How to precondition battery before morning commute

[pdx_m3s]

I have a short morning commute (5 miles) and rarely does my battery get up to the temperature required for full regen capacity (the regen dots are always there in the morning... and it's summer).

What is the best way to ensure the battery is preconditioned/heated before unplugging and heading out for work?

- Remote Cabin HVAC?
- "Turn On" feature?
- Timing charging via the scheduled charging feature so it finishes near a particular time?

I would really love a "finish charging by [time]" feature, which would ensure the battery is up to temp by a set time.

 

[Rocky_H]

Timing charging via the scheduled charging feature so it finishes near a particular time?

That's about the only thing that's useful. Charging with some significant amps, like 30+ will build some heat in the battery pack. And since you need to charge at some point anyway, it's not just wasting energy. It's about the one thing that's most helpful.

But really, I think too many people are beyond obsessed about having FULL REGEN.

 

[pdx_m3s]

That's about the only thing that's useful. Charging with some significant amps, like 30+ will build some heat in the battery pack. And since you need to charge at some point anyway, it's not just wasting energy. It's about the one thing that's most helpful.

But really, I think too many people are beyond obsessed about having FULL REGEN.

Honestly, it's more about ensuring the battery is at optimal operating temp from a longevity stance, not necessarily regen ability. OCD, I know.

 

[Rocky_H]

Honestly, it's more about ensuring the battery is at optimal operating temp from a longevity stance, not necessarily regen ability. OCD, I know.

Oh really? You want to go there? Then I'm going to talk about heat cycling. The more moves of hot/cold/hot/cold electronics has to do, and the farther apart those moves are, creates more physical materials stress and stresses on solder joints as different metals expand and contract at different rates. So if you have a short 5 mile commute, where it doesn't have a chance to warm up much, then that is a blessing that it doesn't get much of a chance to temperature shift much in your daily use.

 

[pdx_m3s]

Oh really? You want to go there? Then I'm going to talk about heat cycling. The more moves of hot/cold/hot/cold electronics has to do, and the farther apart those moves are, creates more physical materials stress and stresses on solder joints as different metals expand and contract at different rates. So if you have a short 5 mile commute, where it doesn't have a chance to warm up much, then that is a blessing that it doesn't get much of a chance to temperature shift much in your daily use.

You sound like a fun person.

The same could be achieved (reduction of heat cycling) by timing charging to finish at or around morning commute time. The battery heats up while charging, and if I could save it from cooling down when it finishes charging and then attempting to heat back up while commuting in the morning, then there is one less heat cycle, if that makes sense.

 

[Rottenapplr]

You sound like a fun person.

Lol I needed the laugh.

 

[TexasEV]

There’s no need to even think about the battery. Let the battery management system manage the battery and just enjoy your car.

 

[bpjones]

Hey @pdx_m3s, if you’re an iPhone user, the iOS app Stats App has the feature you’re looking for.

 

[pdx_m3s]

Hey @pdx_m3s, if you’re an iPhone user, the iOS app Stats App has the feature you’re looking for.

Thanks! I built a quick Google Sheet that calculates charge start time based on target charge % and what time you'd like it to finish charging by. I can access it from my iPhone home screen in a couple seconds.

 

[AlanSubie4Life]

have a short morning commute (5 miles) and rarely does my battery get up to the temperature required for full regen capacity (the regen dots are always there in the morning... and it's summer).

What charge level do you have set? Since you have a very short commute, I would recommend something like a 70% charge level for typical days, if it works for you, as that should reduce the amount of regen dots. The regen dots are a function of both the state of charge and the temperature. (In summer, you may even be able to set a somewhat higher percentage, depending on temperature...you'll just have to experiment.)

Obviously, if it is chilly enough (in my experience, you start to have problems in the 50s - even warmer if you use 90% for your SoC), and you park outside, then you may have problems regardless, and then the timed charging is the way to go (the only downside is a little less flexibility if you have an unexpected long second trip during the day that you can't plan for).

The other thing (if it's an option for you), is to park your car inside the garage at night. Helps a lot, assuming it is an attached garage.

Keep in mind a few regen dots are also no big deal - practically, if you're driving somewhat conservatively, they won't impact the amount of regen, unless you happen to have a fairly steep hill to descend first thing in the morning.

In general, it's fine to think about these things, but I agree that mostly you should enjoy the car and not worry it too much. There probably is an "optimal" way to treat the battery, but it's not always possible to do, and it's not clear how much it would actually help over the long term.

 

[pdx_m3s]

What charge level do you have set? Since you have a very short commute, I would recommend something like a 70% charge level for typical days, if it works for you, as that should reduce the amount of regen dots. The regen dots are a function of both the state of charge and the temperature. (In summer, you may even be able to set a somewhat higher percentage, depending on temperature...you'll just have to experiment.)

Obviously, if it is chilly enough (in my experience, you start to have problems in the 50s - even warmer if you use 90% for your SoC), and you park outside, then you may have problems regardless, and then the timed charging is the way to go (the only downside is a little less flexibility if you have an unexpected long second trip during the day that you can't plan for).

The other thing (if it's an option for you), is to park your car inside the garage at night. Helps a lot, assuming it is an attached garage.

Keep in mind a few regen dots are also no big deal - practically, if you're driving somewhat conservatively, they won't impact the amount of regen, unless you happen to have a fairly steep hill to descend first thing in the morning.

In general, it's fine to think about these things, but I agree that mostly you should enjoy the car and not worry it too much. There probably is an "optimal" way to treat the battery, but it's not always possible to do, and it's not clear how much it would actually help over the long term.

Thanks for the info. I charge to 80% every night. I could certainly bump it down given that I rarely use more than 15% in any given day, and if I do, rarely is it unforeseen. I live a pretty simple, suburban life Monday through Friday lol.

 

[ScottLo]

It looks to me like my M3 always has a few Regen dots left until I get the battery under 80%. I charge to 80% (250mi) and always see some on my commute until I'm down to 249mi. I charged to 90% for a few days before a trip, and was seeing dots for my whole commute until.. 249. I second the suggestion to try charging to 70% and see if that gets you what you're looking for. =)

 

[darth_vad3r]

There’s no need to even think about the battery. Let the battery management system manage the battery and just enjoy your car.

Some people enjoy things more by thinking about it.

 

[ewoodrick]

By far, the best way to handle it is to get in car and drive.
Anything else is going to use a lot of power for no reason at all.
No Regen is just a reminder to let you know that you may have to use more brake. It's not a bad thing. It doesn't hurt the battery.

 

[AlanSubie4Life]

Anything else is going to use a lot of power for no reason at all.

This really isn't true; for people who live in chilly places, timed charging offers some benefits as far as limited regen goes, and is of minimal or zero cost.

Limited regen can be a real problem for cold climates, and there are ways to address it.

There are situations where you definitely shouldn't worry about limited regen, of course. Sometimes, there is nothing that can be done.

 

[ZOMGVTEK]

Lower cell temperatures also means lower degradation.

 

[darth_vad3r]

It looks to me like my M3 always has a few Regen dots left until I get the battery under 80%. I charge to 80% (250mi) and always see some on my commute until I'm down to 249mi. I charged to 90% for a few days before a trip, and was seeing dots for my whole commute until.. 249. I second the suggestion to try charging to 70% and see if that gets you what you're looking for. =)

Interesting. I have to pay closer attention to see if there is something similar on the SR+.

Did anyone notice if they changed how the dots are displayed? I could have sworn I saw them on the grey line before all the time (if regen was limited), not just while regen is occurring. Or am I misremembering.