Am I Charging Correctly?

[AndyEVTM3]

Hi any advice is very welcome...
I’ve Had an M3 RWD for about a week and just wanted any views on my charging regime.

I do about 150 miles per week and charge at home with a Gen 3 wall connector, I can charge at 30A as required.
My car has an LFP Battery which I understand likes to be charged at 100%

What I normally do is set the charging to start at 00:00 as I have economy 7 tariff.
The car is normally finished charging at about 4 in the morning.

As I have retired I don’t set any time for the charge to complete or precondition as I don’t go out at a regular time.

I then drive the car when required.

Question is is this the correct procedure, and should I leave the car plugged in all the time even if it doesn’t need charging? And do it every day?
What about driving after charging in the cold weather?

Thanks fo any comments.

 

[NewbieT]

Sounds fine to me. Tesla advise to leave plugged in all of the time, but I don’t bother if I don’t need to charge.

If you don’t normally use all 7h maybe set it to be finished by 7:00am. When charging, the battery is warmed. If it finishes at 7:00 it might still have some heat in it when you do your first drive = increased efficiency and range.

 

[Stranger Dings]

Yep. You’re all good.

Drive it, plug it in when at home. Job done. It really is that simple.

 

[GeorgeSymonds]

I don’t have an LFP battery but I doubt it would change what I do, I charge once or twice a week and keep the car anywhere between 40% and 90% (100% for your LFP). Don’t be a slave to it. If it’s more convenient for you to plug in every time then by all means do so, but if it’s awkward then don’t worry about it every day. They’re simply not as brittle as some would make you think.

 

[Jason71]

Battery does NOT like to be charged to 100%. Tesla tell you to do it to calibrate the BMS which is harder to do on LFP. But it is still bad for the battery. If you must then charge to 100% just before departure once a week. Do not leave on 100% all night if you value the long term health of your battery. There are other threads on this if you search.

 

[a1psx]

Yep, carry on. Car will be at 100% every time you need it.

 

[Rangefright]

Battery does NOT like to be charged to 100%. Tesla tell you to do it to calibrate the BMS which is harder to do on LFP. But it is still bad for the battery. If you must then charge to 100% just before departure once a week. Do not leave on 100% all night if you value the long term health of your battery. There are other threads on this if you search.

From the Tesla manual

CAUTION
Tesla strongly recommends leaving Model Y plugged in when not in use. This maintains the Battery at the optimum level of charge.

Note
For vehicles with Lithium Iron Phosphate (LFP) high voltage Batteries, Tesla recommends you keep your charge limit to 100%, even for daily use, and that you also fully charge your vehicle to 100% at least once per week. To determine if you vehicle is equipped with an LFP battery, navigate to Controls > Software > Additional Vehicle Information. If your vehicle has an LFP Battery, "High Voltage Battery type: Lithium Iron Phosphate" is listed. If your vehicle does not have an LFP Battery, the high voltage Battery type is not specified. See Lithium Iron Phosphate Batteries for more information.


Follow Internet influencers if you so desire.

 

[AndyEVTM3]

Note
For vehicles with Lithium Iron Phosphate (LFP) high voltage Batteries, Tesla recommends you keep your charge limit to 100%, even for daily use,

This is also in the Model 3 handbook.
For something under warranty it seems sensible to follow the manufacturers guidance?..

“Follow Internet influencers if you so desire.” ...No I don’t.

I think I’ll only deviate from this when Tesla tell me too.

Thanks all for the comments

 

[DJP31]

I would only add one thing to consider, and it's nothing to do with charging, but related to preconditioning the car before leaving on a journey. This has to be one of the best features of an EV, and I'm sure we've all had smug faces of late as the car does its thing and the neighbour is hacking away at the ICE

Whilst plugged in the car will draw power from the wall when preconditioning, so you would be using expensive non economy 7 electricity. You could unplug the car e.g. 15 mins before leaving and then start the preconditioning. I am not sad enough to try and calculate what this might save in a year, but I mention it for what it's worth - which might be £1 for all I know

 

[Jason71]

From the Tesla manual

CAUTION
Tesla strongly recommends leaving Model Y plugged in when not in use. This maintains the Battery at the optimum level of charge.

Note
For vehicles with Lithium Iron Phosphate (LFP) high voltage Batteries, Tesla recommends you keep your charge limit to 100%, even for daily use, and that you also fully charge your vehicle to 100% at least once per week. To determine if you vehicle is equipped with an LFP battery, navigate to Controls > Software > Additional Vehicle Information. If your vehicle has an LFP Battery, "High Voltage Battery type: Lithium Iron Phosphate" is listed. If your vehicle does not have an LFP Battery, the high voltage Battery type is not specified. See Lithium Iron Phosphate Batteries for more information.


Follow Internet influencers if you so desire.

I know what the manual says. I didn't say don't charge to 100% I said I would not recommend leaving it at 100% for extended periods.
That is not in conflict with what the manual says and is in accordance with everything we know about lithium batteries of all chemistries including LFP.
Maybe it won't make enough of a difference over the life of the car to be worthwhile. Only time will tell. Just trying to give the Op all the facts.

I don't really use social media so not sure about the final reference.

 

[AndyEVTM3]

You could unplug the car e.g. 15 mins before leaving and then start the preconditioning. I am not sad enough to try and calculate what this might save in a year, but I mention it for what it's worth - which might be £1 for all I know

Thanks, this is the “defrost car” button on the phone app?
Have been using this to wind up the neighbours

 

[Jason71]

I would only add one thing to consider, and it's nothing to do with charging, but related to preconditioning the car before leaving on a journey. This has to be one of the best features of an EV, and I'm sure we've all had smug faces of late as the car does its thing and the neighbour is hacking away at the ICE

Whilst plugged in the car will draw power from the wall when preconditioning, so you would be using expensive non economy 7 electricity. You could unplug the car e.g. 15 mins before leaving and then start the preconditioning. I am not sad enough to try and calculate what this might save in a year, but I mention it for what it's worth - which might be £1 for all I know

It could be £1 per day depending on how long you precondition for given the difference between day and night rates can be 30p+ at the moment

 

[DJP31]

Thanks, this is the “defrost car” button on the phone app?
Have been using this to wind up the neighbours

Yes, you can use that which fires max heat to the screen and car. I must admit I've tended just to turn the climate on via the app as that is slightly more gental - I have read of a few windscrens seemingly just cracking. I suspect that's me just being overly cautious but given the difficulty in getting parts for Tesla's I'm afraid I try to minimise risk whereever I can, (within reason)

 

[Buzzliteyear]

Do what is best for you, the car won't overcharge if you leave it plugged in. Just don't leave it at the opposite extreme (less than 10%), driving close to 0% isn't a problem if your traveling towards a charger.

 

[MrBadger]

Whilst plugged in the car will draw power from the wall when preconditioning, so you would be using expensive non economy 7 electricity. You could unplug the car e.g. 15 mins before leaving and then start the preconditioning. I am not sad enough to try and calculate what this might save in a year, but I mention it for what it's worth - which might be £1 for all I know

It could be £1 per day depending on how long you precondition for given the difference between day and night rates can be 30p+ at the moment

As point of reference, we consumed just over 3kWh of energy preconditioning the car last Thursday. So thats (3 * 31p = 93p) vs (3 x 7.5p = 22.5p), a saving of 70p had I not unplugged from shore power the night before - would have been pretty much impossible on the day as everything was frozen.

However, in addition to the cost, there is also the likelihood of a higher carbon emissions cost to charging at morning peak. As it happened, the time that I preconditioned and the time that the majority of the electricity that was added to the battery several days earlier was pretty much identically on the high side, so that precondition would have been pretty dirty carbon intensity wise irrespective of whether it cam from battery or shore power, but in general, peak times (AM and PM) generally have more reliance on dirtier sources of electricity. Today is a pretty good time to charge the car if needed, carbon wise - less than half the typical impact of last week. Carbon Intensity

 

[Rangefright]

The reference to internet influencers was my own experience in the months I spent reading whilst waiting for my car to arrive and seeing much conflicting advice. What is interesting is that I cannot find any Tesla advice of what they recommend to be the ideal set point for nonFLP batteries.

 

[GeorgeSymonds]

The reference to internet influencers was my own experience in the months I spent reading whilst waiting for my car to arrive and seeing much conflicting advice. What is interesting is that I cannot find any Tesla advice of what they recommend to be the ideal set point for nonFLP batteries.

The only consistent thing on non LFP is < 100%, the car will also complain if you charge to above 90% a couple of times in a row

To add a 3rd party internet view, and explains some of the contradition with LFP

The Puzzling Reason Why Tesla Misleadingly Recommends Charging the LFP Batteries to 100%

When Tesla started deliveries of the Model 3 RWD with lithium ferrophosphate (LFP) batteries, it made a strange recommendation on its website and in the ...

www.autoevolution.com

 

[WannabeOwner]

I am not sad enough to try and calculate what this might save in a year, but I mention it for what it's worth

If you sit down to calculate it over Yuletide then your sums could also include the reduction on the number of cycles on the battery (compared to setting off and THEN warm the car). Heat car after setting off also uses, say, 10% more energy - the loss from inefficiency of Charge-Battery plus use-from-battery.

Could you also help me with how I can get into the habit of turning Climate On when I pay the bill in the restaurant ... rather than when I get in the car? Asking for a friend wife ...

should I leave the car plugged in all the time even if it doesn’t need charging?

My only thought is if you are in the habit of always plugging in you won't get into a situation where you want to go somewhere (planned, or not) only to find you forgot to plug in and ain't got enough juice, and need to add stop time for a rapid charger on your journey.

If the car just sits there once in a while the battery will fall enough percentage points that the overnight charge will top it back up again

 

[AndyEVTM3]

Just one further simple question...

If the car is plugged in but outside scheduled charging times, can it still draw electricity from the house to do updates or whatever mysterious things it wants to do when it’s parked. Or does it have to use the battery as the charger is stopped?

I.e. is the supply from the house always available and the “priority” source of supply for the car.

Apologies if this has already been explained.

 

[MrBadger]

If the car is plugged in but outside scheduled charging times, can it still draw electricity from the house to do updates or whatever mysterious things it wants to do when it’s parked. Or does it have to use the battery as the charger is stopped?

If its plugged in, it will take power from grid, unless the charge point/wall connector is set to not supply electricity/turned off. Charge time built into car has no effect on limiting when car will draw power from the grid. Its only to tell car when to charge its battery. ie. You go sit in the car and its plugged into mains electricity, it will start drawing power from grid to heat/cool the car.

So yes, grid is priority source. Personally, I wish there was an option, so those that need the range can choose to get it from mains as now, those that don't need range, can choose to get it from battery, lose a bit of range, but can chose if they want the impact of drawing from grid etc.