I continue with the assembly of the two LiFePo4 Lithium batteries by adding all the components, that connect and control the different parts of this setup.
The assembly so far, indicates a slightly taller battery than expected; that forces me to enlarge the storage area access first.
Now that I know that the battery boxes do their job as expected, I will add four threaded rods to hold pressure on the sides of the battery cells, which will avoid undesired bulging of the cells when charging. A washer and nylon lock nut at each end will lock everything in place.
In the previous video I was unsuccessful in attaching the ceiling panel with the 3M Dual Lock, velcro-type fastener. Today I have a different approach and use the van’s own hydraulic jack with an extension pole, to force the Dual Lock strips together.
It is a slow process, where I follow each of the two ceiling cross members from side to side and apply force to the panel where the strips of Dual Lock meet.
This is one of a series of articles, describing my journey of assembling and installing Lithium battery cells, as part of my van conversion. I will likely make mistakes and may not even reach my goal of a cheap, yet large Lithium battery bank. This is the continuation of Part Two of my journey.
I used a small 12V Lab power supply to top balance the battery cells. I connected all the positives with bus bars and separately, all the negative ones. My LiFePo cells accept a max. of 3.65V and that’s how I set the power supply. Then set the amperage to maximum (<1C) and I let them charge until the charging amps showed <0.1A. Actually I disconnected the power supply a bit early, when the cell terminal voltages rose above 3.65V
Two simple battery boxes will hold four cells each, making a 12V configuration, each with their own 120A charge/discharge BMS. Together they can handle 240A max (240A * 12.8V = 3072W max. output). Charging will probably be limited to 60-80A.
I continue where I left off in the previous article Van Ceiling Panel Part II. As a reminder, I use an automotive tweed protected against daily wear and UV, very similar in color and texture as the front seats of the van.
Before I can install the ceiling panel, I still have to finish and attach this black foam block above the sliding door, as well as a small cabinet that houses two switches and the gas heater control knob and a top cabinet.
I continue where I left off in the previous article Van Ceiling Panel Part I. As a reminder, I use an automotive tweed protected against daily wear and UV, very similar in color and texture as the front seats of the van.
In this video, I start by gluing the edges of the fabric to the plywood panel and cut the holes in the fabric, where the puck lights will come and glue the fabric there too. After I spray the glue, the 3M 77 will dry to a tacky feel within a few minutes; then you can finish be applying the tweed.
With the glue is dry to the touch, I pull up the fabric for a sharp edge and then fold it over onto the surface of the panel. Finish with a few strokes of a J-Roller. Try to avoid too much fabric at the outside corners, otherwise the thickness will become obvious.
Much of the ceiling has been covered by 1in – 1-1/2in insulation and it’s time to cover it up.
I plan to use a 4′ x 8′ (~120cm x ~240cm) sheet of 3/16″ (~5mm) thick plywood covered with an automotive tweed fabric, which I also use on some of the walls and around the windows of the van. On some parts, the sheet is trimmed to fit between the cabinets; other parts are the full 48″ (~120cm) wide. That means, I have to use some narrow filler boards to span the entire ceiling. These boards will also support the edges of the panel.
With the Van Build coming to an end, several important projects need some attention. Today I’ll start working on the battery bank of my solar system. Originally, and that was at the beginning of the van build, I installed two 6V Golf cart batteries. This netted me only ~100Ah at 12V nominal. Sufficient for only the most basic usage. At the time also more than sufficient, with only a minimal number of trips planned.
The main reason however, was that only 3-4 years ago, Lithium battery technology was hardly existent and very expensive. As I look back now, much has changed. We know now, that charging a Lithium battery at below freezing temperatures, is a big No-No, cell balancing must be part of the setup and many more issues are better understood. The development of low priced BMS’s (Battery Management Systems) has also made the DIY setup a possibility.
Still have a small piece of window, next to the storage closet that needs to be finished. I’ll install a window frame/sill made from Hard Maple and add a plywood cover around it. Later I will use an automotive tweed to finish it. The corners of the frame are made differently than those of the window at the Murphy Bed , but give a similar result.
In the process of finishing up the passenger side of the interior, I need to insulate the walls. Before I do that, I pulled the last wiring through the wall cavities.
The wall insulation consists of rigid Poly-Iso, separated about 0.5 inch from the skin of the vehicle with a few dots of spray foam, with the Poly-Iso pressed into it. This void acts, both as a barrier and a way to drain any condensation, without wetting the insulation.