New T6 Battery issue with heater on

[simon parker]

Can someone tell me if this is normal? 6 month old T6 Cali, went for first night without hookup and only the fridge on. Battery was at 100%. In morning battery was 90% so all good. So then turned on the heater as it was a bit nippy, only to level 1. Heater came on, eventually blew out warm air as it should so turned heater off again after it had done its thing. I guess 15 mins after turning it on. Battery was now at 50%!!! That right? 40% drop in 15 mins? Dropped vehicle in to VW Birmingham today and told thats normal. If so, how on earth would I be able to be without hookup overnight with the heater on level 1 and still have a battery with charge in the morning?

Doesn't make sense to me

 

[ArunAlec]

It doesn’t sound right. However the panel readout is (l think) in 10% increments so depending how it rounds up/down the readout may not be that accurate, nevertheless it still doesn’t sound right.

 

[simon parker]

I agree it doesn’t seem right. VW tell me batteries are fine, heater works as it should but how can battery go to 50% in only 15 mins. It would never last the night so cannot possibly be ‘normal’ as they say it is.

 

[ArunAlec]

What current is being drawn when the heater and fridge are on according to the control panel?

 

[simon parker]

Not sure. Vehicle is still with VW. They tell me it’s working as it should. 90% to 50% in 15 mins just doesn’t seem right. How can you run a heater all night if that’s normal

 

[Emil Silenhag]

The battery will usually recover after 15-30 min of starting the heater. When starting the heater, the heater will activate the glow plug in short bursts, some times up to 20 times. The load is usually between 15-20 amps when the glow plug is active. You can se this in the control panel. When it is up and running the heater only consumes from 2-4 amps. The battery recover, and hopefully go from 50 to 90 % again?

Remember to hook up power to the vehicle once a month so the battery can fully charge. Only driving will not charge the batteries enough.

You should always start the heater on full blast, and before shut it of, full blast again. Once a month you should let it burn for an hour on full blast.

 

[simon parker]

Ok. When I turned it off it was at 50%. I did then leave it for an hour before driving away and wondered if it would go back up. It didn’t though. Was still at 50% when I drove off though and didn’t go back to 90%. Concern as mentioned is if it’s goes to 50% so fast how can you run the heater amongst other things all night and not be on hookup.

 

[Emil Silenhag]

Ok. When I turned it off it was at 50%. I did then leave it for an hour before driving away and wondered if it would go back up. It didn’t though. Was still at 50% when I drove off though and didn’t go back to 90%. Concern as mentioned is if it’s goes to 50% so fast how can you run the heater amongst other things all night and not be on hookup.

I guess you will have to try it out? Charge the batteries first of all.
The heater should go on continuously for 2-3 days before the batteries go below 11,9 volts or so, 20-30%...Remember to charge the batteries as soon as possible afterwards...

 

[WelshGas]

Not sure. Vehicle is still with VW. They tell me it’s working as it should. 90% to 50% in 15 mins just doesn’t seem right. How can you run a heater all night if that’s normal

1. Heater shouldn’t be run for short periods. Not good for longevity. Either leave On or run for an hour at a time.
2. The % calculation is a guide. The actual Voltage is more important. The heater takes a lot of current to start up, but not to run when upto temperature. The Control Panel % might well drop initially but climb back up when the heater is fully warmed up and running.
3. The rear Leisure Battery has a 50 or 75amp Cube Fuse On the Red +tve terminal connecting it to the Front Leisure Battery. The Mains Charger is connected to the Rear Battery BUT it is the Front Battery that is connected to the camping equipment.
IF that Cube Fuse blows, not uncommon, then you will be running on 1 Leisure Battery only, and that could be your problem.

 

[TripleBee]

Don't forget that we only have 12V batteries, so 12,3V is still 12V, but then you will read out 50% or less. When the heater stops, it might be that the voltage is going back up to 12,4 or 12,5V, but the load will be 50 or 60%. Normally the voltage of the batteries will stay fixed at 12,3V for a long time when being used. That is the working voltage.
If you fully charge your batteries and wait for about 2 hours to get the batteries at their (rustspanning?) voltage at ease, it will show 12,8V. From the moment you put on some lights, charge your phone, use the fridge the voltage will drop quite quick to 12,6V or less, but that doesn't mean the batteries ar dying. As long as there is still enough amperes left to take out there is no problem. The voltage will drop once the charge of the batteries is near to an end. Till that point the voltage will stay quite stable at 12,3V.

 

[simon parker]

Don't forget that we only have 12V batteries, so 12,3V is still 12V, but then you will read out 50% or less. When the heater stops, it might be that the voltage is going back up to 12,4 or 12,5V, but the load will be 50 or 60%. Normally the voltage of the batteries will stay fixed at 12,3V for a long time when being used. That is the working voltage.
If you fully charge your batteries and wait for about 2 hours to get the batteries at their (rustspanning?) voltage at ease, it will show 12,8V. From the moment you put on some lights, charge your phone, use the fridge the voltage will drop quite quick to 12,6V or less, but that doesn't mean the batteries ar dying. As long as there is still enough amperes left to take out there is no problem. The voltage will drop once the charge of the batteries is near to an end. Till that point the voltage will stay quite stable at 12,3V.

Sort of makes sense, though when I turned it off after 15mins it said 50%, from 90%. I wasn't still running it when I checked what battery had left. It hadn't gone back up an hour later. That normal then?

 

[Hotel California]

I've never seen my status drop from 90 to 50 % in such a short time with the heater on , and this would mean my fridge also as i always use it while camping....
Not good on a new Cali ....

 

[TripleBee]

Sort of makes sense, though when I turned it off after 15mins it said 50%, from 90%. I wasn't still running it when I checked what battery had left. It hadn't gone back up an hour later. That normal then?

Don't focus too much on the procent. You need to check the voltage. After 1 hour it must climb back to 12,4 or 12,5V.
My heater uses up to 30A when starting up, draining the battery fast, as it seems, but the voltage drops immediately to about 12,3V and stays there, showing half or less of battery left, but the panel only estimates battery life from the voltage and tells you the battery has half or less left.
If the voltage drops below 12,1V or even in the high 11's, there is something to worry about.
Normally after a couple of hours turning everything off, will rise the voltage back to about 12,5V, if not, there MIGHT be a slight problem with the health of the batteries.

You bought the California on order, or did you buy a showroom model? If so, it could be that the batteries were not maintained well during it's stay in the showroom, or outside in the cold and wet.

 

[simon parker]

VW are testing it again tomorrow, so we'll see what they say. Told them it can't be right to go from 90-50% in 15 mins and not go back up again after though they assure me it's normal. But as mentioned above if it doesnt go back up again it can't be, would run out of battery in no time. We'll see what they say. Hopefully they'll run the heater and check the battery level and voltage straight after then an hour or so later and see if indeed as you say, it goes back up again, otherwise there is a fault

 

[WelshGas]

VW are testing it again tomorrow, so we'll see what they say. Told them it can't be right to go from 90-50% in 15 mins and not go back up again after though they assure me it's normal. But as mentioned above if it doesnt go back up again it can't be, would run out of battery in no time. We'll see what they say. Hopefully they'll run the heater and check the battery level and voltage straight after then an hour or so later and see if indeed as you say, it goes back up again, otherwise there is a fault

Ask them if they have checked the Cube Fuse on the Rear Leisure Battery. Don’t presume they have checked it.

 

[MartG]

WG - Just for my info, is the purpose of the 'cube' fuse is to leave you with one good leisure battery should there be a short causing the seat battery to discharge?
Each battery is 75Ah, so if it had blown, and the heaters glow plug taking 20A bursts, assuming 100% initial charge, the seat battery should last about 3.5 hours continuous 20A drain, to 0%, or drop to 50% in 1.75 hours, not 15 mins? Two batteries should go for about 4 hours continuous 20A to 50%?
It does sound like a low capacity battery(s) or more load being taken... Just my take.
I do agree that battery voltage recovers after the load has been removed, as TripleBee says, the only real way to test is to put a known load on each battery and time their discharge.

 

[WelshGas]

WG - Just for my info, is the purpose of the 'cube' fuse is to leave you with one good leisure battery should there be a short causing the seat battery to discharge?
Each battery is 75Ah, so if it had blown, and the heaters glow plug taking 20A bursts, assuming 100% initial charge, the seat battery should last about 3.5 hours continuous 20A drain, to 0%, or drop to 50% in 1.75 hours, not 15 mins? Two batteries should go for about 4 hours continuous 20A to 50%?
It does sound like a low capacity battery(s) or more load being taken... Just my take.
I do agree that battery voltage recovers after the load has been removed, and as TripleBee says, the only real way to test is to put a known load on each battery and time their discharge.

The Rear Battery is connected to the Mains Charger, so can be charged to a full 100% capacity. The Front Battery is connected to the Alternator via the Split Charge Relay. Due to the smart Alternator Function, in relation to BlueMotion functionality, the Alternator can only be charged to about 80% capacity, although the Control Panel May show 100%. The 2 Batteries are wired in parallel IF the Cube Fuse is functioning.
All the power for the camping equipment comes from connections to the Front Battery.

So, Cube Fuse fails, so instead of having a capacity of 150 amps total, you have in fact only 75 amps capacity to draw on.



If running On only 1 Leisure Battery you will not have 3.5 hrs of current draw at 20 amps. The Heater will Switch Off if the voltage drops to 11.5 v or thereabouts. This is a battery protection measure. This only works with the Fridge and Parking Heater.

 

[MartG]

Great, thanks for the info.
Looking at the diagram, both batteries (A1&A24) are charged by either alternator or mains hook-up. The control panel shows the 'common' battery return current to earth, so if the fuse (right hand S) had failed, it would still register battery A1's discharge from 90% to 50% - still rather quick for a 75Ah battery at 20A continuous?

I see your edit comment regarding the 11.5v cut-off, good point

 

[mchbiker]

We had a similar problem that they struggled to diagnose. They changed batteries but eventually it turned out to be (If I recall correctly) a faulty overhead display.

 

[simon parker]

Got the vehicle back. They assure me everything is fine so I’ll just have to try it and run heater on low and leave fridge on say 3 and see. I’ll know tomorrow as off grid this evening.

Response from VW was
“The technician has been checking your heating this morning and had the vehicle switched off and left the heater running for approximately 50 minutes – the battery was fully charged before the heater was switched on – the display dropped to 90% - the battery was showing 12.59 after being run for 50 mins. The technician has printed out the battery monitor slips, which I will give you later on.

Yesterday, when the technician turned on the heater, he said it did dip to 50% but was then + 90% again.

If the fuse had blown as mentioned on the forum, the rear battery would not charge.”

 

[Esandar#1]

1. Heater shouldn’t be run for short periods. Not good for longevity. Either leave On or run for an hour at a time.
2. The % calculation is a guide. The actual Voltage is more important. The heater takes a lot of current to start up, but not to run when upto temperature. The Control Panel % might well drop initially but climb back up when the heater is fully warmed up and running.
3. The rear Leisure Battery has a 50 or 75amp Cube Fuse On the Red +tve terminal connecting it to the Front Leisure Battery. The Mains Charger is connected to the Rear Battery BUT it is the Front Battery that is connected to the camping equipment.
IF that Cube Fuse blows, not uncommon, then you will be running on 1 Leisure Battery only, and that could be your problem.

1. Heater shouldn’t be run for short periods. Not good for longevity. Either leave On or run for an hour at a time.
REALLY...? Dealer never mentioned that. We've hardly used our Aux Diesel Heater but I hadn't realised it is better to run it for a long period than in shorter bursts (say 25 mins)...

 

[WelshGas]

1. Heater shouldn’t be run for short periods. Not good for longevity. Either leave On or run for an hour at a time.
REALLY...? Dealer never mentioned that. We've hardly used our Aux Diesel Heater but I hadn't realised it is better to run it for a long period than in shorter bursts (say 25 mins)...

The Dealers don’t know. This is from Eberspacher who make the Heater.