T5 Cali Battery bleed

[chrisswash]

Hi
I have had my T5 Cali Comfortline for 6 years. About a year ago my battery started to go flat if I did not use the van for a week or so. I have since found that the van has developed a batter bleed. When the ignition is off there is still about 1 amp being drawn off the battery. Does anyone know of a common cause of this in Cali's or experienced a similar problem. Your help would be greatly appreciated.

 

[calikev]

Impossible to say you will need to remove the fuses in turn to see what circuit is draining it

 

[WelshGas]

Hi
I have had my T5 Cali Comfortline for 6 years. About a year ago my battery started to go flat if I did not use the van for a week or so. I have since found that the van has developed a batter bleed. When the ignition is off there is still about 1 amp being drawn off the battery. Does anyone know of a common cause of this in Cali's or experienced a similar problem. Your help would be greatly appreciated.

Have you had the vehicle from new?
I presume you are referring to the Engine Battery?
Have you had any electrical work carried out prior to this problem such as a new aftermarket radio system fitted?
Do you have anything plugged in such as a Traffic Camera ?

 

[chrisswash]

the van is 2005 and I imported it from Germany.
Yes, it's the engine battery.
No electrical work has been carried out on the van and nothing is plugged in.
This problem started out of the blue with no apparent cause.

 

[WelshGas]

the van is 2005 and I imported it from Germany.
Yes, it's the engine battery.
No electrical work has been carried out on the van and nothing is plugged in.
This problem started out of the blue with no apparent cause.

Is this the original battery?

 

[VW Guru]

There is a way of checking without removing fuses as this can make other circuits be live and give you failed readings depending on your skill with a multimeter. But if you have the original battery fitted then there is a chance this could battery could be giving you a faulse reading and indicating a drain when there is not one.

 

[WelshGas]

Hi
I have had my T5 Cali Comfortline for 6 years. About a year ago my battery started to go flat if I did not use the van for a week or so. I have since found that the van has developed a batter bleed. When the ignition is off there is still about 1 amp being drawn off the battery. Does anyone know of a common cause of this in Cali's or experienced a similar problem. Your help would be greatly appreciated.

Problem sorted?

 

[sidepod]

There is a way of checking without removing fuses as this can make other circuits be live and give you failed readings depending on your skill with a multimeter. But if you have the original battery fitted then there is a chance this could battery could be giving you a faulse reading and indicating a drain when there is not one.

Just expand on how removing one fuse can energise another circuit?

 

[VW Guru]

Just expand on how removing one fuse can energise another circuit?

Hi if say you remove a fuse for the convenience system the canbus will see that control module drop out and for a period of time the can system will keep looking for that control unit causing a voltage spike

 

[sidepod]

But the OP stated the battery drain was present despite the vehicle being unused.
Are you saying a vehicle with the keys removed from the ignition and a fuse removed from any particular circuit will still cause CAN activity?

 

[sidepod]

Hi if say you remove a fuse for the convenience system the canbus will see that control module drop out and for a period of time the can system will keep looking for that control unit causing a voltage spike

Hmmmm? Really? Any item connected to the CANbus will only respond to digital signals carrying its own signature. If a module is removed (fuse removal) it will simply not respond to the data signal from the bus. This shouldn’t cause any voltage spikes?

 

[VW Guru]

Hmmmm? Really? Any item connected to the CANbus will only respond to digital signals carrying its own signature. If a module is removed (fuse removal) it will simply not respond to the data signal from the bus. This shouldn’t cause any voltage spikes?

Well trust me it does I’ve worked on these electrics for years and by removing fuses other systems will live up I’ve used can as an example but take for instance the onboard power supply control unit it has several fuses to power the different sections of the unit if you close down one side by removing a fuse the rest of the unit will wake up and keep sending signals expecting a response. Thus giving you a faulse reading is your looking for a drain. The best way to look to find what circuit is staying live to drain the battery is to open the doors and bonnet lock all the latches over switch off the interior monitoring and wait 20minutes for the canbus to enter sleep mode then using a multi meter set it to millivolts and go across each fuse anything more that 0.1 of a millivolt indicates a drain on that circuit. Removing fuses causes voltage spikes leading to an incorrect diagnosis.

 

[sidepod]

I’m not doubting your experience I’m just trying to understand the connection (unfortunate use of the word in this case) between CAN traffic on the bus (CAN-H/CAN-L) which is about 2,5v and actual power supply from a fuse to a module.

The two systems are electrically separated.

 

[VW Guru]

I’m not doubting your experience I’m just trying to understand the connection (unfortunate use of the word in this case) between CAN traffic on the bus (CAN-H/CAN-L) which is about 2,5v and actual power supply from a fuse to a module.

The two systems are electrically separated.

Hi the problem being is that everything is linked by the data bus control unit if a module drops out and the data bus unit is coded for that unit being present it will wake up and look for that unit it will continue to do this until that control unit is found again this causes a draw of around 0.25 amps the maximum permissible limit for any vw excluding crafter is 0.05amps.

 

[Loz]

I’m just trying to understand the connection (unfortunate use of the word in this case) between CAN traffic on the bus (CAN-H/CAN-L) which is about 2,5v and actual power supply from a fuse to a module.

Transport mode might be an example, where the can gateway tells all modules to go into low power mode?

 

[sidepod]

Hmmm not convinced.

 

[chrisswash]

The battery is new but the bleed is still happening. I was just hoping that there might be a common cause of battery bleed on Cali's. If I use the van a couple of times a week it is not a problem but if i don't use it for a week its as flat as a pancake!!

 

[chrisswash]

New battery, same problem. I thought there might be common cause of battery bleed on Cali's