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How are LFP batteries holding up?

kelvin 660

White SR+ with LFP battery
Aug 21, 2020
570
488
Stonehouse
LFP batteries have been around now for about 9 months and I was wondering how they are holding up in terms of degradation.

So do you have a SR+ with LFP batteries? Do you use TeslaFi? If so, can you post a PDF of the battery degradation chart?

As an example, I have posted a PDF of mine. However it uses NCA batteries. According to the chart it has lost 9% in 12 months. It will be interesting to compare this with LFP to see if there is a major difference...
 

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Well I went for a 160 mile drive yesterday, as the weather was sooo nice...
I travelled 75 miles along straight A roads (Foss Way, etc) at just around speed limits and returned using the motorway (M42 & M5) for 96 miles at ~75 mph. According to the car, it's consumption was 241 wh/mile and in total used 80% of battery. Therefore 75+96=171 miles / 80% gives 213 mile real world range!

Whilst travelling back along the M42, I thought it would be a good idea to make sure the car can charge using the supper chargers (better to find out now when I have enough juice) so stopped at Hopwod Park. On arrival the car was at 50% SoC and it took 12 mins to charge to 80%. It started with taking 125kW and ended taking 69kW, so not too shabby. Not bad...

kelvin 660

White SR+ with LFP battery
Aug 21, 2020
570
488
Stonehouse
Here is my 3 month update on my SR+ LFP M3;
  • Battery degradation has been ~0.2% over 3months/3,000 miles or less than 1 mile! Compared to my old NCA SR+ car that had lost 10 miles @ 3,000 miles. So LFP is looking about 10 times less battery degradation than NCA chemistry.
  • Charge speed has been good but I only charge from 7 kW home charger. It probably would be slow on at a supercharger if the battery was cold according to others but if you charge on a long journey that shouldn't be a problem as the battery will be preconditioned prior to charging.
  • Running costs have been low at 960.76 kWh (£53.68) used for 2,938.04 miles driven, giving a 327w/m (including all losses) or 1.83p/m (energy running cost)
  • Regeneration works at 100% SoC but probably at only 1/2 rate and isn't as strong during cold weather 1- 5C at all SoC, so I have to use the brakes sometimes... However not a bad thing as it does exercise the brake pads and stop them seizing up...
  • The car is running well with no rattles, etc. and no software/hardware issues and is still the best car I've owned. Even with it's problematic wipers, auto headlights & phantom braking.
3-month bat deg.jpg
 

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kelvin 660

White SR+ with LFP battery
Aug 21, 2020
570
488
Stonehouse
Some more data on supercharging LFP batteries in cold weather;

LFP battery in the cold (5C) when preconditioned and charging using a SuC- starts charging at ~20kW @ 22% SoC
After 30 minutes SoC went from 22% to 98%

LFP battery in the cold (5C) and not preconditioned and charging using a SuC- starts charging at ~150kW @ 18% SoC
After 30 minutes SoC went from 18% to 47%
 
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kelvin 660

White SR+ with LFP battery
Aug 21, 2020
570
488
Stonehouse
For those people that said LFP batteries might not hold up well in winter time, Bjørn Nyland 1,000 km test proves otherwise...

Battery degradation on my car after 4 months = 0.58% (263.49 > 261.95 miles)
Life time efficiency = 264 Wh/Mile
Life time consumption 1,491.90 kWh used / 4,426.24 Miles driven = 337 Wh/Mile
Not too shabby for mainly winter time driving...
 
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GeorgeSymonds

Active Member
Moderator
Mar 16, 2018
2,158
2,143
UK
From one of his other videos is seems Tesla really screwed up on the software to start with with the heat pump sucking all the heat out the battery and it then performing badly. They seem to now keep the battery warmer which has cured things. I know friends in Switzerland who had an early LFP car and were getting under 50kw charging at a low SoC on a supercharger having driven it for an hour, they'd owned other Teslas which performed much better, they sent the car back within the 7 day rule at the time. Bjorn has since shown a video comparing his early results and shows the battery much warmer, at least it was when navigating to a charger. So its good news they're working ok, but like many things Tesla. a little frustrating they didn't do proper winter testing before releasing the thing.

Kevin - if I understand your figures, there's a big difference between efficency and consumption, its 25% more - am I reading that right?
 
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yessuz

Active Member
Dec 30, 2021
1,085
716
Midlands
I have even noticed the difference having the heater on, when just driving to a supermarket 50KW charger, compared to the same supermarket with no heating this month.

Can't understand why people spend hours on the free 3 or 7KW chargers, LOL
If I had a free 7kw charger very close to home - I would charge it there :D because.. well it's free
 
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kelvin 660

White SR+ with LFP battery
Aug 21, 2020
570
488
Stonehouse
if I understand your figures, there's a big difference between efficiency and consumption, its 25% more - am I reading that right?
You are correct @GeorgeSymonds there is a big difference of around 22.5% between what the car has received compared to what it reported to have use...

Some of that comes from charging losses. For example 1,491.90 kWh used but only 1,375.13 kWh added to the battery accounts for a 7.8% loss to charge the battery, leaving 14.7% for other losses.

These losses could be;
1) for sentry use when parked away from home (I don't use sentry at home)
2) when not sleeping (although my car does sleep well)
3) when stopped in traffic, because the car doesn't count kWh when stationary. So the heater, computer, etc. will be running but not counted
4) battery losses due to its internal resistance. These losses actual heat up the battery.
5) and some on preconditioning, although I haven't done that much this year as its not been very frosty...

I'd be interested to see what losses other people are seeing to see if my car is very different?

Note: all my data is taken from TeslaFi that I have been running since owning the car
Drives > Lifetime map> kWh used whilst driving
Charges > charge summary > kWh added to the battery & kWh used for total consumption
 
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kelvin 660

White SR+ with LFP battery
Aug 21, 2020
570
488
Stonehouse
I found some more information on this subject... Maybe 22.5% loss isn't so abnormal...


 
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Energy loss is everywhere, people think about the charging losses. Petrol and diesel don't have charging losses, but they are only 20 to 35% efficient.
I had a Toyota hybrid before the Tesla and that was let down by the size of the battery and wasn't a plugin. So going down a long steep hill the battery would charge, then you had to waste energy to prevent brake fade once the regen had charged the battery to the 80% limit.
I'm sure going down the same hill in the Tesla would recover a significant amount of charge, because it's not being wasted.

The only regret with buying the Tesla is, I wish i had done it 6 months earlier, when It was nearly £6K cheaper.
 
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GeorgeSymonds

Active Member
Moderator
Mar 16, 2018
2,158
2,143
UK
I knew we had things like vampire drain and sentry mode was hungry, but about 1/4 more was a bit if a shock. I don’t use sentry and I might lose 1 or 2 miles range per day (excluding fluctuations due to temp), but the formula:

Cost per mile = unit cost x wh/m / 1000 appears very optimistic

Out and about, if I rapid charged at 40p kWh and thought I was doing 250 kWh I’d think it was costing 10p a mile, in reality it seems it’s really 12p or so. A bit of reading and think it’s more complicated as some measure kWh used by the charge point and some supplied to the car but the significance of that I’m still not clear, That’s given me some homework to read up on!
 
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Adopado

Well-Known Member
Aug 19, 2019
6,148
4,707
Scotland
Out and about, if I rapid charged at 40p kWh and thought I was doing 250 kWh I’d think it was costing 10p a mile, in reality it seems it’s really 12p or so. A bit of reading and think it’s more complicated as some measure kWh used by the charge point and some supplied to the car but the significance of that I’m still not clear, That’s given me some homework to read up on!

I believe Tesla is one of the few (only?) to cost the charge on the basis of the electricity going into your battery. Most charge the amount of AC they use in their chargers before it is converted to DC and delivered to the car. The concern with that is that they suffer no penalty for running inefficient chargers because you are paying for their losses.
 
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kelvin 660

White SR+ with LFP battery
Aug 21, 2020
570
488
Stonehouse
As the cars efficiency is not just for LFP batteries, I've started a new thread to continue exploring this subject
 
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kelvin 660

White SR+ with LFP battery
Aug 21, 2020
570
488
Stonehouse
Here is my 7 month update on LFP SR+ verse NCA SR+ cars.

Degradation has been 1.5% over 7,300 miles compared to ~7% at the same mileage/age for my NCA.
So I would say that on the degradation front things are looking good.


Battery-1.jpg


Battery-2.jpg


The best difference between my old SR+ (NCA and the new SR+ (LFP) is the increase in range. This is due to how much more efficient the new car has been with the heat pump (worth an addition 26 miles) and the slightly bigger battery capacity of 53kWh (worth an additional 17 miles) giving an average range increase of 43 miles!
That means this car has 20% more range than the old car!


Battery-3.jpg

Graph shows range when charged to 100% for both NCA and LFP

Being able to charge it to 100% every day means the car has a lot more usable range on tap for those impromptu journeys.

So far, I'm very happy with the LFP batteries. There has been no problems with cold weather charging (I mainly charge from home at 7 kW) however I would say that the regen hasn't been as strong as the NCA batteries meaning I have has to use the brake pedal sometimes although that has dramatically improved now the weather is warmer.

I'll update this post when I have one years data...
 
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Here is my 7 month update on LFP SR+ verse NCA SR+ cars.

Degradation has been 1.5% over 7,300 miles compared to ~7% at the same mileage/age for my NCA.
So I would say that on the degradation front things are looking good.


View attachment 799374

View attachment 799375

The best difference between my old SR+ (NCA and the new SR+ (LFP) is the increase in range. This is due to how much more efficient the new car has been with the heat pump (worth an addition 26 miles) and the slightly bigger battery capacity of 53kWh (worth an additional 17 miles) giving an average range increase of 43 miles!
That means this car has 20% more range than the old car!


View attachment 799379
Graph shows range when charged to 100% for both NCA and LFP

Being able to charge it to 100% every day means the car has a lot more usable range on tap for those impromptu journeys.

So far, I'm very happy with the LFP batteries. There has been no problems with cold weather charging (I mainly charge from home at 7 kW) however I would say that the regen hasn't been as strong as the NCA batteries meaning I have has to use the brake pedal sometimes although that has dramatically improved now the weather is warmer.

I'll update this post when I have one years data...
Thanks for the update @kelvin 660, mine has done a similar mileage with same duration and I fully agree LFP is more consistent and the ability to charge 100% everyday is a big relief. I guess the newer 305 miles (60kwh) battery may be the ideal one for my sort of use scenario but LR definitely trumps even if we do occasional long journeys as we do not have to stop just for charging and free to chose wherever we want to stop for comfort break.

I realised that when I was off during Easter break to Cornwall on my way back I completely forgot it was Easter Sunday and planned as per ABRP/Tesla a break at Dart form charging to experience the farm shops etc.,. Only after reaching their I realised it was Easter Sunday and there was no way to use the toilets as Dart farm shopping centre was closed. I had my seven year old with me and he wasn’t buying another stop over for toilet break two miles down in Exeter services. Anyhow at the end we had to stop at Dart form then Exeter and then Amesbury before reaching home. With an LR i could have avoided the stop over in Dart form and moved to Exeter for comfort break and possibly a charging break somewhere else.

SR+ isn’t bad but long trips may be more comfortable, I know @Medved_77 and others had done European road trips on SR+ with good planning, so feasible but with other interests like kids, dogs, nagging wife etc., life is easier with an LR.

LFP batteries aren’t too bad and there is very little reason to chose the LR just based on fears and worries about long term battery performance. In the end a 18 month old LR vs a current SR (305 miles WLTP) may yield the same range other than the practicality of charging 100% everyday and a slightly less powerful car.
 
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Adopado

Well-Known Member
Aug 19, 2019
6,148
4,707
Scotland
Here is my 7 month update on LFP SR+ verse NCA SR+ cars.

That's great LFP info ... and even more useful if you manage to keep the collection of data going for a couple of years.

The very different battery packs in respect of capacity and chemistry clearly make the lion's share of that difference but I am also curious about actual efficiency comparisons, if that's possible i.e. Wh/mile. I have the impression (but little hard data) that my 2019 car with no heat pump has actually improved in that respect in it's second year over its first year. Perhaps this has come via under the hood changes with software updates. (If I had changed to driving a heat pump car over the past year I would have been convinced that I was getting a benefit from that!) My lifetime average dropped from around 260Wh/mile to presently 245Wh/mile and I can't think that there's been much of a change to my overall usage pattern. My figures do benefit from including a low proportion of motorway miles so may not necessarily be comparable to others.
 
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