Night heater power - leisure or main battery?

[Jjj]

Hi,

I have a multivan with factory fitted auxilary/second battery and webasto heater. Unfortunatelly my dealer does not know if the main battery is disconnected (or will be disconnected when some threshold voltage is reached) during camping with heater on.
I would like to know if I can be sure that the main battery is protected from discharging when camping. Or is the second battery used in parallel with the main one and I have capacity of both batteries but when discharged both baterries are gone?

Does sb. have a wiring diagram for multivan T6 with second battery and webasto?

Thanks in advance,
JJJ

 

[Pauly]

Mit will disconnect, would be pretty pointless having two batteries if they both went flat
They are joined together by a relay that turns off when you turn off the ignition

 

[Dan M]

For clarity - does anyone know if the factory fit air blown heater run from the second battery or the starter battery? There is (or was) an option to have the heater without additional battery so not sure how they are wired.
Thanks

 

[Deaky]

The factory air heater runs from the second battery under the passenger seat.

 

[Dan M]

The factory air heater runs from the second battery under the passenger seat.

Good stuff - I'll stop worrying about it flattening the starter battery! Thanks

 

[Ricardo T]

Is it possible to run a night heater, gas or diesel, without a leisure battery..
Is there any kind of night heating where you would not need a leisure battery?

 

[Pete C]

You don’t need a leisure battery to run any form of night heater, you could just run it off your van starter battery. But the risk is that you drain the starter battery overnight, and can’t start the following morning.
Having a leisure battery removes this risk. Even if you flatten the leisure battery, at least your vehicle will start in the morning.

Pete

 

[Ricardo T]

Thanks Pete..that was my feeling. I guess the blower is constantly running when the heater is in use, therefore drawing power.?

 

[Pete C]

Yes, whether it is gas or diesel, the electric fan is what draws the significant current.
It is only on when the heater is running (triggered by the thermostat) so not running continuously.

Pete

 

[Robert]

You don’t need a leisure battery to run any form of night heater, you could just run it off your van starter battery. But the risk is that you drain the starter battery overnight, and can’t start the following morning.
Having a leisure battery removes this risk. Even if you flatten the leisure battery, at least your vehicle will start in the morning.

Pete

Just to add, there is coding setting which prevents completely the risk of flattening the battery. Basically if supply voltage drops too much parking heater stops regardless of timer or remote control commands.