dual battery wiring

[schnydz]

Hello all!

Not sure if I'm posting this in the right area, someone can move it if you need to.

So I've mounted a second battery on my trailer and I was wondering if I should use one battery until its dead and then switch to the second or run off both batteries at the same time?

Eventually I will switch to 6v batts and solar panels, but the ol' wallet's still cooling off from buying the trailer lol

thanks!
Bert

[Rustic Eagle]

Welcome to JOF ......, and yes, your thread is in the right forum.

Ideally you don't want a battery (or battery bank) to deplete itself below 50% capacity (especially a standard Marine/RV battery), it starts to greatly reduce the amount of recharge cycles.

I would monitor the existing 12V battery's capacity, then switch over to the new back-up 12V battery. Mounting a battery bank control switch would make the process easy.

Adding a new 12V battery in parallel with an older (possibly weaker) 12V battery makes the new one work harder, and eventually will make it as weak as the old battery. If your going with a dual battery system connected together (6V or 12V), the batteries should be the same model, size, and ideally purchased together.

Also, the standard Marine/RV Deep Cycle batteries don't take as many re-charges as a true Deep Cycle GC battery.

Bob

[Mustang65]

2x what Bob said.

If your old battery is over 6 months old, been drained below 12VDC many times, I would go with the battery switch AND A VOLTAGE METER, so you can monitor the battery.

When you are ready to upgrade to DEEP CYCLE batteries, make another post and you will get all the latest battery info...

There are a lot of posts regarding batteries, just do a search and you will be amazed.

Don

[schnydz]

Thanks guys. I should have given more information, but you hit the nail on the head anyway. I like your idea. I have the battery the trailer came with, idk how old it is, no one knocked out the date on it. And I had my own deep cycle battery already that is a few years old that I mounted on the trailer as well. They are a different size and age and rating so I will run them one at a time. I don't really want to travel with my $400 Fluke multimeter but I might have a little cheapy hiding in a drawer somewhere I can take along.

I was thinking for an easy(cheap) switch I would hook them both up and just pull the fuse at the battery for one of them and just switch the fuse when I want to switch batteries.

thanks again
Bert

[RoyBraddy]

May I suggest one ot the BLUE SEA four position SWITCHES (AMAZON). Not all that expensive and this will give you the option of both batteries OFF or select BAT 1, or BOTH BATTERIES, or BAT 2...

When the batteries is not selected it is disconnected from the other battery.

looks like this photo from google images

[Mustang65]

One last item... make sure your TT's break-away switch is ALWAYS hooked to a 12 volt source and not fused.

Don

[schnydz]

The switch is nice but I'm working on the cheap right now lol

and thanks for the reminder on the break-away

[FiredguyAZ]

Will someone explain to an electricity idiot (me) the proper wiring sequence for dual batteries and cascade charging, please?

[Mustang65]

Originally Posted by FiredguyAZ

Will someone explain to an electricity idiot (me) the proper wiring sequence for dual batteries and cascade charging, please?

I am assuming you are asking about wiring in (2) 12VDC batteries.

Here you go

Don

[Flyrotor]

Originally Posted by Rustic Eagle

Adding a new 12V battery in parallel with an older (possibly weaker) 12V battery makes the new one work harder, and eventually will make it as weak as the old battery. If your going with a dual battery system connected together (6V or 12V), the batteries should be the same model, size, and ideally purchased together.

I understand your theory, and I'm not defying your input, but I can say personally I would run them together, all the time, that would be so much less of a hassle!

When they give out and die off, then upgrade to your next option...