Tesla Model S 85D
Discussion
March 2024
I have had the car for 7 years now and is still running well. I just spent a little money on it to tidy up some scuffs and dings the car has picked up over the years as I may be starting a new business and want the car to be tidy and £1570 got me:
The Range is holding pretty well with over 88% still remaining:
Costs to run so far, adding in insurance this year which has jumped to £774.
Vaguely on topic, to complement the car, I have gone solar. I have had a home system fitted which comprises:
The Home Assistant set up has been an experiment to help make the best of the system and a good excuse for some top geekery (Cue rolling eyes from the rest of the household!)
Here it is with a case and a little custom 3d printed cover for the SSD drive living in the loft:
Before the Solar system was installed I was limited to starting charging using the car’s timed controls at 12:30AM to maximise charging at the cheap rate up to 4:30AM, after which the car would continue to charge until it hit its set limit (usually 80% for me).
After getting the Zappi system I set the car to charge whenever power was available at the charger and set the Zappi charger to charge using 1) Eco+ mode which only charged the car when there was spare solar power available and 2) a fixed charge period from 00:30 to 4:30 so that I never charged on the expensive rate.
As winter approached and I needed to be at work more often, there were days when the 4 hour nightly charge did not cover all of my commuting energy and as the week progressed the battery would drop quite low. This is where the Home Assistant came in. So a little background: Home Assistant is some freeware software designed to run on a Raspberry-Pi computer and integrate and control anything around the house that is “smart”. You install the HA SW and it wakes up and discovers what you have on your home network and then you can link them into the system. Some devices are already recognised and some you need to install “Integrations” and “Add ons” from freeware libraries to get them to work. Here are some of the things I have installed:
I have the app on my phone and Ipad and here is the main page on the web application:
It’s a bit messy but you get the idea. The Tapos need setting up again with fixed IP addresses on my home mesh network - the IP address changed when I unplugged them!
You can click on an item and get historical data - here is the February data on the solar generation:
For the Budding eco-geek the amount of data you can pull and analyse is amazing and you can quickly see where savings can be made. I also set up connection to my RpI using a free DuckDNS server which provides a secure connection to the RPi from the outside world and so I can see what is going on at home when I am out and about - more useful when I add cameras etc.
My key problem with the Tesla was charging enough during the week without paying the 31p/kWh day rate. One of the features of Home Assistant is “Automations” where you can interrogate your devices and control actions at different times.
My 1st attempt to play with this was to control the amount the home battery charged up at night based on the expected solar generation during the next day. I set up an automation to read the projected solar for the next day at 23:00 and based on that told the inverter how much to charge during the night.
With this working I set up a number of automations at 21:00, 22:05, 23:010 to look at how much juice was left in the home battery and if there was more than say 6kWh left and that the amount of power to charge the Tesla was more than the 28.4kWh I get in the cheap 4 hour window, then to tell the inverter to discharge the battery into the grid for an hour. While the inverter did this, the Zappi charger (in Eco+ mode) would sense the spare juice and feed it into the Tesla. The battery would then recharge itself on the cheap power at 00:30. I did the same thing at 4:45 and 6:30 for half an hour but with the limit ensuring there was enough power in the battery to run the house with the predicted solar for the next day after putting the extra power into the car.
Here is one of the automations - you can see you need to disable the Eddi to stop the power going into the hot water tank and also making sure there is actually a car plugged into the charger. I need to add another command to make sure the Zappi is actually in Eco+ mode:
Here you can see it working below which shows the plot of the power from the charger into the car over time:
The system is working well at the moment but will need some refinement when we get another EV. What is good with it is that if I set the car to charge to 100% for a road trip it does its best to fully charge on cheap power. So far it has not left me with less than 95% charge when asking for %100 which is ok for me.
I will keep an eye on the system and see what else I can do but at the moment I am only charging the car on night rate power and using as much of the Solar power as I can while avoiding using any grid power during the day.
The only glitch I have seen so far is a warning from the Zappi that the mains supply is too high, while it has not stopped charging it is not ideal. The logs show my mains peaking at 255V while discharging the house battery which is over the grid limit, and SSE have agreed to fit a logger with a view to putting us on a lower transformer tap to drop the average supply voltage by 2.5% which would fix the problem. The engineer who came out had never seen a system like mine and agreed that this sort of thing would come up more and more often!
While this is definitely early adopter territory, eventually all home power systems should be able to do this stuff automatically!
I have had the car for 7 years now and is still running well. I just spent a little money on it to tidy up some scuffs and dings the car has picked up over the years as I may be starting a new business and want the car to be tidy and £1570 got me:
- Fixed and painted crease on the rear wing,
- Fixed and painted crease rear door
- Fixed and painted some corrosion bubbles on the front passenger door
- Fixed and painted a car parking bump someone left me on the front bumper
- Refurb all 4 wheels
The Range is holding pretty well with over 88% still remaining:
Costs to run so far, adding in insurance this year which has jumped to £774.
| Total Expenditure | £18,162.60 | |
| Cost per mile | £0.17 | |
| Price I paid | £57,000.00 | Mar-16 |
| Value now | £18,000.00 | Mar-24 |
| Depreciation | £39,000.00 | |
| Total Cost of ownership | £57,162.60 | |
| Cost per mile including depreciation | £0.55 |
Vaguely on topic, to complement the car, I have gone solar. I have had a home system fitted which comprises:
- 6.4kW of panels split equally over and east and west facing roofs
- 19kWh of batteries
- A 5kW GiveEnergi dual inverter which will deliver 4kW of power out of the batteries when there is no sun.
- 2 Zappi programmable chargers
- An Eddi hot water manager which takes any spare solar and heats the hot water with it.
- A Raspberry-Pi with a 250MByte SSD card running Home Assistant
The Home Assistant set up has been an experiment to help make the best of the system and a good excuse for some top geekery (Cue rolling eyes from the rest of the household!)
Here it is with a case and a little custom 3d printed cover for the SSD drive living in the loft:
Before the Solar system was installed I was limited to starting charging using the car’s timed controls at 12:30AM to maximise charging at the cheap rate up to 4:30AM, after which the car would continue to charge until it hit its set limit (usually 80% for me).
After getting the Zappi system I set the car to charge whenever power was available at the charger and set the Zappi charger to charge using 1) Eco+ mode which only charged the car when there was spare solar power available and 2) a fixed charge period from 00:30 to 4:30 so that I never charged on the expensive rate.
As winter approached and I needed to be at work more often, there were days when the 4 hour nightly charge did not cover all of my commuting energy and as the week progressed the battery would drop quite low. This is where the Home Assistant came in. So a little background: Home Assistant is some freeware software designed to run on a Raspberry-Pi computer and integrate and control anything around the house that is “smart”. You install the HA SW and it wakes up and discovers what you have on your home network and then you can link them into the system. Some devices are already recognised and some you need to install “Integrations” and “Add ons” from freeware libraries to get them to work. Here are some of the things I have installed:
- GiveEnergy Integration to allow me to read data from and control the batteries and solar inverter
- MyEnergi integration to allow me to read data from and control the Zappi chargers and Eddi heater controller
- Tesla integration, to allow me to read the state of charge - max charge level and a load of other things from the car - including its location which can be shown on a map.
- My underfloor heater integrations
- Tapo smart plug integrations so I can track power consumption of stuff and switch it on and off
- Solcast and ForecastSolar integrations - these are services which if used sparingly are free and by feeding in your location and position of your panels can get 1,2, and 3 day predictions of what you should get from your panels
I have the app on my phone and Ipad and here is the main page on the web application:
It’s a bit messy but you get the idea. The Tapos need setting up again with fixed IP addresses on my home mesh network - the IP address changed when I unplugged them!
You can click on an item and get historical data - here is the February data on the solar generation:
For the Budding eco-geek the amount of data you can pull and analyse is amazing and you can quickly see where savings can be made. I also set up connection to my RpI using a free DuckDNS server which provides a secure connection to the RPi from the outside world and so I can see what is going on at home when I am out and about - more useful when I add cameras etc.
My key problem with the Tesla was charging enough during the week without paying the 31p/kWh day rate. One of the features of Home Assistant is “Automations” where you can interrogate your devices and control actions at different times.
My 1st attempt to play with this was to control the amount the home battery charged up at night based on the expected solar generation during the next day. I set up an automation to read the projected solar for the next day at 23:00 and based on that told the inverter how much to charge during the night.
With this working I set up a number of automations at 21:00, 22:05, 23:010 to look at how much juice was left in the home battery and if there was more than say 6kWh left and that the amount of power to charge the Tesla was more than the 28.4kWh I get in the cheap 4 hour window, then to tell the inverter to discharge the battery into the grid for an hour. While the inverter did this, the Zappi charger (in Eco+ mode) would sense the spare juice and feed it into the Tesla. The battery would then recharge itself on the cheap power at 00:30. I did the same thing at 4:45 and 6:30 for half an hour but with the limit ensuring there was enough power in the battery to run the house with the predicted solar for the next day after putting the extra power into the car.
Here is one of the automations - you can see you need to disable the Eddi to stop the power going into the hot water tank and also making sure there is actually a car plugged into the charger. I need to add another command to make sure the Zappi is actually in Eco+ mode:
Here you can see it working below which shows the plot of the power from the charger into the car over time:
The system is working well at the moment but will need some refinement when we get another EV. What is good with it is that if I set the car to charge to 100% for a road trip it does its best to fully charge on cheap power. So far it has not left me with less than 95% charge when asking for %100 which is ok for me.
I will keep an eye on the system and see what else I can do but at the moment I am only charging the car on night rate power and using as much of the Solar power as I can while avoiding using any grid power during the day.
The only glitch I have seen so far is a warning from the Zappi that the mains supply is too high, while it has not stopped charging it is not ideal. The logs show my mains peaking at 255V while discharging the house battery which is over the grid limit, and SSE have agreed to fit a logger with a view to putting us on a lower transformer tap to drop the average supply voltage by 2.5% which would fix the problem. The engineer who came out had never seen a system like mine and agreed that this sort of thing would come up more and more often!
While this is definitely early adopter territory, eventually all home power systems should be able to do this stuff automatically!
Love the statistics and data
The 17p per mile threw me a tad, is this pure electrical cost I had assumed closer to 11-13p per mile. This could be me being off on my own metrics.
I run a diesel van which is circa 15-16p per mile. And we briefly had a LPG car that was nudging 10-11p per mile.
I am only including fuel costs in my measures, are you including insurance and servicing ?
It’s impressive none the less for the performance at hand
I’m looking at moving over to EV once I can support it via solar
Got me looking now !
The 17p per mile threw me a tad, is this pure electrical cost I had assumed closer to 11-13p per mile. This could be me being off on my own metrics.
I run a diesel van which is circa 15-16p per mile. And we briefly had a LPG car that was nudging 10-11p per mile.
I am only including fuel costs in my measures, are you including insurance and servicing ?
It’s impressive none the less for the performance at hand
I’m looking at moving over to EV once I can support it via solar
Got me looking now !
Spunagain said:
Hi Mintmansam
the 17p per mile takes account of all costs - fuel, insurance, tyres, service, repairs, just not the depreciation!
My average fuel cost per mile over my ownership so far is 3.2p per mile.
Oh that is fantastic! the 17p per mile takes account of all costs - fuel, insurance, tyres, service, repairs, just not the depreciation!
My average fuel cost per mile over my ownership so far is 3.2p per mile.
Thanks for getting back to me. Makes my 26p per mile petrol car look totally wasteful haha.
What would you say were significant milestones in terms of energy per mile cost ? Going to solar? Late night topping up?
I hope this doesn’t sound too crazy. The KWh of your battery from new vs now is obviously reduced , does the required KWh input decrease as well? Or are you still inputting 100% charge to get 88% worth of range.
mintmansam said:
What would you say were significant milestones in terms of energy per mile cost ? Going to solar? Late night topping up?
Biggest step is to just go electric I do about 350Wh/mile - which is highish compared with more modern EVsDay rate electric at 30p/kwH so cost/mile is 10 pence per mile so you are already saving.
Using the Night rate electric at 9.5kw/H so cost/mile is 3.3 pence per mile so charging completely at the cheap rate makes a difference
I used to pay a night rate of 5p/kWh!
You can see that with the Auomations above I am pulling about 6kwH out of the battery instead of peak cost electricity so each charge saves me about £1.20 - call it a quid accounting for charge and discharge losses!
During the summer the problem is I am usually not at home, but when I am I take all I can from Solar.
Over last year I was using around 97% of what I generated either in the home, charging the car or heating the hot water. So the battery makes sure no solar power is wasted.
But if you take the 4000kwH I generated from solar last year- that is equivalent to over 11,000 of my miles.
mintmansam said:
I hope this doesn’t sound too crazy. The KWh of your battery from new vs now is obviously reduced , does the required kWh input decrease as well? Or are you still inputting 100% charge to get 88% worth of range.
For home charging at 7kW there is no effect at all. What it has done is slowed down supercharging a fair bit but not enough to effect me even on longer journeys. By the time I have eaten or had a drink etc there is enough to get on my way. The slowing down has not been gradual though, it took a hit a few years in late 2019 back when Tesla throttled it to protect batteries from unrequested ignition events!Edited by Spunagain on Thursday 7th March 16:07
Interesting read. Thanks. Top marks for geekery!
Just got a Model 3 Long Range myself. 5 weeks in.
So far so good.
I don't have a solar/battery setup, but i can see the attraction.
On Octopus Intelligent i've been very happy with the results. We've switched the washer/dryer/etc over to the cheap 23:30-05:30 hours, and the car gets charged as much as it needs in and around those hours. Sometimes Octopus will schedule 10+hrs of cheap charging if the car is particularly low, to get it up to the target state of charge and time.
So far my household average rate/kWh is down to about 12p.
And the car is costing about 2.2p/mile in "fuel".
Just got a Model 3 Long Range myself. 5 weeks in.
So far so good.
I don't have a solar/battery setup, but i can see the attraction.
On Octopus Intelligent i've been very happy with the results. We've switched the washer/dryer/etc over to the cheap 23:30-05:30 hours, and the car gets charged as much as it needs in and around those hours. Sometimes Octopus will schedule 10+hrs of cheap charging if the car is particularly low, to get it up to the target state of charge and time.
So far my household average rate/kWh is down to about 12p.
And the car is costing about 2.2p/mile in "fuel".
Thanks MM, at some point this should all be done automatically for everyone!
April 2024
A couple of small updates
First of all I got called in for a recall to adjust my bonnet latch to prevent a failure from flipping the bonnet up at speed, which took about half an hour at the service centre in reading.
Secondly, I have started getting connectivity problems where the LTE connection for the Spotify and the Navigation system drops out (little banner appears saying “Navigating without data”) and stays locked out until you do a reset (holding 2 steering wheel buttons down until the screen blacks out), this got more frequent until it affected me every trip to work (seemingly by M4 Jn 11).
Oddly, the satellite image data on the map does continue to get updated. I raised the issue on the App and I was advised to change the screen language from English to another language and then, back to English and do a reset. This has made things a little better but the problem is still occurring but a bit less often. I reported back and got a call from the service team: the tech on the line was very apologetic and I remember the following key points:
April 2024
A couple of small updates
First of all I got called in for a recall to adjust my bonnet latch to prevent a failure from flipping the bonnet up at speed, which took about half an hour at the service centre in reading.
Secondly, I have started getting connectivity problems where the LTE connection for the Spotify and the Navigation system drops out (little banner appears saying “Navigating without data”) and stays locked out until you do a reset (holding 2 steering wheel buttons down until the screen blacks out), this got more frequent until it affected me every trip to work (seemingly by M4 Jn 11).
Oddly, the satellite image data on the map does continue to get updated. I raised the issue on the App and I was advised to change the screen language from English to another language and then, back to English and do a reset. This has made things a little better but the problem is still occurring but a bit less often. I reported back and got a call from the service team: the tech on the line was very apologetic and I remember the following key points:
- This is a known SW issue.
- It only affects “MCU 1” Media Control Units powered by the Nvidia Tegra 3 (ARM) processor
- There is no SW fix for it yet
- it is possible to fix by replacing MCU1 with MCU2 which is £2K+
- The bug has been around since late last year
- 300-500 cars in the UK are affected so far
- There seem to be about 3 new cases per day being reported
- Reporting it is good as it increases pressure on Tesla to pull their fingers out and resolve it - so if you are seeing this please report it on your app!
- If it is not resolved in a month’s time I should raise a new case on the App (Again to increase pressure on Tesla to fix it!)
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