Bessacar 2016 question.

[mikebez1]

I don’t think I have a feed to my caravan battery or fridge from my bmw. So my caravan battery was completely flat. But on the caravan control panel if I select the car battery on the right of the panel when the engine is on I can turn all the 12v things in the caravan including the fridge. But there was a red flashing light in the fridge. Could I use this way to keep my fridge going when driving. Bit unsure what is going on.

 

[Buckman]

I don't think it is a standard fit on a BMW due to Smart alternator? It may be an extra?

 

[ProfJohnL]

An increasing number of car manufacturers are working to maximise the fuel economy of the vehicle, and are fitting "smart alternators" which only produce power if the car or the car battery needs power. These systems often ignore the the trailer wiring and stops producing any electrical power in excess of its own specific needs. Consequently we are seeing more caravanners who discover their caravan batteries are not being charged as much by the car and fridges are not keeping cool.

It's also the case that many "standard" towbar wiring looms only provide for the trailers road lights, and you have to specifically request supplementary circuits for battery and fridge operations.

If your car has a "smart alternator" then check the cars user options which might include a way to keep the alternator working. In some cases the cars ECU needs to be reprogrammed. Check with your towbar fitter, and or the cars dealer or manufacturer.

 

[Buckman]

An increasing number of car manufacturers are working to maximise the fuel economy of the vehicle, and are fitting "smart alternators" which only produce power if the car or the car battery needs power. These systems often ignore the the trailer wiring and stops producing any electrical power in excess of its own specific needs. Consequently we are seeing more caravanners who discover their caravan batteries are not being charged as much by the car and fridges are not keeping cool.

It's also the case that many "standard" towbar wiring looms only provide for the trailers road lights, and you have to specifically request supplementary circuits for battery and fridge operations.

If your car has a "smart alternator" then check the cars user options which might include a way to keep the alternator working. In some cases the cars ECU needs to be reprogrammed. Check with your towbar fitter, and or the cars dealer or manufacturer.

An expensive work around is to install a Sterling Power’s Wildside unit. Also have a read HERE.