On another thread, somebody said that they were told that a night heater does not use any electrical power after it has fired up and so does not discharge the battery set.
I suppose this could well be the case, and that the fan is kept running by combustion of diesel alone, but could anyone “in the know” confirm or deny this?
the night heater will use power from the battery to run, but some have a feature fitted that shuts them down if the battery drops below a certain voltage, however this feature does not work on my fh12 as i found out a few years ago!
Yes they use power to turn the fan, create the “spark” or “Glow” and above all to pump fuel up from the tank
ETA… eberspacher.com/products/air … ic-d2.html as an idea 
billybigrig:
Yes they use power to turn the fan, create the “spark” or “Glow” and above all to pump fuel up from the tankETA… eberspacher.com/products/air … ic-d2.html as an idea
Yep pretty much agree, just to turn the fan with any force it would have to work like a jet engine and have a shaft connecting the inlet with the combustion exhaust.
Nice cut away drawing here. 
It just doesn’t draw a great deal of power, so a decent set of truck batteries should be able to run them for a fair while.
Just had a look at the spec for one model, the Webasto Air Top Evo 3900, which lists the power consumption as between 15-55 W, so max draw of 2.3 amps at 24v, running down to under 1 amp, so they’re not self-sustaining. Wouldn’t have thought that an 11 hour rest would have too much effect on a decent set of batteries though, but if they’re not up to scratch…
Me being lame but does anyone make a silent night heater? Can’t leave mine on all night as the noise gets on my nerves. Could put up with it if it was a constant level but cuts out then cuts back in changing pitch. Just have 3 blankets instead.
Silver_Surfer:
Me being lame but does anyone make a silent night heater? Can’t leave mine on all night as the noise gets on my nerves. Could put up with it if it was a constant level but cuts out then cuts back in changing pitch. Just have 3 blankets instead.
The water heating type that blow through the vents are a lot quieter than the cheap ones. The one I had on my mk1 FH you only knew was on by the waft of warm air 
scaniason:
Just had a look at the spec for one model, the Webasto Air Top Evo 3900, which lists the power consumption as between 15-55 W, so max draw of 2.3 amps at 24v, running down to under 1 amp, so they’re not self-sustaining. Wouldn’t have thought that an 11 hour rest would have too much effect on a decent set of batteries though, but if they’re not up to scratch…
Once the heater is up & running it will draw about the same amount of power as a headlight bulb. I found out some years ago that this is unsustainable after leaving it switched on by mistake from Friday night until Monday morning. Middle of Winter as well, so batteries were not in top condition and all I got was a bit of a “click” when I turned the key. I was lucky to find a local garage with a pair of batteries & jump leads.
billybigrig:
Silver_Surfer:
Me being lame but does anyone make a silent night heater? Can’t leave mine on all night as the noise gets on my nerves. Could put up with it if it was a constant level but cuts out then cuts back in changing pitch. Just have 3 blankets instead.The water heating type that blow through the vents are a lot quieter than the cheap ones. The one I had on my mk1 FH you only knew was on by the waft of warm air
Miss that type, don’t like these fitted these days, like sleeping in front of a fan heater.
john-sussex:
billybigrig:
Silver_Surfer:
Me being lame but does anyone make a silent night heater? Can’t leave mine on all night as the noise gets on my nerves. Could put up with it if it was a constant level but cuts out then cuts back in changing pitch. Just have 3 blankets instead.The water heating type that blow through the vents are a lot quieter than the cheap ones. The one I had on my mk1 FH you only knew was on by the waft of warm air
Miss that type, don’t like these fitted these days, like sleeping in front of a fan heater.
Agreed, they’re better all round but more expensive 
Silver_Surfer:
Me being lame but does anyone make a silent night heater? Can’t leave mine on all night as the noise gets on my nerves. Could put up with it if it was a constant level but cuts out then cuts back in changing pitch. Just have 3 blankets instead.
Had a Webasto night heater in a 3 Series low cab Scania once, almost silent compared to Eberspachers version of a Tornado fighter on re-heat.
billybigrig:
Silver_Surfer:
Me being lame but does anyone make a silent night heater? Can’t leave mine on all night as the noise gets on my nerves. Could put up with it if it was a constant level but cuts out then cuts back in changing pitch. Just have 3 blankets instead.The water heating type that blow through the vents are a lot quieter than the cheap ones. The one I had on my mk1 FH you only knew was on by the waft of warm air
Some are cheaper than others but they’re all an horrendous price really for what they are.
how much diesel does a nightheater use? Say when run contiuously for an hour?
triple-tango:
how much diesel does a nightheater use? Say when run contiuously for an hour?
also, if its possible to have a night heater, why can’t they make a system where we could have cold air blown in for the summer months? i know you can get the roof pods etc, but can a system not be made to run via the night heater?
chilistrucker:
also, if its possible to have a night heater, why can’t they make a system where we could have cold air blown in for the summer months? i know you can get the roof pods etc, but can a system not be made to run via the night heater?
you mean something like this on the new FH.
chilistrucker:
also, if its possible to have a night heater, why can’t they make a system where we could have cold air blown in for the summer months? i know you can get the roof pods etc, but can a system not be made to run via the night heater?
With these, you get 8 hours of cold air which is charged up during the day
muckles:
chilistrucker:
also, if its possible to have a night heater, why can’t they make a system where we could have cold air blown in for the summer months? i know you can get the roof pods etc, but can a system not be made to run via the night heater?you mean something like this on the new FH.
exactly that muckles 
wheel nut, who makes that, do you know?
chilistrucker:
muckles:
chilistrucker:
also, if its possible to have a night heater, why can’t they make a system where we could have cold air blown in for the summer months? i know you can get the roof pods etc, but can a system not be made to run via the night heater?you mean something like this on the new FH.
exactly that muckles
wheel nut, who makes that, do you know?
Don’t know the make, but it came standard in all of our MAN TGA, decent bit of kit for Western Europe. Wouldn’t think it could cope in Saudi though
cheers wheel nut