They did, which is why it lowered before they introduced the smaller capacity battery. In WLTP terms it went from 352 to 340 miles.
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2nd HV battery replacement!
- Thread starter M1tch
- Start date
Jason71
Well-Known Member
That is not what the warranty says though. The warranty says that a replacement battery will have the same or more capacity than the battery it replaced. So there is no "fleet average" or "normal curve" argument to make. The difficulty though is in knowing / agreeing what the capacity of the failed battery was in order to prove or disprove the new one is adequate.
If they replaced one of your seats under warranty and the replacement had a stain on it would you accept that the average two year old car has at least one mark on the seat and just accept it even if yours did not?
This is one of the many reasons I recently decided to sign up to Tessie.
MrBadger
Badger out
It’s my understanding from we had our CAC reset that this is maintained by the BMS. The car (computer?) then uses this value to calculate the range ie CAC * expected efficiency = estimated range.
If a battery is refurbished, say a module swapped, then my hypothesis is that as CAC Is not reflecting ‘new value’, the CAC of the battery is that from the battery before it was refurbished and thus totally unrepresentative of the refurbished state.
Over time the CAC will update to better reflect the true value (they are all educated guesses so will never be that accurate) but by this time, owner of new battery will potentially see below expected range.
An alternative is for the CAC to be reset to the as new value - which is what Tesla did to ours but without a battery swap so we got the original 310 mile back for a short period until BMS found it’s level. This would then make new battery owner very happy as they would have as new range but the range would relatively quickly find a new equilibrium which unless Tesla forewarned the new owner (which they sort of did with us). So swings and roundabouts. My experience of CAC reset is that battery started to find a new equilibrium much quicker than it perhaps (based on lead up to having CAC reset) it would have had we not done anything about it.
Before anyone asks (again), Tesla reset our the CAC unprompted (I didn’t even know what a CAC was at that time) as part of a ‘car range not what customer expects’ query. Our iirc <10k mile/year old car was showing 27x mile range at the time and via TeslaFi I could see two sudden calculated range drops that coincided with firmware updates. It was hinted that this may have been a firmware issue, so we got reset and told to monitor. At 4 years now/30k miles, we show 290 miles at 100% give or take a couple of miles depending on our usage/charge pattern.
To OP, might be worth asking if CAC could be reset and see what they say. You would like to think that as Tesla have swapped even the replacement they have evidence that replacements were sub par.
Collected the car today and after voicing my concerns with the manager, they fetched the master tech who had worked on my car. He understood my apprehension and couldn’t share all my battery data but was able to show me on screen.
Their system orders a battery of equivalent or better capacity if you are due a warranty replacement. Unfortunately the last 2 have been ordered using data from after the point of failure of the original hence the poor range and capacity when I got them. For this one, they manually inputted my capacity from 6 weeks before my failure and ordered a battery using those figures. They showed me those figures and the comparison to this one which is ever so slightly better.
The car has been for a few short runs today and now on the home charger to 100%. It’s already got an additional 10 miles from yesterday’s figures. It should use 60-70% for the drive back to work tonight and then I’ll top it up and see what it shows. Will only be back to 80% then shut it down till Christmas.
Hopefully it settles down and this is back to the range I had when this all started in April.
Tesla had a massive amount of data on my car! Made Tessie look very basic
Their system orders a battery of equivalent or better capacity if you are due a warranty replacement. Unfortunately the last 2 have been ordered using data from after the point of failure of the original hence the poor range and capacity when I got them. For this one, they manually inputted my capacity from 6 weeks before my failure and ordered a battery using those figures. They showed me those figures and the comparison to this one which is ever so slightly better.
The car has been for a few short runs today and now on the home charger to 100%. It’s already got an additional 10 miles from yesterday’s figures. It should use 60-70% for the drive back to work tonight and then I’ll top it up and see what it shows. Will only be back to 80% then shut it down till Christmas.
Hopefully it settles down and this is back to the range I had when this all started in April.
Tesla had a massive amount of data on my car! Made Tessie look very basic
All in all, I think this is going to be the one 
As far as i understand it the calculation to determine the amp hour capacity of a battery is to multiply the single cell capacity and multiply it by the number of cells present that make up the entire battery pack. A single cell output is a known figure.
Tesla have a few different chemical compositions and indeed even battery types, plus ongoing development has increased the single cell density, The bigger battery packs have ranged between 75Kwhr, 78Kwhr, 82Kwhr.
The cells used on the S and X were 18650s, for the model 3 they introduced the 2170s in both NCA and LFP formulas.
The standard range used to have 2976 cells and the LR and P had 4416 cells, (based on the 60Kwhr and 75Kwhr battery) each cell had an output circa 4.8MAhr.
Again, as I understand it - The range estimate is based by whatever algorithm is applied from the data provided by the battery management system, The BMS's job is to oversee each module that makes up the entire battery, each cell being collectively managed within the number of modules and making a note of what energy is put in and then deducting what goes out - however, there is always going to be fractions within the calculations that just get lost - so over time the BMS's data gets less accurate in regards to what's left in the battery and of course that affects what it reports is available for the calculation of range.
In this particular case if the battery fitted was a refurbed unit - then assume other used but within spec battery modules have been put in replacing modules that were seriously underperforming (so either individual cells within the module have degraded or indeed the thermal fuse connection has broken) then the entire battery needs to be run through a few discharge and charge cycles before the BMS can truly calculate the capacity to a reasonably accurate standard.
Just to sort of explain that a little easier - we all know that those who are brave enough can run the car until it reports no miles left and still drive for miles - this means the BMS has calculated there is no energy left within the cells it can use to determine how far the car will go because that energy doesn't exist in its memory. Suppose the car was driven until It gave up completely - and then charged to 100% - The BMS will now know exactly how much electricity has passed through the system to charge the batteries until each module indicates it has no more room for any electrons - and charging ceases.
The BMS would report whatever that total charge was as being 100% capacity and the algorithm applied to determine the projected range.
I think that only the test of time for @M1tch on this one and after a few cycles will determine the full potential of this battery, however, time is the one thing in abundance with it - plenty more time under the warranty left plus if the new battery proves to be another defective battery then UK law provides 6 years from the point you discover the issue under the Law of Tort - "Negligence" Negligence is a failure to do something you should have done or you did something you shouldn't have done - so in this case Tesla were negligent in not providing a comparable battery to the original that was fitted - but litigation is perhaps some way off as this new battery will need to be "conditioned" before any judgement can be ascertained.
Tesla have a few different chemical compositions and indeed even battery types, plus ongoing development has increased the single cell density, The bigger battery packs have ranged between 75Kwhr, 78Kwhr, 82Kwhr.
The cells used on the S and X were 18650s, for the model 3 they introduced the 2170s in both NCA and LFP formulas.
The standard range used to have 2976 cells and the LR and P had 4416 cells, (based on the 60Kwhr and 75Kwhr battery) each cell had an output circa 4.8MAhr.
Again, as I understand it - The range estimate is based by whatever algorithm is applied from the data provided by the battery management system, The BMS's job is to oversee each module that makes up the entire battery, each cell being collectively managed within the number of modules and making a note of what energy is put in and then deducting what goes out - however, there is always going to be fractions within the calculations that just get lost - so over time the BMS's data gets less accurate in regards to what's left in the battery and of course that affects what it reports is available for the calculation of range.
In this particular case if the battery fitted was a refurbed unit - then assume other used but within spec battery modules have been put in replacing modules that were seriously underperforming (so either individual cells within the module have degraded or indeed the thermal fuse connection has broken) then the entire battery needs to be run through a few discharge and charge cycles before the BMS can truly calculate the capacity to a reasonably accurate standard.
Just to sort of explain that a little easier - we all know that those who are brave enough can run the car until it reports no miles left and still drive for miles - this means the BMS has calculated there is no energy left within the cells it can use to determine how far the car will go because that energy doesn't exist in its memory. Suppose the car was driven until It gave up completely - and then charged to 100% - The BMS will now know exactly how much electricity has passed through the system to charge the batteries until each module indicates it has no more room for any electrons - and charging ceases.
The BMS would report whatever that total charge was as being 100% capacity and the algorithm applied to determine the projected range.
I think that only the test of time for @M1tch on this one and after a few cycles will determine the full potential of this battery, however, time is the one thing in abundance with it - plenty more time under the warranty left plus if the new battery proves to be another defective battery then UK law provides 6 years from the point you discover the issue under the Law of Tort - "Negligence" Negligence is a failure to do something you should have done or you did something you shouldn't have done - so in this case Tesla were negligent in not providing a comparable battery to the original that was fitted - but litigation is perhaps some way off as this new battery will need to be "conditioned" before any judgement can be ascertained.
Hey this looks pretty awesome. What app is this if you don't mind me asking? It's not the default tesla app right?It definitely wasn’t a new battery. From the readings I’ve taken it has done 45-50k miles. I’m on 23k. Either way the degradation was unworkable, I wouldn’t have got from home to work (or vice Versa) without a charge in the winter.
View attachment 950102
Just look at the drop in range / capacity in just a few weeks!
Tx
Wait, so if your battery is knackered and needs replacing the system automatically orders another knackered one to replace it unless the technician intervenes manually?
It's Tessie app. It also has a web interface. Accesses the Tesla API like Teslafi and the self hosted Teslamate.
Replacement batteries 1, 2 and 3!
The car estimated a remaining percentage of 22% when I left home tonight. This slowly climbed and got back with 33%. I am happy it’s fixed.
And I also didn’t notice a drop in power - but damn this feels quick!
maybe a pseudo effect but it is amazing!Similar threads
