Is always charging only to 80% stupid?

[APotatoGod]

I hate to be another person asking what probably seems to be a pretty simple battery question, but most questions I've seen seem to be from people asking the opposite perspective.

I have a LR RWD Model 3 (the cheapest one that was available when I ordered in June). I almost never charge above 80%, and I've never charged above 90% so far. Most days my commute is short enough that there's not any reason to increase the charge range, and when I am driving farther I just use the Supercharger network. I plan to keep this car as long as possible, probably at least a decade, and naturally don't want to unnecessarily degrade the battery.

I don't really see the point of charging to 100%, given that I rarely drive that far, and when I do I use the Superchargers. The only time I really could see a benefit to a full charge is when going out of range of the Supercharger network (I haven't done so yet), or perhaps when I have several medium range trips on sequential days (I only have 15A 120V home charging so far, so don't always fully recharge overnight). My slow charging also means a full charge would need to be planned a couple days in advance as well.

Is there something I'm missing about the battery care (such as a 100% charge actually being healthier than Supercharging, or being required to rebalance the battery?).

 

[David99]

It is perfectly fine to only charge to 80% for an extended period of time. The battery will have a little less degradation than charging to 90% daily, but the difference isn't going to be significant either. The range estimation can get a little less accurate if you only partially charge and discharge the battery. Say only only go between 80% and 50%. It is not at all harmful to the battery, it just makes it harder for the car to estimate the capacity in the battery. It can very easily be fixed by letting the battery go low (10% or so) and then charging to 90% or even 100%.

As for Balancing, do not worry about it. The BMS does an excellent job balancing the battery on it's own without the user having to do anything or charge the car in a specific way. My old Model S has perfect balance between the cells after 5 years and over 200k miles. I wet not charging it beyond 80% for several months, charging to 100% countless times, driving in brutal heat and Wisconsin winters.

Don't overthing the battery thing. Just drive it as you need. The car takes care of the rest.

 

[TexasEV]

You’re just fine. The only thing I would suggested, if it’s convenient, would be to charge to 100% before you leave on a trip that requires supercharging. It will shorten the time spent at the first supercharger stop and may even allow you to skip a supercharger depending on your route.

 

[buste2]

Has anyone that has been charging at 80% daily change their routine to 90%? I've read recent/new deliveries, Tesla reps are now suggesting 90% daily charge.

 

[ewoodrick]

You'll need to charge to at least 90%, I'd recommend 100% every few months to allow the BMS to correctly balance.

 

[tga]

Has anyone that has been charging at 80% daily change their routine to 90%? I've read recent/new deliveries, Tesla reps are now suggesting 90% daily charge.

It doesn't mean that 90% is any better than 80%. Many times companies formulate these recommendations based on minimizing support headaches, warranty issues, and other costs.

It's easier to give customers a simple rule like "90% for daily use, 100% when going on a long roadtrip" when you're trying to get another delivery out the door vs getting into long winded explanations about why. Sometimes giving people more information just over-complicates the issue, especially now that Tesla has gone mainstream and isn't just a techno-junkie toy for the earlier adopter crowd.

 

[Brian's ReX]

I tend to charge to 80% most of the time. But just to make myself feel like I'm being proactive in managing my battery pack, I'll change it to 90% for a night or two... down to 70% for a night or two... then back to 80%.

I don't think I'm benefitting the battery overall... it just makes me feel better.

In 1 year, and about 14K miles, no degradation at all. The one recent time I charged to 100% for a trip, it was still at 295 miles. I think my best 100% was 296 miles, but most have been 295.

FWIW

 

[buste2]

It doesn't mean that 90% is any better than 80%. Many times companies formulate these recommendations based on minimizing support headaches, warranty issues, and other costs.

It's easier to give customers a simple rule like "90% for daily use, 100% when going on a long roadtrip" when you're trying to get another delivery out the door vs getting into long winded explanations about why. Sometimes giving people more information just over-complicates the issue, especially now that Tesla has gone mainstream and isn't just a techno-junkie toy for the earlier adopter crowd.

Yeah I agree. Just like 85% for the middle people lol.

 

[CameronB]

As @David99 says, don't overthink it.

Your daily needs plus some extra buffer depending on if you need/want that should determine how much to charge to.

Elon said back in 2014 to charge up to 80%. Jeff Dahn (Tesla's lead batter researcher in 2017), recommended 70% (link to article with both citations below).

But whether it is 70% or 80% or even 90%, just do what works for your needs. Myself I usually do about 70-80% which gives me about 180-190 miles on my 75D...though I typically drive only about 30-40 miles a day, sometimes even less. Don't overthink it!

Tesla battery expert recommends daily charging limit to optimize durability

 

[tga]

Elon said back in 2014 to charge up to 80%. Jeff Dahn (Tesla's lead batter researcher in 2017), recommended 70% (link to article with both citations below).

When asked 40-90 or 30-80 for a commute that used 50%, he said 30-80 - Elon Musk on Twitter