Consumption conundrum

[Bootneckshuffl]

Hi all

this may be a daft question and maybe hard to answer but here it goes

Charged the car to 90% today.
Drove 5 miles, parked up with sentry activated for 1 hour.
Drove another 5 miles to home, no sentry.
Drove 4 miles, sentry activated for 20 mins
Drove 10 miles, sentry activated for 40 mins

All driving conservatively, AC on, music playing, sport mode

car used 16% battery

this sound about right?

 

[MrBadger]

Welcome to cooler weather.

Its probably the fixed 'departure tax' creating the 'travelling salesman' issue. The car doesn't like starting from cold. Don't know how much the cabin cooled down, but if the cabin heater got involved especially on higher fan speeds, thats a couple of '3 bar heaters' right there in your cabin and the batteries probably didn't get a chance to get warm. Add in sentry etc. and its not a great scenario.

The good news is that if it was a longer trip when you may have needed the range, then departure trip is a much lower proportion.

 

[Mr Miserable]

Hi all

this may be a daft question and maybe hard to answer but here it goes

Charged the car to 90% today.
Drove 5 miles, parked up with sentry activated for 1 hour.
Drove another 5 miles to home, no sentry.
Drove 4 miles, sentry activated for 20 mins
Drove 10 miles, sentry activated for 40 mins

All driving conservatively, AC on, music playing, sport mode

car used 16% battery

this sound about right?

16% of what?
What car is it?

 

[LongRanger]

The way I look at this (a completely normal use case for a UK car) is that a petrol/diesel would have consumed maybe up to a third additional fuel for example the same scenario. Plus it would be the slow drip-feed of wear and tear on moving parts in the engine, battery charging circuit and cooling system (pistons/crank, pulleys/chain, pumps etc). Cold/hot/cold/hot etc etc

You have used a bit more “fuel” (energy) than perhaps you had hoped - but you have had single motor parts turning within a motor housing, other than that it’s really infinitely minimal wear on the power train for the EV.

I used to hate short journeys in petrol/diesel, always had a thing about avoiding runs where the engine couldn’t warm up fully.

Additionally if you are consuming electricity generated from renewables to charge your car - the CO2 benefit in the exact scenario you have described is what gets us to a far more acceptable emissions position.

All good as far as I’m concerned !

 

[Neilio]

I had brutal consumption on Tuesday whilst driving to a shopping centre. Cold cabin, batteries never got warmed (regen dots stayed on all trip). Cool ambient temperatures and freezing winds combined with driving rain. It was a perfect storm for bad consumption. As longranger says, any vehicle would have had poor consumption on these types of day. I guess people just notice it more with an EV. If you have a home charger you can always mitigate a little bit by pre heating the cabin whilst still on juice

 

[NorfolkMustard]

If you have a home charger you can always mitigate a little bit by pre heating the cabin whilst still on juice

worth emphasising this for new owners going into their first autumn/winter.

Even this early in the season mine has started to precondition the battery the first time I use the car each day, when I turn on the climate remotely before I get in. A good 15 minutes or so of ~10kW usage to heat the cabin and battery, followed by ~2kW to keep the cabin up to temp.

 

[Bootneckshuffl]

16% of what?
What car is it?

Model 3P

90% to 74%
16% use

 

[MrBadger]

If you have a home charger you can always mitigate a little bit by pre heating the cabin whilst still on juice

worth emphasising this for new owners going into their first autumn/winter

Yes. But only if you need to otherwise (in normal times work pattern) you will likely be preheating when peak electricity is in highest demand and worse for grid environmental impact.

source: Carbon Intensity

 

[Bootneckshuffl]

I had brutal consumption on Tuesday whilst driving to a shopping centre. Cold cabin, batteries never got warmed (regen dots stayed on all trip). Cool ambient temperatures and freezing winds combined with driving rain. It was a perfect storm for bad consumption. As longranger says, any vehicle would have had poor consumption on these types of day. I guess people just notice it more with an EV. If you have a home charger you can always mitigate a little bit by pre heating the cabin whilst still on juice

I’ve been getting those regen dots quite a lot lately

Can you explain what the craic is with reduced regen?

 

[Jason71]

Yesterday I was looking at my 308 wh/m consumption on a short journey that would have used 260 wh/m a few weeks ago and thought I wonder when the horrified posts from summer 2020 buyers will start?

 

[NorfolkMustard]

I’ve been getting those regen dots quite a lot lately

Can you explain what the craic is with reduced regen?

It limits the kW going back into the battery until the batteries get warm enough to handle the max of ~75kW

it’s designed to prolong the life of the battery.

if you plugged into a DC charger/supercharger at the same battery temp you’d see a low kW rate there too.

 

[Jason71]

I’ve been getting those regen dots quite a lot lately

Can you explain what the craic is with reduced regen?

When the battery is cold it cant absorb all the electricity that regen generates. So the car reduces the regen. The dots tell you how much it has been reduced. The more dots the less regen you have.

 

[adsheff]

In my experience, multiple short trips gives very poor mileage compared to a single long trip. The battery drain always seems to slow after driving for an hour, and drains even slower after a supercharging session, regardless of the weather. I guess, like others say, it just takes quite a bit of energy to start up and warm everything up, so if you do this multiple times after letting the car cool down then each time you are starting again.

 

[MrBadger]

In my experience, the position of the dots indicate at which point the regen will drop off wrt the green regen bar. eg if you have half regen full of dots and you start going down a hill, all the while the green line stays within the non dotted region, the loss is not noticeable, but if the hill gets steeper and your green line starts encroaching into the dotted area, then you will notice the regen.

You also can get dots on the other/power use side, but its quite rare but is an indicator when performance power is limited.

 

[LongRanger]

Was pretty chuffed on Tuesday did 260 miles M4/A34/M3/M27 and didn’t really worry about sticking to erm 70, erm guvnor, and averaged 297wh/m, I drive on low regen setting. Can’t really fault that with a cold start and lots of very constant higher speed driving.

I did wonder about lower regen setting being more suitable for higher speed longer runs as on the higher setting every time you lift off it’s a lot more energy to get back to cruising speed - but also noticed that on TACC even in lower regen setting it uses the full regen potential to act as a brake when brakes not required to take some speed off following the next vehicle.

 

[Glan gluaisne]

One of my fairly regular trips is into Salisbury and back, roughly 10 to 11 miles each way. In summer this ~21 mile round trip uses about 8%, yesterday morning it used 12%. I've also had the limited regen indications again over the past couple of days, always first thing in the morning when the battery's cold. It's getting to the time of year when I need to remember to plug the car in and precondition it before taking it out in the morning.

As above, the killer is short journeys in cold weather, as a cold start, without preconditioning whilst still plugged in. The heater uses a fair bit when warming the car up from cold, plus the battery is far from being at its best when cold.

 

[Bootneckshuffl]

Big thanks to everyone for taking the time out to comment.

Great info and my mind now at rest.

 

[Mr Miserable]

One of my fairly regular trips is into Salisbury and back, roughly 10 to 11 miles each way. In summer this ~21 mile round trip uses about 8%, yesterday morning it used 12%. I've also had the limited regen indications again over the past couple of days, always first thing in the morning when the battery's cold. It's getting to the time of year when I need to remember to plug the car in and precondition it before taking it out in the morning.

As above, the killer is short journeys in cold weather, as a cold start, without preconditioning whilst still plugged in. The heater uses a fair bit when warming the car up from cold, plus the battery is far from being at its best when cold.

Mmmm I went to Salisbury today (Waitrose) and I also noted a marked increase in power consumption for the return trip.
So much so, that I immediately went to TeslaFi to check the figures only to discover the trip hadn't been logged (seperate thread).
Anyway the lesson to take away is AVOID SALISBURY.

 

[Drew57]

When we returned from holiday last week I had set the car temperature to 18C rather than Low (wife in car so unacceptable) but as the journey was fairly long, overall average was ~280kWh, slightly more than my usual ~250-260.

Forgetting this I couldn't understand why this week the car was showing 700-800kWh when first driven & on typical short local journeys I couldn't even get below 310, often higher.

It dawned on me yesterday that of course, even at 18C the heater was running so once I returned to the Low temp setting (& solo driving) everything is back pretty much as before.

 

[Glan gluaisne]

Mmmm I went to Salisbury today (Waitrose) and I also noted a marked increase in power consumption for the return trip.
So much so, that I immediately went to TeslaFi to check the figures only to discover the trip hadn't been logged (seperate thread).
Anyway the lesson to take away is AVOID SALISBURY.

Waitrose car park in Salisbury seems to be a Tesla hot spot at times. I've regularly seen both a white Model 3 and a blue one parked there.