I've learned a lot reading these forums. For instance, I've learned that keeping the battery at a 50% charge is better for the battery than keeping it at the "Standard" full charge (~90%). I've learned that it might be better to charge at lower amperage than higher, and even if not, doing so is easier on the grid. I've also learned that ideally the car should reach a full charge about 30 minutes before its next driven, so that balancing can be performed.
With that in mind, here's my proposal for what I'm calling ICS: Intelligent Charge Setup, which optimizes battery life and, for those on Time Of Use (TOU) metering, also optimizes charging cost while ensuring that you have a full charge the next day, or at least as much charge as is possible.
Today the driver optionally enters a Start After time and maximum amperage. For ICS, the driver enters:
1) The earliest time you will want to drive the next day. I call this the "Ready By" time.
2) (Optional) The start/end times for Off-Peak, Part-Peak, and On-Peak at your location. That includes seasonality and weekday/weekend differences. (note I have a simpler entry possibility later)
3) (Optional) The maximum amps to draw. Just like today.
That's it. You connect up and your car is ready to drive the next day utilizing the lowest available cost power and at the slowest rate possible so the battery isn't full for too long but yet is fully charged in time to balance itself before you drive off.
So, what's the logic behind this? Pretty simple, really:
The car knows the battery's State of Charge (SOC), and so given the maximum amps it can draw, it can calculate how long it will take to reach a full charge and therefore time that period to a) occur during the cheapest available power rates and b) use the lowest amps to both fit within the cheapest power rate times and be full in time to do a 30 minute balancing before you leave the next day.
From the current time, the car knows if there's an Off-Peak time between now and when you want to drive and it can determine the right amperage to use starting when the Off-Peak starts and ending either 30 minutes before you want to drive or when the Off-Peak period ends (whichever comes first).
If the available Off-Peak period and maximum available amps aren't enough to fully charge the battery (or if there is no upcoming Off-Peak), it can try to take advantage of any Part-Peak times, and if that fails, well, it uses as little Peak kWh as it can to still reach full charge in time for you to leave.
Now, if you don't have TOU metering, or you don't want to bother entering that information (although it's a one-time thing for your home location), you can just enter a Start After time (like today it's optional) as well as a Ready By time. The car will then start charging at the Start time (like today), but limit amps so that it is fully charged a 1/2 hour before the Ready By time. If it wouldn't be ready in time at that rate, it'll start charging sooner - the idea being that it's best to start the next day with a full charge no matter what.
Tesla, please consider this as both a firmware upgrade to the Roadster as well as to incorporate into the Model S from the get-go. "Ready By" times are more important than "Start After" times, and easier to understand, and since many customers are on TOU metering, it would enable the cheapest charge ups without the drivers doing any math.
With that in mind, here's my proposal for what I'm calling ICS: Intelligent Charge Setup, which optimizes battery life and, for those on Time Of Use (TOU) metering, also optimizes charging cost while ensuring that you have a full charge the next day, or at least as much charge as is possible.
Today the driver optionally enters a Start After time and maximum amperage. For ICS, the driver enters:
1) The earliest time you will want to drive the next day. I call this the "Ready By" time.
2) (Optional) The start/end times for Off-Peak, Part-Peak, and On-Peak at your location. That includes seasonality and weekday/weekend differences. (note I have a simpler entry possibility later)
3) (Optional) The maximum amps to draw. Just like today.
That's it. You connect up and your car is ready to drive the next day utilizing the lowest available cost power and at the slowest rate possible so the battery isn't full for too long but yet is fully charged in time to balance itself before you drive off.
So, what's the logic behind this? Pretty simple, really:
The car knows the battery's State of Charge (SOC), and so given the maximum amps it can draw, it can calculate how long it will take to reach a full charge and therefore time that period to a) occur during the cheapest available power rates and b) use the lowest amps to both fit within the cheapest power rate times and be full in time to do a 30 minute balancing before you leave the next day.
From the current time, the car knows if there's an Off-Peak time between now and when you want to drive and it can determine the right amperage to use starting when the Off-Peak starts and ending either 30 minutes before you want to drive or when the Off-Peak period ends (whichever comes first).
If the available Off-Peak period and maximum available amps aren't enough to fully charge the battery (or if there is no upcoming Off-Peak), it can try to take advantage of any Part-Peak times, and if that fails, well, it uses as little Peak kWh as it can to still reach full charge in time for you to leave.
Now, if you don't have TOU metering, or you don't want to bother entering that information (although it's a one-time thing for your home location), you can just enter a Start After time (like today it's optional) as well as a Ready By time. The car will then start charging at the Start time (like today), but limit amps so that it is fully charged a 1/2 hour before the Ready By time. If it wouldn't be ready in time at that rate, it'll start charging sooner - the idea being that it's best to start the next day with a full charge no matter what.
Tesla, please consider this as both a firmware upgrade to the Roadster as well as to incorporate into the Model S from the get-go. "Ready By" times are more important than "Start After" times, and easier to understand, and since many customers are on TOU metering, it would enable the cheapest charge ups without the drivers doing any math.
