Am I doing much damage?

[gozer]

I work 50 miles from home, almost all of my commute is on highway. Fortunately in upstate NY the road is mostly flat, no huge long hills to climb, I have not seen any big jumps in battery temp even in summer. My concern is this: it is almost impossible to get to the EVSE to stop the charge at around 80%. I mostly ( 90% of the time) end up going to 100%. The car ('22 40kwh S) sits at 100% for no more than 5 hours before I go home. That trip consistantly uses 35% of the battery one way. Wash rinse repeat. I know all about the timer and I used to use it but if someone plugs in next to me I only get half of what I was expecting to get. The EVSE is about a mile from work so I'd like to NOT walk 2 miles a day during work....What say you all? Am I hurting the battery or not so much?

 

[Drew21]

Do you charge at home as well, where it would presumably be easier to stop charging whenever you want? If your trip uses 35% of battery capacity each way, you can make the roundtrip without charging at work.

As noted by myself and others here, there are various ways to limit charging at home, either by buying a fancy EVSEs or by using the charge stop timer.

For example:
1) You leave home Mon-Fri at 7AM.
2) You set the charge stop timer for 8AM on those days.
3) Sun-Thu you plug the car in when you get home or before going to bed.
4) The car figures out when to start charging to get you to 100% at 8AM, so when you unplug at 7AM you will reliably be some percentage below 100%. You can adjust the charge stop timer to your specific needs.

Or, if you want to start the day with full charge, you just set the charge stop timer for your real departure time and plug in the night before. Each morning you will hop into your fully charged car without worry that the battery has been sitting at 100% charge for a prolonged time.

Or, don't worry about it. My wife has had free charging at work for the past three years so we rarely charge at home. She plugs in when she gets to work and unplugs and moves the car when she has a chance to get back to the charger. Regardless, her Leaf battery has been at 100% for at least half the work day for multiple days per week for three years. This is a 24 kWh 2014 SV with just under 79,9xx miles. We only recently dropped from 11 to 10 SOH bars.

 

[nlspace]

The car ('22 40kwh S) sits at 100% for no more than 5 hours before I go home.

That's not gonna hurt anything, but is actually the recommended way to use lithium battery packs, i.e. charge them up, then use them.

The prohibition about holding at 100% is for long durations, there is a graph somewhere showing the degradation after holding for 1 year.

 

[gozer]

OK, Thanks for the replies! I was thinking I wasnt doing really big damage, but I just want to check. The EVSE's I have access to are freebies so I'm not charging at home right now. I will be setting up a unit at home before winter. I'm not sure how far the car will go in the cold, this being the first winter. I'm pretty sure it will make 100 miles but I dont want to push it.

 

[Jeffstumpf]

I work 50 miles from home, almost all of my commute is on highway. Fortunately in upstate NY the road is mostly flat, no huge long hills to climb, I have not seen any big jumps in battery temp even in summer. My concern is this: it is almost impossible to get to the EVSE to stop the charge at around 80%. I mostly ( 90% of the time) end up going to 100%. The car ('22 40kwh S) sits at 100% for no more than 5 hours before I go home. That trip consistantly uses 35% of the battery one way. Wash rinse repeat. I know all about the timer and I used to use it but if someone plugs in next to me I only get half of what I was expecting to get. The EVSE is about a mile from work so I'd like to NOT walk 2 miles a day during work....What say you all? Am I hurting the battery or not so much?

 

[Jeffstumpf]

I work 50 miles from home, almost all of my commute is on highway. Fortunately in upstate NY the road is mostly flat, no huge long hills to climb, I have not seen any big jumps in battery temp even in summer. My concern is this: it is almost impossible to get to the EVSE to stop the charge at around 80%. I mostly ( 90% of the time) end up going to 100%. The car ('22 40kwh S) sits at 100% for no more than 5 hours before I go home. That trip consistantly uses 35% of the battery one way. Wash rinse repeat. I know all about the timer and I used to use it but if someone plugs in next to me I only get half of what I was expecting to get. The EVSE is about a mile from work so I'd like to NOT walk 2 miles a day during work....What say you all? Am I hurting the battery or not so much?

Opinions vary, data shows degradation is minimal

 

[DaveinOlyWA]

I work 50 miles from home, almost all of my commute is on highway. Fortunately in upstate NY the road is mostly flat, no huge long hills to climb, I have not seen any big jumps in battery temp even in summer. My concern is this: it is almost impossible to get to the EVSE to stop the charge at around 80%. I mostly ( 90% of the time) end up going to 100%. The car ('22 40kwh S) sits at 100% for no more than 5 hours before I go home. That trip consistantly uses 35% of the battery one way. Wash rinse repeat. I know all about the timer and I used to use it but if someone plugs in next to me I only get half of what I was expecting to get. The EVSE is about a mile from work so I'd like to NOT walk 2 miles a day during work....What say you all? Am I hurting the battery or not so much?

You are hurting the pack but...

If maximum long term viability is not your goal then keep doing it.

The reality is you want a cut/dried no fuss solution and that applies to nearly NONE of my life and I am guessing it doesn't apply to yours either.

The timer is an easy thing to manage, your commute is barely a third of your range so you have a lot of room to play with and the rate of degradation is relative. The closer to full you are, the worse it gets. 80% is MUCH better than half than 90%. So its not how far from full you are, its about the time spent at all SOC ranges. If most of your time (which I suspect) is spent over 50% SOC, then you are only addressing half the issue.

Now needs vary and in your area, I would have a pretty healthy buffer for winter but summer, I would probably be doing stuff that would have you all gray in a week.

 

[TronJockey]

I work 50 miles from home, almost all of my commute is on highway. Fortunately in upstate NY the road is mostly flat, no huge long hills to climb, I have not seen any big jumps in battery temp even in summer. My concern is this: it is almost impossible to get to the EVSE to stop the charge at around 80%. I mostly ( 90% of the time) end up going to 100%. The car ('22 40kwh S) sits at 100% for no more than 5 hours before I go home. That trip consistantly uses 35% of the battery one way. Wash rinse repeat. I know all about the timer and I used to use it but if someone plugs in next to me I only get half of what I was expecting to get. The EVSE is about a mile from work so I'd like to NOT walk 2 miles a day during work....What say you all? Am I hurting the battery or not so much?

Charging the battery to a full 100% (indicated) is actually only about 90%. The BMS creates this offset to protect the battery pack since charging NMC chemistry to a true 100% is hard on these batteries. Still, leaving it at an indicated 100% for any length of time is still not ideal. I used to do this every night and it did accelerate degradation somewhat. I'd come home at 5pm and immediately plug in. After about 3 hours it would be fully charged where it would then sit overnight for the next 11 hours until I left for work. Even worse for weekends where I would plug in after getting home at 5pm on a Friday evening and the car would often sit unused until the following Monday morning. The degradation each time was tiny but cumulative. The moral of the story is to charge to 100% only when you intend to use the vehicle right after it's charged. I suspect you may already be aware of this.
That being said, you are not only charging to 100% but it sounds like you're also doing it via DCFC. You may be unduly stressing your battery especially if your sprint to the charging station was at highway speeds during a hot Summer day. The Leaf battery also doesn't like DCFC if temperatures go below freezing. I spent a few years up in Rome N.Y. at the old Griffiss AFB where I know it can get pretty cold.
Good luck, you have a difficult situation.

 

[gozer]

Thanks for the info! I am not DCFC the car. L2 only. Battery has 16 FC's on it.