JRP3
Hyperactive Member
Fairly sure it's been considered, but I think it would be a difficult case to win since Tesla never specified a specific charge rate in all conditions.
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JRP3
Hyperactive Member
2013 Model S with an 85kWh battery reporting in to say my charge rates have been throttled (confirmed by Tesla), and it seems to be worse than folks in this thread. I'm getting about a 60kW charge peak and 40kW average. I've ruled out the obvious stuff (dedicated circuit, warm battery, outside temps, etc).
Does your AC come on like a jet? Do the front louvers open? Have you had your range nerfed by one of the recent releases?
Bigger batteries charge faster than smaller batteries of the same type (structure and chemistry). Tesla batteries seem to be made of multiple strings of batteries wired in parallel. The strings consist of batteries wired in series to produce 400 volts. Each string can absorb a maximum amount of current when new. As the batteries get older and experience more charge/discharge cycles the ability of the string to accept charge current and deliver discharge current declines. Tesla says the batteries will maintain 70% or more capacity after 8 years.
When capacity goes away it reduces the maximum charge and discharge current. Charging current times voltage equals the power that the battery can receive. Reduced Supercharging power levels is a direct consequence of reduced battery capacity. So, if a new battery could accept 120 kW charging then an 8 year old battery should be expected to accept 70% of that rate which is 84 kW. Attempting to charge at higher rates will result in energy being converted to heat rather than being stored in the desired chemical reaction. Placing a limit on charge rates seems to be the right course of action because it protects the battery and reduces the potential for overheating. The battery should last longer if the charge rate matches the capability of the battery.
Electric vehicle manufacturers should be telling their customers that battery capacity and charging rates will drop over the life of the vehicle and providing a yearly minimum capacity warranty. A battery replacement option should be triggered at any point when the capacity and charge rate drop below the level that the manufacturer has guaranteed at the time. So, for example, if a battery drops below 85% after 4 years and the manufacturer has guaranteed 85% or better then the owner should have the option to receive a new battery at a pro-rated price. The number of high current charge/discharge cycles or distance travelled might also be the basis for determining the warranty. People are used to time and distance for automobile warranties so manufacturers might find these metrics to be more familiar and therefore more acceptable to consumers.
When capacity goes away it reduces the maximum charge and discharge current. Charging current times voltage equals the power that the battery can receive. Reduced Supercharging power levels is a direct consequence of reduced battery capacity. So, if a new battery could accept 120 kW charging then an 8 year old battery should be expected to accept 70% of that rate which is 84 kW. Attempting to charge at higher rates will result in energy being converted to heat rather than being stored in the desired chemical reaction. Placing a limit on charge rates seems to be the right course of action because it protects the battery and reduces the potential for overheating. The battery should last longer if the charge rate matches the capability of the battery.
Electric vehicle manufacturers should be telling their customers that battery capacity and charging rates will drop over the life of the vehicle and providing a yearly minimum capacity warranty. A battery replacement option should be triggered at any point when the capacity and charge rate drop below the level that the manufacturer has guaranteed at the time. So, for example, if a battery drops below 85% after 4 years and the manufacturer has guaranteed 85% or better then the owner should have the option to receive a new battery at a pro-rated price. The number of high current charge/discharge cycles or distance travelled might also be the basis for determining the warranty. People are used to time and distance for automobile warranties so manufacturers might find these metrics to be more familiar and therefore more acceptable to consumers.
I used to see 100-125kwh for a while then 90-80-70-60-50 down to 38 when the battery is over 1/2 full. Now much of the time it will be 90-80 to start(sometimes 100-125 for a few minutes only) then down to 60-50-40 pretty quick: and thats with noone else at the SC.
My 70D throttles quite early too.
Starts at around 110kw, drops to 70.
By the time im at 50% its down to 45kw, 35kw at around 65%.
My car has about 175,000km but the battery was just replaced a few months ago. The new battery should only have around 15,000km.
I wonder if they track the DC charging with the car instead of the battery.
Maybe they need to reset my stats?
Starts at around 110kw, drops to 70.
By the time im at 50% its down to 45kw, 35kw at around 65%.
My car has about 175,000km but the battery was just replaced a few months ago. The new battery should only have around 15,000km.
I wonder if they track the DC charging with the car instead of the battery.
Maybe they need to reset my stats?
I would hope this isn't the case, but at the same time I could totally see this as something overlooked in their software.
/edit. I could see this as useful information (or question) to the get to the dev team, if there was a way. Sadly, I suspect just sending a normal support email the inquiry would probably fall on deaf ears.
Earlier folks in this thread have had cooling louver problems cause this. If the car can't get the heat away from the battery quickly enough you will see exactly these symptoms.
No way. It's not down nearly far enough to be the louver problem. Look at the numbers of the state of charge + kW:
50% + 45kW = 95
65% + 35kW = 100
For the older 400V batteries, like the 85, they had that number around 115 to 120, but with the smaller 350V batteries like the 70 or 75, that number was lower, like about 100 to 110. His numbers around 95 to 100 look perfectly normal to me.
of course this makes sense but for a company this could mean a ton of losses. The battery is the weak link in all these vehicles. Its uncharted territory really. We are all guinne pigs. I mean i see alot of guys here trading up to new models in 3 yrs or less and I for one cant afford to do this and take a hit everytime. So we will just drive till it dies and hope the battery doesnt fail
My cooling louver malfunction prevented me from charging above 66 to 69KW regardless of how empty I was.
Ok yeah, I've never seen those open.
I know there's a new model that prevents this from happening, anyone know if I can fix my existing ones?
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