Questions after 1 Month

[UrbanSplash]

Hi all,

It's been a month but I still have some questions!

All going well overall. It really is an amazing car, no real issues so far. Still amused that most Sentry captures are folks looking through the window etc. Charging from home is fine. No real long distances yet so time will tell. Some things I'm still not sure about:

• Charging every night? I only use 10-20% a day. Is it best to top up every night, or just charge when it gets low? No real guidance on what's best for the batteries. Or the wallet if there is any difference? (charging to 80%)
• Any evidence charging to 80% is better for battery than 90%. I've never charged to 100% yet.
  
• When you leave the car and the heated seats are on, and the heating, does this all switch off when car is locked and left?
• I tend to take my foot off the accelerator to come to a stop and let the car hold, rather than actually brake, even on a hill, I guess this is ok?
• Without using third party apps etc, is there a way to look at battery health?
  
• Is there any way to 'eject' the SSD for cam? I just unplug when in park
• Is there a shortcut to switch heated seats from 3 to off (without having to press it 3 times)?
• How can DAB stations be saved as favorites and accessed easily?

Some things to do:

• Wrap the centre console. The shiny gets too dirty etc
• Swap numberplates to stick on ones.
• Figure out why Hubsta public chargers don't work. Car starts to charge then stops itself
• Fit the trunk hooks that I've just bought

Many thanks

 

[xdcthedoc]

Hi all,

It's been a month but I still have some questions!

All going well overall. It really is an amazing car, no real issues so far. Still amused that most Sentry captures are folks looking through the window etc. Charging from home is fine. No real long distances yet so time will tell. Some things I'm still not sure about:

• Charging every night? I only use 10-20% a day. Is it best to top up every night, or just charge when it gets low? No real guidance on what's best for the batteries. Or the wallet if there is any difference? (charging to 80%)
• Best left plugged in all the time the car is left for a while is the standard advice.
• Any evidence charging to 80% is better for battery than 90%. I've never charged to 100% yet.
• Elon says 90% is fine. Some play it safe with 80.
  
• When you leave the car and the heated seats are on, and the heating, does this all switch off when car is locked and left?
• yes they turn off.
• I tend to take my foot off the accelerator to come to a stop and let the car hold, rather than actually brake, even on a hill, I guess this is ok?
• Yes of course - one pedal driving is good. Shame the regen takes a while to build on cold days.
• Without using third party apps etc, is there a way to look at battery health?
  
• Not sure what you mean about health.
• Is there any way to 'eject' the SSD for cam? I just unplug when in park
• Long press the camera icon before removing the drive.
• Is there a shortcut to switch heated seats from 3 to off (without having to press it 3 times)?
• Use voice command " set driver seat heater to off"
• How can DAB stations be saved as favorites and accessed easily?
• Not sure.

Some things to do:

• Wrap the centre console. The shiny gets too dirty etc
• Swap numberplates to stick on ones.
• Figure out why Hubsta public chargers don't work. Car starts to charge then stops itself
• Fit the trunk hooks that I've just bought

Many thanks

I had a stab at these - in bold.

 

[UrbanSplash]

Thanks so much for the reply, mega appreciated. I've not tried the voice commands yet so will give it a go.

By heath, I guess I mean capacity. Over time I understand that range will drop. How can you see this?

 

[MrBadger]

• Without using third party apps etc, is there a way to look at battery health?

• How can DAB stations be saved as favorites and accessed easily?

You can fit a dongle and read in depth stats, but otherwise best you can do is mimic what TeslaFi appears to do which is, ideally (TeslaFi has an option for this as you know you are at an exact %) charge to a set %, say 90%, then when it completes (see comment re TeslaFi) look at your range and extrapolate up to 100%, ie /9 * 10 to give you your estimate of 100% charge. It will vary up and down but expect it to be somewhere in the 300-310 mark for a LR AWD. As teslaFi does this automatically, you can plot a ready reckoner of battery health over time.

Oh yes, a happy Tesla is a plugged in Tesla according to the manual. I personally find that car will do top ups for a few mins during the day when leaving it plugged in but charged. I’m personally not a fan of that but that’s because I’m not use to high power usage going off when I don’t have a reason for it.

As for setting DAB station as favorite, you can press the favorite star icon near the name - I forget the exact sequence. You can also do that for FM, which can get a bit confusing if you have DAB and FM stations of same name.

 

[LukeT]

On the DAB stations, there's a star icon to toggle a station between favourite and not.

If I only use 10-20% in a day I don't worry whether I plug in or not, but my habit is to plug in always, so in reality it's a rare occurrence I don't.

On 80% vs 90% I have not seen a clear consensus that 80% is materially better but I'm sure it isn't worse. I charge to 80% daily and 90% if there's half a chance I'll need it. In the cold I have charged higher than that quite a few times but only ever immediately before departure; however this is no proof that's OK - my car's only 6 months/15k old.

 

[Jason71]

As xdc says Elon says 90% BUT everything I have ever read about Li batteries says they do not like being held in a high state of charge and degradation increases exponentially with charge state. i.e. 100% is terrible. 90% is much better but 80% is noticeably better than 90 and 70 is marginally better than 80

Generally they don't like to be in very a low SoC either
Now I don't know Tesla battery chemistry and maybe with Tesla cells the difference between 90 and 80 is negligible. Of course there is a little reserved capacity so 90 is probably 86.5% or something and 80 is 76.5% or something. so maybe it makes no significant difference anyway.
BUT
I have never read a single thing where it says 80% is worse than 90% or 70% is worse than 80%. So my battery strategy is charge when I need charge then top up to 80% or 90% as needed by my next journey and don't let it sit at high charge for long periods i.e. if I was going on holiday without it and could leave it plugged in I might set it to 70%.

Maybe this is OTT or plain wrong ¯\_(ツ)_/¯. I plan to keep the car a while so i guess I will find out. If yours is leased don't worry about it either way

 

[RichieC]

I'll have a go at answering these... think some may have been answered already...

• Charging every night? I only use 10-20% a day. Is it best to top up every night, or just charge when it gets low? No real guidance on what's best for the batteries. Or the wallet if there is any difference? (charging to 80%)
  
  Charging every night is fine - or just charging when it gets low is ok too, but best to try to not let it go much below 20% or so too often. Don't think it makes any difference cost wise either way..
  
  
• Any evidence charging to 80% is better for battery than 90%. I've never charged to 100% yet.
  
  I usually charge to 90% but it seems the 80% or 90% is fine. Charging to 100% occasionally is ok too, as long as you're going to use it and not let it sit with 100% charge for days..
  
  
• When you leave the car and the heated seats are on, and the heating, does this all switch off when car is locked and left?
  
  Yes - the car will remember the settings and turn them back on when you unlock and get in the car.
  
  
• I tend to take my foot off the accelerator to come to a stop and let the car hold, rather than actually brake, even on a hill, I guess this is ok?
  
  Yes - this is how hold mode is designed to work.
  
  
• Without using third party apps etc, is there a way to look at battery health?
  
  Not really, other than charging to 100% occasionally and seeing how many miles range it shows.
  Best advise I can give is to set the display to % rather than distance and just not worry about it!
  
• Is there any way to 'eject' the SSD for cam? I just unplug when in park
  
  Yes, hold your finger on the sentry mode camera icon until it turns grey - then remove the usb drive/ssd.
  
  
• Is there a shortcut to switch heated seats from 3 to off (without having to press it 3 times)?
  
  Voice command "Turn off heated seats"
  
  
• How can DAB stations be saved as favorites and accessed easily?
  
  When you have a DAB station (or FM station) selected, press the "Star" icon at the top - the station will be added to your favourites list.
  
  Hope this helps!

 

[Jason71]

even if you use an app they all get the same raw data which looks like this:

{
"response": {
"battery_heater_on": false,
"battery_level": 64,
"battery_range": 167.96,
"charge_current_request": 48,
"charge_current_request_max": 48,
"charge_enable_request": true,
"charge_energy_added": 12.41,
"charge_limit_soc": 90,
"charge_limit_soc_max": 100,
"charge_limit_soc_min": 50,
"charge_limit_soc_std": 90,
"charge_miles_added_ideal": 50.0,
"charge_miles_added_rated": 40.0,
"charge_port_cold_weather_mode": false,
"charge_port_door_open": false,
"charge_port_latch": "Engaged",
"charge_rate": 0.0,
"charge_to_max_range": false,
"charger_actual_current": 0,
"charger_phases": null,
"charger_pilot_current": 48,
"charger_power": 0,
"charger_voltage": 0,
"charging_state": "Disconnected",
"conn_charge_cable": "<invalid>",
"est_battery_range": 116.67,
"fast_charger_brand": "<invalid>",
"fast_charger_present": false,
"fast_charger_type": "<invalid>",
"ideal_battery_range": 209.95,
"managed_charging_active": false,
"managed_charging_start_time": null,
"managed_charging_user_canceled": false,
"max_range_charge_counter": 0,
"minutes_to_full_charge": 0,
"not_enough_power_to_heat": false,
"scheduled_charging_pending": false,
"scheduled_charging_start_time": null,
"time_to_full_charge": 0.0,
"timestamp": 1543187621530,
"trip_charging": false,
"usable_battery_level": 64,
"user_charge_enable_request": null
}
}

and even that does not really tell you much "battery range" is about the only one that relevant and you can get that in car I think.

an OBDII dongle and scanMyTesla app I think provides more since the OBDII data was never supposed to be public but got decoded by smart people so potentially there is stuff in there Tesla never intended you to see where as the above is pretty public and easy to get hold of.

 

[Adopado]

Charging every night? I only use 10-20% a day. Is it best to top up every night, or just charge when it gets low?

Everybody else has already given the good advice that's needed in relation to state of charge and future battery health.

The bit that I will add is that one advantage of a home charged EV is that it's always ready to go in the morning. It's like the petrol fairy came to top up your ICE car during the night! It's very good to know that if something unexpected comes up you know the car won't let you down ... which it will if you try to work out in advance that you are not going to need to use the car for a couple of days so you leave it with 25% ... then you get a call from your elderly parent and you need to fit in a 100 mile dash before then having to take them for an emergency appointment some further miles away. Then your brother says "I told you electric cars weren't practical ... sheesh ... I'll drive out there in my old jalopy and get the job done quicker ... that 0 to 60 time doesn't look so good now, huh?"

Stuff happens and the great thing about cars is that they often help you deal with it ... so keep it topped up and ready to go.

 

[cezdoc]

• Charging every night? I only use 10-20% a day. Is it best to top up every night, or just charge when it gets low? No real guidance on what's best for the batteries. Or the wallet if there is any difference? (charging to 80%)
• Any evidence charging to 80% is better for battery than 90%. I've never charged to 100% yet.

If you want to stretch your electrons a bit further (i.e. looking at charging from your wallet's perspective), particularly in cold weather, then schedule your charge to finish just before you set off. The charging process generates a bit of heat, so the car needs less energy to heat the battery when setting off (and/or can use some of that heat to warm up the cabin). This also has the benefit of preserving more regen when you first set off.

Also if you need to pre-heat the car I believe it's more efficient to do this while plugged in as power can be drawn direct from the mains rather via the battery (avoiding associated energy conversion losses).

Based on the experience to date of older Model S/X batteries (but not Model 3 I should add), the amount of Supercharging plus pure luck has more impact on your battery health than charging to 80% vs 90%. Anecdotally, I tend to charge once a week (I find it easier than plugging in daily, even though I could charge daily) and I've seen <5% degradation in 4 years from my MS. Conversely I know of at least one #battergate affected owner who was extremely careful with the levels they charged to, but they did most of their charging via Superchargers / DC rapids and this combined with a bit of bad luck seems to have landed them with reduced battery capacity (albeit imposed by software apparently to protect the battery in future).

Sounds like you're enjoying the car! Long may it continue

 

[Jason71]

Everybody else has already given the good advice that's needed in relation to state of charge and future battery health.

The bit that I will add is that one advantage of a home charged EV is that it's always ready to go in the morning. It's like the petrol fairy came to top up your ICE car during the night! It's very good to know that if something unexpected comes up you know the car won't let you down ... which it will if you try to work out in advance that you are not going to need to use the car for a couple of days so you leave it with 25% ... then you get a call from your elderly parent and you need to fit in a 100 mile dash before then having to take them for an emergency appointment some further miles away. Then your brother says "I told you electric cars weren't practical ... sheesh ... I'll drive out there in my old jalopy and get the job done quicker ... that 0 to 60 time doesn't look so good now, huh?"

Stuff happens and the great thing about cars is that they often help you deal with it ... so keep it topped up and ready to go.

Fair point but there is a fairly wide line between charging to 90% every night and letting it go to 25%
Personally I charge if it gets down to about 50, Partly for the reason you outlined so eloquently.
Though TBH in my case the only relatives that might apply to are the in laws so its a chance I'm willing to take. .
Having said that I live right by a Supercharger that's never full so I if it comes down to it i'm rarely more than 15 minutes away from 80% SoC (assuming the wife was prepared to cover the cost of course!)

 

[Glan gluaisne]

Re: battery health. I've been playing around with lithium cells running home made electric bikes, a home made electric motor cycle and a home made electric boat for around 10 to 15 years now. I've had loads of battery failures (none spectacular, barring some nickel metal hydride cells that blew up right at the start of my experiments with electric power).

I've learned few things about battery life. The biggest single factor is the quality of manufacture, everything else pales into insignificance, as manufactured quality determines calendar life, and calendar life can easily be the determining factor as to how long cells may last in some applications, especially EVs, where cycle life is really no big deal.

The next biggest factor is depth of charge and discharge. Cycling between a nominal 0% capacity (lower voltage cut-off typically ~3.0 to 3.2 V) and 100% (nominal high voltage cut-off ~4.2 V) will shorten life dramatically, maybe down to just a few hundred charge-discharge cycles, with a loss of capacity with each charge-discharge cycle. Cycling between 10% and 90% massively increases cycle life, maybe by as much as a factor of 10 over the 0% to 100% case. Cycling between 20% and 80% further increases cycle life, but not by much, maybe a 10% to 30% improvement over the 10% to 90% case.

Putting cycle life into perspective, for a car that uses ~275 Wh/mile on average, that has a 75 kWh battery pack and is driven around 10,000 miles a year, then that's roughly equivalent to around 37 full charge-discharge cycles a year, or maybe 46 10% to 90% charge-discharge cycles a year.

The cells I've been using in my home made stuff are nowhere near as good as Tesla's 2170 cells, and yet they will easily give around 1,000 cycles when run over a 10% to 90% SoC (State of Charge) range. I'd be very surprised if Tesla 2170's can't manage at least 2,000 cycles under such a charge-discharge pattern, and suspect they may be capable of maybe 3,000 cycles when used like this.


1,000 cycles, over a 10% to 90% charge-discharge depth, is equivalent to around 21 years at 10,000 miles per year. The cells will die from old age before they die from any cycle life limitation. At a life of 2,000 cycles, that age is doubled, to 42 years at 10,000 miles per year, or 420,000 miles.

In general I'd not be the slightest bit worried about charging to 90% all the time, as the chances are the cells will die of old age long before cycle life starts to have any real impact. The only proviso to that is that if the car is to be stored for a long time (several months) then I'd set the maximum charge to 75% and leave the car plugged in. It will periodically recharge to 75% every few days, to allow for vampire drain, and the 75% SoC point is about optimum for long term storage.

 

[Jason71]

If you want to stretch your electrons a bit further (i.e. looking at charging from your wallet's perspective), particularly in cold weather, then schedule your charge to finish just before you set off. The charging process generates a bit of heat, so the car needs less energy to heat the battery when setting off (and/or can use some of that heat to warm up the cabin). This also has the benefit of preserving more regen when you first set off.

Also if you need to pre-heat the car I believe it's more efficient to do this while plugged in as power can be drawn direct from the mains rather via the battery (avoiding associated energy conversion losses).

If you are using Octopus go, as so many are, not only is charging right before you leave an expensive option ( unless you are setting off at 4am). I would quite like the option to chose to preheat from the battery even when plugged in rather than use the mains so I can use my cheap electricity for that as well!

 

[RichieC]

If you are using Octopus go, as so many are, not only is charging right before you leave an expensive option ( unless you are setting off at 4am). I would quite like the option to chose to preheat from the battery even when plugged in rather than use the mains so I can use my cheap electricity for that as well!

I'm actually not completely convinced that it does use the mains supply for preheating. .

I am using Octopus go and have charging scheduled to start at 12:30am to take advantage of the cheaper rate, and it usually finishes charging before 4:30am unless i've done lots of miles the day before.

I usually preheat the car from the app about 30 minutes before i leave in the morning with the car still plugged in, with charging stopped and charged to 90%. This then uses the battery to do the preheat, and uses about 4 or 5% battery in this 30 minutes (if its cold like it is at the moment). If i manually start charging from the app, it will then charge the battery back up to 90% as it preheats.

Surely if it used the mains supply when connected, then preheating wouldn't deplete the battery and it would stay at 90% SOC until i unplug it? But it doesn't...

 

[cezdoc]

Surely if it used the mains supply when connected, then preheating wouldn't deplete the battery and it would stay at 90% SOC until i unplug it? But it doesn't...

Not sure about the M3 but I believe the Model S heater can pull over 7kW, at least initially, meaning it would need to dip into the battery as well as using mains. You could find out one way or another whether or not mains was being used by watching the electricity meter while preheating is ongoing...

 

[cezdoc]

If you are using Octopus go, as so many are, not only is charging right before you leave an expensive option ( unless you are setting off at 4am). I would quite like the option to chose to preheat from the battery even when plugged in rather than use the mains so I can use my cheap electricity for that as well!

Yep, not just Octopus go but charging outside any cheap overnight tariff would negate any cost saving from efficiency gains due to having a warm battery.

In my area (North Scotland) I've yet to find a time of day tariff that works for me (partly due to needing the electric hob and oven at tea time, and an electric shower in the morning, partly because we don't seem to be offered dirt cheap overnight rates up here, and partly because I don't want to be penalised paying a more expensive flat tariff whilst sitting on a waiting list for a smart meter install). I've managed to stick with OutfoxTheMarket for two years - It's been an interesting ride (expecting them to go bust from time to time!) but they have consistently been the cheapest supplier for me.

 

[Adopado]

I'm actually not completely convinced that it does use the mains supply for preheating. .

I am using Octopus go and have charging scheduled to start at 12:30am to take advantage of the cheaper rate, and it usually finishes charging before 4:30am unless i've done lots of miles the day before.

I usually preheat the car from the app about 30 minutes before i leave in the morning with the car still plugged in, with charging stopped and charged to 90%. This then uses the battery to do the preheat, and uses about 4 or 5% battery in this 30 minutes (if its cold like it is at the moment). If i manually start charging from the app, it will then charge the battery back up to 90% as it preheats.

Surely if it used the mains supply when connected, then preheating wouldn't deplete the battery and it would stay at 90% SOC until i unplug it? But it doesn't...

It really should use "shore power" and should not deplete the battery if connected to the charge point. Maybe it's a charge point issue but it definitely works that way and is intended to work in that way.

 

[LukeT]

It really should use "shore power" and should not deplete the battery if connected to the charge point. Maybe it's a charge point issue but it definitely works that way and is intended to work in that way.

If its set to stop charging, rather than just to a reduced target SoC, does that then mean it'll stop taking shore power for any reason? This could be the difference.

 

[Adopado]

If its set to stop charging, rather than just to a reduced target SoC, does that then mean it'll stop taking shore power for any reason? This could be the difference.

I don't know the answer to that but it would be surprising to me if it worked that way.

 

[NorfolkMustard]

If its set to stop charging, rather than just to a reduced target SoC, does that then mean it'll stop taking shore power for any reason? This could be the difference.

No. It uses shore power any time it’s connected, irrespective of the charge state shown in the app.

The difference is when the app says “charging” then that takes priority over battery warming. it seems to decide range is your priority, not a warm battery. Which is logical.

i did a test a couple of weeks ago while it was charging ( only on the TMC @ 2kW). I turned on Climate but the power use (total of battery + mains) was only 2kW - enough to run the heaters but not drain the battery - even after 10 minutes.
As soon as I hit "Stop Charging" the power use ramped up to 10kW ( 8kW from the battery, 2kW from the mains) to switch to prioritise warming the battery & cabin