2 BATTERIES VS 1 BATTERY?

A general, non-powerplant specific, discussion on airboat technology, ie., hulls, rigging, polymer, etc..
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flcracker9
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2 BATTERIES VS 1 BATTERY?

Post by flcracker9 » Sat Dec 20, 2014 7:04 pm

When I purchased my boat a few months ago, it had 2 group 31 batteries wired in parallel (0340 Lycoming). I'm trying to save some weight (my batteries weigh 57lbs each), but wondering if there's any reason my engine would need 2 batteries (other than the obvious reason of more cranking amps). I could see 2 batteries with a cutover switch so if 1 was dead, you could switch to the other, but not sure why mines has 2 in parallel. I was thinking of going to a single optima (39 lbs), and maybe carry a jump box. Let me know your thoughts.
12' Open Palm Beach, IO-0470-L 260hp, 72" NGQ

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Re: 2 BATTERIES VS 1 BATTERY?

Post by getchasumairboats » Sat Dec 20, 2014 7:22 pm

1 good battery will be plenty.
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Re: 2 BATTERIES VS 1 BATTERY?

Post by terrible ted » Sat Dec 20, 2014 8:41 pm

on a camping trip I pack a spare but normally run with one.

mwood7800
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Re: 2 BATTERIES VS 1 BATTERY?

Post by mwood7800 » Sat Dec 20, 2014 10:26 pm

One good battery (not Walmart) replace it every other year then no spare. If u have 2 batteries and no 1or2 batt switch then the bad battery kills the good one.

Olf Art
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Re: 2 BATTERIES VS 1 BATTERY?

Post by Olf Art » Sun Dec 21, 2014 2:13 am

mwood7800 wrote:One good battery (not Walmart) replace it every other year then no spare. If u have 2 batteries and no 1or2 batt switch then the bad battery kills the good one.
Exactly right. It can also fry your alternator. Boats that need to run reserve power for night fishing and such might have a need for
some battery backup, but for normal everyday use one good one is enough IMO.
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flcracker9
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Re: 2 BATTERIES VS 1 BATTERY?

Post by flcracker9 » Sun Dec 21, 2014 6:02 am

Thanks for the replies. I kinda figured 2 in parallel was not necessary. Just wanted confirmation. 1 battery it shall be!
12' Open Palm Beach, IO-0470-L 260hp, 72" NGQ

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Ol Yeller
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Re: 2 BATTERIES VS 1 BATTERY?

Post by Ol Yeller » Sun Dec 21, 2014 7:33 am

The good news is that I always carry jumper cables for the one battery crowd on my boats.

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kwanjangnihm
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Re: 2 BATTERIES VS 1 BATTERY?

Post by kwanjangnihm » Sun Dec 21, 2014 7:45 am

I run one battery and it does great. Be sure you have good cables and a good ground. :rebel:

here is a link to some good battery info: http://www.southernairboat.com/phpBB3/v ... t=+battery
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Re: 2 BATTERIES VS 1 BATTERY?

Post by flcracker9 » Sun Dec 21, 2014 8:27 am

kwanjangnihm wrote:I run one battery and it does great. Be sure you have good cables and a good ground. :rebel:

here is a link to some good battery info: http://www.southernairboat.com/phpBB3/v ... t=+battery

I do have good cables. I made new ones when I bought the boat. All 2ga and the ends are soldered not crimped or bolted. Thanks for the replies
12' Open Palm Beach, IO-0470-L 260hp, 72" NGQ

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Re: 2 BATTERIES VS 1 BATTERY?

Post by terrible ted » Sun Dec 21, 2014 9:23 am

Olf Art wrote:
mwood7800 wrote:One good battery (not Walmart) replace it every other year then no spare. If u have 2 batteries and no 1or2 batt switch then the bad battery kills the good one.
Exactly right. It can also fry your alternator. Boats that need to run reserve power for night fishing and such might have a need for
some battery backup, but for normal everyday use one good one is enough IMO.

good point here. I relate say frogging / gator hunting or bow fishing similar to shrimping for that I carry one or two batteries for running lights alone.

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Re: 2 BATTERIES VS 1 BATTERY?

Post by Olf Art » Sun Dec 21, 2014 12:10 pm

I like to run two on a Perko switch, but if you do that never run it on "both" ..... that will also fry the alternator.
I'd run on #1 for a while and then switch over to #2 for a while to recharge, but never on "both.

When I wire a boat I like to use a locking Perko for my main power instead of an ignition switch. In "off" and locked there isn't
any battery drain and everything on the boat is shut down. When on either battery, everything (nav lights, bilge, fuel pump,
ignition) is hot ...... just use a starter button for engine start.

Also, if you do that, don't ever switch from one battery to the other when the engine is running. That can upset the
alternator too. If you ground both your accessories and the battery to the riggin' you don't even need to run long
ground wires ..... just switched and fused "hot", and then ground everything else right where it sits. It makes a real
clean job of it, and with never any grounding issues. :wink:
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jopete
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Re: 2 BATTERIES VS 1 BATTERY?

Post by jopete » Sun Dec 21, 2014 6:32 pm

on 3 of the 4 airboats i have owned i ran 2 batteries and a 1,2,ALL, & OFF perko switch.

i always run on the ALL position, unless i need to charge up one or the other. like others have said, i never switch from one battery to the other without turning off the engine.

it may bite me one day, but it hasn't been a issue yet running in the ALL position.
when i do go out in a boat with one battery, i bring a extra battery just in case.

had to jump start too many one battery people in the middle of the swamp. lol

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Re: 2 BATTERIES VS 1 BATTERY?

Post by Lwells » Sun Dec 21, 2014 9:19 pm

If you wanted you could run two batteries and not increasing the weigh much by using a car battery and then use a 300 cranking amp lawn battery for a backup with a little box like used on motorhomes which allows both batterys to charge when needed but separates the two batterys until you need the second one. You just push a button down and hold it and fire the engine with the second battery and then when you let off the button it goes back to charging both batteries but won't allow the primary battery to discharge the secondary. I've started cars, trucks, boats,etc with the lawn battery. Only fault to them is they seem to have a short life if not used regularly but you can help to eliminate that problem by putting a tickle charger on them when setting for periods of time. I like the thought of always having a backup battery. Also, if you know anyone that does maintanence on hospital equipment and replaces the battery packs in their equipment then get one of those batteries. They are about 6 inches square and I have started an airplane with them but you wouldn't think they would do anything to look at them. Most hospitals dispose of these batteries and they are perfectly fine.

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Re: 2 BATTERIES VS 1 BATTERY?

Post by Waterthunder » Mon Dec 22, 2014 9:41 am

I will not own a airboat with two batteries. Everytime I have I had battery problems. I like 1 battery I have never had a problem with 1 battery. Seams like if there is something wrong with your charging system dual battery's mask it and you end up breaking down in the mash instead of at the boat ramp. Me and all my longtime airboating buddies always get a laugh when we have to jump the guy with two batteries. And it does seam like every boat with a dead battery has two of them!
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Big Casino
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Re: 2 BATTERIES VS 1 BATTERY?

Post by Big Casino » Mon Dec 22, 2014 11:32 am

1 vs. 2 is just a mix of personal preference & indented use.... Just out for a ride on the family cruiser, then one battery is perfectly fine ... Out gigging or bowfishing all night with your GPS, VHF, and "arena" lighting on, then two batteries on a A/B/Both switch are a must have!!!

But regardless of one or two, good battery maintenance is the key. Keep them fully charged on a tricker/charger - maintainer, make sure your have a good neutral/return cable. I'm surprised at how little most folks really know about battery theory and up keep. Properly wired and maintained, a two battery system will NOT cause any issues what so ever, its all how you manage the system.

I don't agree with "...never run on both... will fry alternator..." that's not true if the Alternator output is adequate and your not dealing with dead batteries or weak cells. There's also no reason why you cant switch from one battery to another while running, provided your switch it rated for the amperage. If i ever end up with a dead battery on the water it will be from my own stupidity, NOT from a 2 battery system......
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Re: 2 BATTERIES VS 1 BATTERY?

Post by jopete » Mon Dec 22, 2014 1:41 pm

like i posted earlier, i try to always run with 2 batteries, but i can not think of a time i had to get a jump while frogging with my 1 battery boat. lol

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Re: 2 BATTERIES VS 1 BATTERY?

Post by Waterthunder » Mon Dec 22, 2014 3:42 pm

Everybody has a valid point. As for our area none of us ever need two batteries so none of us run them. Accept the really big boats. Obviously if you bow fish you should probably carry a few extra.
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