80% vs 100% charge

[SaaSManKS]

I hope this isn't redundant of any other convos, I tried to vet it!

So I live in KS, and the cold is destroying the range of my Pure. I know I have a heavy foot (it's just too fun!) but I'm averaging about 2mi per kw maybe 2.5 so I got home today and was down to 20% after having gone 136 miles and it's been in the 30s and 40's for temp so I know that's a variable as well.

My question is, I know that battery charging is recommended at 80%, but isn't that for nightly charging? I will only charge when I need to, so I don't plug in but once or twice a week depending on the weather. So if I were to charge to 100% once a week or hopefully a day or two longer than a week, that wouldn't really impact the battery since I'm not plugging in nightly right?

 

[MorganB]

Lucid recommends plugging it in when you aren't driving basically so it's best to plug it in nightly. Charging to 100% frequently will degrade the battery, charging to 80% daily will not.

 

[DeaneG]

Keeping the battery at a very high or very low state of charge degrades it, so it will accept less charge in the future. Life with an EV is much more pleasant if you can charge at home every night to 80%. I've owned five EVs over 12 years, we are an EV-only household, and I would not keep an EV unless I could charge at home. It makes all the difference.

 

[Sandvinsd]

If you are oNly charging once or twice a week, I would actually set it lower, say to 60% or 70% and just plug it in every night. I only charge to 100% if I am leaving for a trip the next morning.

 

[DeaneG]

If you are oNly charging once or twice a week, I would actually set it lower, say to 60% or 70% and just plug it in every night. I only charge to 100% if I am leaving for a trip the next morning.

+1 many smaller charge-discharge cycles closer to 50% are less damaging (aging) to the battery than fewer, larger cycles. It's far healthier for the battery to be cycled from 30%-80% twice than from 0%-100% once.

 

[AirDoll]

I hope this isn't redundant of any other convos, I tried to vet it!

So I live in KS, and the cold is destroying the range of my Pure. I know I have a heavy foot (it's just too fun!) but I'm averaging about 2mi per kw maybe 2.5 so I got home today and was down to 20% after having gone 136 miles and it's been in the 30s and 40's for temp so I know that's a variable as well.

My question is, I know that battery charging is recommended at 80%, but isn't that for nightly charging? I will only charge when I need to, so I don't plug in but once or twice a week depending on the weather. So if I were to charge to 100% once a week or hopefully a day or two longer than a week, that wouldn't really impact the battery since I'm not plugging in nightly right?

I only charge at home once or twice a week as needed. I was told 20-80% is the healthy percentage to live in. I plug it in when it gets to about 20%, and set the limit to 80% as recommended. The only time I charge if it’s above 20% is if I know I need to drive long distance the next day.

 

[SaaSManKS]

Lucid recommends plugging it in when you aren't driving basically so it's best to plug it in nightly. Charging to 100% frequently will degrade the battery, charging to 80% daily will not.

if you remove the word "frequently" do you still have the same opinion?

 

[DeaneG]

I don't drive that much, so I just plug in (in my garage) when the charge level drops below about 70%, then I charge to 80%. It's nice to have a fair amount of range sitting in the car in the winter in case of power failure.

 

[SaaSManKS]

so based on what I am reading above the general opinion of people here is that to charge the battery nightly actually helps to increase it's life rather than fuller less frequent charges?

 

[DeaneG]

if you remove the word "frequently" do you still have the same opinion?

What matters is how long the car sits bear 0% or 100% state of charge. If you charge to 100% once a month, it's not a big deal as long you drive it down to 80% that same morning. Don't let it sit over 80% for days.

 

[DeaneG]

so based on what I am reading above the general opinion of people here is that to charge the battery nightly actually helps to increase it's life rather than fuller less frequent charges?

Yes. Shorter cycles closer to 50% are better than longer cycles near 0% or 100%. Keeping it in the 20%-80% range for daily use is a good compromise between battery life and the car's usefulness as a practical vehicle. If you want the maximum short-term utility from the car and don't care about the battery, charge 0%-100%. If you only care about the battery's health and don't care about getting utility out of the vehicle, keep it at exactly 50% charge and don't drive it. Hence the 20%-80% compromise unless you need more range once in a while for a long trip.

 

[SaaSManKS]

Ok, interesting, I would not have thought that, glad I asked! thanks everyone!

 

[DeaneG]

BTW the exact same thing is true of your cell phone's battery. If you want to keep your phone for several years, keep its charge in the range of 20-80% as much as possible. If you plan to replace the phone every year, don't stress about it and charge to 100% every night.

 

[hmp10]

If you have home charging you should keep the car plugged in whenever it is parked. The battery management system sometimes operates while the car is parked to keep the pack at optimum temperature, and it's better to draw this power from the line outlet than from the pack itself, as using the pack increases the number of recharge cycles to which the batteries are subjected. Remember that, even when plugged in, the batteries will be charging only when they drop a percentage point or two below where you set the charge limit, so most of the time it's as if the car were not plugged as far as what the batteries see.

DeaneG is right about full charging and depletion. The degradation of the batteries comes largely from the formation of dendrites, which is a particular issue at higher states of charge. However, dendrites do not form instantly but rather over time. Thus it's okay to charge occasionally to or near 100% when you need the range for a trip as long as you don't let the batteries sit at that higher charge for long periods.

Even when dealing with winter temperatures, I think the best strategy is to keep the car plugged in when parked at home with the charge limit set to 80%. You'll have plenty of charge whenever you need it for almost any amount of local driving, and if you're anticipating a road trip where you'll need extra range, just move to a higher charge level shortly before the trip commences.

While you can probably eke a bit more life out of your pack by more precise charge management, it's not worth the bother. All the data accumulated as EV fleets are now topping a decade of real-world experience are showing that EV batteries with good management systems (such as most new EVs have) will only lose 6-7% of their capacity well north of 200,000 miles on the odometer. The earliest degradation comes in the first year or two, and then the degradation curve flattens significantly.

 

[SaaSManKS]

BTW the exact same thing is true of your cell phone's battery. If you want to keep your phone for several years, keep its charge in the range of 20-80% as much as possible. If you plan to replace the phone every year, don't stress about it and charge to 100% every night.

Good point, but I usually only keep my cars for about as long as my phones ~2 years is the average haha! however, I wouldn't want another buyer to come in and pull a report on battery health and see I've been neglectful...

 

[HariK]

I only charge at home once or twice a week as needed. I was told 20-80% is the healthy percentage to live in. I plug it in when it gets to about 20%, and set the limit to 80% as recommended. The only time I charge if it’s above 20% is if I know I need to drive long distance the next day.

I agree. Right now I am using ea once in 12 days at 20% to 80% or what ever I get in the time I am shopping. When the 3yr period is over, I plan to charge at home 20 to 80 and not daily.

 

[Tesla2.0]

I agree wholeheartedly with @DeaneG and @hmp10 ‘s recommendations. Here are my own rules of thumb.

- Always plug in whenever your home garage is either too cold or too hot. When you expect Battery Management System is going to make loud fan noise to regulate battery temperature, you rather let BMS draw power externally than from power packs itself which it tries to regulate.

- I unplug whenever I’m on extended trip. Even though my EVSE is on circuit breaker, there can always be slightly possibility of fire hazard that need to unplug or shutdown panel. Out of sight, out of imagination.

- Never DCFC above 80% SOC, even at road trip. Unless you expect next charging stop is too far away and you must to charge more to avoid range risk. It is best to even stop DCFC at 70% or below. It is just too harsh to battery at high DC voltage, it’s scorch hot speed, don’t fry battery pack too often.

- If you travel mostly in short distance inside the city or your neighborhood, then set your daily Max charge even to 70%. On our other Rivian EV, it doesn’t have charging SOC slider like in Lucid, you can only set charge to 100%(normal battery wear), 85%(reduced battery wear) or 70%(least battery wear). So for those options, I set 70% for weekday, 85% for weekend and 100% for road trip.

- Battery life last longest if you stay away from either end of 10% extreme, 20% cushion is even better. Say if you have to use 60% of your battery in one day. 80%->20% beats 70%->10% or 95%->35%. The key is stay in the middle range as much as possible, don’t get close to 100% or 0% if you don’t have to.

- In road trip, I prefer 100% charge by home/hotel level-2 charger than 80% charge by DCFC like in EA or EVGo. Even you have to pay level-2 juice as oppose of free EA, it’s less harsh on battery life. AND, you don’t have to wait in charging station, you can juice it up while asleep. And that is the best part of EV ownership, not bother going to stations!

 

[borski]

BTW the exact same thing is true of your cell phone's battery. If you want to keep your phone for several years, keep its charge in the range of 20-80% as much as possible. If you plan to replace the phone every year, don't stress about it and charge to 100% every night.

In fact, iPhones will by default schedule your charging now to get to 100% roughly before you normally wake up, so that it isn't sitting at 100% for hours before you can start using it.

 

[Babyrocko1908]

I don't drive that much, so I just plug in (in my garage) when the charge level drops below about 70%, then I charge to 80%. It's nice to have a fair amount of range sitting in the car in the winter in case of power failure.

So you leave it connected every night over night after the 80% rate is hit? This is what I struggle with -- leaving the cable connected when not actually charging.

 

[hmp10]

This is what I struggle with -- leaving the cable connected when not actually charging.

Why would this be a concern? When the charge limit you selected is hit, the car switches off any draw from the cable. It's really no different than leaving your TV and toaster plugged in when they're off.

The upside of staying plugged in is that when the battery management system kicks in to keep the pack in its optimal temperature range, it will draw power from the line instead of from the batteries, thereby reducing the charge/discharge cycles the batteries accumulate (and which are a source of degradation). There is a reason that EV makers recommend keeping the car plugged in between use whenever possible.