Performance not performing

[btc1k]

Could someone explain why the blame is being put against the heat pump? apologies if it's in one of the posted videos as I've not watched them.
The sole purpose of a heat pump is to reduce the current draw for heating (and provide cooling). In uk weather (so +5/10 degrees around now) I'd still expect around a 2x return on energy-in to heat-out. So if anything the current draw on running a resistive heater and/or inefficiently running the motors on a 2019 model should have more of an impact on available power to the motors than a heat pump system on the new cars. What am I missing?

Covered previously in the thread.

It is thought the heat pump scavenges heat from the battery for cabin heating; battery performance then drops as we know batteries perform better when warm.

In the tests, the performance on the P dropped significantly as battery temps decreased from 28c to 8c.

With battery temp low, the battery then either struggles and/or limits max power output.

You can see this happening in the data from the spreadsheets that Bjorn made.

In the same tests, a 2019 P with no heat pump - battery temps are stable.

But interestingly the 2021 LR with heat pump also has battery temp reduce but the battery manages to hold peak power output both higher and more reliably.

 

[Mattallica]

Could someone explain why the blame is being put against the heat pump? apologies if it's in one of the posted videos as I've not watched them.
The sole purpose of a heat pump is to reduce the current draw for heating (and provide cooling). In uk weather (so +5/10 degrees around now) I'd still expect around a 2x return on energy-in to heat-out. So if anything the current draw on running a resistive heater and/or inefficiently running the motors on a 2019 model should have more of an impact on available power to the motors than a heat pump system on the new cars. What am I missing?

The heatpump tech employed in the M3 is designed to scavenge heat from other sources - one being the battery. As we know, the battery needs to be at a set temperature for optimum energy release, so this constantly saps the balancing of the battery temperature.

 

[Jez_GB]

But interestingly the 2021 LR with heat pump also has battery temp reduce but the battery manages to hold peak power output both higher and more reliably.

There are sufficient comments and thoughts along these lines, and from people far cleverer than me, that are the main reason I'm sticking with my order for a P rather than swapping to an LR - this should be a relatively easy fix via software and the parameters are known for the LR - so once sufficient data is gathered for the P (if it's not already) a fix will be forthcoming.

I reserve the rights to eat my words at some future point!

 

[btc1k]

There are sufficient comments and thoughts along these lines, and from people far cleverer than me, that are the main reason I'm sticking with my order for a P rather than swapping to an LR - this should be a relatively easy fix via software and the parameters are known for the LR - so once sufficient data is gathered for the P (if it's not already) a fix will be forthcoming.

I reserve the rights to eat my words at some future point!

You would think so.

What concerns me is that these issues were first reported in January and yet here we are end of April with the OP reporting worse performance than the original reports.

So thats 4 months, in winter, where a fix could (and should) have been quickly applied.

if i bought the top spec model, i’d kind of want it to work to specification rather than being a beta tester.

seems to be how Tesla operate though

 

[M3P_W8]

What concerns me is that these issues were first reported in January and yet here we are end of April with the OP reporting worse performance than the original reports.

So thats 4 months, in winter, where a fix could (and should) have been quickly applied.

I had thought that the 2021 M3P with heat pump first hit the streets in October 2020. 3 months (in winter) before the Bjorn video that seems to have brought the issue to everyone's attention.

 

[btc1k]

I had thought that the 2021 M3P with heat pump first hit the streets in October 2020. 3 months (in winter) before the Bjorn video that seems to have brought the issue to everyone's attention.

Stand corrected

 

[15Peter20]

Having been told my battery issues (intermittently getting zero regen, reduced power) would require a replacement battery, I've now been informed that a firmware update should have done the job.

Picking the car up later so hopefully that's it sorted, but I'm a bit concerned the battery may have been damaged, or at least suffered accelerated degradation as a consequence. I guess TeslaFi is my friend.

 

[Dangerous Fish]

Agree.

I guess from a physics point of view - and this is the same with ICE cars - once you get into the realm of a 4 sec 0-60, you need an ever increasing amount of power to achieve marginal performance gains.

I was surprised to see, in one of the Carwow videos, that the LR had a shorter stopping distance than the P as well. I guess the extra inch on the front discs would just help with cooling as you say - you'd have to be driving pretty mental to have a brake overheating problem on UK roads

I think this video is much more informative regarding the difference in brakes on the LR and P:

 

[CorneliusRox]

I think this video is much more informative regarding the difference in brakes on the LR and P:

Just for everyone's reference, a big brake kit is not supposed to be superior in a one time event. They're very much designed for dissipating heat.
If you were to take a standard LR brake package to a tight track with standard pads, you'd find yourself with a lot of brake fade pretty quickly. Both from degassing on the pads, but also from boiling the fluid. The BBK's would likely be very consistent.
If you have your BBK for show, there are other pads you can get that give you more bite at the trade off of brake fade at a track. EBS Yellow Stuff is typically my go-to for that.

 

[Mrklaw]

What does the heat pump do? Does it onjynscavenge heat from the battery/motor for the cabin, or does it scavenge from ambient air also for the cabin and heating the battery?

Heat pump is for efficiency but in normal driving doesn’t the battery need to warm up so you don’t want to pull heat from there so I’d assumed it just pulls from the air and it’s more efficient than a resistive heater mainly for the cabin

edit: I see covered but is this known that it pulls from the battery or a theory? If so it seems a pretty obvious misstep which is strange as Tesla seem big on battery temperature management

 

[Adopado]

edit: I see covered but is this known that it pulls from the battery or a theory? If so it seems a pretty obvious misstep which is strange as Tesla seem big on battery temperature management

The battery also requires to be cooled as well as warmed... there's an entire system in all our battery packs for that purpose. The heating and cooling can go in either direction. ... and yes, of course the heat pump takes heat from the air as well (basically AC in reverse) and from the motors too.

 

[GeorgeSymonds]

I've mentioned it before but the significance seems to have been missed, and i can't be certain but I think its material info for those thinking of switching to the LR.

The new BT42 battery was ONLY fitted to the M3P to start with, and it now being fitted to the LR so comparisons of early 2021 LR cars and 2021 M3P were almost certainly comparing the old battery with new. It's therefore entirely possible that the the LR on the new battery will have the same issues (and same fix when it comes) as the first crop of M3Ps are experiencing

 

[Aggs18]

Had the below from Tesla today after I expressed my concerns about people having problems with performance and only took 5 days so quite quick for them:


I assure you, once you have taken delivery of your new Tesla, the doubts you currently may have will be hopefully change.
I assure you, once you have taken delivery of your new Tesla, the doubts you currently may have will be hopefully change.
Tesla is aware of some customers concerns raised against the operation of the 2021 Model 3 Performance vehicles in low temperature climates and we are currently investigating those concerns. Rest assured that we take our customer concerns seriously and ensure that they are investigated with the appropriate urgency and diligence. Some improvements have been made in the Software version 2021.4.11 that is now being rolled out to vehicles with Over-The-Air update. Additional investigations to further improve the performance are still underway.
You will find that all Tesla vehicles will reduce their acceleration capability to preserve battery charge. This however starts to come into effect around 15% battery charge.

 

[MrBadger]

Good to see that all that experience of writing dodgy instruction manuals has paid off and landed them a job at Tesla

 

[NewbieT]

Latest update a couple of weeks ago did something but no idea what “Minor cold weather improvements”.



Throughout winter I religiously pre-heated. Now a couple of times recently c10deg I have noticed that when I don’t preheat, the give-way junction at the bottom of my road, the car feels like it almost stalls. It moves off the line, then pauses momentarily before finding power from somewhere. Really disconcerting when pulling out of that junction. Fine after a little driving to warm the pack.

2021 LR heat pump. Dec ‘20 delivery. No idea what the battery is (has anyone bothered checking the label on the froof theirs?).

 

[Plagued]

Covered previously in the thread.

It is thought the heat pump scavenges heat from the battery for cabin heating; battery performance then drops as we know batteries perform better when warm.

The heatpump tech employed in the M3 is designed to scavenge heat from other sources - one being the battery. As we know, the battery needs to be at a set temperature for optimum energy release, so this constantly saps the balancing of the battery temperature.

Thanks. This is where my confusion was, as the standard octovalve in the pre heat pump model is also set to scavenge heat from where it is needed, which I was failry sure Munro had stated included the battery. But it does seem that the way the new heat pump prioritises the heating is perhaps different.
Should be a nice easy fix, people who wanted the faster car will just have to sit in the cold until the battery is nice and warm, then they can have some heat! That's no different to some of the earlier performance cars that wouldn't output any water to the heater matrix until the thermostat on the engine side had opened when the engine was nice and warm

 

[Jason71]

Well lets hope its software because Tesla's track record of acknowledging / fixing anything hardware related on existing vehicles is not great, Not saying they are necessarily any worse than any other manufacturer in that regard, but that's not saying much.

 

[AndrewGR]

One problem often experienced with heat pumps in cold damp climates like ours is that the ‘radiator’, or coil through which the air from which the heat is taken, gets covered in frost. The system then has to be reversed for a while to defrost the coil. I wonder how well the M3 copes with this problem given that most of.it doesn’t seem to have been designed with damp air in mind? I like the way the electric heater in my pre heat pump M3 heats the cabin very rapidly and although regen is reduced in the cold I’ve never noticed a power difference.

 

[CorneliusRox]

You will find that all Tesla vehicles will reduce their acceleration capability to preserve battery charge. This however starts to come into effect around 15% battery charge.

This is exactly what I noticed on mine. I don't have a Dragy box or anything fancy, but a crappy phone app and my butt showed that 15% was the tipping point for sure.

 

[jliver33]

Apologies for the delay in updating the thread.

I wanted to give Tesla an opportunity to rectify the issues. The car went into a service centre for them to have a look but the official line remained the car was operating "within spec". It came back to me with a software update which helped a little, but not much.

To cut a long story short, with the latest software the car maintains good acceleration at a slightly lower SoC (until 40% now)... and then it just tails off.

There was a new problem though in that the car was just "laggier"
You'd be rolling slowly out of a junction, floor it, there would be a little power for a second, then it would quickly build up to full but it wasn't snappy.

Sub 40% the acceleration is SLOW and you can physically feel something is holding it back. All the testing I could do, I did at night, luckily for me it's been relatively cold overnight despite the sunshine in the day and it's the cold temperatures where it suffers. Had one night where it was 6c and another where it was 11c.

I did manage to get a long chat with a tech at the service centre who was quite open with his thoughts and let's just say this is not an "easy fix". He said that the delivery delays to new P's which is now apparently many months is related.

Anyway. My personal problem is I didn't buy a performance car to have it operating as one only half the time so it's gone back and in time I might look at the long range, my workmate's one is absolutely fine in the same conditions. The P's seem to be a bit of an egg.