EV Discussion thread

JKenH

Your maths seem ok and the figures are impressive, but the only real way of calculating your consumption is to fill your battery to 100%, drive the car and measure the miles driven then see how much electricity you draw (and pay for) from the mains to refill the battery - just as you would with an ICE car filling up with petrol. 

I found my Leaf to be a little optimistic on indicated mpk, as indeed are most ICE cars, so brim, drive and refill is the only way. 

Martyn1981

Grumpy_chap said:

OK, so I am trying to understand my "MPG" or miles/KWh for my drive home on Friday evening.
My understanding was that anything over 4 miles/kWh is good.

I collected the car, TM3 LR, with 90% battery charge.
Official range is 374 miles, so 90% means 335 miles.
My journey was 71 miles with lights, wipers, air con, motorway speed. 
70 mph where possible, but some roadwork sections at 50 mph.
Started at sea level, ended in London, so a slight overall elevation gain
Battery charge showing on arrival 69%

When I found the energy meter, it says average 181 Wh/mi.
Unless my maths is wrong, that would mean >5.5 miles/kWh.
Is that correct " 1 divided by 0.181" to invert from Wh/mi to miles/kWh?

The same graph shows estimated range at 292 miles.  
I read that as remaining estimated range.
It could mean estimated range on that full charge ("tank").

The notes said to accelerate more smoothly - consider chill mode.

I know 71 miles is a short test, but is that correct that I calculated such a high miles/kWh.
I feel I may have made a mistake somewhere.

EDIT:  Another way to look at this is start 90% charge, finish 69% charge.  That means 21% used.  Against range of 374 miles, that would be 78 miles so my 71 miles was under-par.

181Wh/m is extremely good (well done), but for warm weather (not too hot, nor cold), and avoiding high speeds, that should be possible. But a few 'fun' pokes on the go pedal will change things.

As silvercar suggests, have a play with the menus under the trip option. You'll have lifetime, but at the top will be 'last trip' which resets everytime you park the car, and 'since last charge', which will average out those trips, resetting when you charge again.

One small thought, that I was going to mention, but realised I was really fussing too much, is to check tyre pressure. Just click on service, or waggle your finger across the bottom right of the screen where the music source is shown. I mention this as it has been common for the ship loads to arrive at high pressure, possibly 50psi, instead of ~42psi (depending on model). Probably not an issue, but worth checking, as that would boost your efficiency, but at a small loss to grip and braking.

Tesla's really are very efficient, and if you drive well as it appears you do (and I don't (lifetime average of 272Wh/m on TiMmY)), you'll get some great range. Wifey and I have managed 250Wh/m (4m/kWh) in both the older 3 (pre-heat pump), and the Y, in extremely hot weather at a constant 70mph (apart from the first couple of miles). But it did take about 35 miles to get down to 250Wh, having started a mile or two in at 600Wh/m+ (before falling fast) due to the very hot interior being cooled down.

So your 4m/kWh target is perfectly reasonable, and doable over a full year, though the long term average will deteriorate some in the winter (or when the roads are very wet), but annual average of 250Wh ..... yeah, doable.

Grumpy_chap

Thanks all for confirming my maths was correct.

The figures are purely those indicated by the car as power consumed, not total power including charging losses.  I have not actually charged as yet, so only have the initial "90% charged" as advised by the car on collection to go against.  I am having a meter installed for the charge point when that is done so I should be able to know full power consumption, not just the car-indicated figure but for now it is just the car's own value.

silvercar said:

 Are you sure you were looking at the trip and not the total since last reset?

I thought the official range is 360 not 374. 

That's a good question.  I think that trip and total since reset will be the same thing as the car was on charge when I arrived and I only made the one trip.  I double-checked, though, and it seems as though it was only the last 30 miles that showed the 181 Wh/mi (the 286 mile projected range has changed since yesterday because I was sitting in the car playing with menus).  I'll have to play with the menus some more to get the "trip" or the "since charge".  The only "since charge" data I could locate is a graph but that does not seem to give actual consumption number.

Official range on the website says 374 miles for inventory vehicles.  If I configure the same car to order, it says 389 miles.  Verbally, in the store when we ordered, the Assistant stated 385 miles.  If you read 360 somewhere, that's probably also correct.  It's in that order of magnitude somewhere between 350 and 400 miles

JKenH said:

the only real way of calculating your consumption is to fill your battery to 100%, drive the car and measure the miles driven then see how much electricity you draw (and pay for) from the mains to refill the battery - just as you would with an ICE car filling up with petrol. 

I will be having a meter installed when the EV charge point is installed so that will allow me to clog accurate data.
I'll build a new spreadsheet to get my pence-per-mile total cost, just as when I had an ICE, but different input metrics.

Martyn1981 said:

One small thought, that I was going to mention, but realised I was really fussing too much, is to check tyre pressure. Just click on service, or waggle your finger across the bottom right of the screen where the music source is shown. I mention this as it has been common for the ship loads to arrive at high pressure, possibly 50psi, instead of ~42psi (depending on model). Probably not an issue, but worth checking, as that would boost your efficiency, but at a small loss to grip and braking.

According to my app the tyre pressures are 44 psi (driver side) and 45 psi (passenger side).  I'll check once the car has a few miles under the wing as tyres pressures fluctuate anyway when new.

Mrs G-C has expressed her concern at my new demeanour and wondering where the regular-specification G-C has gone

Martyn1981

Hiya GC, choose the 'car' menu/image on the main screen, and you'll get a long list of options (plus the glovebox button  ). From memory (Wifey is out with TiMmY), about 2/3rds of the way down the list is the option 'Trips'.

Choose that, and you'll have a selection of info. And you'll see this updating as you drive.

Have fun.

silvercar

There is also Trip A and Trip B, if you want to measure a journey that includes a stop or recharge. To reset these scroll right to the bottom for a reset trip A button and a reset trip B button. Took us a while to find them as we didn't scroll down far enough.

Grumpy_chap

Thank you both - I found that "trips" menu and the energy was 202 Wh/mi since recharge, 222 Wh/mi since the beginning of time.  Both good figures - not far short of 5 miles / kWh.
I will do the settings so that these show in real time once I figure that out.

The big thing I am trying to understand is whether there is any option for cruise control that is not adaptive "traffic aware". 

The full feature cruise control is not any use in built up areas as it sees every parked car and every traffic island as a stationary vehicle ahead in the lane and brings the car to a stop.  No understanding that these are obstacles that the driver will need to manoeuvre around - I assume that is an indication of just how far FSD needs to develop.

In my wife's Fiesta, we use the standard cruise control at minimum setting and then use the cancel / resume features.  Even better was a previous Citroen C5 we had once upon a time with variable speed limiter - ideal for these 20 mph zones we have everywhere now.  The TM3 "speed limiter" feature is not for that purpose and not readily adjustable while in motion - plus the minimum cap is 50 mph (according to the manual).

JKenH

Elon Musk smashes delivery records at Tesla

Tesla delivered a record number of vehicles in the second quarter of this year after slashing prices in an effort to stoke demand.

The carmaker, run by tech billionaire Elon Musk, handed over 466,000 vehicles in the three months to June.

Analysts had expected Tesla to deliver 445,000 cars, according to polling by Refinitiv.

https://www.telegraph.co.uk/business/2023/07/02/tesla-delivers-record-number-evs/

1961Nick

Grumpy_chap said:

OK, so I am trying to understand my "MPG" or miles/KWh for my drive home on Friday evening.
My understanding was that anything over 4 miles/kWh is good.

I collected the car, TM3 LR, with 90% battery charge.
Official range is 374 miles, so 90% means 335 miles.
My journey was 71 miles with lights, wipers, air con, motorway speed. 
70 mph where possible, but some roadwork sections at 50 mph.
Started at sea level, ended in London, so a slight overall elevation gain
Battery charge showing on arrival 69%

When I found the energy meter, it says average 181 Wh/mi.
Unless my maths is wrong, that would mean >5.5 miles/kWh.
Is that correct " 1 divided by 0.181" to invert from Wh/mi to miles/kWh?

The same graph shows estimated range at 292 miles.  
I read that as remaining estimated range.
It could mean estimated range on that full charge ("tank").

The notes said to accelerate more smoothly - consider chill mode.

I know 71 miles is a short test, but is that correct that I calculated such a high miles/kWh.
I feel I may have made a mistake somewhere.

EDIT:  Another way to look at this is start 90% charge, finish 69% charge.  That means 21% used.  Against range of 374 miles, that would be 78 miles so my 71 miles was under-par.

181Wh/mile is not really possible without hypermiling & you'd need to be under 50mph to have any chance.

From the range used, it looks to have achieved around 4.5 miles/kWh which is bang on what you should expect at this time of year. That would give you a real world range of 340 miles + the hidden 20 miles when it gets to zero.

1961Nick

The bottom right hand corner of the screen by default shows the audio settings. You can swipe this left to get trip information & tyre pressures.

Martyn1981

Grumpy_chap said:

Thank you both - I found that "trips" menu and the energy was 202 Wh/mi since recharge, 222 Wh/mi since the beginning of time.  Both good figures - not far short of 5 miles / kWh.
I will do the settings so that these show in real time once I figure that out.

That sounds more like it. 181 may be possible (just), but 202 is more probable. But still an excellent start, puts me to shame, I really should try to do better. 

Nick mentions hypermiling, and a forum friend sent me a screenshot ( a year or two ago), where his home commute had heavy slow(ish) traffic, so he tucked in behind a truck, activated autopilot and minimum follow distance, and managed about 140Wh/mile .... show off!

Better stil was my friend with his first drive of my TM3, when we went on a Tesla group tour of the Brecon Beacons. First leg I drove, ended up on the top of a hill, where we could all admire the PV and wind farms. His leg took us to a gin refinery in the bottom of the next valley, and he 'scored' -24Wh/mile.