Connecting batteries in parallel

[campingne]

Hello
I have a question on connecting batteries in parallel. I was camping in Vermont last weekend at a state park. I had a problem with my battery, it is a 1 year old interstate battery SRM-29. I went to walmart and bought a Everstart maxx-29 battery. When we returned back home I brought the Interstate back to the distributor and they replaced the battery with a new one. I would like to connect both batteries to the camper for extra capacity when we camp at state parks. Can these 2 batteries be connected in parallel?????? I have read on other sites the the batteries should be the same. These 2 batteries are the same 29 series, but I dont know if the amp hours are the same.

This site is a great asset to Sunline owners. I am proud to be a Sunline owner.

Thanks Chris

[MACK C-85]

Yes, ideally the amp hours should be the same.

Do you have a battery switch on the front of your trailer?

If no switch: They can be paralleled by connecting the positive posts together, i.e. connecting a cable between the two (+) post on the batteries, then the trailer cable on either positive post. The negative side can either be connected together and grounded to the frame or just ground both batteries to the same frame ground.

If you have a single switch: one cable between batteries pos. posts, one from a positive post to the switch, trailer fed from switch.

That being said, when I add a second battery to my trailer, I intend to replace the single battery switch on my trailer with a dual switch. In this application, the positive cable from each battery is connected to it's own pole on the switch and the trailer cable is connected to another pole. The advantage of this way is you can select to use battery 1, battery 2, or both, and turn off the battery supply simply by turning the switch.


Do not connect the positive to one battery, the ground to other battery, and run a cable between the batteries pos to neg. This will give you 24 volts.

[Honda03842]

Where does one buy a battery switch like yours?

Thank you,

Norm

[campingne]

I just did a quick search on the internet and it looks like this is a common switch in the Marine world. There are many marine sites that have the same switch along with other brands. I will look into a switch with some local marine parts stores.

Chris

[MACK C-85]

Yes, it is a common switch used in the marine world. Most boaters will run with both batteries on, then when they start to fish, party, whatever, they will turn to one battery, saving the second one to restart the motor!!

I copied the pic off a web site by googling "Battery Switch"