# Eberspacher - Fan -  Battery Drain ?



## ForresGeek (Nov 8, 2011)

Hi All,

 I have an AutoSleepers Symbol (2008) with the Eberspacher diesel / electric heating.. When on a site, with hookup, the heating is provided by electric. When wilding, the heating is obviously provided by burning diesel.

The hand-book says that on full-blast the Eberspacher will burn something like 0.28 litres of diesel an hour.. I'm fine with this. Thing is, although diesel provides the heat, it's an electric fan that blows the resulting warm-air around the van..  Does anyone have any idea what kind of drain running the fan will place on the leisure battery ?   The van has a 100Ah battery.


Thanks.

--
 ForresGeek


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## MOS (Nov 9, 2011)

Hi it depends on which heater you have. if its an old model without electronics the unit will draw 4 amps ish whilst running slightly less whilst in off stages ,if its a later type it will cycle more because its more accurate on the thermostatic controll in the unit ,chances are you will also have a sepetate fuel pump in a camper as the tank will almost certainly be under the  floor .
as for the battery useage due to the type of heater newer ones will switch off at low voltage which means you will only get  1/3  1/2 of the available amps from a given amount 
so in reply to the quertion ,gawd knows .i have never fitted two that where the same ,the only thing in can say is when its cold switch it on at home and see how long it lasts on a full charge ,then use that as a yardstick  MOS


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## ForresGeek (Nov 9, 2011)

MOS,

 Thanks for this... So as a rough guess.. 4A x 10 hours = 40Ah

 I have a 100Ah battery, assuming low voltage cuts the fan out at 50% capacity, then I could still leave the Eberspacher (and fan) on overnight without completely flattening the leisure battery.

I'm getting soft in my old age, and it's getting cold at night 



MOS said:


> Hi it depends on which heater you have. if its an old model without electronics the unit will draw 4 amps ish whilst running slightly less whilst in off stages


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## Bigpeetee (Nov 9, 2011)

Why not connect a simple room thermostat in line with the power to the heater. Most are rated at 10A so when it gets warm it switches off


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## ForresGeek (Nov 9, 2011)

Bigpeetee said:


> Why not connect a simple room thermostat in line with the power to the heater. Most are rated at 10A so when it gets warm it switches off



Bipeetee,

 Thanks, the heater already has a thermostatic switch, but I'm not sure I've ever seen it switch the heating off... My concern is not with the amount of electricity the heating uses... When it's running on electricity I'm on hookup... I'm more interested in  how much battery the fan uses when it's blowing air from the eberspacher around.

I've had a look in the auto-sleepers handbook, and I think it says 4 or 5 watts in "constant ventilation mode" and upto 34 watts at full-power.

I think that means   34watts/12v = 2.85A  ?

So when the eberspacher is generating 2200W of heat from diesel, the fan is sucking 2.85A to blow it around ?

--
 ForresGeek


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## Bigpeetee (Nov 9, 2011)

Seems reasonable to me, most fans in appliances are about 40w, plus there will be power to pump fuel etc.

If you have a digital multimeter, move the red lead into the 10A socket and set to 10A dc.

If there is a convenient fuse in the supply to the heater, remove and put the meter terminals in its place, now you will get an accurate reading of current drawn.

Failing that, disconnect the negative supply from the battery and just hold the leads, one on the batt and one on the cable, this will show the total current draw from the batt.

Get someone to switch individual appliances on and you can see how much current each takes.

NB, with everything switched off you should get a zero current draw, but even having the TV on standby can draw upto 0.5A

It doesn't matter which way the leads are connected, but pref the red to the batt terminal and the black to the earth.


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## jogguk (Nov 9, 2011)

I'm no expert on the Eberspacher (a lot of stuff if you google)

The newer ones work a bit different from the older models. The older ones would start get to temp and switch off,  thermostat would then restart and run, switch  off etc.  The low amp draw of the circulating fan is no problem, it is the power to start up the diesel burning process via  a high amp drain glowplug every time it starts up.

The newer models are more efficient as when the get to nearer the required temp they switch to a low power burner mode (still lite up burning diesel) to avoid unnecessary relighting the burner.

John


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## NicknClair (Nov 9, 2011)

ForresGeek said:


> Hi All,
> 
> I have an AutoSleepers Symbol (2008) with the Eberspacher diesel / electric heating.. When on a site, with hookup, the heating is provided by electric. When wilding, the heating is obviously provided by burning diesel.
> 
> ...



Hello,

For you to be able to rely on just a single 100ah Leisure Battery with any diesel heating system can prove difficult.
I used to sell Webasto heaters for a living (similar if not the same as your heating system) and to survive on a 100AH battery, with a system that on start-up takes 8-12 amps all be it for only a few minutes, can chip away at your battery capacity very quickly. 
The amp hour rating on your battery is a rating from 0v to full capacity meaning that at a certain voltage, your heater will not even start up as on average you will only have 30% of your battery strength that will be within the heater's operating parameters.
I installed a Dual Top Webasto system and removed the Truma (madness in some people's eyes, but it suits how and where I use the Motorhome). To be able to run the system for a sensible time, meant that I was looking at a minimum battery capacity of 200AH. Christmas last year at -12 deg proved it's biggest test and keeping the internal temp @ 18 deg (including the hot water @ 70 deg), we managed to see out 14 hours with a 220ah battery. We then had to get power back into the battery asap, which is where the uprated split charge and large alternator helped.
This year we have fitted a 270ah battery, so it should give us a couple more hours. This will still mean that I will be starting the van to get power back into the leisure battery, as I do not want to use a genny for personal reasons. 

When I have monitored the Dual top, it's fan system draws 0.7-1.3amps, but ramps right up to 5.5 amps to get the van up to temp. Once to temp, it drops to the other figures but this doesn't include the ignition process (which can be up-to 9-12 amps), nor anything else in the van.

Assuming you have a D2 Airtronic system, you have a rough amp use of 1.1 to 2.4 amps when the ignition process has finished. So if you take the lowest figure over a 300 minute time frame, you would have used an est 6ah. Doesn't sound a lot, however you have to bear in mind of other factors such as TV's, lighting and any other equipment (even your Consumer unit can draw power!!!). Now lets say for arguments sake your 100ah battery has 30% of capacity within the operating voltage of the heater, that only leaves you with 24ah to run everything else (as you have to keep things within the diesel heater's operating parameters). 

The only answer I can possibly suggest is the battery capacity and the ability to recover this away from mains hook up. Modifying the heater will (I very much doubt) make any difference to the underlining fact that it will come back to lack of power when "wilding" using this type of system. I have since then been asked to work on a number of van's to upgrade them, as after showing what we have done and where we have been.
Sorry if this has been a bit mind blowing, but it has taken me a long time testing and finding out the best way to get our system to operate when we really go off the beaten track, as we are not scared to be "wilding" out in any conditions.


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## Airecraft (Nov 10, 2011)

Some great info on Eber heating, thanks. We have the D2 and I don't understand why any motorhome has diesel heating. It guzzles amps and you miss out on the main advantage of not having a second fuel supply as you still need to carry gas for cooking and water heating.


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## Bernard Jones (Nov 11, 2011)

*Do eberspachers still stop working when it gets cold?*

Do eberspachers still stop working when it gets cold?
I had one in a lorry about 15 years ago.  When the temperature of the diesel fell to about -2 deg c and so got a bit thicker, the eberspacher would stop working because it had to suck the diesel up through a very narrow pipe.  I had to have a separate tank strapped on the back of the lorry to run it off paraffin, which was easier to buy in those days as there were more paraffin heaters.  (Modern diesel engines will still pump the diesel when its quite thick because they have a submerged electric pump inside the fuel tank, pushing it through a much wider pipe.)

I recall it was quite heavy on battery power but that wasn't usually a problem as I was doing a lot of driving every day to recharge the battery.
It was also noisy outside the vehicle.  I got used to the noise but I don't know how much it bothered other people.  Probably not as much as it would bother people on a quiet side street or camp site because I was usually in noisy lorry parks.


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## jann (Nov 11, 2011)

*Eberspacher*

Ours doesn't use much diesel, But the battery can be a problem. We do have two batteries on the van .Both will start the engine. We always isolate one of them to make sure we can always start the van.Also swop over which battery is going to be working.
If we move on each day then there is not a problem, if we are going to stop for a couple of days we start the engine for ten minutes to charge the battery.


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## spooker (Nov 11, 2011)

I had a D2 Eberspacher in my self build a couple of years ago. The thing that really used up the battery was when it got to temperature and shut off, then restarted when the van cooled down.

On startup the unit draws about 8 amps for 2 minutes to heat the glow plug before firing.
When it was running flat out if draws about 4 - 5 amps to power the fan. As soon as the van warmed up it slowed down, until on its lowest setting it used about 0.5 amp.
When it shuts down - again it uses about 8 amps for a minute or so as the glow plug lights to burn off any unspent fuel in the system.
So if you judge it right it can run all night for very little draw on the battery, if it keeps restarting - it'll drain even a couple of batteries in no time.
I don't know on the more modern ones if you can over-ride the shut-off when temperature is reached on the thermostat?


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## NicknClair (Nov 11, 2011)

jann said:


> Ours doesn't use much diesel, But the battery can be a problem. We do have two batteries on the van .Both will start the engine. We always isolate one of them to make sure we can always start the van.Also swop over which battery is going to be working.
> If we move on each day then there is not a problem, if we are going to stop for a couple of days we start the engine for ten minutes to charge the battery.



I know that Eberspacher's competition (Webasto) did revised the operation on the AirTop 2000ST to try and overcome the issue surrounding power use, but the simple problem is still power draw over long periods. Even the good old fashioned blown air gas system still will chip away at the battery over a time-frame.
I have just installed a new style Truma Combi E 4kw heat/hot water unit to a project van, but still the power consumption is around 19-21W of use (1.5-1.7A) when running. Okay you may be thinking that the amp is very low granted, but it still can kill single battery systems over a small time-frame.
My main reason for the change of system is that I wanted a system that wouldn't use the Gas quick, which in the 1st year before the modification we would burn through a 13kg bottle of gas in 10 days! Take into account that during Xmas and new year, getting the bottle replaced was a pain, but it was more the rate in which we were replacing it. Yes I could have fitted Gaslow/Tank etc but again as I was settled in an area as we were, having a  65lt diesel tank compared to 52lts of gas (2lt per 1kg) which was also needed for the fridge and cooking etc, I felt that spreading the demand of resources meant less visits to fuel and gas refills meant more time touring around. 

Bottom line, its all about Power, Power and um..................................................Power.
There are mixed opinion on how you go about power, how you replace it, what's the best solution. I'm afraid it will be down to you digesting on all the experiences of the lovely people on the forum and finding common ground and saying, yeah I want to use the van that way too!
Don't think that the Diesel heater you have is bad, it's not. As for the operating in low temps, I can only say look at how the system has been installed and ensure that the fuel lines are as weather protected as they can be. We certainly didn't have any issues at -12 deg!!! You also have to understand that diesel fuel has improved over the years, with additive added to prevent freezing problems. Initial noise when on it's first start can be loud, but the dual top in my van soon goes quiet once upto temp and remains quiet and so far have had no complaints.

My advise............................................. minimum of 200ah battery capacity and look at upgrading the split charge circuit as the factory one (if it's a branded coach-build such as Swift/Autosleeper/Autocruise) is simply not man enough for "wilding" in the winter. If you are thinking genny, look at upgrading the mains charger to say a 50A unit, meaning less time that the genny has to run to charge the leisure battery back up. Personally i've gone for an upgraded split charge system, as running the engine is no different than running a genny on a battery charging point of view, but I'm not carrying any extra weight and another different fuel source to worry about.


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## aake (Nov 12, 2011)

*New diesel heater*

I've got many years of experience w Ebersprachers in cars and in boats but not until now as main source of heat. This summer I got a Truma combi 6D (made in cooperation w Truma and Eberspracher) installed in my camper van (a Knobloch Heyerdahl on MB Sprinter 4WD). This heater is not as noisy as the standard Eber heaters and has capacity enough even for the winter where I live in the northern part of Sweden. The el power consumption is around 1,8 A on average and I hope my 2 x 155 Ah batteries (plus 2 x 100Ah for starting) will be enough for both the heater and for my compressor refrigerator. In any case I carry a 2kW Honda generator onbord.
The primary reason for the change of heating system from Truma gas heater to diesel was that this German built car did not have a large enough case for Swedish gas bottles. Now only the stowe works on gas, and for that two small camping bottles will be enough.
I can come back w report after the winter as I intend to use the camper for ice-fishing tours.

aake


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## NicknClair (Nov 12, 2011)

LOL this new heater is the same concept as the Webasto Dual Top, which was already released back in 2008!
It was only a matter of time before they played catch up :lol-053:. Only complaint I have is that it still relies on it being fitted inside the motorhome, taking up space, whereas mine is fitted under the motorhome, which has added space under the wardrobe.

This heater will perform the same as the system in my van, so it would be interesting how they compare after your trip. I find it interesting that you are still using a generator in your travels mind. What mains charger are they using?? If it's an electroblok, then the re-charge time might be a long one, so make sure you're carrying plenty of petrol for the gen!!

Have fun and look forward to your findings :wave:


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## aake (Nov 12, 2011)

NicknClair

The Truma combi 6D contains a boiler of 10 l, hardly something to carry under the car. About the genset. It's a precaution, a backup, as is also my standard Eber under the car, wich also is a necessity to preheat the engine and the drivers compartment in winter.  We do have severe winters here in northern Sweden, up until the end of March it can easily be -25*C on a clear winter night, not to mention the cold I've experienced in the middle of winter.
If everything else fails I can heat the engine of the car w my electrical motor heater.

As a further adaptation of the camper to our clima I've got an isolated (w 23 mm pu-foam) separation w door made behind the drivers compartment made. See pics:
From front and from back w door open and closed  




aake

PS. The two 155 Ah batteries is charged w a separate 30A charger when 220V is attached.


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## ForresGeek (Nov 13, 2011)

Thanks for all the great advice here..


I'm pretty sure that my Eberspacher is one of the newer ones that keeps the diesel lit, and "ticks over" without having to re-light it... It does seem quite noisy when running (inside the van), but from the outside it's not that bad.

I think my main focus has to be getting more battery capacity, and possibly improving the split-charger. 100Ah doesn't seem like a lot when you start adding up all of the lights, TV etc.

--
 ForresGeek


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