Anyone experienced with solar panels or LED grows?

[whiskeySipper]

So I’ve been trying to do research on this, but a lot of what I’m finding online is pretty dated, and with how much solar panels and LED’s have developed in the last few years I’m hoping to impose on you folks for some more current information. Basically, I’m trying to use solar panels to power my grow, possibly with LED lamps, but I have some questions:

1. Are batteries necessary if I’m running my lights during daylight (and essentially off the energy the panels are providing)? If so, can I get by with less than 12 hours (this setup would only be used during flowering) by only storing enough to ensure a consistent flow?
2. How can I determine the number of panels I will need for a single 600W HPS? I’m seeing panels rated at ~300W for less than $400 when I just google “Solar Panels”, but are the manufacturers referring to a continuous possible output, or only with peak sunlight, or something else? From what I’m seeing available, I’m thinking 2-3 panels should be just enough to handle a 600W HID, but that’s a guesstimate at best.
3. I read this article: http://theweedbusiness.com/solar-powered-grow-room/ from 2009 that said an LED using 250W was as effective as a 1KW HPS, which doesn’t seem to jive with other things I’m finding. What seems to be the best info I’m seeing is .5g per watt pulled from the wall, but that would have a 250W LED, labeled as an effective 600W lamp, producing around 125 grams (if my math is correct) not 500g - 1kg. Anyone have an idea about current models of LED lamps? I picked up one of these: http://www.ebay.com/itm/like/3812653...&ul_noapp=true, but haven’t done a full grow with it or tested any other LED yet. As I understand it, there’s a lot of variation in models, so specific models’ yields in actual grows would be most helpful (along with vertical distance from leaves). I don’t get how LED’s are more efficient than HIDs if they’re pumping out less grams per watt (maybe because they require less secondary expenses in the form of heat management and ventilation)? Obviously electricity is my most limiting factor working with solar, so if there’s any people with real experience growing both HIDs and LEDs I would love to hear from you as to whether LEDs would actually be a better option.

I’m planning to build this grow incrementally, starting with a single 600 - 1000 watt HID bulb or LED equivalent and the requisite solar panels. After I get that fully working, then I'll add more lamps and solar panels. Once I’m up to 3 lights I’d love it if I were able to get the panels surface area to fit on the hood and roof of a cargo van (which I’d imagine would be a lot easier to fill with LEDs than HIDs and their heat ventilation), but that’s a whole other story. Thanks in advance.

[Chemichael]

Each 3 foot by 5 foot panel produces approx 275 watts. You need 4 to make 1k kWh

you also need to figure out how to store the extra power it produces I would think.

So 12 feet width give or take a foot for the physical footprint

[whiskeySipper]

Thanks for your response. I'm not expecting too much extra power Do you have any information / experience with panels operating during peak usage vs regular usage? Also, do you know of setups that don't involve a battery at some point, or only use battery as a caching mechanism before passing on the power?

[Tika]

Chem...wish I had your mind !

[whiskeySipper]

Based on these dimensions, the roof and hood of a van might not be sufficient to generate the power needed, although it doesn't seem too far off the mark. Maybe if the panels are mounted in a way that can reduce their footprint (placing them at even a slight angle could reduce one dimension's length), or allowing for a certain amount of overhang (which may effect street legality, anyone know about that?) then we could fit more on the roof. I'm also thinking that if I mounted additional panels on one side, I could rotate the van halfway through the day, so that the one side of paneling would always be pointed in the direction of the sun. Because the van itself is mobile, I have some flexibility, but obviously I don't want to spend all day chasing the sun in a grow van .

Another option I'm considering is leaving the grow entirely out of the van, storing the electricity it harvests during the day and then driving it in to a garage at night to provide supplemental power to a grow. Unfortunately this would bring the need for some serious batteries, and I'm hoping to avoid that to make the thing cost effective. Also where are you seeing 3' x 5' panels @ 275 watts? I'm seeing slightly wider and much longer panels that I believe are peaking @ 340 watts with google, but any links you have to those shorter panels would be appreciated.

[South Sierra Dude]

Why? Electricity is cheap.

[Tika]

Serious SSD...lol! Our pge is off the charts! Wakes me up at night ! Or were you joking and I missed it?

[South Sierra Dude]

No. I've done some cost benefit comparison and I am not convinced that switching to solar is better long term. So no, relative to the amount of work that would go into installing and maintaining a solar system electricity from the grid is cheaper, I'm not joking. At least that's the way I see it. So for me solar is something I'd consider if I had limited options but otherwise not. I would like to see an estimate on a complete system from somebody who has grown with one.

[whiskeySipper]

I would love to see some actual numbers too, hence this post. I also mention several other reasons to switch to solar in the comment below. If you're growing only small amounts for personal use or for a limited number of cycles then I would be very surprised if solar were something you'd be interested in.

However, the biggest expense of solar is actually the battery, and one of the key points of this question is to see if I can avoid that altogether or minimize the expense by using a smaller battery as a caching mechanism (which would essentially cut the up front costs in half). That being said, I've read several discussion forum threads about people spending (what I would consider) an inordinate amount of upfront costs or going through insane amounts of effort (like lugging around suitcase sized batteries to people's work / school) to stay off the grid. I think the approach I'm taking has a relatively high return on investment, but of course, without actual data (rather than opinions) I have no way of knowing for sure.

I'm mostly interested in responses that actually contain useable data, or can point me to good sources of information, rather than hearing whether solar is a good idea or not for whatever you're trying to do in your own personal setup.

[dontknownuttin]

Why? Electricity is cheap.

What he said

[whiskeySipper]

Couple of reasons...

(1) Electricity costs are relative. If you're in an area that has higher rates, or higher demands (e.g. A/C cuz it's hot year round) and you're already in a high tier usage situation, then no it's not that cheap.
(2) After first harvest, initial setup should be paid for and electricity should be primary expense...therefore anyone focusing on return on investment that can re-use solar panels for dozens of grows would hopefully see a benefit.
(3) Weed legality varies, and getting your power off grid is key for stealth growing.
(4) Did you read the part about the van? It's pretty hard to get electricity from a cigarette lighter.
(5) Climate change, Oil Industry, ISIS + OPEC...need I go on?

I hope most people can see the benefit of a grow that has little recurring costs, and that being relatively self sufficient has value. Not sure why really matters, as much as if it's possible. Of course, the fact that a lot of people aren't doing this already speaks to the challenge involved, but as solar becomes cheaper (and hopefully lighting becomes more efficient; anyone got real info about LEDs?) I would expect this kind of a grow to become viable, if not more profitable as well.

[whiskeySipper]

Here's some rough estimates that should help explain how it can be cost effective (I'm hoping to get enough information from this site and an electrician / solar discussion board to validate or correct these numbers, but this where I'm at so far):

Each 600 watt bulb that I add to my system pulls down 7.5kWh a day (assuming I'm only running them 12 hours, rather than trying to alternate for a total of 24 hours; which I actually do in real life but wouldn't be possible with solar). I'm well into the highest payment tier at this point (40 cents per kWh), so that means each 600 watt bulb that I add costs me an additional $3 / day ($.4 x 7.5kWh / day). Since I'm an industrious fellow that vegs / cures off site I have flowering going on about 350 days a year (maybe more to be honest, I rarely spend 48 hours switching out cycles).

This comes to a total of $1050 per year per bulb ($3 x 350 days) going to the electric company.

What I'm seeing online, and this is where I need help validating estimates, I can get some of these guys: https://www.altestore.com/store/sola...FYhefgodBUgMIA which are rated at 340 watts for $250. Now I need to buy 6 of these at a time minimum (but I can afford to work at scale if I have fairly trustworthy numbers), but theoretically 2 of these should be enough to power a 600 watt bulb, at least at peak usage (on the shortest days of the year peak usage would be 4 hours, but around summer solstice it's longer, and I am still trying to figure out how much the wattage will drop off in the mornings and evenings and whether that can be accounted for with mobile positioning). Now the solar system still needs a converter / inverter, but I might be able to spread that cost across multiple systems, depending on how I configure and whether or not I need batteries. At this site http://www.mysolargoods.com/collecti...rs-accessories, I'm seeing large inverters (3000 - 7000 watts?) for $1860 or per panel inverters ~ $150.

So without batteries, each solar panel is costing me about $400 ($250 / panel + $150 / inverter), and 2 panels should (theoretically) handle the needs for a single bulb. Let's be conservative and say 3 panels per bulb (although I'm thinking it should be more like 2.2 - 2.5 panels per bulb in the right geographical area). That comes to a total of $1200 per bulb per year in the first year, and $0 per bulb per year in future years.

That means, if we're lucky enough to exclude batteries and I don't have to replace any parts over a 5 year period (I've been involved with growing for 8 years now and don't expect to end anytime soon), my power costs per bulb per year is $240 while the electric company is still charging me $1050 per year per bulb (assuming that they don't raise my rates or cap my usage). Even if we have to add battery costs, and we conservatively estimate the battery needs at 2x the cost of the panel + inverter (which I think is fairly high, but not that high) we get a total of $720 per bulb per year ($240 original cost + $480 / batteries).

So yes, if I'm growing at lower tier rates in my specific area ($0.18 - 0.26 per kWh) or for only a single year, or if I don't have other electric costs pushing my fees up, the solar option is more expensive (but potentially as low as 12.5% more, which maybe totally worth it to keep your grow off grid). On the other hand, each successive cycle with parts that don't need to be replaced brings down your costs significantly. Over an extended period that adds up: 2 years = $1200 - $3600 vs $2100, 5 years = $1200 - $3600 vs $5250, 10 years = $1200 - $3600 vs $10500, etc...

A lot of that is based on assumptions and educated guesses, but until I get more real data that's the best estimate I'm seeing. This excludes any benefits from switching to LEDs (which I was hoping I'd have an easier time getting real numbers for) as that would have nothing to do with power generation. Also, if I am able to fit this grow into a van, then there's no access point to the power grid. Hope this explains why I asked the question, and if anyone can help me tweak these numbers to make them more accurate I'd be super grateful.

[alltatup]

Welcome to the forum, Whiskey. I can't answer your questions, but I agree with you that solar is the way to go. I just got panels installed on my roof and it should save me $75-90 a month in electricity. Good choice for lowering your carbon footprint (for those of us who beileve that global warming is actually happening....)

[alltatup]

"Modelled Annual Energy Yield: 6,441 kWh"

[Tika]

Certainally agree with you on that for footprint alltatup...and even tho I'm in sunny CA I'm also costal (got fog) so to merit the expense of installation of panels / how much would I save or not would have to be a risk $. My LEDs did not lower my cost at all but did reduce ambient temps.

[whiskeySipper]

Hi Tika. Thanks for participating in this discussion. I'd love to see some numbers from your transition; it would be really informative.

For Solar:
Were you putting panels on your roof to supplement your house's power (traditional use of solar) or did you build a panel/converter/battery system specifically for your grow (customized and used by the grow exclusively)? What gear did you use, or what actual kWh did you get out of the system? Did the system include any kind of recurring costs (e.g. maintenance).

For LED's:
How many watts were you using and lbs were you yielding in your previous system? What did you upgrade to, and how did that effect your yields? Were there other benefits for switching besides ambient temps, and how much electricity did you save from not having to deal with the heat? Any other details that might be useful (such as environmental factors, labor man/hours, additional changes that might have effected the yield, etc...) would be great.

If we can get some real numbers from a few grows up here, I can start doing the math, and of course I plan to keep people informed about my own numbers once I have enough information to get started. Thanks in advance.

[South Sierra Dude]

So Whiskey, is this a philosophical interest, logistical concern or fiscal frugality?

[whiskeySipper]

This is more than philosophical, I'm researching to actually build. I like the idea of being somewhat mobile and not requiring electricity from the power grid, which I would pay a premium for, but if it's not cost effective than I'll probably abort. That being said, it seems doable in the 3 - 7 lbs range, possibly more cost effective in a non-mobile setup with higher yields and in the right regions. Just need some people to point me in the right direction.

[bobsakamoto]

i'm really glad you asked this, Whiskey. i've been considering going solar and wondering specifically about using it to first power a grow as a test case....

[whiskeySipper]

Thanks. I hope to be able to put up some numbers and pics over the next few months. Getting the proper information to plan is the only thing holding me up right now.

[D-TrainCA]

As you're probably aware, the current tend in home solar is systems that sell real-time surplus power back to the grid instead of storing it. This can be good, but if you're trying to keep your power consumption off-grid (pun intended...), it's exactly the opposite of what you want. Trends are toward using these systems to monitor power usage in real-time, collecting and storing data from households and businesses to make a smarter power grid. Just FYI...

The older-style systems that store surplus in batteries and draw reserve from the grid are what you want. It's getting harder to find solar contractors that know how to do these systems, at least where I live. I just wanted to hire someone to install panels on my roof and let me do the rest, and it was all but impossible to find someone. You can readily buy all the hardware to build a system on the Internet, however.

[whiskeySipper]

Thanks for your post. I'm pretty capable with electrical systems, so I'm going to be purchasing equipment off the web and getting DIY on it, but I'm interested in what you're saying about the new systems that support direct usage and offload their surplus rather than storing to the battery. Are these systems self-contained (i.e could I leverage them for what I'm doing with a little hacking), or do they require components on the grid to function? Is there something about these 'live' usage systems that makes them fundamentally different, or is it simply an issue of scale / manufacturer / etc...

[D-TrainCA]

The new systems are usually installed in cooperation with your local utility and include mechanisms for communicating usage (how much power your drawing from or feeding to the grid) back the the utility. ZigBee radio technology or similar. I can't speculate on how you could hack one of these systems to take it off-grid. Other than the comm component, the big difference is that, in one of these new systems the DC produced by the solar panels is converted to AC that is either used by your house or, absent that demand, fed back to the grid, vs the battery system wherein the solar DC is converted to AC for your house or stored in batteries later AC house use, and grid power is only used when solar/battery can't meet house demand. Conceptually, electrically, they systems aren't really fundamentally different, but the off-the-shelf hardware probably does one or the other.