Mischief Managed
Guru
- Joined
- Oct 24, 2018
- Messages
- 678
- Location
- USA
- Vessel Name
- Mischief Managed II
- Vessel Make
- 1992 Tollycraft 44 CPMY
I'm helping out a fellow boater in my marina with some electrical issues on his 36 foot open sportfish style boat. The boat has 4 battery banks:
Starboard engine/house
Port engine
Genset starting
Bow thruster
The boat had horrible galvanic corrosion in the past. The owner installed a galvanic isolator and is hoping that fixed the problem.
Other people have found and fixed starting and dim light problems with the starboard engine/house +12V wiring. AFAIK, they did nothing to the -12V connections
I checked continuity of the bonding bus and -12V bus to the battery banks. Only the starbard engine/house bank -12V has good continuity to the bonding a -12V buses. The other three banks have 55 to 75 ohms of resistance from the -12V battery posts to the bonding and -12V buses.
I don't see any deliberate connection made between the -12V battery posts to the bonding and -12V buses on the other three banks. It seems like any "continuity" (55 to 75 ohms) is purely by chance.
I plan to recommend adding a bus bar and 5 wires, one to each battery bank -12V post, and one to the existing -12V bus (it's too small to connect properly-sized battery cables to). This will tie everything together at the batteries. Any reason not to do this?
Starboard engine/house
Port engine
Genset starting
Bow thruster
The boat had horrible galvanic corrosion in the past. The owner installed a galvanic isolator and is hoping that fixed the problem.
Other people have found and fixed starting and dim light problems with the starboard engine/house +12V wiring. AFAIK, they did nothing to the -12V connections
I checked continuity of the bonding bus and -12V bus to the battery banks. Only the starbard engine/house bank -12V has good continuity to the bonding a -12V buses. The other three banks have 55 to 75 ohms of resistance from the -12V battery posts to the bonding and -12V buses.
I don't see any deliberate connection made between the -12V battery posts to the bonding and -12V buses on the other three banks. It seems like any "continuity" (55 to 75 ohms) is purely by chance.
I plan to recommend adding a bus bar and 5 wires, one to each battery bank -12V post, and one to the existing -12V bus (it's too small to connect properly-sized battery cables to). This will tie everything together at the batteries. Any reason not to do this?