How-to: Building a Lithium House Electrical System | Component Installation

Just a Bit of Background

This is my second take at a house electrical battery system installation in the Tacoma. My first system was based around a 12v AGM battery and worked well for more than 6 years. In fact, it worked so well that I'm mostly copying the overall design for this system, with a few minor improvements that I've realized since I put the first setup together.

Before we get into the actual build-out, here's a refresher of the system itself:

Everything getting squeezed into the Tacoma.

Safety Glasses

I'm not generally one to get up on a soapbox about safety, instead allowing folks to take whatever safety precautions they feel are appropriate. This likely comes from years of being a woodworker - I started when I was in my single-digits years old, working with my dad's tools and under his supervision - where there were scant tool guards, definitely no SawStop's, and plenty of attention paid to "learning how to do things in a way that felt safe." Following that, years of building and remodeling homes helped to introduce me to working with high voltage/current circuits, natural gas lines, and a broad range of power tools.

Still, in this case - since LiFePO₄ battery tech is still relatively new to most - I think it's important to mention the raw unbridled power that sits inside that little box of energy. Unlike the battery technologies we're used to using in vehicles, LiFePO₄ batteries have very low internal resistance. Any short and the entire 280 Ah (or whatever capacity you've chosen to use) will flow through it. A wrench or screwdriver or wedding ring will vaporize, sending shrapnel in all directions.

One of those directions may be toward your eyes. And so, in the immortal words my favorite woodworker

There is no more important safety rule than to wear these, safety glasses.

Norm Abram

For more safety considerations, Will Prowse has put together a nice video that I recommend for those new to working with electricity.

Where to Put Everything (and Installation Considerations)

The first time I went through this process, I considered three places to put the house battery:

1. Under the bed, where the spare tire was originally mounted.
2. My next attempt was above the frame just in front of the rear wheels.
3. In the cab, behind the passenger seat.

I ended going with option #3, and the cabinet that I built worked well to hold the battery as well as add some additional organization to the interior of the extended cab for gear that we regularly use on trips. As such, there was no question where the battery would go this time, though I did have some tweaks and improvements I wanted to make since building the first version.

A great first attempt, but after six years, I can do better.

Things I really liked from the first cabinet included:

• The storage area on the top of the cabinet was a great place to store a box of things we use throughout almost every day that we're out on the trail. Binoculars, paper towels, plastic plates, chip clips, toilet paper, etc. These small items can easily get lost in a sea of stuff behind the seats, so it was nice for them to have a spot to live.
• The storage area at the bottom of the cabinet is the perfect size for a Dewalt T-stack case that holds everything I need to air up my tires, as well as a basic set of recovery gear for winching or cutting a small-to-medium sized tree out of the road.
• The small shelf above the battery - empty in the photo above - just happened to fit my camera bag perfectly. Like the items on top of the cabinet, having the camera easily accessible is critical to me, so I'd definitely include a similar spot in the new cabinet.

There were, of course, a few things that I thought could be better.

• To the driver side of the cabinet, we didn't have a great organization system. A couple cardboard boxes helped to keep things "contained," but it was always hard to find what we needed, as stuff would get buried under a pile of stuff that would inevitably get stacked on top of the boxes.I wanted the new version of the cabinet to provide an extra level of storage, and allow easier access to a few things - like my foldable solar panels and the DJI Air 3 drone - that otherwise get lost.
• The electrical shelf itself. I'd mounted as many components as I could to a drawer that slid in/out of the cabinet, thinking that I would have easier access to service things if they weren't buried in a little cubby. Servicing was easier, but it came at the cost of organization and durability. Since everything needed to slide with the drawer, the wires connecting everything had to be long enough to accommodate the entire range of motion. When the drawer was closed (most of the time), those wires were then just a messy tangle pushed into the rear of the cabinet, and when it was open, they were in the way of servicing the components I wanted easy access to.In the new version of the cabinet, I wanted most of the components to be mounted to the sides of the cabinet itself, so they were fixed in relation to each other, allowing for short, clean wire runs that I didn't have to worry about getting tangled up in each other. Plus, that would open up room on the shelf for only those items that I'm accessing regularly, like battery chargers and USB ports (which I'd inset from the front edge of the drawer so that cables were less likely to get tweaked as other gear was moved around in the cab).

Building a Cabinet

Embarrassing, after-the-fact, "pro tip" of the day: Just because you build something that you want to fit in the cab, doesn't mean that it will fit in the cab.

Having figured out where to put everything, it was time to build the cabinet itself. Luckily, I'd done this before, making me aware of some of the larger issues. The largest of those is that there are essentially no 90° angles in the extended cab portion of a 1st gen Tacoma, so building a cabinet is largely a bit of cut-one-piece-at-a-time affair in order to get a perfect fit.

I smiled to myself when I realized that I could disassemble the old cabinet and use the angles on it as a basis for the new setup. That, and I could start from a copy of the original Sketchup diagram to model out my new masterpiece.

One last hurrah!

I struggled more than I should have building this diagram; I've forgotten how to use Sketchup in the last six years.

Another benefit of using the same general design was that it would allow me to secure the cabinet into the rear seat area of the Xtracab using the same mounting locations. These had proven themselves to be strong and secure - a necessity when the roads are rocky and bumpiness is the name of the game.

There aren't many mounting locations in the Xtracab area, but there are some year-2000-era seatbelts back there, so I worked out a way to attach an aluminum bracket to one of the lower mounts. A carriage bolt fit into the opposite end would secure the back of the cabinet.

Just need to figure out a way to get that bar sandwiched in there.

I probably didn't need the heat at all when forming the aluminum.

After a bit of finessing, I had the right curve.

How to drill a square hole.

The second attachment point was easy and obvious. Behind the passenger seat, a small fold-out cup holder - and in the year-2000-timeframe, an acceptable child seat platform - was secured with a couple of M8 bolts. Removing it would allow me to use the holes to secure the cabinet.

Baby-seat anchor points (foreground). And, a custom aluminum bracket with carriage bolt attached to the seat belt anchor (background).

With those details sorted, I set about construction of the actual cabinet. I happened to have a couple nice pieces of ½" and ¾" prefinished A1 grade maple plywood hanging around from some previous projects, so I broke out the Makita track saw and started breaking down the pieces.

Raw material.

A convenient way to get crisp, custom angles.

Reinforcing all the joints by using dados and rabbets, in addition to screws, makes for a cabinet that won't rattle apart.

After a bit of trim work - to cover the exposed edges of plywood with something strips of solid maple in order add a little refinement - everything was really starting to come together. I still had a bit more work to do on retaining blocks and the slide-out drawer/platform, but it was time to make sure that the main cabinet was going to fit.

I should have been test fitting this as I went.

I lucked out when I discovered that the cabinet fit with less than 1/4" to spare in the Xtracab. Even so, both seats and the center console had to be removed to maneuver it into position.

In goes the battery - at least temporarily - as well as the C-channel that would keep it from flopping around.

At this point, the cabinet was definitely starting to come together. The battery fit well in a compartment on the right and I was ready to get started wiring in the components that would funnel the electrons to various gadgets that I wanted to use when I was out on the trail. I decided to remove the cabinet from the cab - and work on it in the shop - for this part of the operation, knowing that I'd have easier access and better lighting by doing the work outside of the truck.

Component Installation

Most of what I needed to stuff into a tiny area.

I started by prepping and placing the largest component of the system - the Victron Lynx Distributor. This would get mounted to the rear of the cabinet, along with the main battery switch on the positive bus bar and the Victron SmartShunt IP65 on the negative bus bar.

Before I could connect the main switch and SmartShunt, I needed to enlarge the holes of the bus bar slightly.

Next, I placed the Victron Orion XS DC-DC charger and the Victron SmartSolar charger. Unlike my first cabinet - where the controllers were on the pullout shelf - this time, they would be mounted to the side of the cabinet so that the wiring could be cleanly fixed in place.

I was having trouble getting the 4-gauge cable to fit into the Orion XS, so I picked up some pin terminals so everything went together like butter.

Like the Victron components, I also wanted to mount my 12v Fuse Blocks - one always-on, the other ignition-switched - to the cabinet, so over the course of a few hours, I played a game of Tetris, eventually finding the position of each component that would work best.

When the table saw is transformed into cable assembly table.

Done! Everything in its place.

The only thing left to do at this point was to finalize the pull-out shelf. This would be where the inverter - along with the battery charger for my camera - sat, and also where I'd mount two 65W USB chargers to keep my laptop (any number of USB devices) full of energy as I needed them on the trail.

I mounted the USB chargers a couple inches back from the front edge in order to protect the connectors from getting whacked by anything moving around in front of the cabinet. Now, only the more-flexible cables stick out past the end of the shelf.

With everything installed, it was time to squeeze the whole shebang back into the cab - hopefully for the last time. Then, all that was left to do was reinstall the seats and center console, before stowing our gear into the various cubbies and shelves that I hoped would provide a bit more organization than we'd had previously.

The final product.

Ready to go camping.

Obviously, the installation of a house electrical system will vary from truck to truck and with different components, but hopefully the overall process and some tips from my experience will help to make the build go more smoothly.

Resources

I have no idea if it will be helpful, and it's certainly not very well designed as my Sketchup skills nearly non-existent, but for anyone interested, here are the sketches for the two cabinets I've built. At the very least, measurements can be taken from them in order to build your own cabinet.

• Battery Cabinet v1 - Smaller cabinet, approximately half the width of the cab.
• Battery Cabinet v2 - Wider cabinet, spanning the entire width of the cab.

These components were all covered in Building a Lithium House Electrical System | Component Selection, but I list them here again for convenience.

Category	Component
Battery and BMS	Wattcycle 280Ah Smart Mini LiFePO₄ Battery
Master On-Off Switch	Blue Sea Systems 6006 m-Series Battery Switch (ON-OFF)
Battery Shunt	Victron SmartShunt IP65 500A
Master Distributor / Fused Bus Bar	Victron 1000A Lynx Distributor
DC-DC Charger	Victron Orion XS Smart DC-DC Battery Charger 12 | 12 50A
Solar Charger	Victron SmartSolar MPPT 100/20 Solar Charge Controller
Constant-Power 12v Accessory Fuse Block	Blue Sea 12-Circuit Fuse Block
Ignition-Switched 12v Accessory Fuse Block	Blue Sea 6-Circuit Fuse Box powered via a quality 4-pin 12v 40A relay
120v Inverter	Cheap, no-name, 175W Inverter

 

 

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