Overland Sprinter Build

[Alloy]

Galley is painted, and electrical/plumbing have been fitted, I will get some photos up tomorrow. I have the main plumbing runs for the drains worked out. Just need to make a bracket to support the drain valve and camlock for the hose.

Planning forward to rebuild the hydronic system, and heating for the underbody lines. I think the easiest method is to isolate from the engine via a plate heat exchanger. I can locate one near the firewall below the brake booster. Then I can run the hydronic system at ambient pressure. A flow through reservoir in the mechanical cabinet (in series with water heater/main loop) should be doable.

View attachment 610315

Under the van I can located a manifold pair with shutoff valves. Coolant feeds will be to the Gray tank, drain line feeds, and eventually the fuel tank/lines. I think I can use the grey tank heating loop return to heat the floor under the show pan, and the drain area. Both for comfort and freeze prevention when showering. I am going to need a bunch of different insulation styles, but I think a system without electric valves will be the most reliable. I will waste some heat of course, but with there being a couple gallons of coolant, plus the heat storage in the water heater (its in the main loop), cycle times should be reasonable. The goal is to calibrate the flow to keep the lines/tank above freezing, while the main loop cycles between 120F and 165F. Which lets me use the built in output control (800W or 5kw) of the hydronic heater. So I can just use a digital thermostat with a temp probe on the tanks/lines set for around 40F. Depending on how it works out, I may need a small circulation pump.


Now how the antifreeze lines are plumbed. I am leaning towards them having their own circulation pump, with a hydraulic separator between both (a double ended manifold will work). That way I don't need to shut all the valves when heat isn't needed in that loop. Instead the vales will be for flow control/calibration in each loop.

View attachment 610316

Watch out for dissimilar metals especially if the sytem is open (non pressurized) system that will allow the introduction of oxygen. Aluminum is a great material but hydronci isn't the best place for it.

You'll want to use some of this on any system.

Amazon.com

A manifold made for hydronic heating will have balancing valves and flow meters. If there is no flow meters balancing can be done with a point and shoot thermostat.

 

[Alloy]

Ended up directional sanding the top, and using a clear urethane.

IMG_20200902_162427165

Did you used a primer?

 

[luthj]

Did you used a primer?

No, I used a direct to metal single part clear urethane.

 

[luthj]

Watch out for dissimilar metals especially if the sytem is open (non pressurized) system that will allow the introduction of oxygen. Aluminum is a great material but hydronci isn't the best place for it.

You'll want to use some of this on any system.

Amazon.com

A manifold made for hydronic heating will have balancing valves and flow meters. If there is no flow meters balancing can be done with a point and shoot thermostat.

I do have some stainless in the system (water heater). However they are separated by several feet of tubing, so galvanic corrosion should be nearly zero. I am also using typical automotive coolant which should help. There isn't any other metal types in contact with the coolant and the aluminum in the same area either.

 

[Alloy]

I do have some stainless in the system (water heater). However they are separated by several feet of tubing, so galvanic corrosion should be nearly zero. I am also using typical automotive coolant which should help. There isn't any other metal types in contact with the coolant and the aluminum in the same area either.

I thought you might be installing the copper manifold in the same system as the aluminum tank.

Not being in contact can be worse. I've seen tanks / individual fitting eaten away over several years that were not bonded.

 

[luthj]

Making progress. Got the heater lines insulated and run back to the heat exchanger.





LCD and temp sensors are working.

 

[luthj]

Got tired of laying on my back. Still waiting on some larger ID insulation tube anyways. Spent the day working on the wiring and controls. Decided to make a shallow panel and mount near our TV. Not the ideal spot, but there is plenty of wiring there already.

Decided to rework the LCD layout. Added a button to control the backlight. I had some latching pushbuttons, and they should do the trick. Plus, colors! I added a temp sensor of the mechanical compartment. This will be mounted near the fresh water tank. If it gets too cold in there, a 120mm fan will come on and pull warm air from the living area. Hopefully between the fan and the hot tank being in there, it will stay above freezing. There is some condensation risk, so I will have to keep an eye on that.


Project box and relay board. I will mount these in/near the electrical cabinet, as there will lots of power wiring running through it.


Its a 6ft run from the cabinet to the head unit. I only need about 40mA for the LCD (30 of that is the backlight). For ease of assembly I went with ethernet termination blocks. Easy to work with, and I can use any straight through ethernet cable for the run between.

 

[DzlToy]

You seem like you know your way around these electronics pretty well, so why not use a product like InfinityBox, that is PDM based, thus eliminating relays, fuses and a ton of wiring?

MoTeC and other quality ECMs run this way and I have to imagine there is something similar in the Linux/Unix/Arduino/OpenSource world that would allow you to build your own PDM box if you did not want to buy an InfinityBox for a simple project such as lighting control or monitoring temperature sensors.

MoTeC > PDM15 > Overview

Default Meta Description

www.motec.com.au

 

[luthj]

There is a bit of a learning curve with those units. I am familiar with coding in C though, and the arduino/embedded ecosystem is well documented. Cost is pretty reasonable too. As far as wiring goes, I am not sure one of those units would be much easier for a one-off like this. I would still need to connect up temp sensor, and the power wires for the pumps/fans.

Your right though, if I was doing something for production, I would not be using these for my final hardware config.

 

[PlethoraOfGuns]

Wow, great build! And a wealth of information! Keep up the excellent work!

 

[luthj]

A quick update on the galley. Its working well. I need to do a little adjustment, as one of the bins sticks. The wider bins take some force to open, but they are not used often. I also don't open the bins past 75" normally, as it takes a little lift to get them going on the return. I have the contents arranged with the most used items near the front, and that has been suitable. The storage is fantastic, much more than the previous model.

One issue is that I don't have enough slope on the drain line where it runs back towards the rear of the van (where it passes through the floor). This causes air lock when the van is slightly sloped down. Its not easy to change though.

 

[luthj]

I have the hydronic system closed up and bled of air. Wiring is at 99%, just need to tidy things up and connect the D+ sense lead.

Here is the approach I am taking with the water lines. I took some 2" pipe insulation and ran 3/8" heater hose along the drain lines. I plan to seal all the gaps. Then the loop goes through the gray tank. It then turns back, and a loop is glued to the underside of the shower pan and drain fitting. Finally it returns to the main hydronic loop. Its setup so when this loops pump runs, it pulls coolant through the water heaters loop, so the water heater serves as a reservoir.



Obligatory project box shot.


I am now debugging. My current issue is that all the temp sensors return exactly 77F, or 25C if I change the return type. I figure there must be some issue with the one wire bus. I messed up the pull up resistor, or something like that.

 

[luthj]

Alrighty, Got the wiring buttoned up, and fixed some bugs in the code. Apparently I often confuse constants with variables. Probably should change my naming scheme.



Tested the engine preheating, took about 20 minutes to go from 70 to 100F. It looks like the D5s pump also pushes a small amount of coolant through the gray tank loop, it got up to 120F before I terminated the test. Of course the gray tank is empty, which would have a major impact.

I need to do a bunch of testing and tweak the temperature setpoints, and the cycle timer for the gray tank loop antifreeze. Otherwise its looking good.

I may add wireless monitoring at some point, but not sure if its worth the effort.

A few features which are real advantageous.

• Hot water tank will heat any time we drive, so we will have free hot water most days.
• If its cold outside, the gray tank and lines will get superheated with the free heat. This includes the shower floor.
• Engine can be preheated in cold weather. It can also be boosted when running. For example starting up at high altitude, and coasting downhill for 40 minutes.
• When I am plugged in, the water heaters 750W element can be used to keep the gray tank loop above freezing. The D5 will run as backup as necessary.

 

[luthj]

Pushing to get the last of the winter maintenance done. Due to the angle of my D2, I think the combustion burner chamber is getting a bit of coke on the high side. So I put some shims under the low side.



I also slotted a socket to make a glow plug removal tool.





I also swapped in new engine mounts. The old ones were getting tired.





In anticipation of some brutal cold weather, I also put some insulation on the inside of the fan lid. This will also reduce rain noise, which can be significant.

 

[luthj]

Since we will be in the USA for a while, we wanted reliable unlimited mobile internet. Lots of background on this but here is the executive summary.

A cheap Visible phone with unlimited data plan. Phone is tethered to the router which has a wifi and wired network available. The router spoofs the TTL on the traffic so Visible can't detect the hotspot/tethering, so no throttling of data.

A Weboost Drive is used to get optimal reception from inside the van. The external antenna is magnetized to a pad on the roof with a fabric strap glued to it for security. The internal cradle and amp are shown in the photos. There are better external antenna options, but they are larger, and would require me to take them down to avoid damage often.