In the van there will be a small plumbing system. Since I don’t have a shower, and also don’t need an outdoor shower, its limited to the kitchen area only.
I also don’t have water tanks underneath the van, since I don’t need huge amounts of water. Also, I don’t think it’s hard to get water, so no need to take huge amounts with me. So i went with 2 small portable water cans of 20 Liter each (5.3 gallon). If needed, I can fill a 3rd one and store it in the back. Both of them can fit in one of the kitchen cabinets. One will be used for fresh water, the other one as grey water.
I use a small submersible pump, which is connected to the kitchen faucet. Inside the faucet is a small microswitch. This switch is connected to a small relay, which switches the actual pump. Some people are reporting issues with the small micro switch switching the inrush currents of a pump, so I added a relay, to save the microswitch.
I also installed a small 12V / 200W boiler. This can hold 6L water (1.6 gallon). I also added a switch so I can disable the boiler if needed to save some power. (I calculated the boiler to use approx 35Ah battery capacity, so it’s quite a heavy user…
The boiler is a plastic one, with rather crappy insulation. I’ve installed it below my bench. In order to add some insulation I’ve wrapped it in some 9mm Armaflex leftovers, made a small box around it, and filled that with sheep wool. And it did fit perfectly, I had just enough to run the duct from the Webasto heater through this compartment as well.
Both the boiler and the water tanks are in separate compartments. I’ve covered both with Vinyl floor liner. Also made all sides fully watertight for at least 3cm (about 1 inch). On the back, there is a gap of 5cm widht (2 inches), so if anything starts leaking, it will leak into the structural framing of the van, which has holes in it so it will drop straight to the ground, instead of damaging my floor.
So as in the previous post, I found the EVE 280Ah cells. People on https://diysolarforum.com/ have had very good experience with these, and also recommended some sellers on Alibaba to source these from.
So I went ahead and bought 4 cells for my build. The seller was able to provide me with DDP shipping (Delivery Duty Payed), so including all taxes and so on. Recommended by users of the forum was to use either boat or train as transport, since that would be much cheaper than shipping by air. Yes, it will be slower (Generally people mention 30-45 days) but that was fine for me.
This BMS is fully adjustable, does have bluetooth and is affordable. It also can handle up to 120A, so a smaller inverter can be connected to the BMS. (In theory: any inverter <1400W, but I tent to not use a BMS above 50-60% of its rated current). So for a <800W inverter: No problem. Since my inverter is 1500W, I’ll use my inverter directly connected, only controlled by the BMS (more on that later)
The BMS – Balances the cells so they remain equally in charge – Protecs the cells for overcharge, and overdischarge
The Daly BMS is a good option, and is easier to install (1 complete unit, unlike a more PCB-like BMS as the one I have), but its very limited. With the LTT BMS I can adjust various settings more specific. Also, it has low-temp protection, where the Daly doesn’t have it. (LiFePO4 cells can’t be charged below 0°C / 32F) There is a new Daly Smart BMS on the market, but there aren’t many reviews yet, and its more expensive, so I did go for the LTT BMS.
As mentioned before, the lead acid battery of 105Ah and the Xenteq 10A charger are for testing and initial setup only. I was planning on upgrading to Lithium.
During the build, I found there are plenty of options for Lithium. You can get a complete battery, eg a Victron, Liontron, Battleborn, NDS, Wattstunde and a whole bunch of other sellers. Also, there are unknown / lesser known brands, slighly cheaper. But in all cases: Still pretty expensive, a 100Ah battery easily is around 800 EUR in Europe
I did some calculations, and based on my requirements (beeing able to run offgrid for approx 2 days) I’ve calculated I needed at least 70-80Ah of usable capacity. So with lead-acid, this would mean around 180Ah, since lead acid can’t be discharged <50% without seriously shorten its lifetime.
If I want to run my water heater also, I estimated I need another 35-40Ah / day. Using the inverter also adds up pretty much, so with 100Ah Lithium I can safely run my refrigerator, lights, fan, but usage of other equipment has to be done carefully and depending on the solar.
So: The bigger: the better. Off course, the drawback is the costs. With 200Ah of usable capacity it would be great, and basicly nothing to be worried about anymore (since the solar will also help, the 315Wp will charge the batteries even in shadown, although very limited. 200Ah = 400Ah lead-acid = way too much weight, so lithium is definitely the way to go.
Also, it would be pretty massive in size. After searching for options, I found there are a bunch of Chinese sellers selling very affordable batteries. Most popular are (as of aug 2020) the EVE 280Ah cells. (There are also 105ah cells available).
These are not Lithium-ion, but are LiFePO4. This is much more suitable for van usage: Safer to use/build and a lot easier: Each cell is 3.2V so you need to wire 4 of them in series. Each cell has 280Ah capacity, so only 4 cells will do. With Lithium-ion, each cell generally has a much lower capacity so you need to run multiple cells in parallel, and joining these into series to make for the 12V. Also, unlike LiFePO4 which is 3.2V/cell, Lion = 3.7V, so slightly more off 12V (4×3.2 = 12.8V) And you need to have (or have access to) a spotwelder to create proper connections on Lion-cells….
The LiFePO4 cells however are much easier to use: Just a ‘block’ with M6 inserts, and included busbars to connect them in serie. And, when sourcing them directly from China, they are much more affordable. Besides the batteries, you also need a BMS (Battery management system, more on that later)
I only have to replace the charger (Which I was aware of).
Lead-acid batteries require a slightly more advanced charging profile than LiFePO4. A decent lead-acid charger will periodicaly equalize the cells using a higher voltage, primary to remove sulphation on the plates in the battery. However, this voltage is way too much for a Lithium battery, so this will overcharge them!
During initial charge, the charger will start with providing its maximum current (Bulk stage). This continues till the battery voltage reaches the absorbtion voltage. Once the batterie continues to charge, the current drops. If the current is below a certain point (or time, depending on the charger), the battery will hit its float stage, and the charger only provides a lower voltage to maintain this SOC (State of charge). This is 3-phase charging… Fine for lead-acid. More advanced chargers include more stages, eg equalizing. This can’t be switched of on all chargers, so you have to be carefull when upgrading to Lithium. Also, not all chargers can set to various voltages. ‘Wet’ lead-acid batteries have slightly different voltage requirements eg compared to Calcium-based batteries.
Also, while a lead-acid battery is limited in its charging capacity (generally recommended to have 1/5 C charging rate, so 20A max for a 100Ah battery), LiFePO4 can handle much larger charge currents (and discharge currents as well). So you can charge the battery much faster (although this slightly decreases its life if you charge it really fast).
Anyway: 280Ah with a 10A charger won’t really do, so I needed a bigger charger.
Since I have also DC-DC charging from the alternator (40A) and solar (about 25A max with optimal sun) I didn’t want to spend a whole lot of money on a charger which I’ll probably use occasionally. So: No expensive Victron or so for me 🙂
I only just needed a ‘huge power brick’. So unlike the well known RV charger brands like Renogy, Victron, Ctek and so on, I went to the industrial market: This also uses batteries for various purposes. And as with a lot of stuff: Anything labeled ‘Campervan’ is way overpriced.. (This surely applies to most electrical stuff: Campervan electrics are overpriced, you can get the same quality or better at a marine hardware shop: Boats are using low-voltage system for ages, while campervans are ‘the new kid on the block’ where they can charge you 200%…
So I ended up at https://www.meanwell.com/, a well known brand in power supplies and similar stuff. On their website I found various chargers. So I found the Meanwell PB-360. This is a very nice, robust charger, aluminium cased, and able to deliver 24A of charging. And its only 3-phase, so will work fine for Lithium. (Note: Not all datasheets of this model include Lithium, but it does work fine, and later datasheets do list it). It was affordable: 100 euro ($120 or so) and the output voltage can be adjusted to some more conservative settings to increase the life of Lithium even more (more on that later). Also, the absorbtion stage is not time-based, but current based. So no overcharging, it will go to float automaticly.
The top of the PIR boards are covered with self-adhesive Armaflex sheets (9mm thick). With this, the insulation was equal in thickness to the support beams, and the wooden timber which I had previously installed. The Armaflex was already black, the wooden timer and everything else have been spraypainted black to make a rather solid black background.
On top of this, there will be a layer of black fabric. I found a cheap black fabric (2.50 eur / m). This is slightly stretchable, perfect for my purpose. Since this is rather thin, white spots might be seen through the fabric, thats why I made the ceiling black and spraypainted where needed.
Once cut to size, I used thumbtacks to temporary fix the fabric in place.
The final cladding will be made from slats of beech wood, just as the countertops and table. Also painted in the same color. The slats were 4.5cm (1 3/4″) width and 1cm (3/8″) thick, I used a wood planer to remove 4mm and make them 6mm (1/4″) thick (Save weight, gain usuable height). After that, I’ve sanded them down, and painted them with dark varnish.
Once the slats were finished, I started installing them to the ceiling. The center slat also contained the lights, so I had to cut the appropriate holes first. Once confirmed everything was fine, I nailed them to the wood structure of the ceiling (About each 25cm / 10″), using a pneumatic stapler (which only created very small holes, barely visible).
I used some leftover wood of 12mm (1/2″) as seperator between the slats, exposing the fabric. Used this as spacer for equal with along the slats, nailed them and went to the next one. The fabric gives it a nice smooth backdrop. And once more slats are installed, I removed the thumbtacks, and the fabric is hold into place by the slats.
In the previous part, I described my primairy circuits (for all charging options and high-current stuff).
In the schematic, there is a 12-port fusebox. All general items are connected to this fusebox. In this post, some more information about all items connected.
I have a bunch of 12V items, which require separate circuits (or at least, I wanted).
Webasto diesel heater
Electric boiler (water heater)
All LED lights
12V outlet near the bed
12V outlet in the kichen area
12V outlet near the side door
For the LED lights, I added a stablisator. This has 8-40V input, and a 12V output, rated for 10A. (All lights on maximum power draw around 6.5A) I did so, since the voltage in the van can vary, depending of the battery state. During absorbtion, it will go up to 14.2V, which is a 20% more than the LEDs are rated for. This definitely won’t increase their lifetime, so it’s easy and to be on the safe side, just add the regulator (its about $15 or so on AliExpress). Replacing lights will be PITA 🙂
In the van, I have plenty of lights. In the ceiling, there are 3 led spots installed, each 3W. Below the cabinets, I’ve installed 2 LED strips, 1 in each cabinet, running the full length. (In total around 3.5m length). I used high power LED strips, so when needed, I can put them on full power. Both strips are indepently dimmable using small soft-touch dimmers. Also the ceiling lights are a separate dimmer/switch. On the cabinet above the cabin and on the panel in the back, I’ve installed RGBWW LED stips. Besides a normal white light, they can have any color.
On the bed area, I’ve installed 2 small 3W led spots, 1 for each bed. These can be used as reading light, or spotlight when needed. Just simple on-off switch, which was factory installed in the base.
All 12V outlets are the regular sigarette sockets. I simply plugin a car USB charger to have USB sockets for phone and so on. No fixed USB, just replace the USB car charger to whatever USB you require. With all the various standards, and evolving techniques, I can easily upgrade to USB-C, QC 4.0, or whatever will come in the future. (Unlike fixed USB chargers)