Fuel tank for diesel heater

[Gorfllub]

Now that my heater has arrived, I have been contemplating fuel tanks.

For convenience I would like the absolute largest tank I can fit.



For those of you running a fuel heater, how big is your tank and where did you put it? I have seen the video where the tank is just zip tied under the hood. That tank looks a little small. Since we get super cold, the heater will get a lot of use in the winter. I would like to not have to top it up every day or 2.

I estimate the heater will get ~10 hours of use per week. Would like to get 2 weeks out of it before refilling. My heater says 0.69L/hr on high and 0.2 on low. I am thinking a 0.5L/hr average? So that's 20L tank for 2 weeks? Seems like a lot. Ultimately I would love to be able to have a fuel level sender in the tank as well.


Any comments on actual fuel consumption and tank size/fitment?

 

[Don]

I don't have the heater in my car, but from my experience with those using similar heaters in boats, you could not stay in your car if you were actually using .5 liter per hour, so that's making your tank choice lots bigger than I think it needs to be

I'm sure you'll get some good advice here from those using the heater - Doubt if anyone has a 10 liter tank, let alone 20

Don

 

[Gorfllub]

Well, and that's what I was wondering.


I thought I read somewhere it heats the water to 80 degrees C and then drops to low. Not sure what temp it kicks back in at. On mine there is no option to manually run it on low. Its on or off and that's it. Well it has a pump-only mode for circulating with the heater off. I'm thinking that's only valid for applications with huge volumes of water to store heat and use residually.

The volume of water is a lot less than a normal vehicle so it will heat that fast.


Just don't want to be filling it up every couple of days. I mean that's still better than using the electric heater, but......


Lots of room behind the motor, but filling could be problematic.

 

[Don]

Well, and that's what I was wondering.

Lots of room behind the motor, but filling could be problematic.

I was contemplating installing one, years ago, and my plan - For a non ChaDeMo equipped car - Was to put the tank in the back as you suggest and then fabricate a fill hose which I could access from the ChaDeMo door on the drivers side

You could maybe do something similar and have the fill inside one of the removable panels inside the back cargo area of the car - It would need a sealed, non-vented cap, but you could vent the tank externally

Don

 

[Gorfllub]

Anyone using a heater have comments on actual fuel usage?

 

[sandange]

I can run the heater 3 - 3 1/2 hours with my 2 liter tank of diesel ,
depending on the temperature.

 

[Gorfllub]

Ok, great info, thank you.

I have managed to fit 4L tank without any fuss.

At my current commute, that's roughly a weeks worth of heat. The new commute will be about 3 days of heat. So a bit of a bummer but not terrible I guess. Maybe next year fab something up for a rear tank.

 

[Gorfllub]

I have found that the heat output is less than I had expected.

Well actually its exactly what I initially expected, but after reading some posts I thought it would be more.


Its rated at 5kw. Which is the same as the electric heater, no? So my initial thoughts were that it was going to be similar to the electric heater just without eating up a ton of range. Which is what I think it feels like.


The hoses get super hot which also led me to hope for higher heat output.


But a couple of comments about my installation.

1 - I did not insulate the hoses. I will probably do that.

2 - I'm tied in high up near the coolant reservoir. It was easy connection without draining much coolant. But now its a full flow circuit before it gets to the heater core. Meaning the flow goes into the reservoir first, then down to the electric heater and then on to the heater core. I am assuming considerable heat loss going that way. I may re-plumb the system so that the output goes straight to the heater core.


As it sits though, it will do the job. Just maybe not maximizing the output.


On a side note, electric and fuel heat combined is a nice boost in temps and even more importantly it heats up way faster.


Still worth every penny.

 

[sandange]

Some times to initiate the heater mode you need to move the temperature setting into the red for 10 seconds and then move it back to the green neutral position to get the diesel action in motion.
I don't have the pipes insulated and also tied into the tank return installing the one way flow valve . I find the heat is much hotter than the electric heater.

 

[Gorfllub]

As far as I know, there is no "valve" on the heater core. So turning to red shouldn't be required.

I have no check valve either. Simply cut the factory hose and ran it in/out the diesel heater. So now when using the electric heater, the coolant flows through the diesel heater as part of the circuit.

My heater didn't come with a check valve, and in this scenario, I could not see a real reason for using one.


Im still pleased though. And it is fairly warm yet. Only -7c

Im thinking the diesel heater may run hotter in colder weather when the electric one cant keep up.

 

[Don]

You do want 100% of your hot water to flow to the heater core within the car and then back to your fuel heater to be reheated - You don't need to be flowing any diesel heated water through the uninsulated electric heater under the car which would waste a good percentage of your heat. Part of the OEM heater's problem is that electric heater under the car radiates nearly as much heat to the outside air under the car as it does to the heater core - Very wasteful

Don

 

[bradleydavidgood777]

I was thinking about that last winter - how much cool air hits the front of the car and there is no hot engine or exhaust manifold to heat it up. And how the legs and feet get so cold no matter what you have on.

I wonder if there is room to insulate around that heater?

 

[Don]

I wonder if there is room to insulate around that heater?

Why not install a check valve to make sure none of your diesel heated water flows through that cold heater core under the car?

There are a few who have insulated everything under the car having to do with the heating system - There are threads here if you search for them

Don

 

[Gorfllub]

I just realized that turning the heat to red in the car will engage the water pump, increasing flow.

I may experiment with operating the oem pump without the electric heater on.


Also I didn't even consider the possibility the heater tank could be uninsulated.


So a couple of potential cures could be to run the diesel heater only through the heater core. Have it able to be isolated from the rest of the system..

Or a least make it so the diesel heat output goes into the heater core first.

And of course insulate. I can see how even just one of these ideas could make a substantial increase in usable heat into the cab.