Anyone ever put deep cycle batteries in V berth/ bow area

[Tomfoolery]

The longer inverter/charger cables are also 4/0 welding lead. I've seen charging function put more than 150A into the battery, and the inverter drawing more than 150A when running the microwave or roof air conditioner off battery power, and the system can output even more if so demanded. So there's a good reason they're so heavy.

[Sheppie62]

I put the (2) AGM group size 31 house batteries under the galley seat for now (105ah x 2= 210 total). I’m installing a breaker panel with (6) 15 amp breakers. Will #6 wire be ok going up to the panel (10 feet?), with a 20amp battery post breaker? From each individual breaker I’m thinking I’ll use 16ga wire to a bus bar then add a fuse at each individual device powered. I’m not an electrician so sorry if I’m suggesting something dumb. Does this sound right?

[Starscream]

I put the (2) AGM group size 31 house batteries under the galley seat for now (105ah x 2= 210 total). I’m installing a breaker panel with (6) 15 amp breakers. Will #6 wire be ok going up to the panel (10 feet?), with a 20amp battery post breaker? From each individual breaker I’m thinking I’ll use 16ga wire to a bus bar then add a fuse at each individual device powered. I’m not an electrician so sorry if I’m suggesting something dumb. Does this sound right?

Depends on what the panel is going to be powering, but 6ga sounds like overkill for typical things like lights, instruments, and accessories. I have two panels and wires each one in 10 gauge. The original Macwiring was something like 18 gauge.

Adding in-line fusing for each device on a circuit can create a wiring mess. They sell fuse blocks with automotive type fuses and labels, and these can really clean things up if you have space. And make finding the right fuse much simpler,when needed.

[Be Free]

#6 copper wire should be good to at least 55 amps so your 20 amp fuse at the battery will protect it ok.
#16 copper wire is only good for 10 amps and that's for runs up to 20 feet (6 feet if voltage drop is going to stay under 3%). You need a bigger wire or a smaller breaker.

[Sheppie62]

I just looked at my wire spool it’s 14 ga not 16. And the wire I ordered for from battery to panel is 10ga. Not 6ga. Sucks getting old. Oops

[Inquisitor]

The batteries I would use are 105 amp hour x 2 = 210 total, battery charger is 40 amps and would use 2500 watt inverter. Not sure what size cable I would need to do this, inverter could be placed close to batteries.

When the Inverter was mentioned, I too was thinking just put the inverter next to the battery and run the A/C lines (Far less current that way). My 2200 watt inverter has 2' long cables with it and they're labeled as 1x35 mm^2 (1/2" diameter). I'd hate to see what they'd need to be if they had to run to the back of the boat.

The charger is a different matter... unless you're doing from shore power... then do the same thing... put the charger at the battery and run the AC to the charger up front.

[Be Free]

You said that you were guessing 10' from the panel to the breaker. Distances need to be round trip (includes the return to the negative terminal). All of the numbers I'm giving you are maximum round trip distances. I'm also giving you two distances. One is for a 10% voltage drop and the other is a 3% voltage drop. Your wire from the battery to the breaker panel should be at 3% (don't want to lose that extra 7% in the first few feet). Whether you use the 3% or 10% number for the branch circuits depends on how sensitive the equipment is that you are connecting to it. The other thing to remember is that everything that goes out has to come back. You need to size your negative wires to match the positive wires in the same circuit.

#10 is good for 30 amps (10' 3% drop, 30' 10% drop). Again, the 20 amp fuse at the battery will work.
#10 is good for 20 amps (15' 3% drop, 50 feet 10% drop). The 20 amp fuse is just going to protect the wire.
Anything longer and your wire is no longer protected by the fuse.

#6 will carry 15 amps for 60' with a 3% drop and 200' with a 10% drop.

If I'm reading your design right you have 6x15amp branch circuits (80 amps) being fed by a 20 amp connection at the battery. If you really need anything near 80 amps you are going to need at least #4, maybe #2 depending on the round trip length for your connection back to the battery.

These are rough numbers that are making a lot of assumptions about your design and giving you the best-case values. If you are running through conduit, bundling with other wires, any number of other things, then you may need a different type or different size wire. Odds are these numbers are good enough since I know the design of your boat and what your choices are for running wires in it but if you are close to the limits of any of these suggestions going up another size would give you some wiggle room.

[Be Free]

When the Inverter was mentioned, I too was thinking just put the inverter next to the battery and run the A/C lines (Far less current that way). My 2200 watt inverter has 2' long cables with it and they're labeled as 1x35 mm^2 (1/2" diameter). I'd hate to see what they'd need to be if they had to run to the back of the boat.

The charger is a different matter... unless you're doing from shore power... then do the same thing... put the charger at the battery and run the AC to the charger up front.

35mm^2 is a 2AWG. To run it to the back of the boat you would need at least 4/0.

[Inquisitor]

Wire Gauge Calculator
https://grealpha.com/resources/dc-load- ... ire-gauge/

[ris]

We have two 6Volt trojan105 batteries aft of the galley under the seat and two 6 volt Trojan 105 batteries under the v-berth starboard side wired together series/parallel. They are the house/starting batteries. Worked well for the last5 years.
Boat is a 26X
Richard

[Sheppie62]

You said that you were guessing 10' from the panel to the breaker. Distances need to be round trip (includes the return to the negative terminal). All of the numbers I'm giving you are maximum round trip distances. I'm also giving you two distances. One is for a 10% voltage drop and the other is a 3% voltage drop. Your wire from the battery to the breaker panel should be at 3% (don't want to lose that extra 7% in the first few feet). Whether you use the 3% or 10% number for the branch circuits depends on how sensitive the equipment is that you are connecting to it. The other thing to remember is that everything that goes out has to come back. You need to size your negative wires to match the positive wires in the same circuit.

#10 is good for 30 amps (10' 3% drop, 30' 10% drop). Again, the 20 amp fuse at the battery will work.
#10 is good for 20 amps (15' 3% drop, 50 feet 10% drop). The 20 amp fuse is just going to protect the wire.
Anything longer and your wire is no longer protected by the fuse.

#6 will carry 15 amps for 60' with a 3% drop and 200' with a 10% drop.

If I'm reading your design right you have 6x15amp branch circuits (80 amps) being fed by a 20 amp connection at the battery. If you really need anything near 80 amps you are going to need at least #4, maybe #2 depending on the round trip length for your connection back to the battery.

These are rough numbers that are making a lot of assumptions about your design and giving you the best-case values. If you are running through conduit, bundling with other wires, any number of other things, then you may need a different type or different size wire. Odds are these numbers are good enough since I know the design of your boat and what your choices are for running wires in it but if you are close to the limits of any of these suggestions going up another size would give you some wiggle room.

Thanks that really helped! Great information!

[Be Free]

We have two 6Volt trojan105 batteries aft of the galley under the seat and two 6 volt Trojan 105 batteries under the v-berth starboard side wired together series/parallel. They are the house/starting batteries. Worked well for the last5 years.
Boat is a 26X
Richard

Do you have them as a single large bank or two 12V banks?