Aux heater and leasure battery

[bmassaer]

We put on the heater for about two hours at low level. It worked perfectly. In the morning, I wanted to start the heater again, we heared the ventialtor but there was only cold air coming out. When switched tot 220V electricity, the heater worked again the way it should.
Do you think this is due to low battery? How long does the heater normally work before the battery runs dead?
(As we live on a full leasure battery for about three days, until now I found it not necessary to change the battery)

 

[snowy55]

Give us a clue as to which vehicle type and year you are talking about.

 

[bmassaer]

OK - didn't realise this was important... We drive a T5 Cali build in 2007!

 

[WelshGas]

OK - didn't realise this was important... We drive a T5 Cali build in 2007!

Is it the Original Battery?
There should be a date stamp on the battery if you are not sure.
The Parking Heater takes a fair amount of current to fire up. An oldish battery might work fine in the summer months but a drop in temperature can really stress an older battery.

 

[snowy55]

OK - didn't realise this was important... We drive a T5 Cali build in 2007!

Please fill in your details to avoid this in the future

 

[bmassaer]

Don't know if it's the original one; we bought the car second hand...

 

[WelshGas]

Don't know if it's the original one; we bought the car second hand...

Check the date on the battery then. If it is the original one then it will need replacing as it will be 9 years old which is a good age for a Leisure battery. Also if it is a California SE then there are 2 such batteries and both should be replaced as a mixture is only as good as the oldest battery.

 

[bmassaer]

OK - thank you, I will check this!

 

[MattBW]

If you have access to a volt meter you will also be able to see if the battery is low or struggling to hold charge.

If it works on 220v it certainly suggests the battery voltage is low.

 

[Alibee]

We put on the heater for about two hours at low level. It worked perfectly. In the morning, I wanted to start the heater again, we heared the ventialtor but there was only cold air coming out. When switched tot 220V electricity, the heater worked again the way it should.
Do you think this is due to low battery? How long does the heater normally work before the battery runs dead?
(As we live on a full leasure battery for about three days, until now I found it not necessary to change the battery)

I would say it's your battery voltage dropping too low. I had exactly the same on my T4 for most of the time I owned it. If the battery wasn't nearly full then I would just get cold air, but if I started the engine (or had just done a long drive) then it worked fine.

I seem to remember that the Eberspacher units draw more current for the first few minutes and then drop back to a very low current draw (just the metering pump and fan).

 

[sidepod]

I would say it's your battery voltage dropping too low. I had exactly the same on my T4 for most of the time I owned it. If the battery wasn't nearly full then I would just get cold air, but if I started the engine (or had just done a long drive) then it worked fine.

I seem to remember that the Eberspacher units draw more current for the first few minutes and then drop back to a very low current draw (just the metering pump and fan).

Indeed.

Initial load is the glow plug plus the fan. I can't recall what it's rated at but it's probably enough to overwhelm a tired battery. They get pretty damn hot. Ask me how I know this!!

Once the initial start phase is complete the glow plug shuts off and the load reduces to that of the fan.

New battery time.

Whilst we're on the subject, low fuel level in the main tank will have your heater over also.

 

[Sp0_0k]

Just buy a cig lighter voltmeter from ebay for like $5 and you can track the voltage on a battery the whole time. Even how it drops under the load. Can even tell if a battery is bad if voltage is dropping much.

 

[Emil Silenhag]

You have bad batteries and/or Earth Shunt Fault. I have done Earth Shunt Repair (check download section) in 3 cars now.

 

[Alibee]

You have bad batteries and/or Earth Shunt Fault. I have done Earth Shunt Repair (check download section) in 3 cars now.

Ah yes, good point. Had to do that once in the T4 too.

 

[sidepod]

Ah yes, good point. Had to do that once in the T4 too.

WHAT???? T4's don't break!!

 

[Alibee]

WHAT???? T4's don't break!!

She wasn't broken, just looking for a little attention!

 

[bvddobb]

You have bad batteries and/or Earth Shunt Fault. I have done Earth Shunt Repair (check download section) in 3 cars now.

We had exactly the same issue on our Jan 2008 Cali, and it turned out to be the earth shunt fault. With your build (2007), that would be the first thing to look for.

When we had this fault with our heater, we delved into possible causes, We found basically 4, see our post in this older thread:

We have had the same basic issue a few weekends back: when having the heater on without electrical hookup, it stopped after about 1,5 hours and would not start again. Whereas before in the cold we happen to have been on hookup always, and it would go the whole night.
When we let the engine run a few minutes, it would start again, but then again stop quite soon. The moment the first few rays of sun hit our collectors on the roof the next morning, it would run again. While there are reports on the web where the heater would go all night when just on batteries.

We have researched the web extensively, and found FOUR possible reasons for the heater switching off too early when on battery alone. They are independent, so one can suffer from each four of them, and they are all worth checking when you have these kind of heater issues:

1. the earth shunt problem, as discussed above and elsewhere on the forum.
2. simply the batteries being old, and no longer having enough power (dûh).
3. the threshold switch-off value in the board computer. Not so obvious. It turns out a certain series of Cali's had that threshold value programmed in at a higher voltage then before and nowadays again.
4. the smaller battery fuse. We have two leisure batteries in the Cali, one has a fuse of 80A (quite adequate), the other of 50A (just barely enough). Quite often, it seems, the 50A fuse goes, but you don't really notice: your leisure system still goes, but you think you have two batteries where in fact you have one. So, only half the power you think... Especially when the power goes down quickly when not on hook-up, this is worth checking...

Ad 1: As that can also cause other erratic behaviour, we have ordered the earth shunt repair set from the german forum, and have built it in last Sunday. Already found the lights no longer flickering when the heater started up, and indeed the heater ran to 0,5V drain further down than before, and it didn't switch off (did not have the opportunity to let it run until it switched itself off and see how far down it would go now).

Ad 3: Ours is in that series, so we need to check this. We have found someone with the software to look into this, and indeed saw that a fault was registered where the heater had switched off because of the battery voltage dropping below the threshold level. But with that version of the software we couldn't check or change the actual threshold value. Still looking to find a Dutch forum member who could help us there.
It is register 0B (aux heater), record 08 (threshold value). The value in there used to be 153, meaning that the heater would switch off when the voltage on the leisure circuit would reach 9 + 1.53 = 10.53 V. On the german forum one can find many reports where people have found their Cali's have higher values programmed in, and they lower it to 153 again.
The forums say VW set that value higher to try and mitigate the aux heater/earth shunt problem. Once the earth shunt problem is fixed, it seems you can safely go back to the lower value. In newer Cali models it seems VW have fixed the earth shunt problem, and the value is lowered again. Not my wisdom, here I am just repeating what I have read.

 

[Wojciech Jerzy]

We had exactly the same issue on our Jan 2008 Cali, and it turned out to be the earth shunt fault. With your build (2007), that would be the first thing to look for.

When we had this fault with our heater, we delved into possible causes, We found basically 4, see our post in this older thread:

Hi there, quick question - how do you identify if earth shunt is broken? Any specific symptoms? I have just installed new batteries and would like to keep them working as long as possible. My Cali is 2006. Thanks!

 

[bvddobb]

It is not so that the earth shunt is broken, necessarily. It is that the factory earth connection of the shunt is not good enough. The community on the German forum have developed a better connection kit some years ago. And their shop is selling that kit.

The clearest symptom of an inadequate earth connection of the shunt is the flickering of the interior lights (when they are on) when the heater fires up.
You may also have strange readings of battery status, rest voltage etc. as a result of the bad earth connection. Other symptoms may again result from those wrong readings, like functions that shut down systems when the rest voltage drops below a certain point (like the interior heater, or the fridge running). If the rest voltage is not measured right, the shut off will appear earlier than necessary. But you will only see these symptoms if you are not on hook up and living off your leisure batteries.

 

[Wojciech Jerzy]

It is not so that the earth shunt is broken, necessarily. It is that the factory earth connection of the shunt is not good enough. The community on the German forum have developed a better connection kit some years ago. And their shop is selling that kit.

The clearest symptom of an inadequate earth connection of the shunt is the flickering of the interior lights (when they are on) when the heater fires up.
You may also have strange readings of battery status, rest voltage etc. as a result of the bad earth connection. Other symptoms may again result from those wrong readings, like functions that shut down systems when the rest voltage drops below a certain point (like the interior heater, or the fridge running). If the rest voltage is not measured right, the shut off will appear earlier than necessary. But you will only see these symptoms if you are not on hook up and living off your leisure batteries.

Thanks a lot for this. I bought Cali less than a year ago, a second hand, this is really the first season using aux heater and I found out it wasn't working. I have just changed the batteries, which I suspect weren't changed since the car was new! It seems to be OK although the dash lightning flicker when the aux heater is on, just at the beginning. Must be the earth shunt as per your explanation. We usually camp wild and planning to camp this weekend wild too although as the batteries are new, I might stop at some campsite to charge them up (if there are any open). Thank you again for you help.