Should LFP batteries be charged to 100%?

[MrT3]

What usable capacity do you think you’re Mic LFP has? Ive got a 2021 SR+ Mic which was delivered on the 30th Sep. I’ve done 500 miles and it’s bloody fast and very efficient. My first 500 miles have been around 200wh/mi.

But……

On my current charge I’ve averaged 186wh/mi, covering 70 miles and used 29% (13kWh). Unless my Maths is out that only gives me a 44-45kWh battery. I thought these were 55kWh with a usable around 53kWH? I’m up to date with software.

The Energy graph is predicting 212mi and the basic range display is 184mi remaining.

Effectively the % seems the odd one out.

Thoughts?

Are you regularly charging to 100% to allow the system to calibrate battery % accurately?

 

[Lord Farquad]

Are you regularly charging to 100% to allow the system to calibrate battery % accurately?

I’ve done a couple of mid battery small top ups and charged once to 100 and once to 99% (this week).

I’ll let it run down and give it a full charge to 100 this time.

 

[SR-Plus]

Yes I think they are 52.5kwh as per Bjorn Nyland

 

[Js1977]

Drifting off topic a bit, I wish if my Y was to come with 4680 battery, It would be LFP. Other than that, not fussed about the structural yada yada malarky as its more for teslas benefit than mine. Its nice just to charge to 100% for the daily runs overnight, specially if you have more than one EV in the house and sharing the charger.

 

[Lord Farquad]

Yes I think they are 52.5kwh as per Bjorn Nyland

That’s my impression too. But I don’t have a scan my Tesla set up so I’m left wondering. I’ll have to let the battery cycle somewhat and keep checking. If it was a few kWh it wouldn’t bother me, but nearly 10 is a lot!

 

[Js1977]

That’s my impression too. But I don’t have a scan my Tesla set up so I’m left wondering. I’ll have to let the battery cycle somewhat and keep checking. If it was a few kWh it wouldn’t bother me, but nearly 10 is a lot!

Do you think you are getting less range than the non LFP SR+ charged to 100% ?

 

[Bobly]

Other than that, not fussed about the structural yada yada malarky as its more for teslas benefit than mine.

I would have thought that the structural pack would also mean less additional strengthening, so less weight - and therefore better efficiency and more range? which is good for you, no?

 

[Lord Farquad]

Do you think you are getting less range than the non LFP SR+ charged to 100% ?

No idea….if the % is correct then possibly (200-237mi).

If the efficiency is correct and the battery is 53kWh then I should be good for over 275 miles.

 

[Js1977]

I would have thought that the structural pack would also mean less additional strengthening, so less weight - and therefore better efficiency and more range? which is good for you, no?

Well yes, theoretically speaking, of course. However. Both our SR+ behave the same even though one has a heavier battery than the other. I cant explain reason as to why the Model Y has less performance the the 3 like for like Yet model X is more on par with model S.

 

[Js1977]

No idea….if the % is correct then possibly (200-237mi).

If the efficiency is correct and the battery is 53kWh then I should be good for over 275 miles.

And the advertised range is (not real world) ?

 

[Lord Farquad]

And the advertised range is (not real world) ?

278miles

I actually think I could match or beat that if the efficiency is correct. It’s doing over 5 miles per kWh, which is bloomin good.

I’m hoping the % is just a glitch of some sort.

 

[Js1977]

278miles

I actually think I could match or beat that if the efficiency is correct. It’s doing over 5 miles per kWh, which is bloomin good.

I’m hoping the % is just a glitch of some sort.

Well there you go. If you can exceed or achieve the wltp quoted range worst case scenario, you are doing better than everyone else and I would not think of a Ducatista as being a Sunday driver

 

[MrBadger]

If the efficiency is correct and the battery is 53kWh then I should be good for over 275 miles.

Efficiency as from the trip meter - it only measures the efficiency of the drive itself - lots of other losses (and gains) to be had with the car just sat there doing nothing, sentry or not.

 

[Lord Farquad]

Efficiency as from the trip - it only measures the efficiency of the drive itself - lots of other losses (and gains) to be had with the car just sat there doing nothing, sentry or not.

Yes I’m starting to gather that. So the kWhs lost during inactivity are effectively “lost” in the figures?
I’m going to let this charge run as low as I can afford it to, then see how much energy I can actually put back in. Maybe that’ll be more representative.
From all the stats the car presents, it’s only the battery % that seems to suggest a smaller usable capacity. If I read any other metric, the car thinks it’ll do a range that indicates an expected battery size of 53kWhs at an efficiency better than 200wh/mi.
Plus due to circumstances it’s never dropped under 39% since new. So maybe it needs a lower SoC to recognise where its limits are?

 

[Adopado]

Plus due to circumstances it’s never dropped under 39% since new. So maybe it needs a lower SoC to recognise where its limits are

Quite possibly.
Also some of the percentage losses will be temperature changes that come back to you when you drive and the pack warms up. Though it’s interesting to get a handle on what goes on with consumption it’s very hard to be definitive and to draw specific conclusions about battery capacity. By all means establish a baseline but getting overly drawn into consumption hypersensitivity is probably not advised for a relaxed life!

 

[Lord Farquad]

Quite possibly.
Also some of the percentage losses will be temperature changes that come back to you when you drive and the pack warms up. Though it’s interesting to get a handle on what goes on with consumption it’s very hard to be definitive and to draw specific conclusions about battery capacity. By all means establish a baseline but getting overly drawn into consumption hypersensitivity is probably not advised for a relaxed life!

So having measured what energy I can put back into the battery it confirms the pack is around 55kWhs
The loss I didn’t account for was overnight drain, preconditioning and general messing about with the car/app.

Thanks for all the replies. I’m happy now.

 

[Dave Br]

Really good explanation, thanks.

 

[MartinA65]

Really good explanation, thanks.

I’m sure the answer to this must be here somewhere but I can’t find it. Does the advice of not leaving the battery standing at 100% for long period also apply to LFP?

 

[kelvin 660]

LFP batteries can be left sitting at 100% without any problem, unlike NCA.

 

[MartinA65]

Thanks Kelvin, I guess that clears it up.