Listen to radio with ignition switched off?

[stepheneric]

Is it possible to listen to the radio of RX450h with the ignition switched off?

Obviously I must have missed something in the manual or on board menus

 

[Spottedlaurel]

It's raining and windy so I'm not going to go out just now and try it, but from memory you can press the start button without your foot on the brake and it'll then go into the equivalent of 'accessory' mode, with the "Ready" light not showing.

However, it won't do that for long and I recall it will switch it off to maintain charge in the small 12v Battery.

If I'm sitting there like that, perhaps having stopped for lunch between visits, I just leave it in "Ready" - the engine barely kicks in, if at all, unless the hybrid Battery is low on charge. The only downside is that the DRLs will be on.

[Herbie]

58 minutes ago, stepheneric said:

Is it possible to listen to the radio of RX450h with the ignition switched off?

Obviously I must have missed something in the manual or on board menus

 

As Nigel says above, it can be done but it's not wise to do it. If things are working as they should, the radio will shut itself off after about 20-30 minutes to conserve 12V Battery power, otherwise it'll just flatten it.

Always put the car in P and READY mode. That way, you can listen to the radio indefinitely and the petrol engine will fire up as and when needed to keep the batteries charged.

As an aside, don't use N. Either keep the car in D with your foot on the brakes when waiting for short periods at lights for instance, or for longer periods, maybe at railway crossings, put it in P, but don't use N because the traction Battery will not charge when the car is in Neutral.

[stepheneric]

Many thanks for the info.

Actual reason was that when I popped into shop or somewhere for five minutes and passenger was listening to item

on the radio and I switched ignition off they could not follow the story, unless I left vehicle running. 

[NemesisUK]

Not sure if it's the same with your model but in mine if I press the Ready button with the gear selector N the system doesn't shut down but goes into ACC mode. I can then slip the shifter into P and the radio continues to play.

As has been said above do not leave the car in N and don't leave it in ACC mode for more than 5-10 min. The car will automatically shut down but it won't guarantee not to flatten the 12v Battery first! 

[200h]

unless you didnt trust your passenger and thought they may go off with your car

i would of left the car turned on still as the engine would of stopped and been

ready to recharge if / when necessary.

 

[LenT]

37 minutes ago, 200h said:

unless you didnt trust your passenger and thought they may go off with your car

i would of left the car turned on still as the engine would of stopped and been

ready to recharge if / when necessary.

 

I don’t have a hybrid so I comment merely out of curiosity - and ignorance.

If you’re saying, Mark, that you are leaving your Lexus on a public road with no one in control of it - albeit with a passenger - but in a condition in which the ice will fire up to protect the battery…is this legal?

In a non-hybrid this can result - in some circumstances- in an offence that will attract a fine, but not points.

I wonder if this has ever been tested in a Court?

[200h]

never thought of it from that point of view

some old auto's have been known to slip into drive

by themselves this couldnt happen with the lexus hybrid system

 

[Thackeray]

On 7/6/2021 at 2:23 PM, Herbie said:

As Nigel says above, it can be done but it's not wise to do it. If things are working as they should, the radio will shut itself off after about 20-30 minutes to conserve 12V battery power, otherwise it'll just flatten it.

Always put the car in P and READY mode. That way, you can listen to the radio indefinitely and the petrol engine will fire up as and when needed to keep the batteries charged.

As an aside, don't use N. Either keep the car in D with your foot on the brakes when waiting for short periods at lights for instance, or for longer periods, maybe at railway crossings, put it in P, but don't use N because the traction battery will not charge when the car is in Neutral.

With at least an hour to kill, waiting to give someone a lift, I thought I'd do a test to see how much impact the radio has on the 12v Battery. This is on an IS300h but I expect other hybrids are similar.

I checked the 12v Battery voltage. It was 12.5v.

I pressed the Power button once without pressing the brake pedal and the Accessory mode came on. (If you press it twice the Ignition or On mode comes on.)

With "Accessory" displayed next to the speedometer, I turned on the radio. Within a minute or so, the Battery reading was 12.4.v. I thought this might be a sign that the voltage would start declining and waited to see what happened.

But the voltage stayed at 12.4v and then dead on twenty minutes later the radio turned off. The manual says it will do this in Accessory mode and it seemed to be almost exactly 20 minutes that the radio was on before it was switched off.

With the radio off, I checked the voltage again and the Battery was back to 12.5v.

This doesn't tell you much about what the impact would be if you listened to the radio for 40 minutes or an hour. But it does seem that if the 12v Battery is in reasonable condition, the radio in Accessory mode has very little impact on the voltage of the 12v Battery and there seems to be virtually no risk that the car wouldn't start after 20 minutes of radio in Accessory mode, unless the Battery is on its last legs.

The advantage of Accessory mode is that the lights don't come on, which might be irritating if you're just having a picnic or a break from driving and don't want the headlights on.

I also suspect that in On mode when the lights and other things do operate, the 12v Battery would be run down much more quickly. But that test is for another day.

[NemesisUK]

2 hours ago, Thackeray said:

The advantage of Accessory mode is that the lights don't come on, which might be irritating if you're just having a picnic or a break from driving and don't want the headlights on.

As I posted in another similar thread, if one doesn't want the headlights on when parked up and in the Ready mode just turn the light switch away from Auto to the positional lights (sidelights) setting and the headlamps will not be illuminated but the just the sidelights.