I just reserved a Model X. Woo Hoo! Pretty excited about that. And now I have an interesting question about how to charge the car because I currently live off the grid and rely on solar panels (and a backup generator) for all my electricity. I have 4000 watts of panels and on a good day I can generate 20 Kwh per day. Obviously this will not be enough to charge the house and the 80 kWh battery of Model X in a reasonable amount of time. I see two options:
1. Get on the grid
2. Install more solar to meet the additional needs of the car
To get on the grid I would need to run about 600 feet of underground service. 5 years ago I got a ballpark estimate from the utility of about $40,000. This is what led me to using solar for the house in the first place since the cost of the solar power system was less than $40K and included the added benefit of no electrical bills.
Now, with the prospect of buying an EV on the horizon, I am faced with the same cost/benefit calculation. I like the idea of just increasing my solar capacity. PV panels were $4 per watt when I bought my system. Now they are below $1 making them even more attractive. So I am looking into what sort of setup I would need to do off-grid charging of the Model X.
I live about 20 miles south of Monterey, CA and our typical driving pattern would be to do a round trip of about 50 – 60 miles three or four times a week. So with each trip I would typically have one to two days to add back in 60 miles of range. According to the Model S calculator that would require 17 kWh which is a reasonable amount to expect a 5000 watt PV array to produce in a day with good sun.
In a worst case scenario if I returned home from a long trip and an empty battery I would need to generate 80 kWh which would require about 4 days of charging off a 5000 watt array. And I suppose the absolute worst case would be to return home empty on a cloudy day and then charge the battery from the generator (it is a 20 kWh propane unit) which should be able to charge enough for a round trip in about an hour.
Another consideration for an off-grid Model X would be the charging equipment. My current off-grid system uses a single 80 amp DC charge controller to feed PV power into a bank of lead acid batteries. I then have two 4000 watt inverters which provide 240 v AC to the house. Since the Model X batteries are also DC it seems like the best way to charge them would be solar DC direct to battery DC and bypass the inverters. I believe the Model X has a direct DC input path when it is hooked up to a supercharger so I am wondering if I will be able to use the same circuitry to do direct DC charging?
Another interesting question is if there will be a way to draw power out of the battery bank to run my house? The 80 kWh lithium battery bank would be a monster compared to my lead acid battery bank and using it to power the house would help justify the cost of the car since it would be doing double duty.
So I am wondering if there is anyone else who is or wants to power their Telsa only from solar? And does anyone have any feedback on my calculations and assumptions about solar sizing and charging?
Thanks!
1. Get on the grid
2. Install more solar to meet the additional needs of the car
To get on the grid I would need to run about 600 feet of underground service. 5 years ago I got a ballpark estimate from the utility of about $40,000. This is what led me to using solar for the house in the first place since the cost of the solar power system was less than $40K and included the added benefit of no electrical bills.
Now, with the prospect of buying an EV on the horizon, I am faced with the same cost/benefit calculation. I like the idea of just increasing my solar capacity. PV panels were $4 per watt when I bought my system. Now they are below $1 making them even more attractive. So I am looking into what sort of setup I would need to do off-grid charging of the Model X.
I live about 20 miles south of Monterey, CA and our typical driving pattern would be to do a round trip of about 50 – 60 miles three or four times a week. So with each trip I would typically have one to two days to add back in 60 miles of range. According to the Model S calculator that would require 17 kWh which is a reasonable amount to expect a 5000 watt PV array to produce in a day with good sun.
In a worst case scenario if I returned home from a long trip and an empty battery I would need to generate 80 kWh which would require about 4 days of charging off a 5000 watt array. And I suppose the absolute worst case would be to return home empty on a cloudy day and then charge the battery from the generator (it is a 20 kWh propane unit) which should be able to charge enough for a round trip in about an hour.
Another consideration for an off-grid Model X would be the charging equipment. My current off-grid system uses a single 80 amp DC charge controller to feed PV power into a bank of lead acid batteries. I then have two 4000 watt inverters which provide 240 v AC to the house. Since the Model X batteries are also DC it seems like the best way to charge them would be solar DC direct to battery DC and bypass the inverters. I believe the Model X has a direct DC input path when it is hooked up to a supercharger so I am wondering if I will be able to use the same circuitry to do direct DC charging?
Another interesting question is if there will be a way to draw power out of the battery bank to run my house? The 80 kWh lithium battery bank would be a monster compared to my lead acid battery bank and using it to power the house would help justify the cost of the car since it would be doing double duty.
So I am wondering if there is anyone else who is or wants to power their Telsa only from solar? And does anyone have any feedback on my calculations and assumptions about solar sizing and charging?
Thanks!
