Adding a 2nd battery to my Micro Minnie 1706FB question

[Duercos]

Hi everyone, I am new here and have a question regarding fitting 2 batteries on my TT. I have bought 2 12v 100ah AGM batteries (group 27) instead of a single group 24 factory one. There is no way I can fit both on my a frame hitch tongue length wise. Has anyone done something similar? I was thinking to mount them in the storage area under the bed towards the from of the trailer, but all the wiring is hidden under the floor. I just want to go the easiest way if possible.
I am also installing 2 solar panels for charging the batteries.
Thanks a lot!

[Wyatt]

Just an FYI, AGM batteries need to be vented, so make sure where you put them, has that option...
Other than that, I can’t help on the best spot, having not owned your unit.

[Marine359]

Originally Posted by Duercos

Hi everyone, I am new here and have a question regarding fitting 2 batteries on my TT. I have bought 2 12v 100ah AGM batteries (group 27) instead of a single group 24 factory one. There is no way I can fit both on my a frame hitch tongue length wise. Has anyone done something similar? I was thinking to mount them in the storage area under the bed towards the from of the trailer, but all the wiring is hidden under the floor. I just want to go the easiest way if possible.
I am also installing 2 solar panels for charging the batteries.
Thanks a lot!

Group 27 are about 12.5” wide. You should be able to find a battery box that fits them side by side. Try to find a box that is less than 9” deep (front to back). If the box is at least 30” long, you can mount it on top of the tongue frame rails between the tank cover and the front of the coach. You can attach the box to the rails using self tapping screws, or as I did with the toolbox below, with brackets and heavy duty shock cords. I used the brackets and shock cords so I could easily remove the tool chest.

You could use this toolbox. I use it to stow ground tackle. My LiFePo4 mounted in pass thru. Both of your batteries would fit, but it is not waterproof, the top won’t open 90 degrees, and you’d have to ventilate it by drilling holes on the sides. If you can’t find a dual battery box that works, pm me for link to this toolbox. It’s cheap.

[Duercos]

Hi, as far as I know, sealed agm batteries require minimum to no ventilation. And that big underbody storage has doors on both sides of the trailer, which are not fully sealed. But thanks anyway

[Duercos]

I can't find a proper box.. I am actually going to buy some angled steel slotted poles from home depot and install them on top of the a frame with some self tapping screws and put 2 batteries in their own plastic boxes on top. I think that would be the cheapest and easiest way. Will keep you posted!

[Marine359]

Originally Posted by Duercos

Hi, as far as I know, sealed agm batteries require minimum to no ventilation. And that big underbody storage has doors on both sides of the trailer, which are not fully sealed. But thanks anyway

Hey there Duercos,
R.V. manufacturers do not install AGM batteries in enclosed spaces because it’s against the law. The pass thru is not ventilated. You could put AGM in there yourself, but you could never legally sell your trailer. For the scoop on AGMs and venting, you might want to read this:
https://rvnerds.com/2017/11/01/elect...ging%20process.

[Duercos]

Originally Posted by Marine359

Hey there Duercos,
R.V. manufacturers do not install AGM batteries in enclosed spaces because it’s against the law. The pass thru is not ventilated. You could put AGM in there yourself, but you could never legally sell your trailer. For the scoop on AGMs and venting, you might want to read this:
https://rvnerds.com/2017/11/01/elect...ging%20process.

Good to know. I have decided to install the batteries outside on the hitch tongue.

[orangeminnie]

Plastic battery boxes are "yesterday".

Try: https://www.torklift.com/rv/powerarmor
They have a variety of sizes. They're lockable and vented.

We installed the 58" model on our Minnie, which can accommodate 4x Group27, and up to 5x Group24 batteries.

[Duercos]

Originally Posted by orangeminnie

Plastic battery boxes are "yesterday".

Try: https://www.torklift.com/rv/powerarmor
They have a variety of sizes. They're lockable and vented.

We installed the 58" model on our Minnie, which can accommodate 4x Group27, and up to 5x Group24 batteries.

Thanks, but I find it very hard to justify spending $400 on a battery box.. also trying not to overload my hitch, since I wasn't planning on using a weight distribution hitch just yet.

[Elkman]

Originally Posted by Marine359

Hey there Duercos,
R.V. manufacturers do not install AGM batteries in enclosed spaces because it’s against the law. The pass thru is not ventilated. You could put AGM in there yourself, but you could never legally sell your trailer. For the scoop on AGMs and venting, you might want to read this:
https://rvnerds.com/2017/11/01/elect...ging%20process.

Lance installed the battery in my camper in an interior space with no flow through ventilation. My Prius has the secondary battery which is an AGM and sits under the rear cargo deck where it does not vent anywhere. Same was true for the battery on my Mercedes CLK that had the battery in the trunk and no vent to the outside. Why do people keep parroting this nonsense, it is not helpful at all.

The advantage of an AGM as compared to a flooded lead acid battery is that it can be on its side which provides additional mounting options.

I would look for a trailer box designed for two large batteries and then have the frame reinforced if needed to support the load. Welding shops are cheap or you can bolt on a metal frame to support the box.

It does not have to be a purpose built "battery box" as such and it can be made out of roto molded plastic or metal. Even the commercial grade NOCO box that is 24.4 x 15.4 x 12.3 inches sells for only $79 on Amazon. More costly will be the cabling and connectors.

Recommend delcity.net for connectors as they have ones that use a solder slug that melts inside the terminal with heat from a torch and then you push the exposed wire on the cable into the terminal. Makes for a strong electrical and mechanical connection and no need to buy a special crimping tool (which provides an inferior connection).

[FlyingBiskit]

You mean this vent in the Prius that supposedly doesn’t exist? https://priuschat.com/threads/exide-...nstall.173677/

[Marine359]

There is room on this forum for legitimate disagreement on this topic without either side being called nonsense. The topic is regularly discussed on all R.V. forums. I’ll stand my ground that it is unsafe to mount AGM batteries in an unventilated area. And, I don’t think that makes AGM batteries bad. I’ll side with a majority of evidence to support it.

1. AGM battery manufacturers advise against it and issue cautions.
2. The RVIA considers it unsafe
3. I owned a 2005 Prius for 15 years and drove it 300,000 miles, replacing the 12v battery twice. There was a vent in my Prius where my AGM battery was mounted. Maybe that has changed on later models. Idk. Can’t speak to a CLK. Never owned one.
4. AGM batteries have a built-in vent which is designed to expel hydrogen gas if the battery is overcharged.

Although I may disagree with you, I feel you are entitled to your position and opinions, and I would never consider them nonsense. What’s really not helpful is to claim your position is the only legitimate position. I misspoke when I called it illegal. But, I will continue to state that it is an unnecessary risk until evidence proves otherwise.

[Wyatt]

Originally Posted by Elkman

Lance installed the battery in my camper in an interior space with no flow through ventilation. My Prius has the secondary battery which is an AGM and sits under the rear cargo deck where it does not vent anywhere. Same was true for the battery on my Mercedes CLK that had the battery in the trunk and no vent to the outside. Why do people keep parroting this nonsense, it is not helpful at all.

The advantage of an AGM as compared to a flooded lead acid battery is that it can be on its side which provides additional mounting options.

I would look for a trailer box designed for two large batteries and then have the frame reinforced if needed to support the load. Welding shops are cheap or you can bolt on a metal frame to support the box.

It does not have to be a purpose built "battery box" as such and it can be made out of roto molded plastic or metal. Even the commercial grade NOCO box that is 24.4 x 15.4 x 12.3 inches sells for only $79 on Amazon. More costly will be the cabling and connectors.

Recommend delcity.net for connectors as they have ones that use a solder slug that melts inside the terminal with heat from a torch and then you push the exposed wire on the cable into the terminal. Makes for a strong electrical and mechanical connection and no need to buy a special crimping tool (which provides an inferior connection).

FYI. My E500 Mercedes came with FLA batteries so of course there’s a vent in there, so I didn’t worry about swapping it out for an AGM.

[Elkman]

Having a vent tube that goes down is a poor solution should a battery vent out hydrogen gas as it is only effective while the vehicle is moving. The hydrogen is lighter than air and will rise up into the compartment unless there is a vent at the top as with a gas furnace that releases combustion gases into the atmosphere. This also presupposes enough gas being expelled and the presense of a spark or a flame to ignite the gas. This is where the situation is quite different from house batteries in an RV as compared to a battery in the engine compartment.And what happens when the AGM battery is placed on its side which is considered OK by the battery manufacturers?


What is different with an AGM battery is that it has a valve and this blocks gas from escaping unless the pressure builds up to 2-3 PSI. This is why there is no loss of electrolyte as is the case with flooded lead acid batteries.

[Duercos]

Thank you so much for your input guys. I wanted to share my progress here. I used a slotted metal angle from home depot, screwed it into the a frame with a few self tapping screws and mounted 2 plastic battery boxes on top of the rails. I spread the boxes slightly apart to make sure the weight is distributed between the middle of the rails and the hitch frame itself just in case as I was worried the weight of 2 batteries might brake the angles in the middle. I also had to trim the battery boxes slightly with my dremel cutting tool in order for the lids to close. Next step is a battery cut off switch and installing a chain with a lock for security.

[Marine359]

Nice work Duercos!

[Wyatt]

Originally Posted by Duercos

Thank you so much for your input guys. I wanted to share my progress here. I used a slotted metal angle from home depot, screwed it into the a frame with a few self tapping screws and mounted 2 plastic battery boxes on top of the rails. I spread the boxes slightly apart to make sure the weight is distributed between the middle of the rails and the hitch frame itself just in case as I was worried the weight of 2 batteries might brake the angles in the middle. I also had to trim the battery boxes slightly with my dremel cutting tool in order for the lids to close. Next step is a battery cut off switch and installing a chain with a lock for security.

Agreed. Nice work!

[Duercos]

Much appreciated!

[Marine359]

Yo Duercos,
You should post these photos to an album on your User CP. That way other people can with the same or similar challenge can see how you solved it. Put explanations under the photos when you post them.

[Duercos]

To be honest, I can't figure out how it's done maybe I meed to log in from my computer and not the phone?