I haven’t seen Vandweller around in a while, but I’ve seen similar designs on Youtube.
It sounds like your heater’s not getting enough power because something between the battery and the unit is cutting voltage. If you’re reading 13.7 at the source but only 1.9 at the plug, that usually means a loose or corroded wire, bad fuse, or weak ground connection. Check every fuse holder and wire joint carefully, especially around the connectors. You can test it by running a direct fused wire from the battery to the heater to see if it powers up; if it does, the problem’s in your wiring.
Gary, Your homemade heater …
Will it keep you warm at night?
Van_Dweller has 3 of these in his bus, one in the living area, one in the bedroom area, and one in the bathroom. They keep his bus very cozy in the worst weather. They use veggie oil, and very little of it.
I’m also using veggie oil heaters, but mine are portable and don’t require holes in walls or roofs. They cost less than $10 to build DIY from dollar store parts, and about 15-20 minutes easy assembly. I use mine for both heating & cooking, and could use it for cooling as well. I add a $20 heat powered woodstove fan to have battery/electricity free fan forced heating.
I also have a DIY veggie oil table top fire pit, which can also be used for heating/cooking. Same set up, just different shapes. The fire pit uses a meatloaf pan, and the other uses a 8” square cookie tin (round would work too).
A single $8 gallon of cooking oil will last me a month in the winter, or all summer.
I’m a big fan of power free stuff, less to go wrong.
You also might want to look into the Vesta self powered heaters at:
They used canned heat, which can get expensive, but can be easily converted to using veggie oil by using refillable containers instead of disposable ones.
A friend did this, and has been really happy with it since he switched away from the chinese diesel heaters.
Even vegetable oil gives off fumes and smoke and you are using these indoors without venting the smoke?
They don’t smoke or give off fumes if the wicks are adjusted correctly. I do keep a window open for ventilation though, and prevent it from getting too hot inside. The windows act as my thermostat.
I also found the following on the Mobile Warriors site:
chinese diesel heaters work well and for a long time when properly installed and used.
For what they are and cost they’re a bargain.
They will be more expensive in the future.
Because they are cheap AND work.
Many people want AND/or need heat for a decent price.
This is just that.
As for how well they are built: you can and must check it well before you install/use one.
In a van or even in a house/room you want it heated for cheap.
I use it in a 3/4 meter room .2.5 meter tall.
Even when it’s minus 12 Celcius outside it will get the room temperature at plus 20 Celcius in about one hour set at 2 Hz .
Not even close to its 5 Hz “top power” setting.
Been using it for about 2 years now and hundreds of liters of diesel.
No failed components so far.
Just dissasemble completely every spring ,new gaskets , shiny cleaned inside out ,even the combustion “room”/burner and works like new.
So far I haven’t replaced the steel mesh gauze around the ceramic ignitor .
Doesn’t needs it.
Who wants more high tech fancier heating devices ,hey ,go buy them for thousands of euros/dollars.
It’s your money, you can even burn it 
I’m happy with chinese diesel heaters!
So happy I have one in use, one ready to fully replace should the on in use fail completely and one “lonely/forgotten” unit brand new that’s been waiting “for action” for about 2-3 years now…
Hasn’t been needed so far.
At the time I paid about 300 euros for 3 completely new diesel heaters. NOTHING or any other manufacturer can beat that!
If they ALL keep working like this, I’ll be old and gray until these chinese diesel heaters fail so bad they need complete replacements…
Oh ,and don’t believe me: ask around for user experience!
Cheers and a good day!
I forgot the pictures…
As for power source it uses a 20 Amp chinese adjustable SMPS “thing”.
Because it no longer “lives” in its original case.
I like custom stuff.
Also, for fuel tank it has an ex-LPG fuel tank barely used as that/LPG tank very thick steel able to withstand 30 Bar pressures(tested it myself for about 45000kms in a car I owned and for various reasons got crushed).
Couldn’t give up the LPG tank,was too nice/pristine
I threw away those 10 liter plastic fuel tanks.
Steel is real and in this configuration/setup where it sucks/draws fuel from the top hole and close to the bottom of the 90 liter tank volume, it cannot physically leak in any way.
Anything else like a hole close to bottom of tank WILL leak in time.
Been there done that with a plastic fuel tank. No thank you! 
