How many go full send when charging at home?

[BCondrey]

I don't have any TOU advantages, Virginia Dominion Power doesn't have a good deal for this. I charge at night so that my wife can charge her Tesla during the day / evening. Don't want to have both charging at the same time.

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[docwhiz]

Years ago I read a study on charging efficiency for the Tesla.
Turns out charging at 30 to 35 amps is most efficient. Above that, heat in the wires, battery, and charging system reduced efficiency.
Since then, I've usually set my home charging to 32 amps which is plenty fast for overnight charging.

 

[Deleted member 26425]

I have a Tesla wall charger and charge at 48A (to 70%) whenever my R1T is home. Tesla recommended keeping the vehicle plugged in to reduce strain on the low voltage battery so I adopted the same strategy with the Rivian.

 

[TexasBob]

Both of our chargers are rated at 32A (Rivian mobile and a 2011 aerovironment from when the Leaf was first introduced). I have never found a need to upgrade the units even though the are both on dedicated 50A circuits. That said, I plug in whenever I get home. No TOU so I set to 70% and forget it.

 

[2kwik4u]

Can you go into the energy tab on your Rivian infotainment with your mobile connector plugged in and manually adjust the amperage?

I am pretty sure I did that like 1.5 years ago when we went camping and all I had was a slow 110 volt outlet. I think I took the amperage down to 10 amps.

Edit: I would only do this in a one off situation where you need to pull down less.

Normally, I leave it at stock 48 amps and let it pull what it can pull from my home charging station.

I know that setting exists, but I've never messed with it. Mobile charger pulls 32A, and I have my 14-50 outlet setup as a full 50A circuit (so it can pull a constant 40A). Since the 32A is another 20% derate, I don't worry about it at all.

 

[carsly]

Charge nightly (or every few days in warmer weather) to 70% to take advantage of off-peak rates. I typically charge at 32 amps on my garage connection which is similarly a 50 amp sub-panel and I'm on a 40 amp breaker. I also have a hardwired charger attached to the house on a 60 amp breaker so could charge at 48 amps if/when needed but 99% of the time any vehicle attached to that charger is also charging at 32 amps off-peak.

My electrical inspector recommended capping charge rate at 32 amps regardless of wiring and EVSE capability to minimize heat build-up in the panel. I have a 200 amp main panel for the house. As 32 amps is more than sufficient for my needs, that's where it's at, no need or desire to push thermals on my electrical panels.

 

[JamuJoe]

Curiosity got the best of me, and I'm wondering what some people's charging habits are.

I have had my Rivian for one year, and I have a detached garage that has a 50amp sub panel in it. Because I also have a 30 gallon vertical compressor in there that could draw 15 amps, I opted to put in a nema 14-50r that's on a 40 amp breaker, and configured my grizzl-e to max 32amp out put.

However for the most part, I think I only used the 32 amp output on a handful of occasions. Because I have set electric rates, I just plug in when I get home at night and I find myself lowering the charge output on my dash to between 16-22 amps. This allows my car to charged from 50% to 70% in 6-8 hours which is plenty for me. I guess in my head limiting the charging rate also gives me a lot more more peace of mind that nothing is going to melt. I just rarely full send it.

I guess if you have time of use or some type of variable utility rate then going with the 60 amp setup would make sense. But I'm curious on everyone else charging habits. Am I a outlier? Who goes full send all the time?

With rooftop solar and net metering, it behoves me to charge our two EVs when my solar production exceeds my household consumption. This means midday. Fortunately, I am retired and don’t commute to a job, so I have this option.

 

[ddujnad]

We have an Emporia charger plugged into a 14-50 outlet in our garage. We have 2 EVs and are basically charging one of them every night. I derate to 32 amps because that’s plenty of juice to get the R1 to 70% or our MachE to 90% overnight, and it reduces the risk of a meltdown until I get the charger hard-wired. If I need a faster charge for some reason, I’ll up the amps to 48 temporarily.

 

[DayTripping]

What is shocking reading through this thread is how many people are charging to such a high SoC (state of charge). The hotter the climate you live in, the less tolerant Lithium batteries are of high SoC.

There is a reason I set my resting charge rate at 50%, and that is to allow more heat tolerance in the summertime. If you are in a cold climate, it doesn't matter as much. Lithium batteries tolerate much higher SoC when cold.

Just because you don't see degradation on your truck yet doesn't mean it isn't there. It is there, most likely just covered up by the buffer. Basically keep your charge level between 30-70% to minimize degradation. The longer it is at a higher SoC, and in higher temps (80F+) the faster it will degrade.

Here is a great vid if you are interested in making your battery last with minimal degradation. It is done by Dr. Jeff Dahn. His research was funded by Tesla. Here is a brief bio for him.

"Jeff Dahn is recognized as one of the pioneering developers of the lithium-ion battery that is now used worldwide in laptop computers, cell-phones and electric vehicles. Dahn's recent work has concentrated on increasing the energy density, improving the lifetime and lowering the cost of lithium-ion batteries. He is the author of over 820 refereed journal papers and co-inventor of 78 inventions with patents issued or filed."

About 42:49 into the video is a good summary but worth a watch overall as well as some of his Q&A vids on YT.



I've been following a similar protocol as mentioned earlier for several years now, and it has resulted in minimal degradation. This has allowed my Teslas to maintain almost their entire rated range 3+ years into ownership. They didn't have a large buffer like the Rivian does.

 

[carsly]

What is shocking reading through this thread is how many people are charging to such a high SoC (state of charge). The hotter the climate you live in, the less tolerant Lithium batteries are of high SoC.

There is a reason I set my resting charge rate at 50%, and that is to allow more heat tolerance in the summertime. If you are in a cold climate, it doesn't matter as much. Lithium batteries tolerate much higher SoC when cold.

Just because you don't see degradation on your truck yet doesn't mean it isn't there. It is there, most likely just covered up by the buffer. Basically keep your charge level between 30-70% to minimize degradation. The longer it is at a higher SoC, and in higher temps (80F+) the faster it will degrade.

Here is a great vid if you are interested in making your battery last with minimal degradation. It is done by Dr. Jeff Dahn. His research was funded by Tesla. Here is a brief bio for him.

"Jeff Dahn is recognized as one of the pioneering developers of the lithium-ion battery that is now used worldwide in laptop computers, cell-phones and electric vehicles. Dahn's recent work has concentrated on increasing the energy density, improving the lifetime and lowering the cost of lithium-ion batteries. He is the author of over 820 refereed journal papers and co-inventor of 78 inventions with patents issued or filed."

About 42:49 into the video is a good summary but worth a watch overall as well as some of his Q&A vids on YT.



I've been following a similar protocol as mentioned earlier for several years now, and it has resulted in minimal degradation. This has allowed my Teslas to maintain almost their entire rated range 3+ years into ownership. They didn't have a large buffer like the Rivian does.

tis true. My Cybertruck is set to daily charge to 70% and only charge at the end of my off-peak window (e.g, early in the AM). So charge level is typically sitting somewhere between 50-65% overnight before ramping up to 70% just before I unplug and go for the day. In nicer weather I still regularly average over 3 mi/kwh on 35" all terrains for real-world range of 350+ miles, well above rated EPA range. I'm at a year post-purchase.

 

[hammick]

We have two 48 amp chargers. One has wiring to give the full 48a and the other wiring only allows 24a. Our lightning powers our house daily so it gets the 48a charger. R1S is a commuter of about 25 miles daily so gets the 24a. R1S is our road tripper so will get the 48a charger the night before a trip.

 

[Trinculo73]

Currently I have my charge limit set to 70%, and only plug in every couple of days or so. I also have an Emporia charger connected to WeaveGrid which manages the charger. When I plug in, it texts me in case I want to charge immediately vs charging overnight to match my ToU rate plan. I've never bothered detrating my charge amperage tho, since it's level 2 - it's convenient to have it charge "quickly" if I'm plugging in during the day, and if it's overnight I don't care in the slightest.

 

[Mark_AZR1T]

Who did your solar? I’m in Az as well

Tesla with multiple Powerwall's. It was absolutely the best solution for us.

 

[Zoidz]

I can lock in the charge rate of my OpenEVSE via its app. I charge at 38 amps to reduce heat and improve efficiency unless I have a short charging window. We don't have TOD available in our area. In the winter I typically charge to 70%. In the summer I have been charging to 60% to 65% .

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