Traffic Jams and Battery

[biffo]

This is likely something obvious, but coming from an ICE car, where the engine spins and charges the 12V battery as well as turning the aircon, etc - what happens to an EV when I stop in traffic jam and use aircon? Does the main high voltage battery keep charging the 12V and run all the accessories? Do I risk running the 12V battery flat?

I suspect that the main high voltage battery will power everything once the car is running - so do traffic jams just deplete the range as power is consumed?

 

[Cocijo]

When in ready state the HV charges the 12v. This happens when moving or stationary. This is why it’s always best to be in ready if sitting in the car with it turned on.

 

[Alb]

To answer your second question, yes the main battery will slowly deplete but you need to view this in context.
You will probably use less energy overall crawling at 5mph for 10 miles (2 hours) with the A/C on continuously than you would doing the same journey at 70mph even though it would take less than 9 minutes.

 

[Jomarkh]

We have just stopped due to a bin lorry catching fire on the A31.
Been here 30 minutes so far.

 

[biffo]

Perfect real world test!

We have just stopped due to a bin lorry catching fire on the A31.
Been here 30 minutes so far.

 

[Alb]

If you are stationary long term you do of course have the option of shutting down completely.

 

[Jomarkh]

We were stopped for just over 2 hours in the end.
Car was completely off as weather was good. Not sure about being stuck in a snow drift like my bother in law was three and a bit years ago

 

[Alb]

When I lived in Scotland some years back I always kept a shovel and some blankets in the car during winter!

 

[biffo]

When I lived in Scotland some years back I always kept a shovel and some blankets in the car during winter!

I’ve got a foldable snow shovel kit under rear seat and tend to swap winter wheels on when cold. Will possibly fit all season tyres on MG5 at some stage, if I can find A rated efficiency model in the size.

Only issue with winter tyres is that although you can move and stop in snow and ice, doesn’t help if the cars blocking road ahead can’t. Or worse, car behind can’t stop

 

[Alb]

It doesn't even need to happen in the middle of nowhere. I can remember drivers being stranded by snow overnight on the M8 between Glasgow and Edinburgh.

 

[biffo]

It doesn't even need to happen in the middle of nowhere. I can remember drivers being stranded by snow overnight on the M8 between Glasgow and Edinburgh.

I had mates trapped in that. Luckily I’d changed job or I’d have been the same. The M8 at Harthill has its own micro climate!

 

[Cocijo]

The good news is that the MG will last for many hours (several days) in ready using the heater or aircon - so keeping it turned on for example overnight should not be an issue.

 

[Lguk]

Glad I found this on the forum search.

I sat in a traffic jam for just over 2 hours earlier in the week (yay 3 hour commute!). It was between -1 and 0 for the vast majority of it. Only around an hour was completely stationary, and I did shut off the diesel for that bit, the rest was start/stop shuffle forward 1 car.

That got me thinking... what happens when I get my EV and experience the same traffic jam. Winter needing heat or summer needing the A/C (did 3 hours in a jam a few years ago when it was 28c out and got heat stroke) and would it run out the HV battery too quickly, would I be be stuck like the lady in front of me that ran out of diesel. Looks like if you have allowed enough range buffer for your journey, unless you're stuck for 10's of hours you're not really at risk of an issue when you've burned your range.

 

[Jomarkh]

I can't see that you would use all the capacity of a 50kw battery sat in traffic either with heating or Aircon on. Worth putting a large coat in the boot just incase

 

[Lguk]

It's the "what if" - same with the diesel, if I head to work with an estimated 50 miles of diesel for my 35 mile drive then get stuck in freezing temps and need to keep the engine running for 2 hours, I would be getting very twitchy about running out of fuel before my destination, I would just stop at a petrol garage. My entire commute corridor is devoid of public charging without a serious detour or one 5 miles from my destination.

If I have 50 miles of electric for my 35 mile journey, intending to charge at work on arrival, I'm going to be getting twitchy in that traffic jam. The big coat/hat and gloves are permanently in the car, I don't handle cold well. The above info put my mind at ease.

I should have done the basic maths tbh.
2kw heater = 2kwh for each hour in traffic. Say 2 hours. We've used 4kwh (if it's going full tilt all the time). At an average of driving like I stole it 3 miles per kwh, I've lost 12 miles range (obviously more if I'm managing 5m/kwh). As I should be aiming at keeping above 20% battery unless I need the range. I should have plenty of wiggle room for traffic jams in arctic conditions.

 

[Gomev]

Don't worry about traffic jams. It's a total non-starter to even think about, like one of those things that an Anti-EVer would dream up.

Electric cars in traffic jams - will your battery cope? - Which? News

We tested how air-con, lights and heated seats affect an electric car's battery

www.which.co.uk

 

[mj224]

Also, check the weather forecast before leaving the safety of home, and at least make sure you are fully charged before diving into those snow drifts....

 

[Alb]

I was recently stuck in a jam for 2½ hours and the charge dropped at around 1%/hr.

 

[EVsince2016]

An ICE burns through 0.5 to 1.5 litre per hours without heating / lights / AC etc when warm.
When cold, add heating, wipers, lights or worst AC this can go up to 2 - 4 litres per hour, slow moving traffic makes that even worse!

At minus 1 my MG5 used 1% per hour with heating, lights & wipers, without it's much less.