Daily charging vs every few days

[ChuckieDude]

I just got on a new electric plan that gives me free electricity between midnight and 3am. 3 hours gets me about 30% so it’s not enough to charge from my usual 30% to 80%. With the virus, I am working from home so have some flexibility.

Is it worst for the long term battery health to charge more often (charge at 50%) so I can always finish under 3 hours?

Another alternative is just to charge daily which should almost always keep the times to less than 3 hours. Too bad there is not the option to stop charging at a specific time.

 

[jdw]

Shallow (more frequent) charging and discharging is better for the battery than deeper charging and discharging. Charging anywhere between 50 and 90% is fine, but longer term storage at lower SOC is better for the battery but worse for the accuracy of the battery management system - your estimated rated range will likely drift lower. This is usually recoverable and in any event, is just an estimate.

 

[Missile Toad]

I've intermittently charged two Teslas (per figure) for a year. This is a snapshot of each night for the last 6 weeks (and by night, I mean the 12 midnight on). Each row is a week, each block is an overnight charge, with the largest blocks being 25 kWh. The S70D actually has less battery degradation than expected -- maybe it has to do with me allowing the car to sit for days at 70% or less.

Bigger bars indicate bigger charges. Flat bars indicate no charge that night. Note, when I do charge, it tends to be a 30-40% increase in charge (or about 23 kWh), which is deeper than an every-night-charge. So I tend to disagree that depth of charging has adversely affected the S70D. Rather, the lowered average charge on the battery has tended to improve its resiliency.

 

[jrweiss98020]

Another alternative is just to charge daily which should almost always keep the times to less than 3 hours. Too bad there is not the option to stop charging at a specific time.

The bulk of the charging will be done earlier in the session. The charge rate drops off once the SOC hits 80% or so, so you won't be buying too much electricity at the end if it goes over 3 hours...

 

[vickh]

I just got on a new electric plan that gives me free electricity between midnight and 3am. 3 hours gets me about 30% so it’s not enough to charge from my usual 30% to 80%. With the virus, I am working from home so have some flexibility.

Is it worst for the long term battery health to charge more often (charge at 50%) so I can always finish under 3 hours?

Another alternative is just to charge daily which should almost always keep the times to less than 3 hours. Too bad there is not the option to stop charging at a specific time.

you can stop charging at a specific time, with an outlet timer.

 

[justsomeguy]

The bulk of the charging will be done earlier in the session. The charge rate drops off once the SOC hits 80% or so, so you won't be buying too much electricity at the end if it goes over 3 hours...

This might be true on older S/X vehicles that can charge at 80 amps (I don't actually know, I'd assume not though) , but any of the newer vehicles which max out at 32/48A probably won't taper until well past 90%.

 

[Missile Toad]

A contrasting view (to mine & S70D) -- more applicable to the Model 3's:

 

[jmaddr]

Wow! Very nice. What electric company is that?? I'd attempt to stay in that free time at all costs. If you get a wall charger (48A) you can get 15% per hour or 45% which is pretty close to your 50% but I don't think you need to worry. I would plug at least when you get to whatever your max hourly charge times 3 gets you to 80% and be done with it. Plugging it in more than that won't hurt and I certainly would do exactly that if we had a free tier.

 

[ChuckieDude]

Wow! Very nice. What electric company is that?? I'd attempt to stay in that free time at all costs. If you get a wall charger (48A) you can get 15% per hour or 45% which is pretty close to your 50% but I don't think you need to worry. I would plug at least when you get to whatever your max hourly charge times 3 gets you to 80% and be done with it. Plugging it in more than that won't hurt and I certainly would do exactly that if we had a free tier.

I’m in Texas and did a comparison with the last years energy usage. While the rates are slightly higher with the midnight to 3am plan, if I save $10 or more per month within the 3 hour free window then I come out ahead. Need to find more excuses to take the Tesla since it’s sort of free now!

I went with MP2 energy as they had the best rates with some free hours. Other providers had entire nights or weekends free but the base rates were a lot higher.

Tesla Energy

 

[KenC]

I know Stats, the app, can stop charging at a specific time, so maybe the solution is to get a 3rd party app.

 

[ChuckieDude]

I know Stats, the app, can stop charging at a specific time, so maybe the solution is to get a 3rd party app.

Excellent! I have been using the Stats app for a while now but didn’t know they have this functionality.

I wonder how the app stops the charging. Does it suck up battery on my phone? Has anyone tried the Stats app for this function?

 

[Nmpool]

Should I charge my M3 everyday?

 

[danarcha]

Should I charge my M3 everyday?

Yes, the manual states the M3 should be plugged in whenever possible. It is always best to keep it charged to 70%-90% depending on how much range you need to use during the day. If you have long daily commute, charge to 90% every night. If your commute is shorter, charge to 70% or 80%.

 

[Optimus_Loop]

If your concern is longevity (for ternary lithium battery), finish charging right before using that energy; in fact this could be the primary orientation of the departure mode in charge scheduling. Source: Extending Battery Lifetime by Avoiding High SOC, Chalmers University of Technology.

In other words,minimize the duration when you car stays inactive with SOC higher than 90% or lower than 20%. Were i you, i will set charge limit to 85% for daily use, charge everyday, and set the departure time no longer than 1 hour eariler than my actual departure. (Trip? 95% limit and set the departure time exact)

However you dont have to do this if your 3 are using LFP battery.(Made in Giga Shanghai China)

 

[Rocky_H]

Should I charge my M3 everyday?

"everday" as one word means ordinary, by the way.
As long as you are not running the battery really low, skipping a day or two doesn't matter. If you go two or three days of use, but the battery is only getting down to 40 or 50% before you refill it, that's still perfectly healthy for the batteries and is a little less cycles on mechanical stuff like your charge port latch. So either way is fine--charge daily or a wait a couple days--doesn't matter.

Yes, the manual states the M3 should be plugged in whenever possible.

That is to try to build habits in people, so they are not intentionally trying to run it down low all the time and get caught unable to drive somewhere because of not having enough range, or to disprove that fear some people have of thinking it's harmful having it plugged in a lot.

 

[davewill]

I'd just plug it in every night, set to start at midnight. If you can get your app to stop it at 3AM, and that fits your needs, then fine, but I wouldn't worry about it. Set to 80% is fine, but setting it to 90% might give you more flexibility against the days when 3hrs isn't enough to charge you all the way back up. There's certainly no reason to go out of your way to try and charge less often.

 

[MikeyC]

My mentality is this (someone slap my wrist if my understanding is wrong)...

When my Model 3 is in my garage, it is plugged in, period. The way I see it, there is no need for the car to be sitting next to my own L2 charger and not plugged in because if I do that, phantom drain will drain a fraction of the charge over time which counts as a partial "discharge cycle". If you keep it plugged in, any juice the car needs while not in use will come from the charger and the charge is maintained at the set level: thus avoiding a partial discharge/charge cycle.

Given this, logic dictates that leaving it plugged in when not in use will marginally reduce degradation over time.

Mike

 

[jjrandorin]

My mentality is this (someone slap my wrist if my understanding is wrong)...

When my Model 3 is in my garage, it is plugged in, period. The way I see it, there is no need for the car to be sitting next to my own L2 charger and not plugged in because if I do that, phantom drain will drain a fraction of the charge over time which counts as a partial "discharge cycle". If you keep it plugged in, any juice the car needs while not in use will come from the charger and the charge is maintained at the set level: thus avoiding a partial discharge/charge cycle.

Given this, logic dictates that leaving it plugged in when not in use will marginally reduce degradation over time.

Mike

I think thats mostly correct, with the exception of "any juice the car needs will come from the charger and is maintained at a set level". There have been some pretty darn smart people here who are pretty passionate about this type thing, and I think the conclusion is, the power in general comes from the battery (even if plugged in), then the charger refills the battery when it drops a certain amount.

I am not one of those "smart, passionate people", so dont quote me on that 100%, but its what I remember the discussion ending up with.

TL ; DR, still just fine to leave it plugged in, the car will maintain the percentage you set while going about its business, however it does that by using power from the High Voltage (HV) battery, and then requesting power to refill the battery from the wall connector.

What ISNT needed, is "running the car battery down, to charge it back up". If thats the only way one can charge, because they have no home charging or something, it is what it is, and the car wont blow up.. but its not necessary to run the car down to 20% before charging it up, like some people think it is for some reason.

 

[Nmpool]

Yes, the manual states the M3 should be plugged in whenever possible. It is always best to keep it charged to 70%-90% depending on how much range you need to use during the day. If you have long daily commute, charge to 90% every night. If your commute is shorter, charge to 70% or 80%.

Thank you for the recommendation.