Solar Power Stuffs - Questions and Answers

[Nyhillbillies]

Does anyone have experience with unsolicited mail solicitations for solar panel installation? Do they keep you hooked into the grid?

 

[arizona_chicken_noob]

Ah, so it's inside? I don't mean fully-enclosed, but covered overhead so as to preclude the use of off-the-shelf solar LEDs with integrated motion sensors. It sounds like you only need the area illuminated for short periods at a time rather than all night, so it sounds like you'd need just 2 or 3 100W-equivalent LED fixtures (or thereabouts), which typically draw around 13W). That should be very easy to power with a single 100W solar panel and a 50Ah lead-acid battery. You can find DC versions of those that would eliminate the need for an inverter, though you'd still need a (relatively inexpensive) charge controller. If you want it lit for more than an hour per night then you'd need more batteries, or a single bigger one.

I have always been interested in solar but never had the time to really dive in. I'm realizing that I have a similar area to illuminate at this other poster.... I don't suppose we could expand on this 2-lightbulb project or do a small tutorial post, for the greenhorns (which I definitely am!)?

 

[AntiqueB]

Thanks for starting this @Ascholten !

I was just pondering using solar for a coop and run I have in my school's garden. There is no electricity, yet water must remain in the liquid state throughout the winter.

My problem has been sizing panels to generator, and also feasibility. There is an open lean-to facing south, so the roof would be perfect for panels, but I worry about cloudy days. It's in New York City, so there will be spells of below-freezing weather for days at a time, and I can't risk having the girls' water freezing.

 

[DParker75089]

I don't think our other solar lights have any of that stuff. They're wired right to the panels I think, don't think there are any charge controllers and definitely no batteries or motion sensors.

That's not possible unless you're only using the lights during the daytime. The solar panels only produce electricity when the sun is shining, so that energy has to be stored somewhere if you're going to use it later to power lights (or anything else) when there's not sunlight to produce a current in the panels. If the panels are wired directly to the lighting fixtures and you use those lights when the sun isn't shining then those fixtures have batteries (and charge controllers) built into them, which is the case with all of the all-in-one solar powered lights.

 

[DParker75089]

I have always been interested in solar but never had the time to really dive in. I'm realizing that I have a similar area to illuminate at this other poster.... I don't suppose we could expand on this 2-lightbulb project or do a small tutorial post, for the greenhorns (which I definitely am!)?

I think a beginner's tutorial of any real usefulness (and that isn't grossly oversimplified) is beyond the scope of a discussion forum thread...unless the OP wants to devote the time and effort to such a considerable task. Perhaps in this case the better approach is to just define the parameters of the problem that you're trying to solve, identify the options for doing so and then just take it from there on a case-by-case basis.

So, you say that the area you wish to illuminate is similar to the one described by JacinLarkwell. OK, good start. Now let's ask some really basic questions about what a solar solution needs to do for you:

1. Will the lights be used any time that the sun isn't shining enough to produce enough current directly from one or more solar panels? This might sound like a silly question, but I'm accounting for the possibility of some edge use cases like lights that are needed for the inside of a structure that is only used during the day time, but receives little or no natural light even then. I'm assuming that isn't the case here, but I could be wrong.
2. I'm further assuming your intent is to use LEDs rather than something less efficient, like incandescents, flourescents, et al. Is that accurate?
3. Will you be needing to use the energy from the solar system to power anything other than lights?

There will be more questions as we go, but let's start with just these for now.

 

[Ascholten]

How many bulbs of what wattage (either actual watts used or their incandescent equivalent) are you needing to adequately light the area in question?

That is a question that is going to vary from each place. How big is your area, how dark is it? weeds around? How about YOUR eyes, what might be fine for me, is dark ass tripping hazard for you ! LED's are very good now, you can get stupid bright ones but they will burn a few watts. Are we talking you want it lit like a stadium, full brightness like you are having a night party with friends and want people to see each other pretty well, or just a gentle lighting so you can see the sidewalk and where the bushes are sticking out at so you can make it into the house?

You'd have to figure out how bright you need, then get the lights, see their watts, how many you want to use, and do some math. then times that by about 1.5 and that is how much power you probably want to have in reserve to do them.

Aaron

 

[Ascholten]

Absolutely no clue. Just something that let's me see if that mass running away is my cat or a racoon

might be better off with a microphone, if it's screeching and screaming, it's probably the cat

 

[Ascholten]

Really wanna be here too. Michigan averages 160 days of sunny/partly sunny per year.

Aaron, is that enough? While we'd LOVE to be totally off grid, I don't know if we can do it. One question we keep bumping up against, how far away can collector panels be from the house? We have a nice open area that is probably 500 feet (or more? maybe?) from the house. It's an open field.

Another possibility is the roof of a pole barn, but it's about 3x as far away.

In Your case, Id do micro inverters. You convert the DC into AC right at the panel, and then send AC back to the house / barn etc. 500 feet is a fairly long way, but 10 Amp of 240 volt AC you could probably get away with 12 or 10 gauge wire. as an example, where DC you'd need probably 2 gauge or start into the aught sizes to lessen the horrible drop.

AC is always better for transmission until you get into extremely high voltages (talking utility kilovolts here).

Aaron

 

[Ascholten]

Really wanna be here too. Michigan averages 160 days of sunny/partly sunny per year.

Aaron, is that enough? While we'd LOVE to be totally off grid, I don't know if we can do it.

Sally. that is a great question . EVERYTHING is doable with enough collection and storage areas. Also, how much power do you need? If you are running a fridge, a fan, and a small light in a cabin, and heating water / house etc with wood / gas / etc, then yes it might work. But if you are wanting internet, water heater, garage door opener, wifi, etc etc. then the power requirements go way up. You also need to factor in, like in florida here, ok so we have a week of rain coming up. thanks god..... do you have the batteries to hold a weeks worth of crappy production / cover for??? if you burn 10 kw a day you'd need 50 kw of batteries, lets say 55 to be safe. ok, how fast do you want to replenish this? a day, 5 days? I always say to go MORE generation than your numbers say, it's always better to have a little more and the panel curtails, then the breaker turning off because your battery volts are critically low.

You'd have to do a work sheet, see how much power you use and go from there. Also your useage is seasonal, your generation is seasonal, that will need to be taken into account too.

Aaron

 

[Ascholten]

Does anyone have experience with unsolicited mail solicitations for solar panel installation? Do they keep you hooked into the grid?

Be VERY wary of unsolicited mail companies. Most are shady.

Most every installation HAS to keep you hooked to the grid unless YOU specifically tell them to design it otherwise. Many municipalities won't let you disconnect so you don't have a choice. You may have to stay hooked to it, but that does not mean you have to use it.

aaron