The instance the car is unplugged it is no longer at 100% and you are only putting back in a fraction of what you take out when you start moving so there is always capacity available. It just has to limit the current when SoC is very high so you cannot get full regen.
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Should LFP batteries be charged to 100%?
- Thread starter SaffaT3sla
- Start date
I think 200 is a reasonable average, unless you drive only short trips and constantly use sentry mode. Driving style makes a big difference.
kelvin 660
White SR+ with LFP battery
My worste case figure (55kW LFP) is 180 miles for a full charge. That's for winter time and many short journeys. I only use sentry when away from home at shops, school runs, etc..
However even if it was only 100 miles per charge that's still 320,000 miles before the cars end of life!
However even if it was only 100 miles per charge that's still 320,000 miles before the cars end of life!
Just out of curiosity have you driven until 0%?
Personally I have gotten to 3-7% without pushing my luck.
In the video linked earlier Bjorn managed over 50km on 0% charge so I'm pretty comfortable arriving to chargers with like 3% predicted
As I said in my post, I want to keep my car and battery health for a long time
For me personally, I want to keep the battery tip top, and to me that means charging to the most optimal state. I'm not fussed about getting the extra 45 miles charging to 100%.
HenryT
Active Member
Aren't the two statements above contradictory? What relevance is the 'saved capacity' if you'll never use it?
It's not that I "never" use the full capacity, I only charge to 100% when I need to (as I said, I don't need the extra 45 miles I'd get every single day).
We all know letting a battery sit at a high V / SOC will degrade faster.. I don't understand why this is such a hard concept to get.. and apparently so controversial!
I think that being the point. A high state of charge in an NMC battery is based on the voltage being up at 4.2v per cell which is where the damage is done. High VOLTAGE rather than full capacity.
The LFP never gets to that voltage. 3.7v being the nominal voltage at a full charge state, a fair way away from where the damage is done.
The battery will still degrade, I think we all agree. I’m at 60,000 after 18months charging to 100% once a week on average. I usually run around in % but flick it back to km every so often out of interest and my battery has lost 12km.
Ha yes - I've given up looking at the rated distance because who knows how they calculate (based on recent Vs long term averages, "maximal expected" etc).
I think some of the "mystery" Tesla leaves in communication (even simple things like stating exact battery capacity and therefore actual Vs estimated buffer) can be frustrating, and that's probs partly why I don't necessarily trust the buffer estimates we have - the voltage does still increase a fair amount going from 95-100%, especially if left in a charging state (eg off peak charging), and who really knows how much buffer is left at the top end.
Be nice if they were a bit more forthcoming with some of the details, but that's never really been their thing
For what it's worth, My car originally displayed 271 miles when fully charged and now shows 265 miles, after 9000 miles. I can drive about 4-5 miles before it starts counting down. So has the car really lost any range or is it just displaying it differently from the older software when it was built?
I don't think it's software versioning, but I had a similar point to make. We can't really measure the degradation on the displayed mileage because realistically you were never able to achieve the miles lost at full anyway. I've lost just over 10 displayed miles over 2 years but in the real world I've been able to travel the exact same distance I always have.
Exactly.
There's obviously interest in monitoring the degeneration of battery capacity but I have to remind myself that in everyday use there is absolutely zero difference in how far I drive my car after 3+ years. You would have to drive from 100% to 0% to notice, but I have never done that ... I leave that to Youtubers. Of course because LFP battery cars can routinely make full use of an extra 10% this does mean that for daily use they effectively have a longer range car than a non-LFP battery pack car with the same nominal capacity (assuming that the owner of the non-LFP is using at a 90% daily limit to help maintain battery health).
HenryT
Active Member
I took it from your comments that you didn't charge the battery to 100%, hence my comments.
I wasn't suggesting you should let it sit at a high state of charge, simply that the guidance for LFP batteries is that they should be charged to 100% on a regular basis.
I was just reading up on LFP goodies as i stumbled into this gem. Have to congratulate on the clearsight, as Idle fees were introduced two years after your post!
“Idle” or overstay fees have been around a long time, possibly a translation issue as I don’t think English is your first language, but they have started to introduce a penalty fee/surcharge when charging above 80% at some locations although I’m not aware of any in the U.K., and I guess that’s what you’re thinking off. Also as you suggest, good foresight by the poster
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