I have just picked up a 62 Reg RRS and a newbie to this vehicle. I am planning to go for an outdoor drive-in cinema and am told that the audio for the movie would be played through a FM channel. I am worried that if i am going to switch my engine off and play the radio to watch the movie the battery may drain out since am looking at around 2 hours of radio playing with the engine off. Is it possible that the battery could drain out if I play the radio for so long ? Is there any other alternative ?

Need advise since based on the response i would like to think about going for the movie.

The battery will drain very quick I'm afraid. I had the radio playing on mine for 45 mins once and could not start the car !!! In the end I replaced the battery.

Better to take a portable FM radio with you - then you only flatten some C or D cell batteries and not the car's battery. On more recent cars you only get 10 minutes radio use before it closes down............... 2020 Pangea Green 1st Edition D240 New Defender 110 is here and loving it
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Thanks...thinking a portable radio may not give a good audio experience. Additionally I need to buy one as well.

Another option is to let the engine run , which is not ideal however thats an option. Any advise on this option ?

It's very sad you can't listen to it though your premium radio.

Take a different car to the movie ?

I'm (obviously) no expert, but I wouldn't have thought the radio would draw that amount of current to drain the battery in such a short time. From memory following a couple of hours drive (when you would expect the battery to be fully charged) car shut down radio after only 10 mins showing something like "low battery"

I guess the big amp doesn't help.

And powering up many systems and displays.

Andy K wrote:

It's very sad you can't listen to it though your premium radio.

Take a different car to the movie ?

Unfortunately I don't have a second car. Moreover the idea of drive in cinema was to enjoy it with the RRS

I think LR being over cautious with the radio running time, as Tim mentioned mine only gives 10min before it shuts down, while audio system could draw lot of power if its running at high volume it's not the same with low volume as many would do.

Ianm wrote:

. From memory following a couple of hours drive (when you would expect the battery to be fully charged) car shut down radio after only 10 mins showing something like "low battery"

For what it's worth, I think the 10 mins thing is only when the key is out (RRS1).

I also notice the volume is limited to 20? when the engine is off. A further attempt to prevent power drain.

They have implement some stuff !

Turn the key to "accessory" and the radio will stay on for as long as you want. With the key in the ignition but in the off position the radio only stays on for 10 minutes.

When my battery was good (it is not at the moment) the radio could be on at moderate volume for a couple of hours before there was an issue.

Garry 07MY RRS TDV6
Arctic Frost
Aspen Interior

The OP has a 62 plate car which has keyless entry and pushbutton start, they do not have a "accessory" position as such and it all shuts down after around 10/15 minutes or at least mine does whether using Radio or TV etc.

Cheers
Col

Consider buying a Ctek charger to keep your batteries at top form.

Moving your seat back and forth before entering the key is something you should try to avoid doing too as it uses alot of the battery over time. Ctek is great if the car does alot of short trips and battery doesnt get a full charge.

I bought one after being advised to on the Mercedes forums when I had my SL500 - THat used two batteries and it was an essential bit of kit to have !

Oh and cant you monitor the battery rate on the built in screen on the car?
Maybe keep a booster pack with you - again a good thing to have !