USA MY RWD has soft limited LR battery!

[bzobzo]

From my POV, a software limited NCA pack and an LFP (w/o software lock) offer many of the same advantages. I think I’d be happy with either. The only scenario I wouldn’t like the current RWD is a smaller NCA pack.

I'm actually happier to have this software limited NCA pack than the LFP because you have decent charge speed right up to 100% making the capacity usable on longer trips. And I have a feeling a NCA pack that is never charged past 80% will have comparable life to an LFP that is regularly charged to 100%. If one goes with the recommended 80% charge (for a physical 64% charge) the degradation of the battery should be extremely low.

Id love to see a full charge curve, or at least a test of peaking charging speeds from 10-20%. If it can hit 250kw that’s also very strong evidence it’s a big pack (although I guess they may limit charging speed artificially as well)

The specs of the RWD show the peak charge speed at 170kw. However, this is probably software limited by the handshake between the car and the charger. I guess confirmation of this would be if there was a flat charge rate of 170kw from 0% to whatever charge state the regular LR pack reduces down to that speed. It'll be a while before I am able to test this as I don't drive a whole lot and it'll take some time to run down the battery.

 

[ucmndd]

Would be interesting to see a real full charge test with proper preconditioning. If ~20% of the battery is really locked out it it should be charging more like 60kw at 99%.

There’s obviously more room in the pack based on that charging speed so clearly there’s a software limit, but I wonder how much. The 170kw supercharging speed limit is head scratching. Not sure why they’d do that if it’s a full LR battery (product differentiation doesn’t make a lot of sense here, not at the expense of cars clogging superchargers by charging artificially slower than they can).

Is there a visible battery part number / sticker anywhere on the 3/Y like there is the S/X?

 

[mborkow]

Would be interesting to see a real full charge test with proper preconditioning. If ~20% of the battery is really locked out it it should be charging more like 60kw at 99%.

There’s obviously more room in the pack based on that charging speed so clearly there’s a software limit, but I wonder how much. The 170kw supercharging speed limit is head scratching. Not sure why they’d do that if it’s a full LR battery (product differentiation doesn’t make a lot of sense here, not at the expense of cars clogging superchargers by charging artificially slower than they can).

Is there a visible battery part number / sticker anywhere on the 3/Y like there is the S/X?

OP posted this: “At the supercharger at 99% charge it was still charging at a 35kW rate”

 

[ucmndd]

OP posted this: “At the supercharger at 99% charge it was still charging at a 35kW rate”

And?

 

[mborkow]

And?

Sorry, I misread your post. I thought you were asking what the charge rate was at 99%.

 

[bzobzo]

Would be interesting to see a real full charge test with proper preconditioning. If ~20% of the battery is really locked out it it should be charging more like 60kw at 99%.

There’s obviously more room in the pack based on that charging speed so clearly there’s a software limit, but I wonder how much. The 170kw supercharging speed limit is head scratching. Not sure why they’d do that if it’s a full LR battery (product differentiation doesn’t make a lot of sense here, not at the expense of cars clogging superchargers by charging artificially slower than they can).

Is there a visible battery part number / sticker anywhere on the 3/Y like there is the S/X?

From what I have read, the battery sticker is not easily accessible on the 3/Y.

In this video showing the charge curve of the LR, it only sustains a greater than 170kW rate up to about a 28% SOC. Given that people will rarely be charging from less than 10%, it's a pretty small window of greater than 170kW speed, and would make a minor difference in overall charge time. The LR at 80% SOC, which is presumably about what the software limited 100% is, the video is showing a 47kW speed.

 

[gsmith123]

since they publicly state max charging speed as 170kw wouldn't it follow that they would also software limit that?

It's certainly possible Tesla elects to software limit the charging curve. But I'm not totally convinced they'd want to heavily limit it.

The reason they wouldn't want to artificially limit speed is it clogs up Superchargers. They have a huge incentive for the charging experience to be as good as possible for everyone. And they want to make as much revenue from their installed Superchargers as possible, so fast charging = more money from the same charger.

Admittedly one reason they may want to limiting charge speed is to reduce DC fast charging incurred degradation, which in turn reduces warranty costs. But warranty replacements for 3/Y are pretty rare already, and it's not clear that DC fast charging speed actually has any impact on degradation or warranty rates. Tesla has this data; we don't.

In theory it could reduce demand for higher margin LR trims (assuming people know which is questionable)

 

[PeterAAA]

fingers crossed, hoping this is true. I have one to deliver in next week. my vin is 7SAYGDED9PF943XXX vs 7SAYGDED9PF946XXX. does that mean mine was manufactured 3k units earlier?

 

[bzobzo]

Did another charging session today from 50% to 100%. Preconditioned longer this time, not until the notification showed preconditioning complete, but at least 20 minutes and at warmer temps. Based on the results, I'm starting to think the battery is top and bottom limited, using something like 10% to 90% of the battery. This seems more sensible, as it would protect the battery on both low and high charge extremes. If this is true, I wonder if the car lets you access a whole 10% of the battery as buffer when showing empty???

I found a more comparable charge curve to compare with on a US MY LR, as the video I linked previously is an EU car.

RWD Displayed SOC	Charge Rate	LR SOC at Charge Rate	LR SOC % of RWD SOC %
50%	137kW	43%	86%
60%	100kW	56%	93%
70%	85kW	66%	94%
80%	71kW	72%	90%
90%	48kW	83%	92%
95%	40kW	88%	93%
99%	35kW	90%	91%

Average LR SOC % of RWD SOC % at given charge rate - 91%

US MY LR charge curve source:

 

[ucmndd]

I'm starting to think the battery is top and bottom limited, using something like 10% to 90% of the battery. This seems more sensible, as it would protect the battery on both low and high charge extremes.

This would be different than every other software lock Tesla has ever done and there aren’t really any good “battery health” reasons for locking out that much of the bottom of the range.

My completely baseless speculation: I wonder if they’ve brought something like the old Model 3 “mid range” pack back, which was a LR pack missing some cells.

That pack capacity with 8-10% of it locked out would just about fit what we’re looking at, explain the lower max charge rate, etc etc.

 

[bzobzo]

there aren’t really any good “battery health” reasons for locking out that much of the bottom of the range.

From what I have read, my understanding is that both high and low states of charge increase wear on the battery. You'll often see the advice to try and use the 20%-80% charge state in general for lithium ion batteries.

 

[Boedha-Online]

In the Netherlands a rwd weighs 1884 kg / 4153.5 LBS and that's a LFP battery

If you hook op scan my Tesla you can check the pack voltage when fully charged and might determine if it's a LFP or not

Battery LFP​

Nominal Capacity *	60.0 kWh
Battery Type	Lithium-ion
Number of Cells	106
Architecture	400 V

Useable Capacity*	57.5 kWh
Cathode Material	LFP
Pack Configuration	106s1p
Nominal Voltage	340 V

Battery Long Range​

Nominal Capacity	78.1 kWh
Battery Type	Lithium-ion
Number of Cells	4416
Architecture	400 V

Useable Capacity*	75.0 kWh
Cathode Material	NCM
Pack Configuration	96s46p
Nominal Voltage	357 V

 

[ucmndd]

From what I have read, my understanding is that both high and low states of charge increase wear on the battery.

A lot of what you read on any subject is untrue. Low states of charge do not increase “wear” on lithium batteries in any way. In fact, the lower the better to minimize calendar aging.

 

[ucmndd]

If you hook op scan my Tesla you can check the pack voltage when fully charged and might determine if it's a LFP or not.

It seems quite clear at this point it’s not LFP.

 

[bzobzo]

This would be different than every other software lock Tesla has ever done and there aren’t really any good “battery health” reasons for locking out that much of the bottom of the range.

One thing I noticed is that the voltage curve on Lithium Ion batteries is still very flat to 80%. They may have needed to let the full charge go higher than that to allow the BMS to reliably determine the full capacity of the pack. Obviously charging to 80% most of the time is fine as that is what they recommend, but I suspect if you don't charge higher than that occasionally, the BMS estimated state of charge will get less accurate over time.

 

[PeterAAA]

I have picked up my MY RWD. Nov. 2023 manufactured. Fremont.
Here are some fast-charging data points. Battery was pre-conditioned.
76%,75KW
80%,71KW
85%,64KW
88%,52KW
90%,49KW
Did not wait to charge to 100%.

I noticed the fog lights actually have glass lens inside, but I was not able to find the switch on the screen.

software version: v11.1 (2023.38.200.....)

 

[kpanda17]

I’m about to buy USA Austin MY RWD and yes, it does NOT have LFP.

Are we all agreeing that this LR pack is software limited to 260 miles and can charge and use to 100% without damage?
If true, that is great news. It’s like having LFP but better in cold temps.
Also if true, shouldn’t the charge curve be the same as the LR pack?

LR 330 miles
RWD 260 miles or 79% of above
Supercharging 3/250KW, the rate should be at 60kw when at 100% or 75% LR pack charge capacity
Someone did the same analysis earlier in the thread?

 

[E90alex]

I’m about to buy USA Austin MY RWD and yes, it does NOT have LFP.

Are we all agreeing that this LR pack is software limited to 260 miles and can charge and use to 100% without damage?
If true, that is great news. It’s like having LFP but better in cold temps.

Depends what your goal is. Charging to 100% itself isn’t damaging to the battery. It’s not great to leave it there for a long period.

If you want to minimize degradation then I wouldn’t charge to 100% all the time. It seems it’s limited to about 80% of the LR capacity so 100% on the RWD is actually about 80% true SoC, which is still not the best for reducing degradation.

Below ~55% is ideal for minimal degradation so I would charge to below ~70%.

Or even just stick with 50% if that’s enough for your use, which would be ~40% in actuality.

 

[bzobzo]

Also if true, shouldn’t the charge curve be the same as the LR pack?

LR 330 miles
RWD 260 miles or 79% of above
Supercharging 3/250KW, the rate should be at 60kw when at 100% or 75% LR pack charge capacity
Someone did the same analysis earlier in the thread?

Check out my figures further up the page. The charge rates seem to map to charging to 90% of the LR battery. If it is the same battery as the LR, that would seem to imply that they are limiting both the top 10% and the bottom 10% instead of just the top 20%. Another theory mentioned was that it could be another battery pack smaller than the LR pack, but still software limited.

We need lower level data from something like ScanMyTesla for a more definitive answer.

 

[mborkow]

Check out my figures further up the page. The charge rates seem to map to charging to 90% of the LR battery. If it is the same battery as the LR, that would seem to imply that they are limiting both the top 10% and the bottom 10% instead of just the top 20%. Another theory mentioned was that it could be another battery pack smaller than the LR pack, but still software limited.

We need lower level data from something like ScanMyTesla for a more definitive answer.

A smaller battery pack that’s also software limited makes more sense, I think, than rate limiting the charging or locking the bottom 10% of the battery. That would allow them to actually reduce their cost while achieving some level of product differentiation. If that was the case, it would mean you could charge up to ~90% w/o any more deleterious effects than charging the MYLR to 80%: 234 vs 264 miles.