Battery packs, a decision factor?

[KungFuJesus]

This is the real world degradation of NMC batteries in Tesla

IIRC these are numbers from Tesla and doesn't reflect real-world numbers reported by users. Car And Driver has seen about 7% loss in just ~38,000 kms (24,000 miles) or so of driving which is slightly better than the figure many people have typically reported. This would be a little more than two years' worth of the average driving done by most car drivers in Australia.

There's a master thread in the Model 3 forum with a few people mentioning upwards of 10% loss in their first year. Candleflame is a regular there and might be able to offer more insight as I've only skimmed the surface.

Battery degradation won't be a huge issue to people who don't keep their vehicle long term.

 

[cafz]

If you rely on "what people have reported on forums", you're going to see a worse value than the true fleet average, because the people most motivated to post on forums about degradation are the ones that have suffered the most.

 

[gm12]

If you rely on "what people have reported on forums", you're going to see a worse value than the true fleet average, because the people most motivated to post on forums about degradation are the ones that have suffered the most.

I agree. For the past few months, I've only been charging my LR once a week, because I'm just driving around town. I dont charge until it gets below 40%, then charge up to 90%. At once a week, its going to take me 57 years to get to the 3000-cycles 'may have issues' with my battery pack. Me, or the rest of the car will be dead before the battery dies.

One of the reasons to buy a Tesla, is they have proven runs on the board about battery degradation and lifespan compared to other brands.
You buy a leaf, you know its going to die quickly due to air cooled.
You buy a Chevy Bolt, its going to catch fire.
You buy a Taycan, rumours coming in about battery short-circuits due to the 800v architecture.
You buy another new brand, you take your chances.

Those other brands are playing catch-up, and maybe taking short cuts.

Tesla is the only safe bet right now. NMC or LFP.

 

[Vostok]

For the past few months, I've only been charging my LR once a week, because I'm just driving around town. I dont charge until it gets below 40%, then charge up to 90%. At once a week, its going to take me 57 years to get to the 3000-cycles

The time it takes you to get to 3000 charge cycles is the same regardless of whether you charge once a week or daily, for the same total distance/energy used over that time.

 

[doggy1]

I also think there is absolutely no way a LR battery is going to go 3,000cycles. This does not worry me. I am hoping that mine goes somewhere from 600 to 1,000 which would likely be 240k to 400k kms. I'm typically charging to 80%.

 

[Flatbat]

I also think there is absolutely no way a LR battery is going to go 3,000cycles. This does not worry me. I am hoping that mine goes somewhere from 600 to 1,000 which would likely be 240k to 400k kms. I'm typically charging to 80%.

I wonder what is considered a cycle? Is it just a charge event?

 

[Lozza12]

I wonder what is considered a cycle? Is it just a charge event?

It’s a full 100-0% battery use.

 

[Flatbat]

It’s a full 100-0% battery use.

Oh good I am never likely to do that. So no cycles on my battery ;-) Has been charged about 1200 times though in two years.

 

[doggy1]

The number of battery cycles is given approximately by the total kwhrs you have put into (or taken out of) your battery divided by the kwhr capacity of your battery. For example, if you have put 1,000kwhrs into a LR battery and the nominal capacity of that battery is 74.5kwhrs, then your battery has done just over 13 cycles. If you regularly charge to 100% on a NCM battery rather than (for example) 80%, your battery will last less cycles. So, you can drive less total distance before a particular degradation level. LFP batteries have less negative impact from full charging and discharging. However, there are other things that also affect lithium battery life. Such as heavy charging/discharging rates (so, if you slam the foot to the floor everywhere and only use supercharging). Also, there is a time based degradation. Also, if you leave any Lithium battery at high (e.g. 100%) charge level for days at a time there will be more degradation than at lower charge rates. Temperature also affects battery life plus SOC versus temperature.

 

[moa999]

The time it takes you to get to 3000 charge cycles is the same regardless of whether you charge once a week or daily, for the same total distance/energy used over that time.

And it's likely we'll over 1 million km

 

[pts260]

Re LFP vs NCA capacity vs cycle life. LFP is the winner. This was an interesting takeaway from this video.

 

[rx80]

Oh good I am never likely to do that. So no cycles on my battery ;-)

That probably is not the right way to look at it.
As far as I know, it doesn't have to be 100-0 in single trip to be considered a single cycle

1. 100 - 0 = 1 cycle
2. 2 times of 50 - 0 = 1 cycle
3. 5 times of 60 - 40 = 1 cycle

 

[Vostok]

That probably is not the right way to look at it.
As far as I know, it doesn't have to be 100-0 in single trip to be considered a single cycle

Did you miss @Flatbat’s smiley?

Your description is correct.

 

[rx80]

Did you miss @Flatbat’s smiley?

Oh yeah, just saw that actually . Hope I didn't offend anyone

 

[CumminsTomic]

Re LFP vs NCA capacity vs cycle life. LFP is the winner. This was an interesting takeaway from this video.

If you apply more weight to earlier life, as what most people would care about in a passenger car, Tesla seems to have balanced them just right

 

[Flatbat]

Oh yeah, just saw that actually . Hope I didn't offend anyone

All good. Yes was tongue in cheek

 

[Hairyman]

And it's likely we'll over 1 million km

1.26 million km for me and I don’t have a particularly efficient driving pattern.

 

[Candleflame]

Forget the lab, This is the real world degradation of NMC batteries in Tesla's.

Redirect Notice

About 9% after 250,000 km.
LR starts with 25% more range than SR+.
And the SR+ will still degrade.

degradation is much higher in hot climates. I.e. I have 16% at 40k kms.

 

[CumminsTomic]

degradation is much higher in hot climates. I.e. I have 16% at 40k kms.

Why would degradation be higher in hot climates?
BMS keeps pack to around 20-50C in normal operation. Even if you park your car out in the sun, it should be perfect for the battery.

 

[Candleflame]

Why would degradation be higher in hot climates?
BMS keeps pack to around 20-50C in normal operation. Even if you park your car out in the sun, it should be perfect for the battery.

So for one the BMS cooling trigger is around 45 or 50C which doesnt trigger in hot climates (as the pack is at 30-32Cish normally) and secondly, when the pack is at 30C you get A LOT more heat related degradation than i.e. at 10-15C which is what the pack sits at most of the time if you dont live in the tropics.

Target operating temperature while driving is 45C - which however doesnt occur all day long but only while you are driving.

Having your batterypack sit at 32C 24/7 is definetely not good for the battery and unfortunately even when you store your car at 40% in the heat, thats still worse than a car sitting at i.e. 100% when its at 5C.