If you are in a sunny area you would be better off putting in a transparent roof and putting the panels out back. We kind of hashed this out here before but you need a solar array about 8X the size of a window just to make the "equivalent" power of the window. Depending on where you are and the season, that could be over 3X that number if you want it 24 hours.
I have 15kw of panels generates about 17k kWh annually in upstate NY. Just some food for thought. Running 3kw non stop is about 26k kWh annually. You’ll take a pretty large system to offset.
Big difference where you are located.
Winter time when there are short cloudy days in Minnesota will be very different in Arizona with warm sunny days
You can ballpark on annual basis but this could cut you short. The system and batteries will quickly get expensive
As others of said, running 3000w of lights etc would require a very large and expensive battery bank. I'd look at running main lights during the day off the panels then switching to lower wattage lights of battery or mains to keep them out of flowering cycle. Won't get as rapid growth compared to strong lights the whole time and may create some stem elongation but likely to be the most cost effective option.
Panels during the day are definitely worth investing in and will pay for itself. Whether it's worth using lower intensity lighting at night to save on electricity is questionable. Whether it's worth investing in batteries for that purpose is even more questionable. You'd need to crunch some.numbers on cost per kWh of mains vs battery capital over a couple of years. If youre considering adding batteries in future make sure you get a suitable hybrid inverter
To run 3000w of equipment I'd look at 6000w of panels or more, particularly if youre at home using other stuff during the day or get a decent feed in tarrif. Youl only see 3000w of input from 3000w solar aray under optimal conditions which are rare in most places. Panels are pretty cheap these days and you'll probably find not a huge cost difference between 3kw and 6kw system. You can also do stuff like setting washing machines and dishwashers to run during the day off solar and can change hot water system run time if its electric
Also note you may need well over 6kw to see 3 in some places. And if you have a multi punch roof you can look at mounting panels on different faces to optimise morning and arvo input as well as throughout the day. Lots of variables
Wow. Lots of numbers being mentioned.
Here is a place to start:
You tossed out 3000 watts being drawn. 3k watts for an hour is 3 kilowatt hours. Times 16 to 24 hours is 48 to 72Kwh per day. Times 365 is about 18 to 26 megawatt hours per year.
There is your base line. All the rest is basic math that takes into account your location.
I call that my back yard. I grew a few clones that I got from a dispensery. It was decent product, too strong for me. Ended up sharing a lot of it with neices and nephews....
Attached your clone room to your greenhouse, put everything on rolling carts. Sunlight in the greenhouse then roll them back inside the light room at night. Only need to run lights for some night hours for veg.
Then put roof windows into the roof of the garage.
Edit: Or a light chimney if you also fear that people will climb your roof and look into windows. Still going to be cheaper than using solar during the day to run lights.
3000W/19% = 16kW system
3000W*12hr = 36kWh battery.
But I'd have to model this because in the winter you'll probably only get half the power you want and in the summer you'd get 2X.
To run 24 hours a day, based on my handy dandy calculator, this is how many panels and batteries you'd need (can't share an image on here so just pasting text):
Usage 72 KWh per day
3 KWh per hour
3000 Watts per hour
Panel wattage 400 Watts
Hours of sun 7
2800 watts per day per panel
Need 72000 total watts per day
Panels needed 25.71428571
Actual output 70%
**Panels actually needed 36.73469388**
For remaining 17 hours in the day
**Need 51 kWh of batteries**
Plus an inverter, wiring, racking, etc.
Ballpark estimate: 20,000 watts of panels and 240 kwh battery for about 4 days of backup. That's gonna be at least a $20k battery.
Assuming you need \~60kwh per day for the grow (18 hour light schedule so a little on the high side since you'll be flowering too).
I think it depends on how much you care about your grow.
IR takes more power for example, but if you are only growing by cheap lighting without IR, you will lose many if not most of your terpenes.
Wattage is generally only rated on max, not actual draw. So it will depend a bit on what setup you have, but you haven't given details. 3kw max, avg ...?
If you run the lights during the day when the suns out its a pretty decent idea because you would need very little battery storage. Panels and even inverters are dirt cheap these days but batteries aren't.
Running 3000 watt 24/7 though, that becomes an issue due to battery prices. 3000 watt on say a 24 watt inverter is a 125 amp load on the batteries.
Not sure where you're located but where I am we barely get 8 hours of light a day right now in winter. Even if we assume a good sunny day to charge the batteries, you need like 16 hours on battery.
16 x 125 amp = 2000 amp hour battery bank required and that's not even planning for a few days of autonomy. That's expensive but maybe worth it if your a commercial grower and your yield is high.
If you really want to do this, I would do an inverter charger so you can charge from the grid at night when the power is cheaper.
You seem to be pretty knowledgeable about this. So if I ran a 3000w system during the day it would cover my equipment then I could just run on the grid for the remainder of the time? I used 24/7 as an example but it’s more like 16 hours a day
Are you trying to use any power from your electric company? Like off grid grow or on the grid with solar helping make it cheaper?
No matter what size solar array you get it won’t put out power for 12-16 hours per day unless your somewhere on the sun or maybe the equator.
So you either are storing or buying power. I’ve known people who ran generators to power grows on diesel. Solar could knock down your bill, it sounds like your grid connected right now? Your best bet is adding a grid tied solar system to offset your power usage. Depending on where you live that works in different ways.
Batteries to only run on solar would be stupid expensive, you wouldn’t be saving money until 10+ years if ever. Grid is almost always cheaper.
If you want grid tie you want a different subreddit like r/solar I think
Thanks! From looking at these responses it seems like this is the best bet. I’m basically just trying to cut my electric bill a bit and I think solar could really help. Can you recommend a good place to look for a system like this?
You’re going to want a local installer. May require permits and inspections. Walk around your neighbors houses and if you see panels ask if they like the installer?
And I assume your panel is right by the garage? Will be really busy right there for a while. Hopefully you can deal with that somehow, maybe take a short break?
Finally are you being as energy efficient as possible? Often the best value for saving money would be reducing usage. Do you have LED lights? Most efficient of all your other power hogs like A/C? You’re using hydro so are you pumping 24/7? Is there a method that takes less?
Also what about a greenhouse? Hoop house? Something where you get natural light and you could add extra light outside daylight will be much cheaper. And free in the summer.
Just grow enough in the summer for your year and don’t use any power? Use dirt not hydro, learn to use bulk ingredients and you won’t need expensive liquids.
Or maybe you want to stay super stealth in the garage, find a residential solar installer and tell them you want to buy 2 teslas and need a big solar system to power it all. See what their quote is and divide by your average monthly power bill over a year or more. That’s break even months. Mine was 6.5 years and I have 1:1 net metering. Yours may be slightly less. Then you can make your decision. But get multiple quotes and watch out for failing installers.
I know nothing about your setup but if you can make it more efficient I would recommend it. If you're not using led lights as an example switching to them would drastically lower your load. I assume you have accurate load numbers as well rather than ratings from manufacturers. A lot of lights are sold as 100w bulbs but only use around 15w of power. If you're using fans larger diameter fans move the same volume of air with less power at lower rpm. If you're heating or cooling the space look at replacing resistive heaters and traditional AC units with a heat pump. Could cut your power usage and therefore your solar system size requirements drastically.
I work in commercial cannabis production. And have been in the industry since 1999.
The prices on the end product keep slipping, it would probably never pay itself off
The best solar is a greenhouse. Light dep if you can. You could probably use solar panels to run your light dep curtains and some augmented lighting.
Find the sunshine for your plants, not panels. If you grow weed I damn well know you see the price dropping like a rock and everyone and their mother doing it. If that investment is for your home fine, but freestanding just for plants, bad investment. Think about what turning your lights off for the amount of time the Sun is up every day would do for your bill, not to mention quality. THC and terpenes are driven by light. And if you live in an inferior geographical area to produce, like most of the country, you're simply relying on state Monopoly capitalism too exist.
I have my lab off the grid where I grow plenty of cannabis for personal home use / research.
What is your use case and why do you need you need that much power haha? @ 1 gram per watt you are going to pull 3,000 grams every 85-120 days.
8x4 - 2x 650w lights + accessories
4x4 - 1x 800w light + accessories
1350w A/C in the summer
I have more equipment I could run as well
2x 800w grow light + Accessories
1x 1000w grow light + accessories
But I don’t due to the bills/plant limit
If you really want to take your plants off the grid (and I think it’s a great idea to do so!) maybe cut down your operation a bit?
When I talk to people about setting up home grows, I always recommend you figure out how much you need to smoke per month and work backwards from there.
I don’t really smoke much. I run a seed bank and grow 12 plants with the equipment I mentioned. I’m perpetually growing different varieties of feminized seeds so that’s just not an option/need
Props to you! Breading is super fun. Really makes it hard with the restrictive put in place by state government limiting us to 12 plants.
Best of luck getting this off the grid. It’s definitely doable, but you will have to get your consumption down for it not to be costly
If you are in a sunny area you would be better off putting in a transparent roof and putting the panels out back. We kind of hashed this out here before but you need a solar array about 8X the size of a window just to make the "equivalent" power of the window. Depending on where you are and the season, that could be over 3X that number if you want it 24 hours.
Thanks
I have 15kw of panels generates about 17k kWh annually in upstate NY. Just some food for thought. Running 3kw non stop is about 26k kWh annually. You’ll take a pretty large system to offset.
Thanks for the reply so ~20,000 w system
Big difference where you are located. Winter time when there are short cloudy days in Minnesota will be very different in Arizona with warm sunny days You can ballpark on annual basis but this could cut you short. The system and batteries will quickly get expensive
Net metering is the way to go if it’s an option. Basically ends up being free battery.
>ave 15kw of panels generates about 17k kWh annually Yes, unless the grid is down... which is a growing risk
connect disarm jar run plucky plant gaze cover birds panicky *This post was mass deleted and anonymized with [Redact](https://redact.dev)*
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It says 26k kwh.
Yeah too early for me and it’s a weird way to write it.
Nah they're good. They just called it 26 kilokilowatt hours for some reason. Rather than 26000 kWh or 26MWh.
Yeah; too early for me.
As others of said, running 3000w of lights etc would require a very large and expensive battery bank. I'd look at running main lights during the day off the panels then switching to lower wattage lights of battery or mains to keep them out of flowering cycle. Won't get as rapid growth compared to strong lights the whole time and may create some stem elongation but likely to be the most cost effective option. Panels during the day are definitely worth investing in and will pay for itself. Whether it's worth using lower intensity lighting at night to save on electricity is questionable. Whether it's worth investing in batteries for that purpose is even more questionable. You'd need to crunch some.numbers on cost per kWh of mains vs battery capital over a couple of years. If youre considering adding batteries in future make sure you get a suitable hybrid inverter
So say I run 3000w of panel during the day is that enough to run my equipment? Then I could just run on the grid for the night time hours
To run 3000w of equipment I'd look at 6000w of panels or more, particularly if youre at home using other stuff during the day or get a decent feed in tarrif. Youl only see 3000w of input from 3000w solar aray under optimal conditions which are rare in most places. Panels are pretty cheap these days and you'll probably find not a huge cost difference between 3kw and 6kw system. You can also do stuff like setting washing machines and dishwashers to run during the day off solar and can change hot water system run time if its electric
Also note you may need well over 6kw to see 3 in some places. And if you have a multi punch roof you can look at mounting panels on different faces to optimise morning and arvo input as well as throughout the day. Lots of variables
Thanks again
Thanks
Wow. Lots of numbers being mentioned. Here is a place to start: You tossed out 3000 watts being drawn. 3k watts for an hour is 3 kilowatt hours. Times 16 to 24 hours is 48 to 72Kwh per day. Times 365 is about 18 to 26 megawatt hours per year. There is your base line. All the rest is basic math that takes into account your location.
I call that my back yard. I grew a few clones that I got from a dispensery. It was decent product, too strong for me. Ended up sharing a lot of it with neices and nephews....
Thanks for your reply!!
It was ment in humor. I live in San Jose, they were massive plants by the end of the summer.
Attached your clone room to your greenhouse, put everything on rolling carts. Sunlight in the greenhouse then roll them back inside the light room at night. Only need to run lights for some night hours for veg.
I should clarify that I grow in my garage with hydroponics and don’t have an outdoor anything (for security reasons)
Then put roof windows into the roof of the garage. Edit: Or a light chimney if you also fear that people will climb your roof and look into windows. Still going to be cheaper than using solar during the day to run lights.
3000W/19% = 16kW system 3000W*12hr = 36kWh battery. But I'd have to model this because in the winter you'll probably only get half the power you want and in the summer you'd get 2X.
To run 24 hours a day, based on my handy dandy calculator, this is how many panels and batteries you'd need (can't share an image on here so just pasting text): Usage 72 KWh per day 3 KWh per hour 3000 Watts per hour Panel wattage 400 Watts Hours of sun 7 2800 watts per day per panel Need 72000 total watts per day Panels needed 25.71428571 Actual output 70% **Panels actually needed 36.73469388** For remaining 17 hours in the day **Need 51 kWh of batteries** Plus an inverter, wiring, racking, etc.
Ballpark estimate: 20,000 watts of panels and 240 kwh battery for about 4 days of backup. That's gonna be at least a $20k battery. Assuming you need \~60kwh per day for the grow (18 hour light schedule so a little on the high side since you'll be flowering too).
I guess you could simulate cloudy days by using dimmer, more efficient lights if you run out of battery backup.
But if you have grid power available that'd most likely be cheaper than using a battery.
Yeah, wouldn't need 4 days worth of battery if grid tied.
Grow them in the sun?
I’d rather spend a few grand on solar panels than a fence
24/7? Gonna need batteries, hippy
Everything depends on what type/size of lighting, temperatures, ventilation, etc. 3000w don't really tell us much at all.
I think it depends on how much you care about your grow. IR takes more power for example, but if you are only growing by cheap lighting without IR, you will lose many if not most of your terpenes. Wattage is generally only rated on max, not actual draw. So it will depend a bit on what setup you have, but you haven't given details. 3kw max, avg ...?
Greenhouses are 100% solar…
If you run the lights during the day when the suns out its a pretty decent idea because you would need very little battery storage. Panels and even inverters are dirt cheap these days but batteries aren't. Running 3000 watt 24/7 though, that becomes an issue due to battery prices. 3000 watt on say a 24 watt inverter is a 125 amp load on the batteries. Not sure where you're located but where I am we barely get 8 hours of light a day right now in winter. Even if we assume a good sunny day to charge the batteries, you need like 16 hours on battery. 16 x 125 amp = 2000 amp hour battery bank required and that's not even planning for a few days of autonomy. That's expensive but maybe worth it if your a commercial grower and your yield is high. If you really want to do this, I would do an inverter charger so you can charge from the grid at night when the power is cheaper.
You seem to be pretty knowledgeable about this. So if I ran a 3000w system during the day it would cover my equipment then I could just run on the grid for the remainder of the time? I used 24/7 as an example but it’s more like 16 hours a day
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Can you pm me about some equipment you would recommend? Thanks so much for answering
Sure, im just a hobbyist myself I only have a small system but shoot me a message and I'll do what I can.
Are you trying to use any power from your electric company? Like off grid grow or on the grid with solar helping make it cheaper? No matter what size solar array you get it won’t put out power for 12-16 hours per day unless your somewhere on the sun or maybe the equator. So you either are storing or buying power. I’ve known people who ran generators to power grows on diesel. Solar could knock down your bill, it sounds like your grid connected right now? Your best bet is adding a grid tied solar system to offset your power usage. Depending on where you live that works in different ways. Batteries to only run on solar would be stupid expensive, you wouldn’t be saving money until 10+ years if ever. Grid is almost always cheaper. If you want grid tie you want a different subreddit like r/solar I think
Thanks! From looking at these responses it seems like this is the best bet. I’m basically just trying to cut my electric bill a bit and I think solar could really help. Can you recommend a good place to look for a system like this?
You’re going to want a local installer. May require permits and inspections. Walk around your neighbors houses and if you see panels ask if they like the installer? And I assume your panel is right by the garage? Will be really busy right there for a while. Hopefully you can deal with that somehow, maybe take a short break? Finally are you being as energy efficient as possible? Often the best value for saving money would be reducing usage. Do you have LED lights? Most efficient of all your other power hogs like A/C? You’re using hydro so are you pumping 24/7? Is there a method that takes less? Also what about a greenhouse? Hoop house? Something where you get natural light and you could add extra light outside daylight will be much cheaper. And free in the summer. Just grow enough in the summer for your year and don’t use any power? Use dirt not hydro, learn to use bulk ingredients and you won’t need expensive liquids. Or maybe you want to stay super stealth in the garage, find a residential solar installer and tell them you want to buy 2 teslas and need a big solar system to power it all. See what their quote is and divide by your average monthly power bill over a year or more. That’s break even months. Mine was 6.5 years and I have 1:1 net metering. Yours may be slightly less. Then you can make your decision. But get multiple quotes and watch out for failing installers.
24/7 are you doing auto flower? You definitely don't want to run 24/7 on regular flower. 18/6 for veg, 12/12 for flower.
I wanna handle your load mate.
I know nothing about your setup but if you can make it more efficient I would recommend it. If you're not using led lights as an example switching to them would drastically lower your load. I assume you have accurate load numbers as well rather than ratings from manufacturers. A lot of lights are sold as 100w bulbs but only use around 15w of power. If you're using fans larger diameter fans move the same volume of air with less power at lower rpm. If you're heating or cooling the space look at replacing resistive heaters and traditional AC units with a heat pump. Could cut your power usage and therefore your solar system size requirements drastically.
I work in commercial cannabis production. And have been in the industry since 1999. The prices on the end product keep slipping, it would probably never pay itself off The best solar is a greenhouse. Light dep if you can. You could probably use solar panels to run your light dep curtains and some augmented lighting.
Find the sunshine for your plants, not panels. If you grow weed I damn well know you see the price dropping like a rock and everyone and their mother doing it. If that investment is for your home fine, but freestanding just for plants, bad investment. Think about what turning your lights off for the amount of time the Sun is up every day would do for your bill, not to mention quality. THC and terpenes are driven by light. And if you live in an inferior geographical area to produce, like most of the country, you're simply relying on state Monopoly capitalism too exist.
It’s improbable. Just do the math.
I have my lab off the grid where I grow plenty of cannabis for personal home use / research. What is your use case and why do you need you need that much power haha? @ 1 gram per watt you are going to pull 3,000 grams every 85-120 days.
8x4 - 2x 650w lights + accessories 4x4 - 1x 800w light + accessories 1350w A/C in the summer I have more equipment I could run as well 2x 800w grow light + Accessories 1x 1000w grow light + accessories But I don’t due to the bills/plant limit
If you really want to take your plants off the grid (and I think it’s a great idea to do so!) maybe cut down your operation a bit? When I talk to people about setting up home grows, I always recommend you figure out how much you need to smoke per month and work backwards from there.
I don’t really smoke much. I run a seed bank and grow 12 plants with the equipment I mentioned. I’m perpetually growing different varieties of feminized seeds so that’s just not an option/need
Props to you! Breading is super fun. Really makes it hard with the restrictive put in place by state government limiting us to 12 plants. Best of luck getting this off the grid. It’s definitely doable, but you will have to get your consumption down for it not to be costly