Tesla reduced range
Discussion
DJP31 said:
The supercharging throttling, and I’m not certain which packs but think it is the 90’s, starts when the DC charging reaches 2,625kWh. It then continues to taper down until 13,125kWh and then levels out. This was the case 18 months or so, no idea if it still is.
The kWh figures vary but ALL S/X Tesla packs throttle after hitting the internal counter, including the 60/75 and 100kWh packs.The only S/X pack that wasn't known to throttle was the 85s, but now that's clearly changing.
Model 3 no one knows yet.
Not sure why anyone is remotely surprised by this - the 18650 cells in an S are very standard stuff, and their characteristics are well known. They’re the same batteries that used to power laptops before Li-Po became popular because you can turn it into funny shapes. If you want them to last a long time, you charge them at less than C, so an 85kW/h battery pack should only ever be changed at 85 kW, max. Ideally it would be charged at 0.5C.
Beating the crap out of them at 3C will lead to reduced life, and all the BMS can really do is throttle the charge current. The BMS may well be really good at balancing the charge across every cell, but you’re still killing the batteries by charging them so fast. The simple rule is that if you charge a pack to capacity in less than an hour, you’re abusing it. Ideally it would take about 3 hours to reach full charge, with about 80% after an hour.
Beating the crap out of them at 3C will lead to reduced life, and all the BMS can really do is throttle the charge current. The BMS may well be really good at balancing the charge across every cell, but you’re still killing the batteries by charging them so fast. The simple rule is that if you charge a pack to capacity in less than an hour, you’re abusing it. Ideally it would take about 3 hours to reach full charge, with about 80% after an hour.
rxe said:
Not sure why anyone is remotely surprised by this - the 18650 cells in an S are very standard stuff, and their characteristics are well known. They’re the same batteries that used to power laptops before Li-Po became popular because you can turn it into funny shapes. If you want them to last a long time, you charge them at less than C, so an 85kW/h battery pack should only ever be changed at 85 kW, max. Ideally it would be charged at 0.5C.
Beating the crap out of them at 3C will lead to reduced life, and all the BMS can really do is throttle the charge current. The BMS may well be really good at balancing the charge across every cell, but you’re still killing the batteries by charging them so fast. The simple rule is that if you charge a pack to capacity in less than an hour, you’re abusing it. Ideally it would take about 3 hours to reach full charge, with about 80% after an hour.
No surprise to me and all good sense above for Lithium ion batteries.Beating the crap out of them at 3C will lead to reduced life, and all the BMS can really do is throttle the charge current. The BMS may well be really good at balancing the charge across every cell, but you’re still killing the batteries by charging them so fast. The simple rule is that if you charge a pack to capacity in less than an hour, you’re abusing it. Ideally it would take about 3 hours to reach full charge, with about 80% after an hour.
Gangzoom's lost 3% in his X?. My Leaf has gone 3 further and has a battery 1/4 the size so has been roughly cycled 10 times as much and yes lost 30%
No surprise.
rxe said:
Not sure why anyone is remotely surprised by this - the 18650 cells in an S are very standard stuff, and their characteristics are well known. They’re the same batteries that used to power laptops before Li-Po became popular because you can turn it into funny shapes. If you want them to last a long time, you charge them at less than C, so an 85kW/h battery pack should only ever be changed at 85 kW, max. Ideally it would be charged at 0.5C.
Are 4 cylinder engines from BMW and Ford look roughly the same from the outside so they must be same right?The whole point of all speculation on the range loss of these cars is there is no consistency on which are are having a cap put on them - or even if the cap is at the top/bottom end of the battery.
Most people with heavy DC Rapid charging use are not been range limited, yet some people who hardly ever use DC charging are.
People are now talking about pulling out fuses mid software updates to stop Tesla from changing the firmware of the cars, which is madness given how complex these things are and these changes were made to the thermal run away fires that made the news earlier in the year.
Tesla can easily solve this situation by telling us the owners what's actually going on and what they found when they investigated the fires thats lead them to put software caps on some cars.
The batteries affected are the ones pre silicon anode, the battery model number is as much a form factor and less a complete chemical composition - ie not all 18650 batteries are the same
This all started with a fire in China, and Tesla have denied these cars catch fire for years, if you’ll excuse the pun, there’s often no smoke without fire. I think they now know there is an issue.
I suspect the BMS can measure something that causes them to reduce the max voltage they charge to, maybe linked to the differentials in cell voltages hence the variability across cars. Maybe if a block of cells refuses to go above a voltage they now cap the whole battery at that level whereas before they carried in charging. What causes that could be manufacturing variability as much as usage.
Tesla didn’t even tell people they were doing this so I’m not surprised they’re not saying why.
They should man up and offer a 70% degradation guarantee at say 150k miles and 8 years (bmw and Tesla Model 3 both have a 70% guarantee) and replace cars that fall below that. 30% loss is quite a lot and more than I think most people have experienced. A5 least we’d know what the backstop was.
This all started with a fire in China, and Tesla have denied these cars catch fire for years, if you’ll excuse the pun, there’s often no smoke without fire. I think they now know there is an issue.
I suspect the BMS can measure something that causes them to reduce the max voltage they charge to, maybe linked to the differentials in cell voltages hence the variability across cars. Maybe if a block of cells refuses to go above a voltage they now cap the whole battery at that level whereas before they carried in charging. What causes that could be manufacturing variability as much as usage.
Tesla didn’t even tell people they were doing this so I’m not surprised they’re not saying why.
They should man up and offer a 70% degradation guarantee at say 150k miles and 8 years (bmw and Tesla Model 3 both have a 70% guarantee) and replace cars that fall below that. 30% loss is quite a lot and more than I think most people have experienced. A5 least we’d know what the backstop was.
gangzoom said:
Are 4 cylinder engines from BMW and Ford look roughly the same from the outside so they must be same right?
The whole point of all speculation on the range loss of these cars is there is no consistency on which are are having a cap put on them - or even if the cap is at the top/bottom end of the battery.
Most people with heavy DC Rapid charging use are not been range limited, yet some people who hardly ever use DC charging are.
People are now talking about pulling out fuses mid software updates to stop Tesla from changing the firmware of the cars, which is madness given how complex these things are and these changes were made to the thermal run away fires that made the news earlier in the year.
Tesla can easily solve this situation by telling us the owners what's actually going on and what they found when they investigated the fires thats lead them to put software caps on some cars.
No, all Ford and BMW engines are not the same, but if you run them without oil, then they break. Similarly, if you charge batteries too fast, they are more likely to fail. Back in the day when I used to do R/C stuff, you could buy "quality" 18650s that would take a beating and still work, and you could buy cheap ones that failed fast. The point was that beating them up caused failure, it just took longer for the expensive ones.The whole point of all speculation on the range loss of these cars is there is no consistency on which are are having a cap put on them - or even if the cap is at the top/bottom end of the battery.
Most people with heavy DC Rapid charging use are not been range limited, yet some people who hardly ever use DC charging are.
People are now talking about pulling out fuses mid software updates to stop Tesla from changing the firmware of the cars, which is madness given how complex these things are and these changes were made to the thermal run away fires that made the news earlier in the year.
Tesla can easily solve this situation by telling us the owners what's actually going on and what they found when they investigated the fires thats lead them to put software caps on some cars.
The reason they can't say much is probably because they are dealing with chemistry and probability. They've put excess capacity in the packs to allow for random events like cells failing. Presumably they can mark out failed strings of cells, and give the impression the pack is unaffected. The harder you beat up the cells, the more likely this is to happen. But there is also probability at work, so you can get cared for packs that fail early and packs that are hammered that last forever. Just as in a population of laptops, some will have working batteries that are 5 years old, other identical machines will be on their second battery.
rxe said:
The harder you beat up the cells, the more likely this is to happen.
But that's the 'mystery' the affected cars have varying mileage, usage pattern, and combination of 'P' and non P cars. It appears to be 'random' but it cannot be random.Some Model 3s have now also had a similar cap introduced with latest software update, I've just had one pushed to my car and will see what that brings.
What ever this is isn't just DC Rapid charging related. Which is why life would be so much easier if Tesla just told customers whats going on.
gangzoom said:
rxe said:
The harder you beat up the cells, the more likely this is to happen.
But that's the 'mystery' the affected cars have varying mileage, usage pattern, and combination of 'P' and non P cars. It appears to be 'random' but it cannot be random.Some Model 3s have now also had a similar cap introduced with latest software update, I've just had one pushed to my car and will see what that brings.
What ever this is isn't just DC Rapid charging related. Which is why life would be so much easier if Tesla just told customers whats going on.
It’s not the owners fault whatever it is.
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