Will Caliban start on Monday morning?

[Rolfe]

My issue is that I arrived on only 20% in the traction battery and I believe the car won't top up the 12v when the traction battery is so low. I wouldn't be worried if the traction battery was at a higher SoC.

I did check the car with the app last night so it seems to be communicating all right. The car park isn't underground.

 

[Rolfe]

What makes you think there would be an issue with the 12V battery - surely EV's are left for weeks on end without being topped up (e.g. airport car park etc,.) - I'm sure I've gone over a week without driving mine at all.

Because the traction battery is only on 20%.

 

[Rolfe]

That's where the app could tell you, 14.5v I think is the full charge target, while it's charging.

The dashboard was showing 14v before I parked the car and the app said 12.5v after it was parked and locked. Which is fine. The question is, will it stay fine until Monday if it isn't topped up from the traction battery?

 

[ReintjeWA]

If you can connect to the car with the app, then I wouldn't be worried about the car trying to connect to the SAIC servers constantly without success, thus draining the battery. I agree with you that you'd expect a 12v battery to hold for a week, especially in ICE, but the batteries in ICE tend to be beefier ones, there is no cranking capacity needed for an EV, just enough juice to let the traction battery wake up I guess.

If you check the car late Saturday, and the battery has drained too far to be of use, would you still have time and opportunity on Sunday to score a booster pack somewhere?

 

[T1 Terry]

The system only needs 12vdc to switch on, a battery built out of torch cells would work, just don't try to turn the steering until the car wakes up, that drags a lot out of the battery.
Would there be anyone with a car close by you could get a jump start from?

T1 Terry

 

[Rolfe]

There's a Halford's branch less than a mile away where I could doubtless get a jump-start battery if need be, even on Monday morning. But if there's any real danger of the battery going flat it would probably be safer just to go to the car in the car park and put it in Ready mode for 15-20 minutes some time tomorrow then maybe again on Sunday. It's only a couple of minutes walk away, I don't even have to go outside.

 

[Anon70]

Another option would be to get one of those ICE type cars and some jumper cables top up the 12v enough to fire up the traction battery...

 

[Rolfe]

Plenty of these around. Might be easier just to get a jump-start pack though. And even easier just to put the car in Ready for a bit once or twice.

 

[Tight Git]

I hope you have the key with you that has the emergency blade in it!

I had to purchase a booster last Friday from Argos - £75 and worked fine out of the box.

 

[Everest]

Because the traction battery is only on 20%.

But with the car switched off and locked, I'd expect its quiescent current draw to be so low that the 12V battery would last at least a month without any topping up.

Caveat is unless the battery is on its last legs and the temperature is very cold.

 

[Rolfe]

But with the car switched off and locked, I'd expect its quiescent current draw to be so low that the 12V battery would last at least a month without any topping up.

Caveat is unless the battery is on its last legs and the temperature is very cold.

Now that's a useful piece of information. It's not desperately cold - I'm in Brighton on the south coast and the car is in an indoor multi-storey car park. I have no reason to believe that the 12V is on its last legs. The car is switched off and locked and probably sound asleep by now.

 

[tsedge]

Because the traction battery is only on 20%.

But what makes you think it won't charge the 12V with the HV battery on 20%?

 

[Alb]

From the manual:

 

[Rolfe]

The snag here is that nobody knows what they mean by "a low SOC". It has been suggested that the cutoff may be as high as 50%.

I saw a video about restoring an old, abandoned EV, and they discovered it would let its 12V die when it got down to 30% on its traction battery.

 

[MG Clive]

I really can't see any reason why the 12volt battery should lose enough charge in five days to make any difference to the car's normal starting. I recently left mine for 2 weeks with about 40% SOC, and it was perfect when I went to use it again.

 

[tsedge]

I've repeatedly left my car while on holiday for weeks at a time with no problems, at varying levels of charge.

 

[tsedge]

I really can't see any reason why the 12volt battery should lose enough charge in five days to make any difference to the car's normal starting. I recently left mine for 2 weeks with about 40% SOC, and it was perfect when I went to use it again.

Exactly. It won't. The only circumstance in which it would be if there's a fault with it or the car has something plugged in to it causing it to stay on and be drained.

It is about time someone tested 12V charging at various low SOC.

 

[Rolfe]

I really can't see any reason why the 12volt battery should lose enough charge in five days to make any difference to the car's normal starting. I recently left mine for 2 weeks with about 40% SOC, and it was perfect when I went to use it again.

I wouldn't be so concerned if it had 40% though. I wish we knew what the actual cut-off is.

 

[Pete G]

We have a 2021 ZS ev, we usually only drive the car once a week. It has never failed to start.
Our 12volt battery died last week while we were in town. Well not really died, a message came up on the dash saying :start car immediately 12 volt battery low"
We took it to a battery shop and had the battery tested, the load tester said it was still Ok but on the bottom end of OK. We changed the battery for a new one , no more messages.
I think the original battery would probably have been Ok but we live in a remote location where the nearest battery shop is 40 kilometres away and I didn't want to walk there to get a new battery.
I noticed that a rat had chewed through the top of the original MG battery too. I have since moved the car to another shed where rats can't get at it. They also chewed through the brake booster vacuum hose, and I had to replace that myself at home as it caused the car to throw up heaps of faults.

 

[Everest]

I wouldn't be so concerned if it had 40% though. I wish we knew what the actual cut-off is.

I still don't see why the 12V battery would need to be topped up anyway within a week.

What is the Ah capacity of the SE's 12V battery? Maybe 50Ah or more? With a 50Ah capacity and, let's say worst case 100mA quiescent draw, then you're looking at it lasting 500 hours without any top up.