FJ55 Dual Battery Tray (1 Viewer)

[fj55tlc]

I don't know if there would be adequate depth for batteries underneath the rear seat like my box. The box is about 8 inches hanging down under the body floor. I am sprung over and have more room than a stock height cruiser. I had often thought of building a water tight box for each battery and installing them in the void behind the front wheels in that cavity that likes to rust through our fenders. It would keep the weight low for us that like to test the side hill limits of our trucks. I have not yet taking action on this idea, just mental design. Also I have changed to Odyssey batteries that are smaller than a group 27 and probably even a group 24. Those would fit into that spot even easier. Maybe someday I will get around to that project.

 

[RUSH55]

Yeah, I checked into it a little bit today. You could get plenty of length and width, but yeah, the depth could be a limiting factor. 3” below that level gets you level with the driver floor.
Thought I’d seen some people lay an Optima on its side.(?) Not sure what the dimensions are of the different Optima’s. If it’s around 6”, you could be 4” - 5” below floor level, and 1” - 2” above floor (depending on seat clearance). How high above floor level does your storage box sit?

 

[RUSH55]

Dimensions of all Optima’s, according to Amazon -
10” x 6.88” x 7.8”

 

[fj55tlc]

You can lay optima batteries on their side, or upside down, or however you see fit. My box is almost 3 inches high off of the floor. I had to raise the rear seat by 1/2 inch or so.

 

[RUSH55]

So, two Optima’s on their sides, end to end would be (should be) about 20” in overall length, 8” wide (in a 13” potentially wide space), 5” below the floor an 2” above. Badda-boom! I’m considering it!

 

[fj55tlc]

Do it!

 

[J Mack]

Badda-boom! I’m considering it!

Spend an hour or two poking around here, Raw LiFePO4 Cells

And here, DIY Solar Power Forum


Wish I would have known about LiFePO4 when I was building my pig.

Looking to do something like this now. Charging Secondary Lithium (remove in winter)

 

[RUSH55]

Uh, hmmm... this looks to be above my pay grade, Jim. I see 3.2v. Would you need to connect 4 in parallel to achieve 12.8v? How would all this work in a normal 12v automotive system?

 

[J Mack]

this looks to be above my pay grade

Nope all easy stuff here.

Yes you’ll run all your “house” 12 volt appliances from the LiFePO4 cells and keep a single start battery AGM our something similar for a start battery.

A single cell is 5.4”L * 1.6”W * 12”H in @6.6 Lbs and you can configure 4 cells in any arrangement to suit your needs and have a 100Ah battery weighing 26# when you’re done.

That’s 4 times the capacity of the “Optima Batteries 8016-103 D34M BlueTop Starting and Deep Cycle Marine Battery” 4 Optima batteries will weigh 174# and take up a lot more space so you can see the advantages LiFePO4 cells if you are using them to run stuff like mini refrigerators electric blankets or any 12V camping accessories.

If you plan for LiFePO4 cells on the front side the wiring and charging requirements are not a big deal.

Just some food for thought.

 

[xtiaan2000]

I have seen a post where a box was cut And sunk behind the passenger rear wheel. Perfect place for an extra battery.

 

[RUSH55]

Been chomping at the bit all day to get home and work this out a little more.
The brainstorm is an opening separate from the compartment, with a hinged, latched lid. The compartment would be hung from the backside of the front cross-brace and the front of the rear seat, seatbelt reinforcement, and possibly some angle pieces on the sides tying the front and rear together. The depth, 5”. The topside opening, 2” high. 23-1/2” in length, 13” wide. Or possibly even 12”. 12 ga sheetmetal. Plugged drains at bottom. Provisions for ground cut-off switch, dual battery hold-downs, hold downs for electric car batteries (LiFePO4 Cells [extremely modern tech]). Closed-cell foam seal around lid.

 

[bobm]

Putting a COOLER under mine!!!

 

[RUSH55]

That would be my next option!

 

[J Mack]

I have seen a post where a box was cut And sunk behind the passenger rear wheel. Perfect place for an extra battery.

I’m guessing @Gordobe second battery post.

Hidden 2nd battery

Had to find a place for a second battery. A group 31 is a big 70 pound mother. I don't like drilling new holes or welding on this original pig so I have to find ways that don't change the integrity of the primodonna. This is what I came up with.

forum.ih8mud.com

If I had known about the 60Ah LiFePO4 cell when I built my pig I would have mounted 4 of them here.

Affordable Electric Vehicle Batteries & Components from Electric Car Parts Company

A little more capacity than two Optima’s and not much larger than three bottles of whisky.

 

[RUSH55]

So would you run your LiFePO system separate from the auto 12v, or would you integrate? I.E. charge off of the alternator or would they need a different charging source, solar panel, etc..?

Be gentle - I read through some of the links but don’t have much of a clue of what they’re talking about.

 

[J Mack]

Be gentle

Like should we cuddle first?

 

[RUSH55]

Yes please. Tuddle.

It’s my first time.

 

[RUSH55]

Aux circuits I’m wanting to go with -

Winch
Aux lights
Rear aux light
CB
Several 12v plug ports
Stereo with amplifier ()

maybe more I’m forgetting

 

[J Mack]

maybe more I’m forgetting

Yes you can charge from an alternator but best to use a DC to DC Charger for Lipo in between to limit the current draw and give the batteries the voltage they like. Lipo batteries will pull high charging amps when fully discharged without something inline to regulate it.

I’m using a cheap Renogy 20A DC to DC Battery Charge in my testing and so far it is working well but there is lots of better systems out there.

You would need to run a dual battery Isolator and separate the AGM start battery form the LiFePO system under normal circumstances but could combine them for heavy loads like winching or jump starting.

Scrapdaddy and I are using the perfect switch but any would do. Dual Rectifier 100 to 300 AMPS (Gen 4.0)

This would keep your start battery separate and let you party all night off the house battery and still be able to start the pig the next morning.

Again if you lived closer this would be the perfect conversation to have sitting around a camp fire having a cocktail or three.

 

[RUSH55]

Again if you lived closer this would be the perfect conversation to have sitting around a camp fire having a cocktail or three.

Don’t get me started. Every new day brings another reason to leave AZ