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BATTERY CABLE SIZE BATTERY SET UP

rich_b

Contributing Member
i am installing 4 huge northst

i am installing 4 huge northstar sealed agm batterys in my boat.i am putting them in the front of boat.i need to run cable around 20' long what size should i use.another question is.im hooking them up as follows:2 banks of 2 batterys with a 4 position switch.1st bank-positive to 2nd battery positive to #1 position on the switch.2nd bank- positive to 2nd battery positive to #2 on switch.i have 2 batterys on #1 and 2 batterys on #2.is this ok.now for the negative.can i run all the negatives together.neg to neg to neg to neg to the engine block.is this ok.FROM THE BATTERYS TO THE ENGINE IS 20'.cable price is outrageous.any suggestions.last question.these batterys are AGM.will these freeze.i am shelling out the dough so i dont have to keep taking the batterys out at the end of every season.i live in upstate n.y. and gets dammm cold here.the batterys will be in the cuddy cabin out of the elements.any suggestions here.this will be the third time i played around with the batterys want to do this right and make it the final time.any other suggestion are welcome.i also have a battery isolator i will be hooking up.and i am running a second alternator just for these huge AGM batterys.the alternator is 20' away from the isolator.what size wire here.the isolator will be mounted by the batterys.i have a 140 amp alternator and a 140 amp isolator. anybody have any ideas. i am listening.i have about $1600.00 invested so far with out the cables and need to do it right.p.s. i cant run just one battery for starting because my alternator wiring runs through the wiring harness and is tied in to everything.lost in space. hahaha
 
"i have removed my isolators a

"i have removed my isolators as the batteries were not getting a proper charge because you drop 1.2 volts across the isolators , so instead of charging to 14 v you only get 12.8v . something to think about!"
 
"Price welding cable of equal

"Price welding cable of equal AWG. Have to solder,
clamp or braze terminals but it can be done. Or check around contractors, welding shops, etc, for a length that they can't use but will fill your needs. Improvise. JW in Dixie"
 
I used 20' welding cable f

I used 20' welding cable for my 24 V. trolling motor and batteries due to the high current capacity of this cable. All three of my batteries are kept in my boat year round but are connected to a three bank 30 AMP automatic battery charger. They are out in freezing weather and are just fine.

What do you need so many batteries for? Storing them up front will subject them to constant pounding of the bow in rough water. Have you considered an onboard generator? Much cheaper.
 
thanks guy for the info.i got

thanks guy for the info.i got a great deal on the batteries.my boat is a 22' searay with a v berth up front.on the back of my boat i have two built in coolers that i made into livewells approx 8 gal each plus a 10 kicker motor on the swim platform plus 2 gas cans for the kicker 1-5gal 1-10gal.that alone is a ton of weight when everything is full and that is almost every trip out.i had 2 small batteries in the back and the platform is only a couple inches out of the water.if i put these monster batteries in the back where they go the swim platform will be swimming for sure.ha ha ha i do a ton of night fishing and i like everything on including the deck lights.let em burn the juice hahaha.so i am figuring if i put the batteries in the front they will keep the swim platform out of the water.the pounding shouldnt hurt the batteries.should it.they are northstar nsb m12-210
heavy duty agm marine battery.do i need a charger on them why they are not being used in the winter?
 
"Harbor Frt has Float Chargers

"Harbor Frt has Float Chargers for $4 - 8, depending on sale or not. I use these on my laid-up batteries with good results. They only charge as needed to keep the v at 12.75 or so. Won't dry out the water. You would need one for each 12v battery. Good luck. JW in Dixie"
 
Richard:

I looked at this b


Richard:

I looked at this battery on the web and must say it is a power plant. The reserve capacity of 400 minutes at 25 amps. is phenominal. They have remote venting which I was concerned about when you said you were putting them in the closed V-berth. Make sure you vent them due to the release of explosive hydrogen gas when discharging.

If you have access to shore power and/or you don't trailer the boat then I would not install the extra alternator to charge them. Buy a four bank 40 amp automatic charger and connect your batteries to it. They will recharge in several hours. The charger will also act as a trickle charger and battery maintainer over the winter.

Are you planning to use one of them as a starting battery? I would use a four battery switch that allows only one battery to be used at a time. You won't need an isolator if they are separated by the battery switch.

Have you thought of using fewer batteries and changing out all of your night lights to LED? They draw a miniscule amount of current and would reduce the need for all the extra weight of 4 batteries. All of my lighting including the gauges are LED except the bow light which I have not tried to find one for it yet. You could get by with just 2 batteries and a 20 amp onboard charger.

I will post a website for LED lighting.
 
Thanks Andrew.
Richard: In


Thanks Andrew.
Richard: Innovative Lighting has some of the LEDs you can use.
 
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