battery isolator .

[Phil Hayward]

I have just measured the current my radio takes with auxiliary ignition, less than 1 amp.
It should run it for 60 hours.
My car still started with 11.6v on the 12v battery, I have been blaming it for HV warning coming on.
if it isn't changed at the first service I will replace it.
I was unable to measure any current with ignition off with 20amp analogue meter

 

[Cocijo]

Why not just always engage the HV battery and you can forget about draining the 12v at all?

 

[Phil Hayward]

I am worried about getting stuck if the 12v fails. I prefer the ignition off if a passenger is sat in the car listening to the radio, also it puts the running lights on in ready.
Just put light duty Jump cables in the boot.

 

[Lovemyev]

I am worried about getting stuck if the 12v fails. I prefer the ignition off if a passenger is sat in the car listening to the radio, also it puts the running lights on in ready.
Just put light duty Jump cables in the boot.

Why not purchase a jumper pack ?.
These have pretty much replaced jump leads now and are able to charger other items like tablet, phones and computers etc,

 

[Cocijo]

Ok - your call. i carry a simple jump starter pack similar to this.
https://www.amazon.co.uk/lifBetter-20000mAh-20℃-60℃-Emergency-Automotive/dp/B08W2Y8RWH/ref=sr_1_9?crid=3MBTHHD0Y6G3C&dchild=1&keywords=car+jump+starter+power+bank&qid=1625590597&sprefix=Car+jump+%2Caps%2C177&sr=8-9

 

[Lovemyev]

Ok - your call. i carry a simple jump starter pack similar to this.
https://www.amazon.co.uk/lifBetter-20000mAh-20℃-60℃-Emergency-Automotive/dp/B08W2Y8RWH/ref=sr_1_9?crid=3MBTHHD0Y6G3C&dchild=1&keywords=car+jump+starter+power+bank&qid=1625590597&sprefix=Car+jump+%2Caps%2C177&sr=8-9

Great shout !.
I have a Halo unit, they are popular unit in the USA.

 

[Kithmo]

I am worried about getting stuck if the 12v fails. I prefer the ignition off if a passenger is sat in the car listening to the radio, also it puts the running lights on in ready.
Just put light duty Jump cables in the boot.

Mine switches the car off after 10 minutes when in auxiliary any way.

 

[Lovemyev]

Mine switches the car off after 10 minutes when in auxiliary any way.

Yeah - Mine does the same.
I found this out a good long time ago, while waiting for somebody who had a hospital appointment.
Sitting there nice and relaxing listening to the radio, then suddenly, the info unit etc just closes down !.
What the hell !.
Quick push on the "Start" button ( foot pressure off the footbrake ) and away we go for another ten minutes or so.
Having the car in the fully booted "Ready" mode ( foot pressure applied to the footbrake ) is a much safer option in my mind.

 

[Coulomb]

Having the car in the fully booted "Ready" mode ( foot pressure applied to the footbrake ) is a much safer option in my mind.

Safer, in the sense that the auxiliary battery doesn't get discharged and therefore degraded as much, true.

But it has the downside of being rather wasteful. You're powering up nearly every ECU, that's 5 A at 12 V, just to run the radio at less than 1 A. A lot of electronics needlessly has high voltage stress on it.

It would be nice to find a work-around. I have no idea what form that would take; perhaps a phone app that squirts a CAN packet into an OBD2 dongle every 9 minutes. With a few smarts to cancel itself when appropriate, without being too onerous to the user, to save the auxiliary battery from accidental discharge.

 

[Cocijo]

How about listening to the radio on your phone and saving even more amps??

 

[Coulomb]

How about listening to the radio on your phone

Yeah, but it's not the same.

 

[FCat53]

I did notice that our ZS has a 63Ah rated SAIC branded 12v battery. However the battery tray has the ability to take a physically bigger battery as there are two battery clamp locations with pre-tapped holes in the battery platform.

The ZS comes in diesel and petrol versions, a larger battery may be required for Diesel engines. For the EV a non cranking leisure battery is probably better as you are more likely to suffer from charge loss than inability to 'crank' a small contactor.

 

[Lovemyev]

Yeah - It’s a bit of a pain in the bum really.
A toss up between loosing a few Amps from the HV battery to power up way to many 12 volt items, vs the possibly of running the 12 volt battery down so low that it will not boot up the car, therefore becoming stuck there waiting for the recovery people.
I think I will waste a little bit of that massive amount of power stored in that HV battery I am sitting on I think ?!.
I do carry a jumper pack around with me anyway, you know - The one I hope I will never need?.
Hey …… Maybe I could power a music device from this folks !.
I try in some small way to cover as many bases as reasonable can, to avoid getting into a sticky situation ?.
Nice to have breakdown cover, but even nicer NOT to have to use it.
Got a nice little collection going on in my car !.
A battery boaster pack, a type 2 cable ( that gets very little use ) a space saver spare kit etc.
Oh …….. Don’t forget the all important 10mm spanner ? just in case ?.
I even have the all important “Cuddly Toy ?Morris” on the back seat !.

 

[Cocijo]

Some EV’s don’t give the option. Tesla for example - open the car get in - it boots up. All EV’s should be like that - no messing/failures/flattening the 12v/aux modes/lights flashing etc etc