Dual battery in parallel

[matt4sure]

I currently have a 24DC (2019) battery which I would like to add a new like battery of the same size. Can I connect these in parallel or do I need to keep them separate? The old battery does not seem that bad.

 

[rjwilliams11741]

Connecting 2 batteries in parallel will increase the amp hour capacity while keeping the voltage the same. Based on my experience with cruising boats and RV's I would replace the old battery as well. Even if the old battery is good, it will, because of age, have less capacity as your new battery and will draw the voltage down on the new battery.

 

[SaltyVetAdventures]

Do not add a new battery to the old battery. You must replace both at the same time with two matching batteries. The reason is that when you add a new battery to an old one, they will never discharge at the same rate. This imbalance will ruin your batteries.

 

[matt4sure]

Thank you for your response. Very good information.

 

[Voyageurs]

Hi Matt. And if you are going to change out two batteries consider putting AGM’s in there. No maintenance and you can deep cycle them to a lower depth. It will be pretty close to having the equivalent of three of your existing flooded batteries. A little pricier but worth it if budget is not a big concern.

Cheers.

 

[TheLooks]

I believe that is AGM?

 

[Voyageurs]

I believe that is AGM?

Whoops. Fat fingers. I blame whoever put the F beside the G on the keyboard.

(I edited the original post. Thanks for the catch)