How about come back in 2, 5 years and compare with a similar car which didn't
Otherwise lots of scientific papers which suggest higher degradation if repeatedly charging to 100%
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Model 3 SR+ LFP Battery Range, Degradation, etc Discussion
- Thread starter Baluchi
- Start date
How about come back in 2, 5 years and compare with a similar car which didn't
Otherwise lots of scientific papers which suggest higher degradation if repeatedly charging to 100%
When you go on a road trip, do back to back charge to 100% (as it goes past 98%, the BMS goes into a CALIBRATION mode), you should recover some miles. You can do the same at home (let it charge to 100% before leaving, do that for a week), you should also recover some miles.
All there is right now are the lab tests and what you see on tesla logger (doesn’t indicate charging habits). From what I can tell here, most cars seem to be reducing at the same rate regardless of charging habits. This has lead to the suspicion by some that the EPA range display is pre programmed.
It will take a few more years to see the full picture.
For now I charge to 100% weekly and try to keep the car below 70% if it is convenient to do so. It isn’t worth stressing about because once the battery degrades last 80% the car will be ready for replacement.
It will take a few more years to see the full picture.
For now I charge to 100% weekly and try to keep the car below 70% if it is convenient to do so. It isn’t worth stressing about because once the battery degrades last 80% the car will be ready for replacement.
AlanSubie4Life
Efficiency Obsessed Member
Can you elaborate? I have been following this thread since I purchased my car just over 2 years ago. To my knowledge there aren't too many outliers when it comes to age vs degradation. I'm sitting around 5% and I believe most others are in that vicinity. From my own research across other sites, the story is very similar. This data also matches what you see on Tesla logger.
AlanSubie4Life
Efficiency Obsessed Member
Lots of data points from people with lower SOC having less aging. Fewer with LFP but I am sure we could find examples.
LFP batteries are less impacted by degradation overall.
But in any case: for ANY battery technology, keeping a battery at higher SOC for longer times has more impact on degradation. Therefore, charging at least once a week (or regularly), is surely not the same as saying that you can charge all the time to 100% and keep it at high SOC all the time. The latter will have a higher degradation impact (even if the impact might be still smaller than other battery technologies)
But in any case: for ANY battery technology, keeping a battery at higher SOC for longer times has more impact on degradation. Therefore, charging at least once a week (or regularly), is surely not the same as saying that you can charge all the time to 100% and keep it at high SOC all the time. The latter will have a higher degradation impact (even if the impact might be still smaller than other battery technologies)
The charging to 100% itself doesnt noticable degrade the LFP cells, it will be calendar aging that does it, which in turn needs time at high SOC.
What we know is that modern LFP cells will do several thousand full 100-0% cycles with very low degradation.
At normal temp these LFPs had a throughut of > 15000 Ah.
Cells being 2.3Ah new, this was around > 7000 cycles and lost ~ 10%.
For driving around 100.000km with an average range of 300km, we get 333 cycles. This would equal 10*333/7000= ~ 0.5% cyclic degradation.
The model 3 LFP 2021 has lost ~6.8% range at around 100.000km at best according to the graph, but this do not show the time or age the car was there and it probably just means that those cars was driven much.
Using the age of the cars would probably present a rather solid loss of range.
The absolute most part is calendar aging.
Just about *Any* research reports shows that calendar aging is about 4-5% for average temperatures the first year for LFP.
A 2021 would be around three years today, and as the calendar aging is square root dependant on time we would expect to see
About 4-5% first year or from the chart above: ~4% for 250 days equals 4.4 for one year (chart only has 100% SOC for 25C)
Thats 4.4 x square root (3) = 7.6%
Looks like 65% charge limit is pretty reasonable to do to get the 62.5% SOC curve for calendar aging which is pretty good.
65% charge limit sets the real SOC at 67.5%, but for a day average thats probably true.
Remember that that 62.5% line is cell temp 15C. Most cars will average higher.
I had 13.5C average over 2.5 years with my M3P living in a very cold area, but the car in a 10C garage when at home.
Most people would have ~25C cell temp and calendar aging would be ~ 20% higher at 62.5% and 25C than 62.5% and 15C.
Wow, does anyone have any idea what’s happening to my battery over the last couple days? My degradation has been entirely slow and consistent over the 3 years that I’ve had the car (Sep 2021 M3SR+ LFP), then it dropped off a cliff over two days when none of my habits or circumstances changed. I know the standard caveats about the car’s rated range being inaccurate, but this has to be a sign of something weird, right?
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Its actually expected that the miles/km/ODO has very low impact on LFP’s.
Determining capacity is much harder in a LFP battery than a NCM/NCA because of the flat voltage curve. It probably did a recalibration, but maybe poorly. It's a bit risky but try driving down to 10% or less and letting it sit in sleep (no sentry no remote access, nothing) for a few hours, then recharge to 100%.
I had the same thought, so I ran the battery health test in service mode yesterday. The results showed battery health at 92%, but the estimated range is still 227 miles. That math doesn’t add up, right (I started at 253, so 92% should be 232)?Determining capacity is much harder in a LFP battery than a NCM/NCA because of the flat voltage curve. It probably did a recalibration, but maybe poorly. It's a bit risky but try driving down to 10% or less and letting it sit in sleep (no sentry no remote access, nothing) for a few hours, then recharge to 100%.
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