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Discussion Starter · #1 ·
Hi all, a two part Q:

1) does the preconditioning, when heating also run the AC? My car seems to get really fogged up inside which is a nuisance, so I am guessing it runs the heater only...

It's good that I can save myself the scraping of frost, but instead I have to wipe down the side windows and rear window which become covered in moisture. The rear window in particular is stupid, why can't it run the window heating elements...

So, the alternative would be a traditional, start the car and leave it "running", which leads to question 2:

2) A question I can't find an answer to on iDrive or in the manual: Can you leave the i3 "running" ?

If I start the car, foot on brake+start/stop button, it starts and I can run climate, heated rear window etc... as soon as I open the door it displays "OFF" and climate stops (fan keeps running for a bit I think). I am guessing this is a safety feature or something, but seriously annoying. Even if you just forget something and need to get out for a few mins, it turns off all climate control etc....

Any advice appreciated. I realise the moisture inside will depend on atmospheric conditions too but most of the time in the UK it will do that I think!
I have searched the forum but to no avail, if there are old threads about this that someone could find please send a link, thanks!

Charlie
 

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2020 BMW i3S 120Ah BEV
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"Climatise" usually engages the a/c for me. Did you turn the air-con off?

And you don't need to leave it in drive-ready mode - it will shut down when you get out the car anyway, unless you're daft enough to leave the key in there! You can engage "auxiliary climate" when you get out the car and it'll run the heaters/fans/a/c for another half an hour or so without you being there (and you can lock the doors too).
 

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Discussion Starter · #5 ·
Slide across and come out through the passenger door. It won't switch the car off
nice one thanks, didn’t think of that. Will try it some time!

"Climatise" usually engages the a/c for me. Did you turn the air-con off?

And you don't need to leave it in drive-ready mode - it will shut down when you get out the car anyway, unless you're daft enough to leave the key in there! You can engage "auxiliary climate" when you get out the car and it'll run the heaters/fans/a/c for another half an hour or so without you being there (and you can lock the doors too).
no, I have the AC on all the time... I can’t imagine the AC is running when using “climatise now” as I am doing, just because the windows are so fogged up.

As soon as I get in and “start” the car properly the climate control fan is much more vigorous and the windows start demisting.

thanks for the responses 🙂
 

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2020 BMW i3S 120Ah BEV
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another thing to try!! Thank you
It has a seat pad sensor so it knows if you're sitting in the seat.

But the fans go up and down based on things far more complex than the plain old position of the LEDs in the control panel. The fan typically starts quite slow and ramps up as the heater/a.c. unit starts actually functioning. Also, the "climatise" setting is a default, it's not the same as the "power on" setting, I think when you engage climatise it attempts to get the cabin to some default like "between 17 and 25" deg C, so when you climb in the car it's not frozen or super-hot, but it's not the same as your normal cabin temp either.

So when you get in, the fans kick into gear trying to reach your chosen set temperature.
 

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BMW i3 REx 2014
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I can’t imagine the AC is running when using “climatise now” as I am doing, just because the windows are so fogged up.
My 2014 i3 demists via 'climatise now' as you can see (with sun at appropriate angle) all the evaporated residue left on the inside of the window.
 

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40kW Leaf Tekna & 22kW Zoë Q210 dynamique intens
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Hi all, a two part Q:

1) does the preconditioning, when heating also run the AC? My car seems to get really fogged up inside which is a nuisance, so I am guessing it runs the heater only...

It's good that I can save myself the scraping of frost, but instead I have to wipe down the side windows and rear window which become covered in moisture. The rear window in particular is stupid, why can't it run the window heating elements...

So, the alternative would be a traditional, start the car and leave it "running", which leads to question 2:

2) A question I can't find an answer to on iDrive or in the manual: Can you leave the i3 "running" ?

If I start the car, foot on brake+start/stop button, it starts and I can run climate, heated rear window etc... as soon as I open the door it displays "OFF" and climate stops (fan keeps running for a bit I think). I am guessing this is a safety feature or something, but seriously annoying. Even if you just forget something and need to get out for a few mins, it turns off all climate control etc....

Any advice appreciated. I realise the moisture inside will depend on atmospheric conditions too but most of the time in the UK it will do that I think!
I have searched the forum but to no avail, if there are old threads about this that someone could find please send a link, thanks!

Charlie
Do you usually drive with the air con running to keep the windows clear?

If so when you switch it off the whole car foggs up because condenser is wet, when I get in and out of the car in the rain I do switch the A/C on to dehumidify and keep the windows clear.

however once I have done this I turn off the A/C for the last couple of miles or so of my journey home, open the windows a crack turn the heat up full and select fresh air not recirculate to dry everything out in the A/C system.

If you don’t do this the condenser stays wet when you park it up overnight.

This leads to mould / mildew / bacteria build up in the system if done regularly and the associated bad smells that go with that.

Also if you don’t everything foggs up the next morning.

My LEAF never steams up in the mornings when I precondition, even if it’s frosty.

You could also leave the heating on on the drive for 5 mins with no A/C and the windows open a bit that would also do the job.
 

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Discussion Starter · #10 ·
Do you usually drive with the air con running to keep the windows clear?

If so when you switch it off the whole car foggs up because condenser is wet, when I get in and out of the car in the rain I do switch the A/C on to dehumidify and keep the windows clear.

however once I have done this I turn off the A/C for the last couple of miles or so of my journey home, open the windows a crack turn the heat up full and select fresh air not recirculate to dry everything out in the A/C system.

If you don’t do this the condenser stays wet when you park it up overnight.
I always have the AC on yes, see no reason to turn it off as energy use is minimal (outside of hot weather!) and it is better for the longevity of the system.

I understand what you are suggesting but it seems like a waste of energy to heat up the whole heating system to then get out the car... my car does not usually fog up at any point, the only time it fogs up is when I use the remote preconditioning.
 

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Discussion Starter · #11 ·
It has a seat pad sensor so it knows if you're sitting in the seat.

But the fans go up and down based on things far more complex than the plain old position of the LEDs in the control panel. The fan typically starts quite slow and ramps up as the heater/a.c. unit starts actually functioning. Also, the "climatise" setting is a default, it's not the same as the "power on" setting, I think when you engage climatise it attempts to get the cabin to some default like "between 17 and 25" deg C, so when you climb in the car it's not frozen or super-hot, but it's not the same as your normal cabin temp either.

So when you get in, the fans kick into gear trying to reach your chosen set temperature.
I can understand that. I do have the climate control set to 17C at the moment as I wear a jacket while driving and this ensures minimal use of the heater, I prefer to use heated seat when I need warmth.
If I turn it down to 16C that seems to act as a "low" function blasting cold air which is not desirable.

When I run the preconditioning the car is definitely hotter inside than when I am driving with climate set to 17C auto with fan on lowest. So there is plenty of heat, the moisture all over the windows is what suggests to me the AC is not on, as when I drive with heating on low (due to 17C setting) I never have any misting up issues...
 

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I always have the AC on yes, see no reason to turn it off as energy use is minimal (outside of hot weather!) and it is better for the longevity of the system.

I understand what you are suggesting but it seems like a waste of energy to heat up the whole heating system to then get out the car... my car does not usually fog up at any point, the only time it fogs up is when I use the remote preconditioning.

During the winter you only actually need to run your A/C for a few minutes every few days, the reason you have to do this is because the refrigerant gas contains a lubricant that oils the compressor and prevents the rubber seals from drying out and allowing the gas to escape.

Thats plenty to protect the longevity of the system.

Use beyond this is not necessary during the winter.

Try switching the A/C off and it will fog up within 30 seconds, then run the heat for a few minutes and it will eventually dry out and the fog will clear, you won’t need to run the A/C while driving if you let the system dry out.

It’s a much bigger waste of energy to constantly run the A/C all winter with the heater on than it is for a few minutes with the heat on to dry it.

The main reason I switch off the A/C it to dry the evaporator out and not leave it wet when parked for a weekend or overnight is to prevent mould growth in the system.

I know Tesla actually changed the software on one of their cars to run some fans after the car had been parked to dry the system because they were all developing bad smells in the cabin.

Also if mould starts to develop within the system that’s extremely bad for your health.

Switching off the A/C and allowing things to dry is a good idea.

You wouldn’t have a shower and then close up the bathroom full of steam and just leave it like that every time.

The room would go mouldy and black, exactly the same thing happens in your A/C system you just can’t see it.

he reason your car is steaming up when preconditioning is because this is the only time the heater runs without the A/C on.

All the bits of your A/C system are permanently wet because it never gets chance to dry out.

This water is then evaporating out of the system while pre conditioning and all that hot damp air is hitting the ice cold glass and condensing.

You won’t prevent this from happening without getting rid of the water that’s trapped in the system.

Try it I guarantee you it will work and you won’t end up with a smelly car driving round breathing mould spores!
 

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... When I run the preconditioning the car is definitely hotter inside than when I am driving with climate set to 17C auto with fan on lowest....
When preconditioning there is a set, predetermined, target temperature of 22 C. This number is within the standard heating system and cannot be altered by mere mortals.

Regards.
 

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Discussion Starter · #15 ·
I haven't had to defrost the car yet, but I have driven it 3-4 times without the AC (apart from a few mins this morning to circulate the refridgerant) and am surprised how it doesn't mist up, the only problem is running the heat to demist instead has resulted in my average miles per kWh has gone from 3.7 ish (already a lot worse than summer) down to 2.5-2.8 :p

Still I will keep up the experiment, it looks like it may freeze here tonight so I may be able to attempt a defrost tomorrow morning and see if it fogs up inside.
 

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the only problem is running the heat to demist instead has resulted in my average miles per kWh has gone from 3.7 ish
How old is your i3?

I’m not overly familiar with them but I believe a heat pump was optional on some of them and if you don’t have one it uses a resistive heater to heat the cabin like the old Mk1 LEAF did.

If yours doesn’t have a heat pump that would explain the inefficiency, I had a BMW 225xe prior to my LEAF and the heater was weak on electric and totally destroyed the range, I used to run without the heating on because my range dropped to a about 8 miles it I used the electric heater in winter.

Even in my LEAF which has a heat pump I run the cabin heat on 21’c and the fan speed on its lowest setting on recirculate.

This drops my range by about 15% on average, but is comfortable with the heated seat / steering wheel on.
 
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