Off grid Tesla Vehicle Solar charging no batteries

[codymccomber]

Hello All,

I currently live in the desert completely off grid with a 2KW solar system on my Fifth Wheel roof and about 10KWH of battery storage and 5KVA Inverter all DIY. The system is fantastic, although I will be expanding to ground solar now that I have a permanent place to stay.

I will be purchasing a Tesla vehicle(Cybertruck!!) in the future and I am working on getting my charging system setup for it. I know I need a significant amount of solar...luckily I have 20 bare acres and live in a sunny climate so there will be plenty of sun and space for the panels. My goal is to charge the vehicle without batteries in-between the solar and the inverter. I would love to charge DC direct, but all my research so far shows that that is not an option at this time outside of super chargers.

I am trying to understand the setup and limitations.

If I go PV to inverter to vehicle, or PV to MPPT to inverter to vehicle:

Will the car start and stop charging as clouds pass over or with the connection need to be reset manually in the vehicle every time the output of the panels dip below the set charge rate in the car? Is this a viable setup to charging a Tesla without battery storage as an intermediary?

(I understand this is over simplified and that fuses, breakers and properly sized equipment is necessary)

Thanks for your help!

 

[DisabledVet]

Have you watched Will's videos with his Tesla?

 

[DisabledVet]

As a Tesla Model 3 owner who has also put his order in for a Cybertruck, I am having these same thoughts.

Based off the tests in the second video in the playlist, you would need 3 of the 5kw 48v MPP split phase inverters to get 23kw at 17 amps. Each of those MPP's would need 7,680 watt arrays attached for a total of 23kw. That is a LOT of panels .. but you said you have the room for it. The question - could you do it without any batteries? Not sure that you could.

Will said he is looking to do this using Lithium-Iron-Phosphate batteries in the garage over the next year. I am eagerly keeping an eye out for those videos. I think Will is right there with you, me, and I am sure others who dream of a versatile electric vehicle like the cybertruck that runs purely off electricity and being charged from an off-grid system. That would be my version of the New American Rugged Individualism - a home connected to the grid so I can sell electricity back and have it there for backup but am completely independent from the grid for my home and transportation energy needs. (Like have a horse and growing all the food your horse needs for a year.)

@Will Prowse - Any updates?

 

[Steve_S]

Wallbox Quasar bidirectional home DC charger will turn EVs into a huge Tesla Powerwall Seth Weintraub - Jan. 6th 2020 1:28 pm ET

Click Title to get to article.

A possible solution, while not inexpensive it appears to be "just the ticket" for V2H with a few bonuses. That being said, it is only a matter of tie before others come out with similar products which may likely be at a lower price point. There are some products now coming from China & Taiwan that can charge EV's from a solar system and bi-directional is being worked on. There are apparently some being develop in Europe, I heard a "rumour" that Victron is involved in a venture related to this as well. It is Early in the game as it were, the pressure for such products will increase as more EV's come onto the market and even VW is working on a few different charging systems, so patience is warranted.

 

[DisabledVet]

Now that Tesla's are being built in China, I expect to see some amazing technology to pop up related to Tesla, particularly in this space - power back and forth between the home and the Tesla. Now that technology being allowed to come to the US, that might be a different story.

 

[codymccomber]

As a Tesla Model 3 owner who has also put his order in for a Cybertruck, I am having these same thoughts.

Based off the tests in the second video in the playlist, you would need 3 of the 5kw 48v MPP split phase inverters to get 23kw at 17 amps. Each of those MPP's would need 7,680 watt arrays attached for a total of 23kw. That is a LOT of panels .. but you said you have the room for it. The question - could you do it without any batteries? Not sure that you could.

Will said he is looking to do this using Lithium-Iron-Phosphate batteries in the garage over the next year. I am eagerly keeping an eye out for those videos. I think Will is right there with you, me, and I am sure others who dream of a versatile electric vehicle like the cybertruck that runs purely off electricity and being charged from an off-grid system. That would be my version of the New American Rugged Individualism - a home connected to the grid so I can sell electricity back and have it there for backup but am completely independent from the grid for my home and transportation energy needs. (Like have a horse and growing all the food your horse needs for a year.)

@Will Prowse - Any updates?

Thanks for the reply!

Yes, going that route for level II charging would require a significant amount of panels haha. I would prefer to start smaller and grow over time. A level I setup that gains a few miles per hour perhaps. I think the lowest charge setting for a Tesla is 10a @ 120v. I don't own a Tesla so correct me if I am wrong. So a single 5kw array would be able to provide above that minimum for a handful of hours per day, just as an example.

I have seen Will's Tesla videos and love that he shares this useful knowledge. The issue that he is stated multiple times is that the batteries are the most expensive part of an off grid solar setup. It seems redundant to buy more batteries just to charge a vehicle battery. There has to be away to charge Tesla batteries without adding another battery as a middle man.

It would be nice to have grid options but where I am at is outside the reach of the grid. Looking forward to Elon Musk brining Starlink online and moving away from cellular as my primary internet. Being independent from the grid is a good feeling, although being truly self sufficient with water and food is a whole other story.

 

[DisabledVet]

I'm right there with you and thinking the same thing. IF I am willing / able to schedule my needs such that the prime solar hours of the day, I think it might be possible to take the batteries out of the equation for those 4-5 hours.

Maybe Will could try using his one inverter with as many panels as he can get hooked up to it, unlook it from the Battleborn batteries, and run it with only solar from 10am - 2pm one day to see what he can do with his Tesla Model S. I think he would probably get 20-25 miles range added in that time if I am spit-balling the math correctly.

If that works then there is our plan. We could start with a single inverter and panels. As you had more money, add another inverter and more panels. Work your way up to three inverters and the 23kwh final solution that could fast charge the Tesla. I still think it would take several days to recharge the whole battery, but that would be good enough for me.

 

[codymccomber]

I'm right there with you and thinking the same thing. IF I am willing / able to schedule my needs such that the prime solar hours of the day, I think it might be possible to take the batteries out of the equation for those 4-5 hours.

Maybe Will could try using his one inverter with as many panels as he can get hooked up to it, unlook it from the Battleborn batteries, and run it with only solar from 10am - 2pm one day to see what he can do with his Tesla Model S. I think he would probably get 20-25 miles range added in that time if I am spit-balling the math correctly.

If that works then there is our plan. We could start with a single inverter and panels. As you had more money, add another inverter and more panels. Work your way up to three inverters and the 23kwh final solution that could fast charge the Tesla. I still think it would take several days to recharge the whole battery, but that would be good enough for me.

Sounds like a plan to me. I do have one other concern that you may be able to test out if willing.

What happens when a cloud goes over...Part of the issue is that you need an inverter that will automatically restart after a low voltage condition, thats fine, they exist. The other issue is how does the Tesla respond to having the power cut and then turned back on mid charge? Do you think this could be simulated by charging the Tesla at home through the grid, flipping the breaker so the Tesla loses power, then flipping it back on after a bit and seeing if the Tesla begins charging on its own of if it complains and requires you to plug it back in or something.

 

[DisabledVet]

Ah ... that I can answer. The power went out while I was charging the Tesla in the garage. It just stopped charging. When power came back, it started the charging again.

 

[codymccomber]

Ah ... that I can answer. The power went out while I was charging the Tesla in the garage. It just stopped charging. When power came back, it started the charging again.

Well that's good sign. That's one of the things I was worried about.

 

[David against Goliath]

@

Well that's good sign. That's one of the things I was worried about.

Hello,

I'am a Tesla owner as well, model x and model S (big family...) and ordered a Cybertruck as wel...I've been following your conversation with big interest and hereunder is another situation:

Yes it is a good sign that the car starts charging again but another thing needs to be checked...if there is a drop of amps because of clouds or because of the movement of the sun at the sky, can the car's charging system handle it?

 

[Willeert]

I charge my Chevy Bolt with an off grid system. A Tesla can use a CCS level 2 charger with an adapter I believe. The Open Evse Level 2 charger is an open source Arduino based charger. Link: https://www.openevse.com/. Using an Arduino I turn my charger on in the morning when there is enough power and then increase and decrease the charge rate as the available power changes. This not that hard to do if one is at all computer code handy.

 

[Ampster]

I charge my Chevy Bolt with an off grid system. A Tesla can use a CCS level 2 charger with an adapter I believe.

So far Tesla only supports the Chademo adapter. Both Chademo and CCS are DC standards as is Tesla's SuperCharger protocol. The power requirements are too great to consider doing DC charging without the expensive equipment to interface with either of those protocols.

The Open Evse Level 2 charger is an open source Arduino based charger. Link: https://www.openevse.com/. Using an Arduino I turn my charger on in the morning when there is enough power and then increase and decrease the charge rate as the available power changes. This not that hard to do if one is at all computer code handy.

You have solved the riddle I have been wondering about. I may have to think about learning more about Arduino's. I am using a CT around my solar output that reports solar output to IFTTT which then triggers a Kasa switch to turn on a relay that turns on my JuiceNet EVSE. I have no control over Amperage except with the JuiceNet app on my phone.
I remember reading about the openevse project years ago and wondered what happened to it. It has been a while since I played around with code but I will look into it. That will be more intellectually stimulating than the puzzles many of my friends are doing to while away the C19 time.

On the subject of charging off grid I will share my recent experience. The above EVSE is powered from a circuit on my critical loads panel. I recently ran a test on my hybrid inverter which powers that critical loads panel to make sure it would work during a grid outage. I turned off the main breaker and without resetting the clock on my microwave or rebooting my router, it switched over to battery power as expected. At the time I was charging my Model X with the above EVSE and it went into a fault condition. I haven't taken the time to research the real issue but I have several other EVSEs that I can test so I don't think it is unsolvable. I just wanted to mention it because there will be issues that will come up. Even my Model X and Model 3 respond differently to starting and stopping the EVSE so there are some challenges out there. For example, when I had a Fiat 500 I was routinely changing the Amperage on my EVSE with my phone app as the solar output varied. Eventually the Fiat stopped charging and would no longer take a charge. Fortunately I found a YT video that explained how to reset the car by disconnecting the 12 volt battery. That worked but as Will said, if you disconnect your 12 volt battery you may have to call a online service tech to reboot your system.

 

[David against Goliath]

Hello All,

I currently live in the desert completely off grid with a 2KW solar system on my Fifth Wheel roof and about 10KWH of battery storage and 5KVA Inverter all DIY. The system is fantastic, although I will be expanding to ground solar now that I have a permanent place to stay.

I will be purchasing a Tesla vehicle(Cybertruck!!) in the future and I am working on getting my charging system setup for it. I know I need a significant amount of solar...luckily I have 20 bare acres and live in a sunny climate so there will be plenty of sun and space for the panels. My goal is to charge the vehicle without batteries in-between the solar and the inverter. I would love to charge DC direct, but all my research so far shows that that is not an option at this time outside of super chargers.

I am trying to understand the setup and limitations.

If I go PV to inverter to vehicle, or PV to MPPT to inverter to vehicle:

Will the car start and stop charging as clouds pass over or with the connection need to be reset manually in the vehicle every time the output of the panels dip below the set charge rate in the car? Is this a viable setup to charging a Tesla without battery storage as an intermediary?

(I understand this is over simplified and that fuses, breakers and properly sized equipment is necessary)

Thanks for your help!

hello,

I am an owner of a Model S, a Model X and have a Renault Twizzy (big family).
I am charging my electric cars off grid thanks to my 'Solax Power' inverter (model X3), this is an inverter who can start up without the grid!!! The electric vehikels that I've got can handle fluctuating amperage!!! I did test this first with my model S and actually they charge all 3 in the same off-grid way. No need for battery to store your energy!!! I've got 16 kw solar panels on my roofs, to charge from april till september it is enough (I live in Belgium...) but for the rest of the months it is not enough, It may be enough if I triple or more my solar panels put at my current home it is not possible.
As I am always charging at low amperages my battery's wear less, my Model S (end 2014) has 450 000 km's on the odometer for your information.

If you need more information don't hesitate to get in contact with me. For your information, I am not a professional electrician and have nothing to do with the Solax company...

Kind regards

 

[David against Goliath]

Ah ... that I can answer. The power went out while I was charging the Tesla in the garage. It just stopped charging. When power came back, it started the charging again.

Yess!!! read my reply!

 

[David against Goliath]

@

Hello,

I'am a Tesla owner as well, model x and model S (big family...) and ordered a Cybertruck as wel...I've been following your conversation with big interest and hereunder is another situation:

Yes it is a good sign that the car starts charging again but another thing needs to be checked...if there is a drop of amps because of clouds or because of the movement of the sun at the sky, can the car's charging system handle it?

Currently I know because I've installed my system, read my reply herunder.

 

[Willeert]

Here is a J1772 to Tesla adapter that is available from the Tesla shop;

SAE J1772 Charging Adapter

Compatible with most Level 2 public charging stations, the J1772 Adapter supports charging speeds up to 19.2kW. This product comes standard with purchase of any Tesla vehicle. Includes: 1x SAE J1772 Charging Adapter Note: Compatible with all Tesla vehicles. Tesla does not regulate pricing or...

shop.tesla.com

This adapter makes the open EVSE level 2 charge available to charge the Tesla. I have 9.8 Kw of panels and have built an energy manager(EM) for my system using two arduino megas. The goal is to emulate a grid tied power output with off grid. This means I always need a load to divert power into. This does not always happen so the system also needs to limit power when required. As excess power becomes available the EM sends power to the hot water tank. A heat exchanger in the HWT suppliers energy (hot water) to the house radiant flow based on a HWT set point. The car charger turns on based on specific parameters ie HWT temp greater than + X Array output greater than X + etc. It then increases or decreases the car charge rate based either on power going into the HWT (winter mode) or a bias between battery charge state set point and actual voltage if the HWET thermostat is open (summer mode).

I tried to attach the code buy I need to take the time to put it into a form the attachment editor will accept. It does not like INO and Doc files.

My experience is that unless one has a fairly large array (10+ KW) to charge a car is long slow process. I am adding 3.6 KW this summer to speed up my charging so I can drive the EV more often.

Will

 

[Ampster]

I have three of those, one for each car and one that stays on my J1772 plug of my charger. I also have a J1772 adapter extension that is about 10 ft long and was useful in my former little beach town which had lots of free charging stations around town. Sometimes it was hard to back into some of those diagonal parking spots and the cords were often too short for some of the parking spaces.

I looked over the openevse site and will probably tackle that in the near future after my pack rebuild. I built Heathkits when I was younger so doing a kit is no problem. My plan is to wire it direct to a Tesla plug if I can find one off a failed mobile adapter. Otherwise I can get one from QC Power where I got the parts for my extension cords.

Thanks again for that referral to openevse.

 

[Picasso]

This will solve all EV charging problems with solar soon. https://dcbel.ossiaco.com/

 

[Ampster]

One can only hope. I will form an opinion when users report how they work in real life. What little i know about the J1772 protocol, is that it is designed to work only to charge a car. Changes in the protocol will have to be made and I do not know of any work that is being done by the standards agency. I hope I am wrong.
In the meantime I am installing some Anderson connectors to my 12 volt battery on my Tesla so I can run a small 120 volt inverter to provide power to my sister who lives nearby. We have frequent power outages in our area.