Anyone experienced with solar panels or LED grows?

[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...

 

[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.

 

[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/sol...mono-p40538/?gclid=CInxmJriqdECFYhefgodBUgMIA 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/collections/inverters-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.

 

[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.