Taken from Honest John website:

For economy reasons, the alternator does not start recharging the battery until the engine is fully to temperature, resulting in flat batteries for cars driven short distances from cold. The answer is to switch on the side lights or headlights creating a need for power that clutches the alternator on so it recharges the battery.

 

i was told last year to drive with sidelights on if mainly doing local short journeys.....so yes its probably right

 

i have heard this too. My sidelights are LED so my amp or A/C hopefully does the trick.

 

Regarding Subaru's it only applies to newage cars, as they have a so called "smart" alternator fitted, so yeah sidelights on all the time if you only do short journeys.

 

Partially true but no clutch as such, all electronic...............

https://www.scoobynet.com/lighting-a...l#post10463571

 

What do they class as short journeys?

 

On some cars this is controlled by the ECU (Mk2.5 MX-5, for example).

 

Most manafacturers have used the smart charge system for about 5 years if not more. You don't have to drive with your sidelights on, you could have your heater fan on low, radio on, heated screen on etc. the car just need to see your using a consumer, that will make the alternator charge.