offgrid house and M3

[ceejay44]

I'm in Southwestern BC, Canada, living in an off-grid house with microhydro and solar as my electricity sources (plenty for running the house). I have had my M3 Long Range AWD for about a month. I charge the car a bit overnight by plugging into a 120v outlet (when only microhydro is powering the house; I set the car to start charging at midnight at 6A draw; I have a 24v system which means 6A translates to 30A; this brings house batteries to about 75% by morning) and then I do a second round of charging during the day when sun hits solar (which adds to what my microhydro is producing; I'll turn up to 8-10A draw from car, which equates to 40-60A on the 24v house system). I can put about 25-35km of range back on the car daily (perhaps more when the summer sun really starts hitting), meaning that I only need to visit a supercharger once every 10 days or so given my daily driving regime.

My question is: is anyone else doing something similar (with just solar, or with microhydro, or other)? If so I'd like to compare notes to optimize my system and car charging capabilities. Please get in touch.

 

[matsoutback]

Hi ceejay44, I’m waiting to get an M3 in Australia. I’m also building a house with total off grid power, all solar and batteries. No wind or micro hydro. I’m planning on charging the car during the best solar hours and leaving the rest to the house. Happy to discuss further if you’d like, in respect to the solar array size and our power consumption.

 

[moonfresh]

Hey,

I am off grid in Southern California. I have a 10.8kw solar array. Making about 40-50kw a day right now. My M3 gets about 25-30kw a day for my commute. I have a battery storage of 64kw--but about 55kw useable because I only charge it to 90percent. Will take picture tomorrow.

 

[ceejay44]

Hey,

I am off grid in Southern California. I have a 10.8kw solar array. Making about 40-50kw a day right now. My M3 gets about 25-30kw a day for my commute. I have a battery storage of 64kw--but about 55kw useable because I only charge it to 90percent. Will take picture tomorrow.

wow to live in sunny Australia or sunny California and be able to produce so much solar electricity! That's awesome that one could charge their car with their solar!
Where I am the sun is only really shining half the year.

I have 16A (24V system) of 24/7 microhydro and 1.6 kW solar so nothing close to what you produce. The microhydro produces enough to run the house and i can put about 15km back on the car overnight (drawing house batteries down to ~72%) then i let the hydro bring house batteries back up to around 85% (occurs by around 10:30am) then solar starts producing and then i start charging car again and can put about 20km on the car by around 3pm, at which time i stop charging car and let solar recoup house batteries for evening house use, then hydro brings house batteries back up to 100% by midnight at which time i start the cycle again.
Effectively i delay going to the nearby supercharger by several days.

Maybe if i chop down a lot of trees and install more panels I'll be able to do a lot more summer time charging during summer months.
cheers

 

[ceejay44]

Hi ceejay44, I’m waiting to get an M3 in Australia. I’m also building a house with total off grid power, all solar and batteries. No wind or micro hydro. I’m planning on charging the car during the best solar hours and leaving the rest to the house. Happy to discuss further if you’d like, in respect to the solar array size and our power consumption.

I'm definitely curious to hear your specs and hear how it goes for you!

 

[ceejay44]

Hey,

I am off grid in Southern California. I have a 10.8kw solar array. Making about 40-50kw a day right now. My M3 gets about 25-30kw a day for my commute. I have a battery storage of 64kw--but about 55kw useable because I only charge it to 90percent. Will take picture tomorrow.

Hi Moonfresh, I'm just coming back to this topic as I'm scheming about expanding my solar power system. I had a look at my solar charge controller and pulled off the production for the last 128 days (what it stores). In summer I'm producing about 3-4 kWh a day from my solar panels (1.6kW of capacity) (on top of the ~9kWh from my micro-hydro daily).

So if I understand you correctly, you produce about 40-50 kWh a day in summer, and you use about 25-30kW per day in your typical daily driving routine? How many miles/km of driving is this a day, approximately? And so I assume that your house uses up to 20kWh per day in electricity?

Please let me know so I can better understand what I would have to do to get myself independent of public chargers.

thanks!!

 

[ceejay44]

Hi ceejay44, I’m waiting to get an M3 in Australia. I’m also building a house with total off grid power, all solar and batteries. No wind or micro hydro. I’m planning on charging the car during the best solar hours and leaving the rest to the house. Happy to discuss further if you’d like, in respect to the solar array size and our power consumption.

Hi matsoutback, how is the offgrid house construction going? I just sent a message to the guy in California about his system. I'm curious as to what the specs are (or are going to be) for your system. I'm scheming about upgrades to my solar (and micro-hydro) to get me to a place of not relying on public chargers at least to cover daily commutes.

chris

 

[jjrandorin]

Hey,

I am off grid in Southern California. I have a 10.8kw solar array. Making about 40-50kw a day right now. My M3 gets about 25-30kw a day for my commute. I have a battery storage of 64kw--but about 55kw useable because I only charge it to 90percent. Will take picture tomorrow.

So, when you say you are off grid, do you mean there is no grid connection at all (as in, you do NOT have an interconnect agreement with any utility, and there is no cabling connecting your home to a utility?

That would be pretty rare in southern california (although not impossible).

To me, "off grid" means "completely off the grid, no grid connection at all, no interconnect agreement". I am betting that is what the OP and @matsoutback are talking about, which would be rare in southern california.



To OP and @matsoutback , super impressive! Nothing to add from me, but looking forward to hearing further how its going for you.

 

[ceejay44]

So, when you say you are off grid, do you mean there is no grid connection at all (as in, you do NOT have an interconnect agreement with any utility, and there is no cabling connecting your home to a utility?

That would be pretty rare in southern california (although not impossible).

To me, "off grid" means "completely off the grid, no grid connection at all, no interconnect agreement". I am betting that is what the OP and @matsoutback are talking about, which would be rare in southern california.



To OP and @matsoutback , super impressive! Nothing to add from me, but looking forward to hearing further how its going for you.

hi yes i'm 100% offgrid.... no electricity from the grid and so I produce 100% myself using microhydro and solar. The water heating, space heating for tenant suite, and cooking is propane (by delivery by truck)... I'm working on cutting down my propane consumption big time too!

 

[jjrandorin]

hi yes i'm 100% offgrid.... no electricity from the grid and so I produce 100% myself using microhydro and solar. The water heating, space heating for tenant suite, and cooking is propane (by delivery by truck)... I'm working on cutting down my propane consumption big time too!

Oh yeah, I could tell from your opening post, you were talking about "off grid" in the sense that I think of it... with no grid connection to a utility whatsoever.

 

[SageBrush]

Hey,

I am off grid in Southern California. I have a 10.8kw solar array. Making about 40-50kw a day right now. My M3 gets about 25-30kw a day for my commute. I have a battery storage of 64kw--but about 55kw useable because I only charge it to 90percent. Will take picture tomorrow.

Brilliant !

Please take a moment to correct the energy units. I presume you know the difference between a watt and a watt*hour

 

[Atari2600]

Why not use 240v for better charging efficiency? Or do you only have 120v?

 

[SSedan]

Why not use 240v for better charging efficiency? Or do you only have 120v?

This is almost a good point.
Letting the car charge at 12amps of 120 would be a big efficiency gain for the OP vs. the 6amps mentioned.

240 isn't more efficient because of the higher voltage it is more efficient because of being more kw delivered reducing waste on system overhead.

OP I would suggest turning up the charge rate if your system will allow to reduce overhead waste.

 

[RFernatt]

wow to live in sunny Australia or sunny California and be able to produce so much solar electricity! That's awesome that one could charge their car with their solar!
Where I am the sun is only really shining half the year.

It's not just areas like southern CA or Australia, I'm in extreme eastern West Virginia and generate enough power from my array to offset the power for local driving in a Model 3 and Leaf and for an all electric house. I am not off grid, but we do have full net metering so that makes it easier. At some point, I'd like to get a Powerwall though.

 

[Atari2600]

This is almost a good point.
Letting the car charge at 12amps of 120 would be a big efficiency gain for the OP vs. the 6amps mentioned.

240 isn't more efficient because of the higher voltage it is more efficient because of being more kw delivered reducing waste on system overhead.

OP I would suggest turning up the charge rate if your system will allow to reduce overhead waste.

You are incorrect.

source: Mobile Connector

NEMA 6-20 = 15 miles range per hour (charging at 20*.8=16 amps)
NEMA 5-20 = 4 miles range per hour (charging at 20*.8=16 amps)

2*4 = 8, not 15.

This is a huge difference. Being a power miser and running the most inefficient setup possible just seems weird to me. That's why I asked if they were limited to 120 V.

Below are pics of lower 240 V rates I just took.
10 mi/hr at 12 A, 5 mi/hr at 6 A.

So you can compare 120 V at 12 A with 240 V at 6 A. Wattage is the same. That is a direct wattage comparison. 3 vs 5 mi/hr which again is a huge difference at the same wattage.

 

[SSedan]

You are incorrect.

source: Mobile Connector

NEMA 6-20 = 15 miles range per hour (charging at 20*.8=16 amps)
NEMA 5-20 = 4 miles range per hour (charging at 20*.8=16 amps)

2*4 = 8, not 15.

This is a huge difference. Being a power miser and running the most inefficient setup possible just seems weird to me.

The higher power setup negates the overhead losses and the tables from Tesla shown there are known to be conservative.

If you had a basic understanding of the subject which you do not you would understand I explained why the same amperage 240 delivers more than twice the rate of 120.

There is a base consumption when charging is active. This is quoted as 3-400watts depending on model from what I have seen.

Without getting into all the math on watts/amps/miles
Say the car has 600watts available to it and 300 go to the process not to charging, that leaves 300 going to the pack. Raise the supply to 1000watts and nearly all 400 additional watts go to the back. You raised the wattage by 67% but raised the charge rate 234%.
The 300watts is a big chunk of 6amps at 120volts but insignificant on a high capacity circuit.

People here report 6-7miles on 5-20circuits running at the full 16amps.

Just because I might not be getting thru it is not the voltage it is the total power.
You turn down a 240 volt circuit to half the amperage of a 120 and you will get the same charge rate because it is the same amount of power.

So while yes on the surface 240 is quoted as more efficient and I am sure someone will come up with some statistically insignificant figure on amperage wasted as heat blah blah blah, the big factor in charging efficiency is the power to run the charging system.
From that perspective the OP will see gains in doubling amperage and halving the time spent charging.

 

[one2many]

I live in Germany, Nov. , Dec. , Jan. , Feb. are a killer.(Dark, rain, snow)
With a 10kwp array (east/west) we make almost enough to go off grid for
8 months. We plan to go with 20kwh to 30kwh batteries for storage this
year so with a few tweaks we should cover all electrical costs including
heat pump for heating. Heating is also a part of the game.

 

[Atari2600]

The higher power setup negates the overhead losses and the tables from Tesla shown there are known to be conservative.

If you had a basic understanding of the subject which you do not you would understand I explained why the same amperage 240 delivers more than twice the rate of 120.

There is a base consumption when charging is active. This is quoted as 3-400watts depending on model from what I have seen.

Without getting into all the math on watts/amps/miles
Say the car has 600watts available to it and 300 go to the process not to charging, that leaves 300 going to the pack. Raise the supply to 1000watts and nearly all 400 additional watts go to the back. You raised the wattage by 67% but raised the charge rate 234%.
The 300watts is a big chunk of 6amps at 120volts but insignificant on a high capacity circuit.

People here report 6-7miles on 5-20circuits running at the full 16amps.

Just because I might not be getting thru it is not the voltage it is the total power.
You turn down a 240 volt circuit to half the amperage of a 120 and you will get the same charge rate because it is the same amount of power.

So while yes on the surface 240 is quoted as more efficient and I am sure someone will come up with some statistically insignificant figure on amperage wasted as heat blah blah blah, the big factor in charging efficiency is the power to run the charging system.
From that perspective the OP will see gains in doubling amperage and halving the time spent charging.

So you can compare 120 V at 12 A with 240 V at 6 A. Wattage is the same. That is a direct wattage comparison. 3 vs 5 mi/hr which again is a huge difference at the same wattage.

This was the first thing I tested back in Sept 2018.

Also, go to Wall Connector

Look at the mi/hr at 12, 24 and 48 amps. Why does the mi/hr double exactly each time you double the amps. You have three data points of wattage increase with no efficiency gain. Again, you are incorrect.

If everyone is limited to 120 V then this is a moot point.

 

[Rocky_H]

So you can compare 120 V at 12 A with 240 V at 6 A. Wattage is the same. That is a direct wattage comparison. 3 vs 5 mi/hr which again is a huge difference at the same wattage.

Jeez, you are wrong. Just stop.
You keep getting this wrong, because you are comparing to a wrong data point in a chart. You are repeating "3 vs 5 mi/hr". That is not correct. It's been covered elsewhere that the 3 mi/hr charging figure is an incorrect number that Tesla copied over from the charging table from the Model S to the Model 3. The Model 3 does get higher charging rates because of being lighter and more efficient, so clearly, it's not supposed to be 3 for both vehicles. The Model 3 DOES get 5 mi/hr charging at that same wattage level, no matter whether it is 120V 12A or 240V 6A. So yes, it is the power difference overcoming the fixed overhead that makes the difference in efficiency, just as @SSedan told you, not just related to the voltage.

 

[Atari2600]

Jeez, you are wrong. Just stop.
You keep getting this wrong, because you are comparing to a wrong data point in a chart. You are repeating "3 vs 5 mi/hr". That is not correct. It's been covered elsewhere that the 3 mi/hr charging figure is an incorrect number that Tesla copied over from the charging table from the Model S to the Model 3. The Model 3 does get higher charging rates because of being lighter and more efficient, so clearly, it's not supposed to be 3 for both vehicles. The Model 3 DOES get 5 mi/hr charging at that same wattage level, no matter whether it is 120V 12A or 240V 6A. So yes, it is the power difference overcoming the fixed overhead that makes the difference in efficiency, just as @SSedan told you, not just related to the voltage.

I received my LR Dual Motor in September 2018 and lived with 120V charging for a while before I got a 240V solution. My charging rates matched Tesla's documentation 100%. Every time.

Personal experience 120V 12A = 3 mi/hr
Tesla documentation 120V 12 = 3 mi/hr

What Model 3 do you have experience with? Also open a case with Tesla and let them know their documentation is wrong.