voltage drop

[ghostrider]

hello all,

i have just noticed in my van that when the car ignition is switched on the voltmeter in the van drops to 0 switch off it goes back to 12v.

everything in the van functions as normal there is no changeover switch either so its not that. the guys who fitted the towbar came out to check it and said it is fine on the car end, all fuses etc are ok.

any ideas? thanks

 

[JeremyClarksson]

This is guesswork but seems quite likely to me.

I think your van battery will be disconnected (from domestic circuits in the van) by a relay once the car is supplying the power and this could also mean that the voltmeter might not work as it might be in the domestic van circuits.

I would not suspect a problem unless the fridge and battery charging do not work.

 

[ghostrider]

This is guesswork but seems quite likely to me.

I think your van battery will be disconnected (from domestic circuits in the van) by a relay once the car is supplying the power and this could also mean that the voltmeter might not work as it might be in the domestic van circuits.

I would not suspect a problem unless the fridge and battery charging do not work.

hi m8

my workmate has said something on those lines as well, he was gonna try it out on his van, cheers

 

[Damian]

When the ignition is switched on, it triggers a habitation relay to isolate all the internal 12v electrics with the exception of the fridge and a charge current to the battery.

 

[Rubix]

To add what Damian has said.

Your battery will still being charged, but the meter part of the circuit will be disconected.

When we first got our 'van, I was puzzled as to why the battery was being charged with the car connected (and engine running), yet the lights (12v) wouldn't work. This relay is the reason.

It also explains why the fridge only works from the car 12v and not the leisure battery (a second relay)

 

[ghostrider]

To add what Damian has said.

Your battery will still being charged, but the meter part of the circuit will be disconected.

When we first got our 'van, I was puzzled as to why the battery was being charged with the car connected (and engine running), yet the lights (12v) wouldn't work. This relay is the reason.

It also explains why the fridge only works from the car 12v and not the leisure battery (a second relay)

thanks guys that has put my mind at rest now,save me a trip over the pennines to the dealer