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Tesla Charging Question

Apologies if this has been asked but I have read the manual and it’s not clear. I have a Model Y which I am picking up in 9 days time and I already have a Tesla Wall Connector installed at my property. My questions are:

- If I set set a time to charge using the car software, such as 0000-0430am. Will the car still draw electric outside those time to run accessories to warm the battery etc. It says in the manual that when plugged in, the car will use the incoming power first over the battery.

- If I set the Wall Connector to charge only at certain times, is it smart enough that the car tells it that it needs juice outside of these times to run the accessories etc.

I’ve probably confused everyone now but I’m just wondering if you really can just plug a Tesla in and leave it. I am away a lot so would like the peace of mind that the car will look after itself in my absence. Appreciate any replies.
 
As far as I can recall, you can set a start time but not an end time on the car. I cant speak for the twc but would say no. It's normally just a on/off timer. If you have access to the charger over the internet you could monitor form time to time and turn it on and off but if its set to charge from 00:30 to 04:30 every day then there is really nothing to worry about as it will top up as it needs it within the slot.
 
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Chris CG

Member
Mar 13, 2021
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You can only set a start time via the app (it’s a PITA and stupid IMHO), so if you need it to stop by a particular time and can’t set it on the charger you need to work out how much charge you’ll get in the 4hrs slot (assuming you’re on Octopus GO) and set the charge limit in the car to that. I had to do this when Anderson went bust and my A2 became a dumb charger for a while when it lost connection to the servers (long story - but it’s working how it should again now).

As for the 2nd point - I have an Anderson A2 (as said above) and set a charging schedule to match with my Octopus Go hours (00:30 to 04:30) so the charger itself doesn’t provide any electricity out of this time slot even if the car asks for it - I would assume the Tesla Wall Charger is the same but who knows with Elon and his little quirks!
 

Drew57

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Apr 4, 2020
1,626
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@Morpheus84 - Tesla via the car or the app only give options to schedule starting a charge or a departure time not both. If this is the case for you then use the scheduled charge start time only and restrict the end SOC required to ensure charging doesn't fall into the tariff peak period.

Using your example 00.30-04.30, a 4 hour period on a 7kWh wall charger will add approximately 10% per hour.

eg:
  • If the car starts at 50% and you want to fill to 90%, starting at 00.30 then charging will stop around 04.30 and the car will hit the 90% target.
  • If the car starts at a lower SOC (eg) 30% and you still want to fill to 90% it will only achieve 70% at the lower tariff but will continue for approx 2 hours more at peak rate until it reaches 90%
  • Alternatively, using this 30% initial SOC example set the target SOC to only 70% to ensure all charging falls within the low tariff period.
Most other 'smart' chargers don't require this work around so we can set both a start and end time with whatever SOC we might need. Tesla make things more complicated than they need to be.
 
- If I set the Wall Connector to charge only at certain times, is it smart enough that the car tells it that it needs juice outside of these times to run the accessories etc.

No, the TWC will only provide power in the schedule that you set, with the exception that if it loses WiFi connectivity it reverts to being a "dumb" charger and will provide any power that the car asks for.

It's also worth noting that it seems to switch summer/winter time on the US dates rather than UK dates, so for a few weeks of the year it might be out of step with your off peak period (I recently found mine would not provide power for the first hour of my off peak and then would provide power for an hour after it finished when the clocks changed).
 
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Drew57

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It must be deliberate how Tesla make things more difficult than with any other brand.
  • For car charging in our little cul-de-sac there are 3 Zappis, a Hypervolt and a Pod Point. All of us can set start-stop schedules whenever required with no requirement to do anything with the cars or the Tesla app (two of us with Teslas). The Zappi also permits 100% solar for charging or any % mix with grid power. A Tesla charger does not have any of this flexibility.
  • Two houses with solar/batteries, one with only batteries. All of us are able to set charge times to either use solar generation or schedule whenever is required including during low cost overnight periods. All can set block discharge timings to stop overnight car charges depleting the house battery SOC.... drawing only from grid if/when required. A Tesla Powerwall does not have this flexibility 365-24/7 without some manual intervention.
Other products seem perfectly able to always deliver exactly what is required to suit the customer, not so with Tesla.
 
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All can set block discharge timings to stop overnight car charges depleting the house battery SOC.... drawing only from grid if/when required. A Tesla Powerwall does not have this flexibility 365-24/7 without some manual intervention.

Not so, my PW doesn't discharge during off-peak unless the grid goes off - so with my car set to charge during that time the battery is not depleted.

Presently it will charge the car from excess solar, but only when the grid is off which is annoying. Broadly speaking I would say that the integration between the car, Powerwall and Wall Connector is woeful, though - if the grid goes down during off peak then the car will charge from the PW and deplete it, for example.
 
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The TWC is quite basic at present, you can set a time window when it will deliver power and that’s about it. The car can do either start time and desired %, or end time and scheduled departure, which is great for daily commuters but annoying if you just want to make the most is off peak tariff. (which the TWC does well)

it’s currently a pain to set up the TWC as you have to join it’s Wi-Fi hotspot and then edit the time window, on mine I often need to restart It in order to see the settings page. Tesla did just send a questionnaire about it, so hopefully theyll improve it with some updates soon. Having said that, for my use case the time window is a set and forget, as of yet I haven’t needed to do an emergency charge🤞
 

WannabeOwner

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Nov 2, 2015
7,266
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To stop charging at end of off peak you'd have to set the Charge Limit to what you would expect it to reach as already mentioned

if you need it to stop by a particular time and can’t set it on the charger you need to work out how much charge you’ll get in the 4hrs slot

So if, for example, you came home "empty" you'd need a couple of nights to fully replenish (and faffing changing LIMIT each day). My daughter uses that approach, and has on more than one occasion forgotten to further raise the limit on the second night and then not had enough for a longer journey some days later!

I think having a Wall Charger that lets you adjust stuff is cart-before-horse. We have 2x EV and 2x Chargers (Tesla and Zappi). I got the Zappi as we were extending the PV and assumed "Zappi will toggle to Car when PowerWall is full". Well, yes it does do that, but my PV generates 15kW max and car can only charge at 7kW so a) I need a more sophisticated method and b) a lot depends which charger which EV is plugged into and which EV is "going somewhere" next ... 'coz that's the one I need to prioritise, and I definitely don't plug same-car into same-charger each time.

Basically my view is that the car should control everything, and not the charger. Sure that would require something to tell the car to start charging when PV generation is "sufficient" / House Battery is full / whatever. Plenty of open APIs which make all that possible. The charger being "off" to stop the car charging (e.g. during Peak) means the car can't get any juice from Grid for pre-condition so uses up battery for that instead, and thus less battery available for a long journey.

I use TeslaFi (3rd party APP that logs data and has scheduler) to turn off charging at the end of Off Peak, so I can just leave the car's LIMIT at, say, 90%. The car is set to start charging at start of Off Peak rate (which has the benefit that if internet is down / whatever the car will always start charging on time - note that includes coming home late after a really good night out! the car will still start charging, I'm not sure how much leaway it allows). TeslaFi also allows me to do things like get an alert if it isn't plugged in, and to set up a precondition before a trip (charge to 100% and hour before departure, turn on climate 15 minutes before ... and turn off Climate 15 minutes after - in case we don't actually leave!)

There are alternatives to TeslaFi (things like TeslaMate), depending on how geeky you are :) you can even just roll your own if you fancy that (or are concerned about security)

If you can get a referral code from someone for TeslaFi the Trial is extended from 2 weeks to a month (if you don't have a better offer you can use my handle here)
 

GeorgeSymonds

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Mar 16, 2018
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There are quite a few after market solutions, some of which are free, but the Tesla built in way is the worst. You can schedule a start, or end, but not both. If you want the car ready in the morning, I'd just schedule it to start when the cheap stuff kicks in, and if it over runs the end of the cheap rate its not the end of the world and better to have charge in the car when you need it than an extra £1 in your wallet

I dabbled with the free tesla-info approach and it worked by creating stop and start shortcuts on my iphone and then using the iphone to schedukle when they ran. I didn't go ahead with off peak charging in the end (complications of smart meters) so I didn't bother taking it any further back then.

There's also homeassitant that works with Teslamate but much geekier to set up from what I've read, but very flexible if you do

I think octopus energy also have a solution, there's a whole thread on the topic somewhere, which is linked to one or more of their tariffs

The warning I feel I always need to give, and this isn't meant to put you off, is that with any 3rd party solution you give your Tesla credentials or token to, you need to understand that you're effectively giving them your cars keys and the ability to locate your car. The risk is somewhere around extremely low that anything bad might happen, but you need to be aware, and if they're compromised, so are you. It's easy to cancel the tokens, just change your Tesla password assuming you suspect something funny happening.
 
The warning I feel I always need to give, and this isn't meant to put you off, is that with any 3rd party solution you give your Tesla credentials or token to, you need to understand that you're effectively giving them your cars keys and the ability to locate your car. The risk is somewhere around extremely low that anything bad might happen, but you need to be aware, and if they're compromised, so are you. It's easy to cancel the tokens, just change your Tesla password assuming you suspect something funny happening.
This. So much this. When I receive my car I won’t be using any third party application or service that communicates with the car. Tesla-made only for me!

I could be rather paranoid, but the experience seems to be good enough without the third party stuff. Even intelligent octopus scares me!

Even if it uses tokens that are scoped to specific activities such as charging, I’d still personally rather not risk it! But then I’m the sort who’d never do anything on a vanilla public Wi-Fi hotspot either.

Quick edit: yes even the centralised Tesla infrastructure/dbs worry me, in the same way all my personal info being stored somewhere worries me (eg bank accounts). All about mitigating risk rather than totally eliminating!
 

WannabeOwner

Well-Known Member
Nov 2, 2015
7,266
4,022
Suffolk, UK
I could be rather paranoid, but the experience seems to be good enough without the third party stuff.

I think you are overly paranoid, not that that is a bad thing, but there are benefits to consider. CCTV like "Ring", Smart Fridges, all sorts of stuff is a risk, some more than others of course, so users are going to need to learn to protect themselves

it depends what the 3rd party stuff does, but for me the amount of data logging I get from TeslaFi I find very useful - but for disclosure I'm a data-geek.

I use the scheduler to do all sorts of stuff that Tesla-native doesn't do - stop charging when Off Peak ends; make sure at max-AMPs when charging starts (in case I have manually lowered it); Charge car to 100% an hour before a "trip", and put climate on 15 minutes before - and turn it off 15 minutes after if we don't actually depart! Remind me if SOC is low and I have not plugged in ... and so on - all things I am prone to forgetting to do "manually".

When I used to commute the charger at work was dodgy and sometimes tripped, so I had an alert in the schedule "If AT WORK and SOC is less than X%" - at various times during the day. Otherwise at 17:30 departure I'd find I didn't have enough charge to get home. Coupled with turning on the Climage before departure for Work - and again before departure for Home - and turn if off after 20 minutes if "departure" didn't actually happen - e.g. on a Bank Holiday!.

The logged data is initially interesting, that wanes ... but I still use it on occasion for business expenses / curiosity (When exactly did I go to X and what was the mileage). Things like battery degradation over time are interesting, and may actually be beneficial if I make a private sale and want to prove / reassure to buyer. But "Spouse seems be parked outside THAT house often on his way home from work" could be detrimental!!

For me the benefit far outweighs the potential risk, and of course a single security breach for a vendor, of the APPs that I use, would be terminal for their business model - so they are incentivised to do a good job (not a great look for Tesla either, so both should be attempting best-of-breed [separate debates as to whether the AUTH that Tesla uses could be bettered vs. it being "good enough"]

For frivolous? here's the TeslaFi where-have-I-been heatmap

tesla02.gif
 

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