I'm still stuck on re working my battery box and cables. I have the new box made up but I cant decide what size battery cables to use. I want to go the "bigger is better" route but was hoping someone here may be able to advise me .
I figured my daily, 24 hr usage to be around 100amp hrs (fridge, water pump, radio etc) . I dont have an inverter or any "high" draw items. length of the entire house circuit is roughly 30ft . 2ga will handle 70amps with a 3% drop. the origional two positive DC leads from the panel are 6ga. they each come off a 60 amp breaker from the panel and there is a single 2ga ground from the panel.
The old set up in the battery box was all 2ga . Im adding battery switches on the bulkhead in front of the battery box . this will be about 5 ft from the box (10ft circuit)
I am planning on buying a single length of wire and crimping all my own lugs. I have a $250 thomas & betts crimper that can do up to 2ga lugs. (i decided against the harbor freight crimper I bought bc the dies are labeled wrong and too small) . if i go bigger i need a larger crimper ($150)
I believe 2ga should be fine but I keep thinking I should jump the main battery wires up to 1/0(for no real reason other than their bigger!) and use 2ga for the house leads.I plan on using two separate 60 amp fuses on the two house leads.
Suggestions???
another battery cable question?
Moderators: BeaconMarineBob, Moderator, BeaconMarineDon
another battery cable question?
Todd Pote
1987 10 Meter Mid Cabin
Double Pote-N_Sea
1992 Scout 15.5 Center Console
1987 10 Meter Mid Cabin
Double Pote-N_Sea
1992 Scout 15.5 Center Console
- prowlersfish
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Re: another battery cable question?
It never hurts to go with heavier gage
Boating is good for the soul
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat

Re: another battery cable question?
that's what I was thinking but I have the "unique ability" to over-do everything!
Figure I'd at least get some input before i move forward. I have "almost" ordered the wire 3 times but keep second guessing myself.
if going bigger makes sense, how big would you go for the main cables from battery to switch?
I'm thinking of going to go from 6ga (102amp) to 2ga (178amp) for the two panel leads which will get me to only a 3% drop up to 70amps (8ga gives a 10% drop). if I do that I need to go from a 2ga (178 amp) ground to at least a 3/0 (327amp) or 4/0 (378 amp)??? does this make sense if im using a 60 amp breaker?
inside the engine room ampacity
2ga 178amps
1ga 208amps
1/0 242amps
2/0 280amps

Figure I'd at least get some input before i move forward. I have "almost" ordered the wire 3 times but keep second guessing myself.
if going bigger makes sense, how big would you go for the main cables from battery to switch?
I'm thinking of going to go from 6ga (102amp) to 2ga (178amp) for the two panel leads which will get me to only a 3% drop up to 70amps (8ga gives a 10% drop). if I do that I need to go from a 2ga (178 amp) ground to at least a 3/0 (327amp) or 4/0 (378 amp)??? does this make sense if im using a 60 amp breaker?
inside the engine room ampacity
2ga 178amps
1ga 208amps
1/0 242amps
2/0 280amps
Todd Pote
1987 10 Meter Mid Cabin
Double Pote-N_Sea
1992 Scout 15.5 Center Console
1987 10 Meter Mid Cabin
Double Pote-N_Sea
1992 Scout 15.5 Center Console
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- Registered user
- Posts: 85
- Joined: Fri Mar 08, 2013 3:34 pm
- Location: NH
Re: another battery cable question?
Same questions I have too. Going to make new battery cables and not sure how big to go for the starting circuits from the starting batteries to the starters. Mine engines still have the pus button 50 amp, or is it 60 amp, circuit breakers too. I was thinking of 2 AWG.
1984 Trojan 10 Meter International Express Cruiser
"The Help Desk"
Portsmouth NH/Kittery ME
"The Help Desk"
Portsmouth NH/Kittery ME
Re: another battery cable question?
Just ordered 3 blue sea 4 way selector battery switches and two 7610 acr's. Found a different lug crimper on amazon for around $30 (seems too good to be true since similar ones sell for around $200!) So we will see! I'm leaning towards using 1/0 just to error on the side of caution.
Todd Pote
1987 10 Meter Mid Cabin
Double Pote-N_Sea
1992 Scout 15.5 Center Console
1987 10 Meter Mid Cabin
Double Pote-N_Sea
1992 Scout 15.5 Center Console