My big project for the winter was upgrading most of my battery-related systems. Though some of this had long been on the list, the whole lot got moved to the forefront when my old Newmar 25 AC charger died. At about the same time, one of my flooded LA batteries was having trouble holding voltage while the other seemed okay. In the end, I wound up installing two new Costco/Interstate 80A-hr FLA deep cycle batteries, a Sterling 30A charger, a 50W Renogy solar panel, Victron 75/15 MPPT charge controllers, and a Balmar SG200 battery monitor and shunt. Here are the details:
Battery Charger Install: The fist step was putting in a new AC charger. As usual, the typical questions were, (1) Where should I mount the charger, and (2) Should I wire it directly to the batteries, or through the main BATT (Off/1/2/All) switch? There are no right or wrong answers, but the best solutions usually have to do with minimizing the length of the charging wires. However, if the battery charger is located close to the BATT switch, you can use the large (typically 1/0 guage) battery cables themselves to carry charging current out to the battery banks, with essentially zero additional voltage drop. This was the driving factor behind my decision to mount the new charger under the nav table. From the charger, Bank 1 (starting battery) is wired to the back of the BATT switch (with an in-line circuit breaker mounted behind the DC panel). That gave a 3-4 ft run of 8 ga wire from charger to BATT switch, then used the existing 10 ft length of 1/0 battery cable to reach the starter battery. Bank 2 (house) was wired directly from charger to bank, as that distance is only 3-4 ft of 8ga wire in total, with a 40A fuse installed in a battery terminal fuse block.
Additionally (and I may be the only person who does this), I installed individual battery kill switches at the output terminal of each battery bank. The kill switches accomplish a couple of things: (1) Since the battery box in the 32-3 is pretty shallow, you can't easily mount an MRBF fuse to the top of the battery post (there is not enough clearance under the compartment's wooden lid). By mounting the kill switch lower than the top of the battery, I was able to accommodate the MRBF fuse inside the battery box. (2) Since current from the 30A battery charger has to pass through the kill switches, I can isolate either bank during charging. I.E., even a "smart" charger, like the Sterling, can't send different charge profiles to different battery banks. If I know the starting battery needs bulk charging while the house bank only needs a float charge (the house bank is kept topped up via solar charge), I can isolate the house bank (via the kill switch) and send all AC charge current to the starting batt (or, vice versa). And, (3) since I haven't yet tackled re-wiring the guts of my DC panel, I like knowing that the battery cables and the back of the BATT switch are completely depowered when I leave the boat (both kill switches off). In that case, the only circuits that remain powered are the automatic bilge pumps, the battery monitor, and the solar charge controllers--all through wires that I know are newly installed and properly insulated, terminated, and fused.
AC charger below nav table
C/B "fusing" of AC charger lead to starter battery (via BATT switch, behind the DC panel)
160A-hr house bank in batt compartment (AC charger wired to battery fuse block), then via kill switch to the battery
Solar Panel Installation: I'd long wanted to add solar charging, and this seemed like the ideal time to do it. The same decisions about location and wiring runs that I faced with the AC charger applied again here. But, with solar, you can typically allow the wires between panel-and-controller to be "long" (as these are 'high' voltage/low amperage, and not so sensitive to voltage drop) while attempting to minimize the controller-to-battery runs (as these are 'high" amperage runs, more sensitive to voltage drop). So, I mounted the Victron charge controllers to the quarterbeth sidewall, just aft of the Nav station. Though I only have one 50W panel installed now (starboard side), I'll add a second one this winter. Each panel will power its own 75/15 MPPT controller connected in parallel to the house bank (in the future, I may add an ACR to charge the starting battery as well). Victron claims that a pair of these "smart" (bluetooth enabled) MPPT controllers can be linked in a network so that one controller will work as "master" to regulate the output of both controllers. I'll have to test that once I get the second panel up and running.
I opted for Renogy 50W rigid panels. They are about half the size and weight (and, yes, output) of the popular 100W panels. At 2ft by 2ft, and about 8 lbs, they're easy to mount, dismount, and store on the boat. From where they sit on the aft 'pulpit,' I suspected they would always lie at a sub-optimal angle to the sun (my boat is on a mooring buoy, and floats predominantly facing either due N or due S). To make up for this, I bought Renogy's tilting brackets, riveted two lengths of aluminum U-channel stock to the bottom, and fastened to a pair of Magma grill rail-mounts. This way, I can tilt the panels both side-to-side and forward-aft to maximize the output of my "smaller" panels. Since I board the boat predominantly from a dingy at the stern ladder, I like that the smaller panels take up less space near the stern. Renogy's tilt brackets add a little bulk to the height of the otherwise "sleek" panels, but at less than $30 off the shelf, I couldn't' see taking on the added time (and, likely, expense) to build my own.
Victron MMPTs on quarterberth sidewall
Renogy tilt bracket with U-channel added to the base
Solar panel installed
Battery Monitor and Shunt: The last part of the upgrade was adding a Balmar SG200 battery monitor and shunt. This turned out to be the hardest part because nothing seemed to fit where I wanted it. The Balmar "smart shunt" is an octagonal behemoth at nearly 5" long and 3.5" wide. As with any shunt, the closer you put it to the batteries, the easier it is to ensure that all circuits are taken only from the "load" side of the shunt (vs. the "battery" side). I wanted to place mine in the battery box, but its size was a problem. Ultimately, I cut off about 3/4" from each of the long edges of the shunt's base, then still had to cut a recessed mount into the battery box sidewall.
Recessed cut-out for Balmar shunt, made with plywood and epoxy.
Then, the Blues Seas Battery Terminal ground block had to be moved off the battery and to the "load" side of the shunt. This required cutting another hole in the battery box to mount a negative "stud" to hold the ground block and then adding a jumper wire to connect to the shunt.
The final product:
As for the monitor display, I had hoped to put in the 2" round hole where the original (square, analog) voltmeter had been on the DC panel (though I had replaced the original voltmeter with a modern, digital one a few years ago). But, due to the spaghetti bowl of wires behind the DC panel, I couldn't insert the Balmar gauge deep enough to mount it on the panel. In the end, I left the existing digital voltmeter in the DC panel, and built a small teak mounting panel for the Balmar gauge to the left of the DC panel.
............. 
The unit above the Balmar is the remote display/control for the Sterling battery charger. To the left of that is an ongoing bilge pump alerting panel I've been working on for a while. That one is on hold since I swore to no more electrical projects until after this sailing season.
Battery Charger Install: The fist step was putting in a new AC charger. As usual, the typical questions were, (1) Where should I mount the charger, and (2) Should I wire it directly to the batteries, or through the main BATT (Off/1/2/All) switch? There are no right or wrong answers, but the best solutions usually have to do with minimizing the length of the charging wires. However, if the battery charger is located close to the BATT switch, you can use the large (typically 1/0 guage) battery cables themselves to carry charging current out to the battery banks, with essentially zero additional voltage drop. This was the driving factor behind my decision to mount the new charger under the nav table. From the charger, Bank 1 (starting battery) is wired to the back of the BATT switch (with an in-line circuit breaker mounted behind the DC panel). That gave a 3-4 ft run of 8 ga wire from charger to BATT switch, then used the existing 10 ft length of 1/0 battery cable to reach the starter battery. Bank 2 (house) was wired directly from charger to bank, as that distance is only 3-4 ft of 8ga wire in total, with a 40A fuse installed in a battery terminal fuse block.
Additionally (and I may be the only person who does this), I installed individual battery kill switches at the output terminal of each battery bank. The kill switches accomplish a couple of things: (1) Since the battery box in the 32-3 is pretty shallow, you can't easily mount an MRBF fuse to the top of the battery post (there is not enough clearance under the compartment's wooden lid). By mounting the kill switch lower than the top of the battery, I was able to accommodate the MRBF fuse inside the battery box. (2) Since current from the 30A battery charger has to pass through the kill switches, I can isolate either bank during charging. I.E., even a "smart" charger, like the Sterling, can't send different charge profiles to different battery banks. If I know the starting battery needs bulk charging while the house bank only needs a float charge (the house bank is kept topped up via solar charge), I can isolate the house bank (via the kill switch) and send all AC charge current to the starting batt (or, vice versa). And, (3) since I haven't yet tackled re-wiring the guts of my DC panel, I like knowing that the battery cables and the back of the BATT switch are completely depowered when I leave the boat (both kill switches off). In that case, the only circuits that remain powered are the automatic bilge pumps, the battery monitor, and the solar charge controllers--all through wires that I know are newly installed and properly insulated, terminated, and fused.
AC charger below nav table C/B "fusing" of AC charger lead to starter battery (via BATT switch, behind the DC panel) 160A-hr house bank in batt compartment (AC charger wired to battery fuse block), then via kill switch to the batterySolar Panel Installation: I'd long wanted to add solar charging, and this seemed like the ideal time to do it. The same decisions about location and wiring runs that I faced with the AC charger applied again here. But, with solar, you can typically allow the wires between panel-and-controller to be "long" (as these are 'high' voltage/low amperage, and not so sensitive to voltage drop) while attempting to minimize the controller-to-battery runs (as these are 'high" amperage runs, more sensitive to voltage drop). So, I mounted the Victron charge controllers to the quarterbeth sidewall, just aft of the Nav station. Though I only have one 50W panel installed now (starboard side), I'll add a second one this winter. Each panel will power its own 75/15 MPPT controller connected in parallel to the house bank (in the future, I may add an ACR to charge the starting battery as well). Victron claims that a pair of these "smart" (bluetooth enabled) MPPT controllers can be linked in a network so that one controller will work as "master" to regulate the output of both controllers. I'll have to test that once I get the second panel up and running.
I opted for Renogy 50W rigid panels. They are about half the size and weight (and, yes, output) of the popular 100W panels. At 2ft by 2ft, and about 8 lbs, they're easy to mount, dismount, and store on the boat. From where they sit on the aft 'pulpit,' I suspected they would always lie at a sub-optimal angle to the sun (my boat is on a mooring buoy, and floats predominantly facing either due N or due S). To make up for this, I bought Renogy's tilting brackets, riveted two lengths of aluminum U-channel stock to the bottom, and fastened to a pair of Magma grill rail-mounts. This way, I can tilt the panels both side-to-side and forward-aft to maximize the output of my "smaller" panels. Since I board the boat predominantly from a dingy at the stern ladder, I like that the smaller panels take up less space near the stern. Renogy's tilt brackets add a little bulk to the height of the otherwise "sleek" panels, but at less than $30 off the shelf, I couldn't' see taking on the added time (and, likely, expense) to build my own.
Victron MMPTs on quarterberth sidewall Renogy tilt bracket with U-channel added to the base Solar panel installedBattery Monitor and Shunt: The last part of the upgrade was adding a Balmar SG200 battery monitor and shunt. This turned out to be the hardest part because nothing seemed to fit where I wanted it. The Balmar "smart shunt" is an octagonal behemoth at nearly 5" long and 3.5" wide. As with any shunt, the closer you put it to the batteries, the easier it is to ensure that all circuits are taken only from the "load" side of the shunt (vs. the "battery" side). I wanted to place mine in the battery box, but its size was a problem. Ultimately, I cut off about 3/4" from each of the long edges of the shunt's base, then still had to cut a recessed mount into the battery box sidewall.
Recessed cut-out for Balmar shunt, made with plywood and epoxy.Then, the Blues Seas Battery Terminal ground block had to be moved off the battery and to the "load" side of the shunt. This required cutting another hole in the battery box to mount a negative "stud" to hold the ground block and then adding a jumper wire to connect to the shunt.
The final product:
As for the monitor display, I had hoped to put in the 2" round hole where the original (square, analog) voltmeter had been on the DC panel (though I had replaced the original voltmeter with a modern, digital one a few years ago). But, due to the spaghetti bowl of wires behind the DC panel, I couldn't insert the Balmar gauge deep enough to mount it on the panel. In the end, I left the existing digital voltmeter in the DC panel, and built a small teak mounting panel for the Balmar gauge to the left of the DC panel.
............. The unit above the Balmar is the remote display/control for the Sterling battery charger. To the left of that is an ongoing bilge pump alerting panel I've been working on for a while. That one is on hold since I swore to no more electrical projects until after this sailing season.
