Charging conundrum - opinions please.

[Soul Surfer]

I used to plug my car into my Wall connector the minute I got to my parking stall. Lately I’ve considered charging to 75% and letting it run down to 30-40% before plugging it in again. I mostly do city driving in the GTA (Toronto). As I’ve been reminded a few times, the battery management is entirely different than my former Volts (Gens 1 & 2) and don’t buffer the same way. What are your thoughts? Will this be better for battery life?

 

[Empiro]

There's been quite a few threads on this, but my opinion is that you can just plug it in any time you want. Remember that any time you drive your car, you're charging and discharging the battery dozens of times due to normal driving and regenerative braking. The power involved is many times greater than your wall charger too.

That said, it's generally best to keep the state of charge around 50%. I've been charging my car to only 60% on most days for months now and never once have I run into any issues. Of course, your mileage may vary.

 

[cgell]

A larger swing in the state of charge is worse, so just plug in. People always worry about plugging in because they think each charge is a charge cycle - it’s not. Plus, at the end of the day you will charge/use the same amount of kWh anyway. Just set it to 75% or whatever you need and keep it plugged in.

 

[ucmndd]

The manual is very clear on this. There is no debate.

 

[Soul Surfer]

The manual is very clear on this. There is no debate.

Could you point me to the page or section? I went back to look and could not find any references to SoC other than when going on a trip to charge to 90-100%.

 

[nwdiver]

Could you point me to the page or section? I went back to look and could not find any references to SoC other than when going on a trip to charge to 90-100%.

pg 91 of my manual.

 

[ucmndd]

Could you point me to the page or section? I went back to look and could not find any references to SoC other than when going on a trip to charge to 90-100%.

 

[Soul Surfer]

pg 91 of my manual.

View attachment 823290

View attachment 823291

Thank you for that. I did see that, but not a mention of the SoC?

 

[nwdiver]

Thank you for that. I did see that, but not a mention of the SoC?

I don't think that's as relevant as long as you keep it between ~50 and 90. You just want smaller cycles vs larger ones. I doubt there's a difference between 50=>55=>50 and 60=>65=>60.

 

[Regaj]

Wrong question.

If your daily mileage is such that you are contemplating charging to 75% SOC, then waiting some days for it to decline to 30-40% before plugging in again... you would be much better served by reducing your charge-to level to 60-65% and plugging in every day.

Charge levels above ~3.92v/cell (which equates to ~60-65% SOC) induce cell stress, with that stress level increasing in a fairly linear fashion until 4.2v/cell (100% SOC). That 3.92v/cell (60-65% SOC) level is the floor at which no further improvement in cycle counts are observed. Said differently, that's the (upper) SOC at which no further degradation (from voltage stress) happens.

A lot of drivers have mileage requirements that require greater SOC's, of course. But if your situation allows it, 60-65% is your golden number.

 

[Soul Surfer]

Wrong question.

If your daily mileage is such that you are contemplating charging to 75% SOC, then waiting some days for it to decline to 30-40% before plugging in again... you would be much better served by reducing your charge-to level to 60-65% and plugging in every day.

Charge levels above ~3.92v/cell (which equates to ~60-65% SOC) induce cell stress, with that stress level increasing in a fairly linear fashion until 4.2v/cell (100% SOC). That 3.92v/cell (60-65% SOC) level is the floor at which no further improvement in cycle counts are observed. Said differently, that's the (upper) SOC at which no further degradation (from voltage stress) happens.

A lot of drivers have mileage requirements that require greater SOC's, of course. But if your situation allows it, 60-65% is your golden number.

Wow! Great points and observations! Thank you for that. I think I’ll leave it closer to 70% as there are often unplanned errand days. Thank you so much for that!!!