single trolling motor battery, depending on which is selected) sits idle at a near-full-charge most of the time. So, I typically only run the ACR a few days every month just to keep everything topped off. A toggle switch, installed below the ACR, deactivates the ACR when not desired.
Here's the basic layout. 8ga wire connects each battery to a small, manual OFF-1-2-Both switch located in the lower cubby aft of the electrical panel. The common post of the switch connects to the solar controller’s output terminal. The Batt 2 connection comes off a 40A fuse in the house battery compartment. The Batt 1 connection comes from a 40A circuit breaker near battery #1 terminal on the Main Battery Switch.
The Blue Sea M-Series ACR is good up to 65A. My solar controllers only put out about 20A max. My Motorola alternator is rated at 50A. Eight-gauge wire can typically handle about 50A at the lengths I used.
The small OFF-1-2-Both switch below the ACR can be used to manually direct solar output to either bank (or both banks), or to disconnect solar output altogether. The ACR can be switched to ON to allow auto combining of battery banks (during charge conditions) unless the manual switch is selected OFF.
I also added a red LED to show when the toggle switch is activating the ACR. Without the red LED, the ACR only flashes its internal LED once every 15 seconds when the ACR is in STBY mode.