Adding second battery

[Dp59]

I want to add a second battery, not connected, just to have as a spare. Can i place it on the opposite side on the motor to keep better weight balance at the back of the boat or does it really matter?

 

[crazy charlie]

Thats one way to do it.Personally I would connect and combine .Only takes 2 battery wires/cables.this will charge both batteries while under way.Leaving a battery on board unconnected will probably lead to a weak battery if and when you need to use it.Charlie

 

[Dp59]

Was just worried about all the 2 battery weight on the same side of the boat.

 

[Dp59]

Thats one way to do it.Personally I would connect and combine .Only takes 2 battery wires/cables.this will charge both batteries while under way.Leaving a battery on board unconnected will probably lead to a weak battery if and when you need to use it.Charlie

Would you connect both positive and then both negative of the 2 battery's together to the starter? In parallel

 

[JASinIL2006]

I want to add a second battery, not connected, just to have as a spare. Can i place it on the opposite side on the motor to keep better weight balance at the back of the boat or does it really matter?

You’d be better off with a jump pack if that is your plan. Either way, you will have to find someway of charging the spare battery or jump pack; they won’t keep a charge forever.

 

[dingbat]

Would you connect both positive and then both negative of the 2 battery's together to the starter? In parallel

No. Connect grounds together. Run hot wire from each battery to a 1/2/both battery switch.

Starter connects to switch

 

[Commander_47]

You don't say what kind of boat you are using, but if its the one in your picture you might want to consider something like this:

Blue Sea Systems ADD A BATTERY

Simplifies switching and automates charging for a complete two battery bank solution. The package includes Instructions for 7650 Add-A-Battery

www.iboats.com

I put this system in a 26 foot cruiser with absolutely no problem, and in fact, am really really happy with it.

In my boat, the batteries are on either side of the motor to balance it out. I have a water tank on one side, and the fuel on the other, so it works out well.

You can have one battery totally dedicated to starting only. The other is for all accessories and such. The splitter will recharge both according to the need of the battery.

In an emergency, you can combine both batteries to start the boat.

 

[crazy charlie]

Would you connect both positive and then both negative of the 2 battery's together to the starter? In parallel

Yes parallel will work.You can put the 2nd battery anywhere you like.Just run battery cables as long as you need.Not a big deal.The jump pack is not a bad idea either.But you still have to keep it charged.Charlie

 

[Rabbit929]

I’m looking to do what commander suggested as well. It’s nice that you can isolate a battery so if you happen to be sitting for awhile with your fish finder on, lights, radio, that when you have that “oh sh*t” moment when your motor doesn’t turn, you can switch to your backup, now knowing your on your last battery, and most likely more than halfway through your day or night.

OR. Run them in parallel (positive to positive, negative to negative) and enjoy double the capacity. I wouldn’t do this permanently, as one failing battery will suck down the other.
I will be installing the blue sea system.

 

[JASinIL2006]

I added a battery with the Blue Sea kit and it wasn't hard at all. I used the opportunity to do some rewiring, added a fuse panel and consolidated electrical circuits to isolate the starting battery from everything that might drain it and leave me stranded. The Blue Sea kit makes it easy.