What's the effect on battery life of regularly charging to 100%

[StanBowlesb]

My wife has a 145 mile round journey for her three days a week commute in an MG Trophy LR (61kw battery). We have been charging to 80% in line with recommendations to preserve battery life. But now that winter is coming she is experiencing range anxiety. I say don't worry but that is easy for me to say as I am not experiencing what she is. Today, for example, she was limiting her speed to around 50mph on roads that are 70mph to ensure she had a decent margin of charge to get her home. When she got home she had 12% left (i.e. she was achieving 3.5 miles per kw and had a decent margin to spare) which would be fine if she wasn't having to limit her speed. Limiting her speed in this way is not at all ideal as it prolongs an already long working day so I think she may have to revert to 100% battery charging. Does anyone have any information or evidence on the impact on battery life of 100% charging?

p.s. she is driving in energy saving mode, max regen etc.

 

[tsedge]

Charging to 100% is fine whenever you need it, it is recommended at least once a month to balance the battery.

The thing that ages a battery is time spent at 100% (or close to it), that's what you want to minimise - so don't leave it with a high state of charge. Rapid charging also has a wearing effect.

However, batteries last so well that it won't really affect you unless you plan to keep the car for 10 years and go well around the clock. All the models should be good for 200,000 miles with a decent battery life left.

Also make sure she has:

• ECO mode on
• Energy saving on in ECO mode
• ECO set on AC
• AC Temperature not too high and low fan speed
• Intelligent battery heating set to OFF

145 miles should be no trouble at all for a LR, minimum I get even driving hard in sport mode is around 180 miles.

50mph should give you around 4m/kWh or more, suggesting that something is not set right.

Finally, there's nothing wrong with getting home with 12%.

 

[StanBowlesb]

Thanks for that reply. I think she is doing all those things but I will doublecheck re point about eco being set on AC. For the work commutes we will charge to 100% and see what the margin of safety is in lower temperatures. If it seems safe to do so, is there any merit in setting the max charge to 90% instead of 100% or is there some 'magic' about 80%?

 

[tsedge]

Thanks for that reply. I think she is doing all those things but I will doublecheck re point about eco being set on AC. For the work commutes we will charge to 100% and see what the margin of safety is in lower temperatures. If it seems safe to do so, is there any merit in setting the max charge to 90% instead of 100% or is there some 'magic' about 80%?

90% is better than 100%, there's a curve so the higher up the curve the more damage if left for prolonged periods. Using 90% three days a week should make no significant difference to long-term life.

80% is simply the compromise most manufacturers have settled on. It is pretty conservative.

With these things you can over years measure the effects and some people never rapid charge and almost never charge to 100% unless the car requests it - but you are talking single digit or fractions of a percentage change to the battery over years, so for most of us, it doesn't make any practical difference.

If you charge to 100% always and Rapid charge loads of times a week, then yes, you'll see some degradation over a few years, but even then not enormous for most people and it will be slow and progressive a change - remember your LR has a buffer at the top and bottom that it can trade to keep giving you 100% and only after that is exhausted will you see a range drop off.

Most people only keep new cars for 3-4 years in any case (because they are on finance / lease).

We should also note that ICE engines wear over time and at 100,000 miles you won't be getting the same power or fuel economy (or range) as when the car was new.

 

[StanBowlesb]

Just checked and we are doing all those things recommended. Looking again at the energy consumption, it was 3.8 miles per kw today but, as I state, that was with some driving speed compromises (but no idea how much she slowed down). Anyway, all very useful and the plan is to charge to 100% overnight, drive at full normal speed tomorrow and then judge what percentage charge is needed for those commuting days. Hopefully some proper cold weather coming up so that should be more of a test.

 

[Bricktop X PWR]

My wife has a 145 mile round journey for her three days a week commute in an MG Trophy LR (61kw battery). We have been charging to 80% in line with recommendations to preserve battery life. But now that winter is coming she is experiencing range anxiety. I say don't worry but that is easy for me to say as I am not experiencing what she is. Today, for example, she was limiting her speed to around 50mph on roads that are 70mph to ensure she had a decent margin of charge to get her home. When she got home she had 12% left (i.e. she was achieving 3.5 miles per kw and had a decent margin to spare) which would be fine if she wasn't having to limit her speed. Limiting her speed in this way is not at all ideal as it prolongs an already long working day so I think she may have to revert to 100% battery charging. Does anyone have any information or evidence on the impact on battery life of 100% charging?

Honestly, unless your keeping your car for the next 10 years I wouldn't worry about charging to 100%
Especially as it seems you use it for a long trip everytime.

I only ever charge to 100% (well it usually stops at 96-97%) as I can't charge at home and fastcharge at Tesla once a week.

But my caveat is, that I drive off immediately and don't let it sit fully charged for any length of time.

Usually back to 80% when I get home.

I think worrying about battery health can become a little obsessive (especially if you've got bugger all range to deal with)

My last EV would only give me 126miles at 80% so I just fully charged that to 100% all the time also.

As @tsedge says, I think the easiest way to manage it, is to put it in eco mode and let the car manage the AC etc.

 

[AndyL61]

My wife has a 145 mile round journey for her three days a week commute in an MG Trophy LR (61kw battery). We have been charging to 80% in line with recommendations to preserve battery life. But now that winter is coming she is experiencing range anxiety. I say don't worry but that is easy for me to say as I am not experiencing what she is. Today, for example, she was limiting her speed to around 50mph on roads that are 70mph to ensure she had a decent margin of charge to get her home. When she got home she had 12% left (i.e. she was achieving 3.5 miles per kw and had a decent margin to spare) which would be fine if she wasn't having to limit her speed. Limiting her speed in this way is not at all ideal as it prolongs an already long working day so I think she may have to revert to 100% battery charging. Does anyone have any information or evidence on the impact on battery life of 100% charging?

Why not do what I do . Charge to 90% , gives you another 25 miles of range and still leaves a healthy buffer below 100% . You are using the car after the charge so not leaving it at a high state of charge so everything will be fine.

 

[StanBowlesb]

Why not do what I do . Charge to 90% , gives you another 25 miles of range and still leaves a healthy buffer below 100% . You are using the car after the charge so not leaving it at a high state of charge so everything will be fine.

Yes I think that is what I said I was planning to do once we're satisfied that there'll be sufficient margin after the test at 100% and 70mph journey tomorrow.

 

[Mennox]

Ok - so I am getting an Xpower on lease next week for 4 years. Should I need to worry about charging to 100% considering I wont have it after 4 years?

I plan on granny charging it so I'm thinking of charging to 100% and charge it again the week after. I generally do a lot of round of door driving so dont do too many miles, though there will be times I will travel to our Leeds office (190 round trip) - they are planning on installing chargers before xmas so can top up whilst on site before driving home.

 

[AndyL61]

Ok - so I am getting an Xpower on lease next week for 4 years. Should I need to worry about charging to 100% considering I wont have it after 4 years?

I plan on granny charging it so I'm thinking of charging to 100% and charge it again the week after. I generally do a lot of round of door driving so dont do too many miles, though there will be times I will travel to our Leeds office (190 round trip) - they are planning on installing chargers before xmas so can top up whilst on site before driving home.

The granny charger will put something like 3% per hour into your battery so bear that in mind when working out how often you charge.

 

[Mennox]

The granny charger will put something like 3% per hour into your battery so bear that in mind when working out how often you charge.

Aye I plan to either charge throughout the day when working from home, or overnight (12+ hours) - I dont plan on letting it get to the low end of the charge (-30) unless on a trip so will just top up a couple of times a week.

 

[STJ73]

I thought with LFP batterys it doesn't affect them. I could be wrong tho. I don't have home charging facility so I only use public chargers and so far I've not had the battery below 30% and charge it to 97% ( for some reason it never gets to 100% ) I've only got the car for 3 years so it's not so much of a issue with me.

 

[fnegroni]

My wife has a 145 mile round journey for her three days a week commute in an MG Trophy LR (61kw battery). We have been charging to 80% in line with recommendations to preserve battery life. But now that winter is coming she is experiencing range anxiety. I say don't worry but that is easy for me to say as I am not experiencing what she is. Today, for example, she was limiting her speed to around 50mph on roads that are 70mph to ensure she had a decent margin of charge to get her home. When she got home she had 12% left (i.e. she was achieving 3.5 miles per kw and had a decent margin to spare) which would be fine if she wasn't having to limit her speed. Limiting her speed in this way is not at all ideal as it prolongs an already long working day so I think she may have to revert to 100% battery charging. Does anyone have any information or evidence on the impact on battery life of 100% charging?

p.s. she is driving in energy saving mode, max regen etc.

I know you already mentioned you’ll be doing a test at 100% to see what is the maximum margin.
I would also suggest: forget eco mode anything. Just charge to 90% and reduce motorway speed to between 60 and 65.
for the rest, just be gentler with the throttle and leave plenty of room and read the road ahead.
I think that will be sufficient.
Moreover, if there’s a Tesla supercharger anywhere on her route, charging 5 minutes will add plenty to feel safe

 

[Rolfe]

If you listen to that very good video with Euan McTurk, he says that the effect isn't really anything to be too concerned about unless you're leaving the car for weeks rather than hours. In fact he actually says, well, don't leave it at 100% if you're going to SORN it!

He also cautions against what he terms "short (or shallow?) cycles", that is an owner driving the car for short trips only, but plugging in and charging to 100% every time they get home regardless. How to kill a Leaf battery, he said.

Oh, can I just stick in the obligatory disclaimer here.

THE ABOVE ADVICE IS FOR OWNERS OF THE LR (NMC) BATTERIES ONLY.

Owners of SR (LFP) batteries should charge up to 100% every time they're on an AC charger and let the car balance for half an hour after it reaches 100%. (Obviously if you need the car sooner than that, you can stop the charge!)

This is how it is recommended to treat the SR battery, and it's a myth that it will damage it in any way you're likely to notice.

 

[tsedge]

This thread is quite clearly about the LR NMC battery, as was made clear in the first post.

I'm starting to want to say "please no SR owners jumping onto this thread to tell us (yet again) that their batteries don't have to worry about this"!

Ok - so I am getting an Xpower on lease next week for 4 years. Should I need to worry about charging to 100% considering I wont have it after 4 years?

I plan on granny charging it so I'm thinking of charging to 100% and charge it again the week after. I generally do a lot of round of door driving so dont do too many miles, though there will be times I will travel to our Leeds office (190 round trip) - they are planning on installing chargers before xmas so can top up whilst on site before driving home.

No, you shouldn't worry about it.

 

[Rolfe]

This thread is quite clearly about the LR NMC battery, as was made clear in the first post.

I'm starting to want to say "please no SR owners jumping onto this thread to tell us (yet again) that their batteries don't have to worry about this"!

Absolutely. However, the problem we have is that advice about the care and feeding of the NMC battery is so widespread that many owners of LFP batteries read this and think this also applies to their cars. So a single post pointing this out is not exactly going to derail your thread and may be useful for some people.

The thread title doesn't mention the battery type, and unless readers already know that the Trophy has an NMC battery while the SE SR does not and advice for Trophy owners is not for them, a newbie might be confused. That's all.

 

[tsedge]

Fine, then in reciprocation, please don't any longer complain about Trophy owners sharing the fact that their cars behave differently on threads about SE issues - because it is the exact same thing, newbies might get confused.

 

[Ian Key]

Going back to the OP.

Reading between the lines it seems that she's doing some of her journey on motorways and dual carriageways so as well as the settings suggested by @tsedge putting the regen into adaptive might also be beneficial.

 

[Vingnut]

First of all 3,8 M/kWh is very low consumtion, I am not even close to that maybe because I do not have anything eco on (like it comfy as we got from -5C to +5C here now).

If I plan to go somewhere and it's likely to get close to 15% or lower when at home (10% in summer), I charge at home to whatever is needed to get above that threshold (normaly charging to 80% soc but 90% or 100% if needed). If I can't do this even at 100% state of charge at start of the journey, I get a little "splash and dash" at a fastcharger during the trip (preferably at the lower end of soc).

When charging at home at night the time the car is at 90-100% soc when using it the same day is really not a big deal, it's much worse to charge it to 80% soc and drive it down to 60-70% soc and then charge it back to 80% soc time and time again.

 

[Rolfe]

Fine, then in reciprocation, please don't any longer complain about Trophy owners sharing the fact that their cars behave differently on threads about SE issues - because it is the exact same thing, newbies might get confused.

I think I was quite clear in my post, which was intended to be a single, one-off public information announcement.