How many batteries?

Post by **Billy Bones** » Sun May 18, 2008 7:09 am

Have an 18 foot Starcraft equipped for Lake Ontario, just set it up over the winter and ready to shake it down. Will be running downriggers, sonar, GPS unit, and starter for the motor, off the battery. Would it be wise to add a second battery with a switch.

Thanks
Billy Bones

Post by **CNs** » Sun May 18, 2008 2:33 pm

A second battery would definitely be wise. Whether you hook it up with a switch or just have it in the boat

Post by **eye-tracker** » Sun May 18, 2008 8:50 pm

Billy,
What we do on our tourney boats is run two matched cranking batteries in parallel with the largest reserve power we can squeeze in the battery area. When running four large screen electronics, two live-well pumps and oxygen generators all day a single battery just wont last.

-sheldon
NPAA 928
sheldonhatch.com

Post by **Billy Bones** » Wed May 21, 2008 4:09 am

Hello Sheldon

Not an electronics major, but if you run two 12 volt batteries, doesn't that give you 24 volts?

Thanks
Billy Bones

Post by **lifeisfun** » Wed May 21, 2008 4:27 am

No, parallel will give you 12V.
Two 12V batteries in series will create 24V

Post by **eye-tracker** » Wed May 21, 2008 6:15 am

Billy,

The batteries are connected + to + and - to - , therefore they stay as 12v with double the cranking amps and reserve time.

-sheldon
NPAA 928
sheldonhatch.com

Post by **CNs** » Wed May 21, 2008 7:11 am

eye-tracker wrote:Billy,

The batteries are connected + to + and - to - , therefore they stay as 12v with double the cranking amps and reserve time.

-sheldon
NPAA 928
sheldonhatch.com

Sheldon,

How do you charge the cranking batteries? Do you need separate chargers? As well how does the motor charge them?

Post by **eye-tracker** » Wed May 21, 2008 9:58 am

Norm,
I have a dual bank charger on my two cranking batteries and the alternator charges them when I am running the big motor. The 9.9 pro kicker alternator is to small to charge up the batteries when they start to run down from all the electronics and 2 live-well pumps running all day. When I make 60 mile runs in a tourney the cranking batteries have no problem staying charged. It is the days when I do short runs with the big motor and spend most the day on the front trolling motor or trolling with the kicker that I need the reserve power.

-sheldon

Post by **karma** » Wed May 21, 2008 2:28 pm

A lot of folks with RVs who dry camp a lot run dual batteries hooked in paralel. RVs come with on-board chargers, but they are only single bank chargers. Not a problem as long as the two batteries are similar in size and age. If one battery charges faster than the other, the charger will continue charging taking it's reading from the battery that still hasn't reached full charge. This means the battery that reached full charge first will then be in an over-charging situation causing that battery to eventually fry. All this to say, if your going to run dual cranking batteries, buy them both at the same time.

Post by **Billy Bones** » Thu May 22, 2008 6:33 am

Thanks Sheldon

told ya I wasn't an electronics major. Sounds like the way to go.

Thanks
Billy Bones