Dual battery in 3825fl

[Leonandpandora]

When we purchased our 3825fl it came with one group 24 battery. It also came with one jumper to hook up the second battery. (red).
Can someone who has this model take a pic of your batteries and how they are wired.
I want to add the second battery but I think my dealer shorted me a black jumper.
(no suprise there...)
Thanks in advance.

[jeepin1]

Don't have the same trailer but here is a photo I was able to load.
There is a complete thread on this if I new how to get there and show you

[Big bird]

X 2

[SS Cruiser]

That is not the right way to wire your batteries. This was discussed recently in another thread and "the twelve volt side of life" was referenced as a good source of information. Look it up and you will see that the positive should come off of one battery, and the negative off of the other battery.

If you do it as in the above image, the battery on the left will experience more resistance due to the wire connecting them. If you run positive from one battery and negative from the other, you even out the loads.

The 12volt Side of Life (Part 1)

[Leonandpandora]

That's the info I was looking for. Very informative reading and the diagrams don't hurt either.
Thanks for the link.

[Leonandpandora]

Apparently the dealership didn't want to use the provided ground on the neutral so they made their own.
Both neutral cables are grounded. Back cable is just laying there.
Will get everything adjusted properly now.
Thanks for the help.

[redjet]

I have a 3850RL with dual group 27 batteries. The grounds (-) go to frame ground individually. The Hot side (+) of the batteries are jumpered together then an additional cable connects the (+) to the 12V system connection.

The trailer has a disconnect in the storage area that only disconnects some of the 12v load. Learned this the hard way. Consequently installed a master disconnect near the batteries which solved the problem of retaining battery charge over an extended storage period.

Whatever you decide - be sure to use the correct cable size and connectors. The cable is marine grade 4 AWG and the connector on the battery is 5/16" and on the camper 3/8". I measured the length needed to install my switch and order ready made cables from genuinedealz.com.

Also noticed that your picture shows two different brands of batteries; consequently ratings. Suggest paralleling ONLY batteries that have the same specs.

[jacknife]

Two twelve bolts should be hooked together in patallel not a series. Parallel will take two 12 volt batteries and give you 12 volt and double whatever the amps are on one battery. Hot to hot negative to negative . if you hook them positive to negative that called a series setup and you will have 24 volt power and screw up alot of electronics . I have 2 6 volt golf cart set up in series which gives me 12 volt and my amp hrs do not change. Set your up in parallel. Ude the exact same batteries same brand . Do not use different brands . The weaker battery will weaken the stronger one and shorten the life .

[Leonandpandora]

Redjet that sounds much better. Now I know why I have 2 grounds.
Thanks everyone for the help and I will trade out for another interstate battery.

[CHICKDOE]

to redjet, thanks for the info. i have a 2015 cardinal model 3825 with two 12 volt batteries in parallel. i'm planning on putting in a true battery disconnect and have been doing the research. today I spent a lot of time on hands and knees tracking all the battery cables. here's what I found:
battery 1 positive - to lippert level up, then xantrex inverter and then into the coach probably ending at 12 fuse panel. (appears to be factory installed)
battery 1 negative - to chassis ground underneath generator.
battery 2 positive - directly to generator positive terminal
battery 2 negative - through bulkhead to leaving to the rear of the trailer - I am unable to trace this cable without opening up the underbody protective membrane. do it go all the way to the ground terminal of the 50 amp power receptacle?


(in the above I excluded the two positive to positive and negative to negative cable that facilitate the parallel connection)


the trailer came with generator prep from the factory but I had the dealer install the generator. it looks to me that the cable that run from the battery to the generator were installed by the dealer as they are thinner than the ones that appear to be factory installed. one question I have is whether these to cable should be on different battery terminals from the factory installed cables or whether all cables should attach to a single set of terminals, ie all negative cables would attach to the same negative terminal battery 1 and all positive cables to the positive terminal on the battery 2.

[redjet]

Not familiar with the battery connection on a generator setup. However, a 6 AWG cable from the battery for starting is probably okay because automotive battery wires are usually 6 AWG.