is my off grid dream out of reach?

good day everyone!
I am planning on living off grid in about a year or so and feel i could easily build a solar set up to power my cabin. however i'm a little concerned about generating enough energy to charge my nissan leaf which has a 30 kwh battery and i would need about 15 kwh - 20kwh a day for my car. also i would like to be able to delivery that electricity to my car on a 220V 30 amp circuit i could do 110v but its not ideal.

I have access to public charging when/if needed but would prefer to generate everything i need.
im not looking to spend a tremendous about of money or have a gigantic solar farm.... i could tie into the grid at a price of $15000

I would prefer not to have any monthly payments to a utility company where most of the bill is fees


thx

sun is free but the equipement to transform light into electricity is not.
So the bill to start is usually huge and be affordable only if ROI is spread over several years.
So forget it for just one year or two.
You need a huge space for generating 30KWh
let's assume in a sunny place you would get about 200Wh per square meter, that is about 1000W for 5 hours.
So you need 30 square meters it is a space of 10 meters by 3 meters or 30 feet by 10 feet

i have an area of 20 feet by 20 feet i was hoping to keep it within. I understand that its a big upfront cost that will be worth it over the years.

at some point i will add a second EV to the mix and hopefully by then there will be a system out to allow bi directional charging so i can power my cabin with the electric vehicle's battery and have my solar system strictly for charging the electric vehicles.... the future looks bright for solar!

Allot of variables. Just one that could make or break doing the project is; will the electric car be available during the day to receive the electricity being generated? If not, batteries would be required, that would run $5,000+ not including backup for cloudy days.

Ok ill take a crank at this foe you.
You need 30 kwh per day that is 30000 watts divide that by 4 sun hours(you may get more I don't know what area you are in) is 7500 watts.
You would need 25 300 watt panes to get that power. If you want to run anything more than that you will need to go bigger say 30-35 panels.
Now for the battery that will be the part that kills you. 30000 watts is 625 amp hours at 48 volts and that will only get you power for the car. If you want more power or need more days backup you will need to double or triple that 625 amp hours.

So you need 4 batteries at $20380 https://www.altestore.com/store/dee...-75kwh-lithium-battery-storage-system-p41420/
25-35 panels $3625-6397 https://www.altestore.com/store/solar-panels/q-cells-solar-panels-p41041/#HAN370QPEAK370M
so far the cost is almost 30k and that is without a controller or inverter.

It can be dune but you may need to start small and build up to it, it will take a few years to get to that point. Start with you cabin and work your way to the car, adding more and more until you can power it. That way you don't need to come up with the money all at once, and as time passes the cost of items will go down.

Gosh Lets fill this glass up 'm not a glass is half full guy I'm like look at least there is water lets see how far we can get.

Lets start with 30Kw of needed energy. For now lets forget about short winter days.

5 hours of sun 6kw of panels thats 20 santan solar. You can fit 22 300 watt panels in your alloted space so lets get 22 panels.

22 panels at $120.00 each $2640 plus shipping say another 350 so lets go $3000.00 panels

I think if you are serious a sol-ARK all in one would be the way to go $6800.00


Batteries 32 eve cells would store 30kw of energy. 2p16s setup with Chargery BMS. $6000.00

Miscelaneous wires breakers $500.00

Solar panel rack $2000.00



Panels $3000.00
Inverter/charger $6800.00
Batteries $6000.00
Misc $500.00
Solar panel structure $2000.00

$18,300.00

All of this is based on 30kw per day which may not be necessary. You could probably save a few thousand if you didnt need 30 amps at 220 volts can you use say 20 amps at 220?

You could cut battery cost by half if you can charge the EV during the day

Bottom line is it can be done for about the cost of having grid power tell us more about your ideas and we can help

jim furlong said:

I am planning on living off grid in about a year or so.
im not looking to spend a tremendous about of money or have a gigantic solar farm.... i could tie into the grid at a price of $15000

I would prefer not to have any monthly payments to a utility company

Click to expand...

$15,000 to bring in grid power makes solar a no brainer and you have a year to build your system.
Hopefully you can provide the labor and make DIY LFP batteries and buy used panels to save a lot.
Does it have to be to code in your location?

You might find these videos informative:

for me this "never pay a bill again" is more a gimmick than an actual thing.
the up front spending to go off grid cost usually several years of a standard bill.
and you never know if your setup will not cost more in the future (technical problems or just maintenance, change in your life etc...)
There are special occasion (living in a place where electricity is random or inexistant) or living a new way (survivalist ?), with almost no electricity.
But if you start to say you need 30KWh a day, well, that is a serious project.
.

To bring Grid Power to my home would have cost $45,000, my solar system after upgrading to LFP from Rolls Surette Lead Acid came in just under $20K now... NB that's $4K of LEAD in that cost which is now headed for secondary duty. Having no Power Co HOSTAGE Fees to pay every month sure is nice !

As Craig pointed out, Santan Solar and other options exist which we know as "Known Good" thanks to the membership here.
Your location is the Lurker here... Sun Hours per day is the biggy, assuming you are in the USA, June 21 is the longest Sun Day with December 21 shortest Sun Day, so your worst production days will be December obviously. The "usual" compromise that results for panel angle is to split the difference and set panels at the angle which would be appropriate for March & September. If you are going to use a Ground Mount there are adjustable ones and more expensive trackers as well, with fixed ground mount as the cheapest to install and tracking the most expensive. Poor angles can result in a lot of wasted energy generation potential so this is something to consider as well.

wow! thx for all the great info and different perspectives... sounds like i could have given more info about my location.
I'm located in southern Alberta, Canada an hour south of Calgary, the sunniest city in Canada, i have 5 peak hours of sun per day.
I am planning on starting small and will continue to add components over the years as my power needs grow. I was thinking a ball park cost of $30,000 over the next 3 years with hopes that it would last a decade or more.... lithium batteries are my first choice just because i am familiar with how they charge/discharge in a variety of temperature conditions as well as well as how to take care of them to prolong their life(ive used a Nissan leaf with a 30kwh battery as my main vehicle for the past 4 years)
I also have the option of incorporating wind power into my off grid system. there are several wind farms already in southern Alberta as the wind are pretty strong and persistent. i think that would help greatly during the winter months and during the night on those windy days

also the comment on using a 20 amp on 220V instead of 30 amp is feasible
I do shift work and work 14 days a month so charging during the day while i sleep will help a lot

If i am charging during the day does the power generated from the panels go directly to the load (my car) or does it go to the battery bank first and then to the car?

Here's the insolation figures I have. I haven't checked them with others, but believe they are correct.
Calgary
Average Solar Insolation figures with panels that are adjusted throughout the year and with a southern exposure.

30 kWh in a day is certainly doable, on a good day I make 3x that.
The biggest question is what hours you'll be charging the car: Between 8:00 AM and 8:00 PM? or between 8:00 PM and 8:00 AM??
Most of us, if we drive to work, leave home in the morning and come home in the evening. Problem is, if we want to charge a car with solar, first we would have to charge a battery bank at home during the day, then discharge that bank at night to charge the car.

Simple solution, buy two Leaf, charge one while you drive the other.

Otherwise, can you make arrangements to charge at work? The PV capacity ought to be grid-tie at that location.
20 kWh/day is about 4 kW AC for 5 hours. Panels can be had for $1500 and an inverter for $1000 or less.

That would leave you needing a battery system only half that size for your home.

Wind, if it blows while you are parking, would be good day or night. Hydro even better, if you have a stream.

As for where the charging goes: PV --> charger/inverter/batteries --> car charging.
Unfortunately, your car probably can't adjust its charging to take whatever surplus your home system has to offer. If an AC charger, it'll just take the watts it wants, and the only thing you could do is set up a relay to switch between 110V, 220V, or neither.
So, if the Leaf wants more than PV produces, batteries in home system get drained.
If Leaf wants less than PV produces, batteries in home system get charged until full, then extra production is wasted.
So, if you put in a relay to switch from 110V to 220V charging whenever a "battery full" signal comes from the home charger/inverter, you could bounce along near full for the home system, taking whatever PV produces. (I'm assuming the Leaf can take 220V, 20A or so, near 5 kW, and your PV will be less than that.)

jim furlong said:

If i am charging during the day does the power generated from the panels go directly to the load (my car) or does it go to the battery bank first and then to the car?

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I think that is adjustable depending on settings on the charge controller. I don't have a specific answer but you may want a charge controller built into the inverter so you can have more control.
I am trying to do the same with a Hybrid inverter in grid zero mode and charge my EVs during the day.

jim furlong said:

If i am charging during the day does the power generated from the panels go directly to the load (my car) or does it go to the battery bank first and then to the car?

Click to expand...

@jim furlong
The Sol-Ark will send it to the loads first, skips the battery (I own one and have seen this behavior, it is also programmable to prioritize load over battery or the reverse.) Agree it is a good option for what you are doing - pricey but it includes a lot of functionality and tech support is top notch and real.

The only thing to be aware of is that is inverter 2 separate pairs of solar panel inputs. (Dual MPPT) with a max PV input or 16,500W (8,250W per MPPT). I have read you can get around this limitation by setting up your arrays in a east / west orientation so that you do not at one time max out the watts but that is highly dependent on your location. So if you're space limited you will need to purchase a stand alone mppt control to make up the difference in production from the array.

I would also do a detail needs analysis - specifically when you would be charging you car. The reason being even with a decent battery bank, 30kw, you could end up dumping excess power within a couple days if you are not charging every day. Somewhat of a rabbit hole and one that I am trying to fill where 3-4 months out of the year my batteries max out with still 2-3 hours of productive solar available (so loosing roughly 8-10kw every time this happens).

Good luck

Ampster said:

I am trying to do the same with a Hybrid inverter in grid zero mode and charge my EVs during the day.

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The issue is still how to adjust the amount of power taken by the EV charger.

Your hybrid inverter or charge controller for house battery will put all PV power above and beyond what is consumed by the house (including car charger) into house batteries. As PV production increases towards full sun, more charging occurs. In the evening, less occurs. No PV production is wasted unless the battery is full, or production exceeds maximum charge rate battery can accept. (e.g., limit set for maximum charging current, battery temperature sensor shows too hot, desired rate tapering off as voltage increases near full charge.)

That is what you would like to do with the EV battery, but through an AC electric plug you don't have control (except switching between 110V and 220V plugs.)
Some EV have a DC input, not sure what control that offers.

If you are a hacker and could bypass the AC to DC portion of the EV's charger, you might be able to access a circuit which accepts all power presented.
Definitely a "Danger Zone!" topic.
If you started at the top of a hill with nearly full battery and rode the brakes going down, wouldn't the EV take all charging current the battery could accept but no more? That is how you would like to operate it with PV direct charging.

Maybe the DC charging input provides such a feature. But, it will be a high-voltage input and there isn't off-the-shelf electronics to operate PV at MPPT while feeding that input. Or is there? I do see PV/EV charging stations, although those are likely grid-tie.

The OP question, "If i am charging during the day does the power generated from the panels go directly to the load (my car) or does it go to the battery bank first and then to the car?" is actually something of a red herring. All power requested by EV charger goes to EV, not to battery, whether it pass through 48VDC on the way or not.

If you have an AC coupled system: PV panel --> Grid-Tie Inverter --> 240VAC --> Battery Inverter --> 48V battery
.............................................................................................................................................................|--> Leaf Charger

If you have a DC coupled system: PV panel --> Charge Controller --> 48VDC --> battery --> Battery Inverter --> 240VAC --> Leaf Charger

Both accomplish about the same thing. PV panels are in a 400V string for AC coupled grid-tie, multiple parallel 100V strings for DC coupled system.
AC coupled lets you use smaller gauge wire and probably no fuses at PV panels, and is a few percent more efficient for the watts that get used immediately for AC loads.
DC coupled may be slightly more efficient at putting watts into the 48V battery. Although the power is presented to the battery as 48V (more or less), it doesn't flow through the battery on its way to the Leaf, just appears on the wires.

Don't feel bad about charging from the grid during the day while away from home, e.g. at work. That just might be performing your civic duty.
Here in California, peak time of use rates used to be Noon to 6:00 PM when demand was highest. Today, it is 4:00 PM to 9:00 PM. The shift is due to all the PV capacity we've installed, which combined with base generation sometimes exceeds all consumption.
PG&E has even paid money to dispose of excess electricity before the wires sprung a leak.

Our lowest time of use rates are Midnight to 3:00 PM. Charging a car from the grid between about 10:00 AM and 3:00 PM is taking surplus PV generation that no one knows what to do with.

In Oregon, wind power generation is curtailed because they don't know what to do with it.

Alberta may not be there yet in terms of PV. But you could try to charge at work during hours off-peak from consumption so more likely to use wind/hydro and not contribute to additional fossil fuel consumption.


And size your home PV system with excess panels so when you are there you can charge during the day, just don't charge at night off batteries.

Hedges said:

The issue is still how to adjust the amount of power taken by the EV charger.

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Exactly. There is a GT inverter from SolarEdge that may do that but not relevant to this thread. Another option is Open EVSE which could be programmed to set the charging rate based on solar output. That is the concept but the barrier for me is learning how to program an Arduino or Pi.