Last weekend we did the first physical steps of our electrical system upgrade which I've been thinking through and preliminarily planning for the recent past. We added a battery monitor so we can see and list our actual loads for different circuits and devices and calculate what size house bank we want. In the process, I added OCP at the battery and at the charger/inverter neither of which had OCP installed by the PO. I also added negative and positive main buses so I could get a clean negative lead for the battery monitor shunt and clean up / organize the multiple wires connected directly to our batteries.
Our house bank and charger/inverter are under the starboard settee.
Here's a photo of the house bank when I started. We have three WM gel cells - two 6v / 180 Ah in series connected to a 12v / 88 Ah for a total of 266 Ah. Here are the connected cables:
Positive:
1-2-Both switch (1/0 AWG at 6v positive)
Fridge (fused 8 AWG at 6v positive)
Heater (fused 8 AWG at 6v positive)
Charger/Inverter (black 1/0 AWG with red heat shrink at 12v positive)
Negative:
Engine ground (1/0 AWG at 6v negative)
DC panel ground (4 AWG at 6v negative)
Fridge ground (8 AWG at 6v negative)
Heater ground or ? (white 12 AWG at 6v negative)
Start battery ground (1AWG at 12v negative)
Charger/Inverter ground (1/0 AWG at 12v negative)
Heater ground or ? (black 12 AWG at 12v negative)
I should have tested which of the two negative 12AWG wires (white or black) is still carrying a load but it slipped my mind. The unloaded one is probably the mate to an unfused wire that we couldn't trace to any device when we fused the two other positive 8 AWG wires soon after buying the boat. Instead, I just re-connected it to our main negative bus.
Here are a couple of photos of what we have after the weekend. I installed two main bus bars, the shunt for the battery monitor, an MBRF fuse at the 12v positive terminal, an ANL fuse for the charger/inverter, and a stud connecting the negative cables coming off the charger/inverter and the start battery to a single cable to the main negative bus.
Here's an "as-is" schematic of our 12v system at this point, with some notes I've made on things we need to address or questions I have.
More to follow as the process continues.
Next steps:
Measure and list existing 12v loads
Measure and list the length of cable runs to existing loads
Make a schematic of the existing 120v system
Decide on go/no-go for three new major loads - electric windlass, Starlink, and a watermaker
Decide on the size and type of solar installation
Decide on the size and type of upgraded alternator
Draft wiring schematics for new 12v and 120v systems
Figure out new distribution panel layout along with buses for 120v and 12v systems plus N2K system in space between the panel and hull
Figure out new equipment layout/locations for the larger battery bank, new inverter/charger, alternator regulator, and MPPT controllers for solar
Our house bank and charger/inverter are under the starboard settee.
Here's a photo of the house bank when I started. We have three WM gel cells - two 6v / 180 Ah in series connected to a 12v / 88 Ah for a total of 266 Ah. Here are the connected cables:
Positive:
1-2-Both switch (1/0 AWG at 6v positive)
Fridge (fused 8 AWG at 6v positive)
Heater (fused 8 AWG at 6v positive)
Charger/Inverter (black 1/0 AWG with red heat shrink at 12v positive)
Negative:
Engine ground (1/0 AWG at 6v negative)
DC panel ground (4 AWG at 6v negative)
Fridge ground (8 AWG at 6v negative)
Heater ground or ? (white 12 AWG at 6v negative)
Start battery ground (1AWG at 12v negative)
Charger/Inverter ground (1/0 AWG at 12v negative)
Heater ground or ? (black 12 AWG at 12v negative)
I should have tested which of the two negative 12AWG wires (white or black) is still carrying a load but it slipped my mind. The unloaded one is probably the mate to an unfused wire that we couldn't trace to any device when we fused the two other positive 8 AWG wires soon after buying the boat. Instead, I just re-connected it to our main negative bus.
Here are a couple of photos of what we have after the weekend. I installed two main bus bars, the shunt for the battery monitor, an MBRF fuse at the 12v positive terminal, an ANL fuse for the charger/inverter, and a stud connecting the negative cables coming off the charger/inverter and the start battery to a single cable to the main negative bus.
Here's an "as-is" schematic of our 12v system at this point, with some notes I've made on things we need to address or questions I have.
More to follow as the process continues.
Next steps:
Measure and list existing 12v loads
Measure and list the length of cable runs to existing loads
Make a schematic of the existing 120v system
Decide on go/no-go for three new major loads - electric windlass, Starlink, and a watermaker
Decide on the size and type of solar installation
Decide on the size and type of upgraded alternator
Draft wiring schematics for new 12v and 120v systems
Figure out new distribution panel layout along with buses for 120v and 12v systems plus N2K system in space between the panel and hull
Figure out new equipment layout/locations for the larger battery bank, new inverter/charger, alternator regulator, and MPPT controllers for solar
