Level 2 Charging Best Practices?

[John Becker]

A separate thread touched on this topic, but I want to expand on it.

I’m more interested in minimizing kWh expense than maximizing battery life. (My battery will likely last, IDK, 30 years and outlive me.)

To that end, I’ve learned from this forum that it is most efficient to charge at the highest rate that your Electric Vehicle Supply Equipment (EVSE) is capable of. Additionally, Always Be Charging (ABC) is best for battery health but not for minimizing charging cost.

Am I wrong about any of that?

Therefore, what is the best charging practice for minimizing cost without unduly shortening battery life? For example, is it best to let the battery charge percentage drop down to, say, 30 percent and then charge it to, say, 90 percent?

What say you? (Educated guesses and gut feelings based on research are acceptable.)

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[Warren]

This has been covered in other threads. I believe the consensus was that smaller charges are better than larger ones. Not sure about coat efficiency, but mY hunch is it is better to stop at 80 to 85 percent rather than go to 100.

 

[jamelski]

Www.google.com

Then type your question. Google is your friend
Or even use the search function at top of this website and type your question.

Then Read

 

[Mach Turtle]

It appears that you've successfully applied the first rule: Don't live in places with outlandishly high electricity costs, or if you do, go solar. (Our rates are about double yours, you lucky people.)

More seriously: Do you park your thunder buggy indoors or out? I would expect based on limited research (lotta reading) that the extra charging cost of ABC is mostly due to battery heating when parked outdoors or in a completely uninsulated garage, shed, barn, etc. If indoors, it's less of a concern.

 

[Pioneer74]

A separate thread touched on this topic, but I want to expand on it.

I’m more interested in minimizing kWh expense than maximizing battery life. (My battery will likely last, IDK, 30 years and outlive me.)

To that end, I’ve learned from this forum that it is most efficient to charge at the highest rate that your Electric Vehicle Supply Equipment (EVSE) is capable of. Additionally, Always Be Charging (ABC) is best for battery health but not for minimizing charging cost.

Am I wrong about any of that?

Therefore, what is the best charging practice for minimizing cost without unduly shortening battery life? For example, is it best to let the battery charge percentage drop down to, say, 30 percent and then charge it to, say, 90 percent?

What say you? (Educated guesses and gut feelings based on research are acceptable.)

ABC

Plug in every day. Charge at your highest rate possible. 80% to 90% max daily unless full range needed.

I charge to 85% daily. I have a commute that uses about 40% a day. I plug in every night.

 

[Runaway Tractor]

You are vastly overthinking this. If you live in a normal place where the cost of electricity doesn't change based on the time of day, this is a completely pointless mental exercise. The electricity costs the same regardless of how slow, how fast, or how long you charge. Quit the mental gymnastics and just set the charge limit for what works best for your day. 80-85% is the usual and will probably be fine for you too. Example: electricity here is about $0.10/kWh. I use 60kWh on my daily round trip commute. Recharging will cost me $6 to recharge. It doesn't matter if charge fast, slow, morning, evening, night, whatever. 60kWh is 60kWh.

If you live in an area where electricity costs more during peak hours, like in the People's Republik of Kalifornia for example, then all you need to do is program everything to only charge during the off-peak billing hours.

If you're trying to figure out if there is more or less "waste" energy lost to heat during various stages of level 2 charging, the answer is no. None you will notice anyway.

 

[Firn]

There is a certain overhead with charging so yes, charging at a higher rate should reduce costs to some extent. The coolant pumps and other stuff run so charging at L1 loses about a third the energy to cooling, charging at 80a would lose a tiny percentage.

There is very little overhead with initiating a charge so there should be very little extra cost associated with charging daily or ABC. I don't see any benefits to charging in larger amounts (say 20% to 90%)

Charging inside should be more efficient as there should be no need for heating of the battery (more energy lost). To the same end charging at ideal temps should help, i don't know if the battery cools if charging when hot, but it does heat. So if you charge when it's at the golden temps (battery temp AND external temp) it should help.

 

[B177y]

This thread on the Mach-e forum may answer the charging efficiency question for you:

https://www.macheforum.com/site/threads/onboard-charger-efficiency-measured.32983/

He graphed the efficiency of the MME level 2 charging at different amperages. Basically anything over 16 amps with a 240-volt level 2 charger was close to the same efficiency. I would assume that the Lightning has a similar efficiency curve.

 

[John Becker]

If you're trying to figure out if there is more or less "waste" energy lost to heat during various stages of level 2 charging, the answer is no. None you will notice anyway.

Yes. That is what I'm exploring.

 

[John Becker]

This thread on the Mach-e forum may answer the charging efficiency question for you:

https://www.macheforum.com/site/threads/onboard-charger-efficiency-measured.32983/

He graphed the efficiency of the MME level 2 charging at different amperages. Basically anything over 16 amps with a 240-volt level 2 charger was close to the same efficiency. I would assume that the Lightning has a similar efficiency curve.

Thank you! That is very helpful.

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