Solor lighting system for neighboorhood enterance Sign

[Amy@altE]

6 x 5W x 12 hours = 360Wh. 360Wh / 4.09 sun hours (Atlanta) / .6 losses = 147W solar minimum.

360Wh x 4 days x 1.4 temp x 2 (50% DoD) / 12V (not sure what 5W lights you are referring to, assuming 12VDC) = 336Ah 12V battery bank.

Edit: I'm not crazy about such a big battery bank with that small of a solar array, so I'd probably recommend getting some more solar.

[Sunking]

Sign located in northern GA. It gets occasionally in the high 20's at night. But usually in the low 40's in the winter Sign will have 6 lights. I'm thinking maybe the 5w LED floods. We really don't need much light at the location. We would like them to be on for 10-12 hours each night.

The devil is in the details which you never provided until now.

You need a 200 watt panel, 15 amp MPPT Charge Controller and a 12 volt 400 AH battery. Going to run you roughly $1200 to $1500 just for the panel, controller, and battery . All the materials required to work are not included. Like I said around $2000 per Kwh with a 5 year battery, or $1500 per Kwh for a 1 to 2 year battery if no one steals it.

Now go shopping and Merry Christmas.FWIW you wil not be using a 12 volt battery, you will be using 2 6-volt 400 AH batteries in series. They do not make 12 volt batteries that large and never ever parallel your batteries. Just so you know what you are asking for batteries will be roughly 50% of the cost and in need of frequent replacement installed outside in a Oven in winter and a Freezer in winter.

FWIW I will never try to sell you anything, I could care less what you do. Just remember when it comes to solar and batteries, once you walk out the door, you own it and no refunds.

[wildduk]

SunKing, Thx

This is what I was looking for. Any chance you could run those numbers again this time with only 2 5w LED's??? That would be a more realistic setup....

[Sunking]

This is what I was looking for. Any chance you could run those numbers again this time with only 2 5w LED's??? That would be a more realistic setup....

My pleasure. OK I assume 12 hours run time and 6 - 2.5 watt LEDS

Daily watt hours = 6 x 2.5 watts x 12 hours = 180 watt hours. Adjusted for 66% overall system efficiency = 180 / .66 = 272 watt hours rounded up to 300 watt hours
Winter Sun Hours = 3.0 Hours.

Panel Wattage with MPPT Controller = 300 watt hours / 3 hours = 100 watts.
Panel wattage with PWM Controller = 150 watts.
12 volt battery capacity = 300 watt hours x 5 day reserve = 300 wh x 5 / 12 volts = 125 AH
MPPT ot PWM Controller = 10 amps.

Now there are a couple of caveats you need to be aware of because they will bite you in the butt if not accounted for.

The above panel wattage and controller size are based on optimum orientation (due solar south), tilt angle, and no shade issues from sunrise to sunset particularly in winter which can be a problem in GA because you cannot see the forest because of all the dang trees blocking your view. That does not change the battery size but does affect panel wattage and controller size.

Here is a golden jewel of info you want to know. Solar panels come in two basic flavors of Low Voltage (battery), and High Voltage (grid tied). This is important due to cost. Low voltage battery panels cost 2 to 6 times more per watt. No real market for them and antiquated by MPPT Controllers. The catch is MPPT Controllers cost roughly 4 times more than PWM. The break point is roughly 150 to 200 watt panel. It takes a 300 watt PWM system to equal a 200 watt MPPT system. Why do they still make Low Voltage panels and PWM controllers?. Because there is a sucker born every minute. However under 100 watts not much difference other than if you use PWM controller with a battery panel turn 100 watts into 66 watts. If you use a PWM controller YOU MUST USE BATTERY PANELS.

How can you tell a Battery Panel from a GT Panel? Price, but the dead giveaway is is the number of cells, Vmp voltage, and to a lessor degree the wattage. A battery panel will have 36 cells. a Vmp of 17 to 18 volts, and <200 watts. A GT panel will have more than 36 cells, a Vmp > 18 volts, and usually =>200 watts. There are some exceptions. Also note you might find some bargains on Battery panels, just remember to use a MPPT Controller as they work on both panel types. PWM just throws away 33% or more of your power. Example use a PWM controller on a 200 watt GT panel and you have a 100 watt panel.

So here is what I am driving at. A 300 watt PWM system just for the panel and controller is going to cost $600 to $1000 depending on how bad you get raped for either 2-150 watt battery panels or 3-100 watt panels plus the the wiring and mounts. You can pick up a 200 Watt GT panel and 15-Amp MPPT Controller will cost you $400 to $500.

If I were you, I would spring for a single 200 Watt GT panel and a $200 15-Amp MPPT Morningstar controller with a 12 volt 125 to 150 AH battery. That will give you a real 3 day run time. At th eend of the 3rd cloudy day, shut down and wait for 3 full winter sunshine days or 1 long summer day before you power back up.

Merry Christmas and God Bless.

[Amy@altE]

Why do they still make Low Voltage panels and PWM controllers?. Because there is a sucker born every minute. However under 100 watts not much difference other than if you use PWM controller with a battery panel turn 100 watts into 66 watts. If you use a PWM controller YOU MUST USE BATTERY PANELS.

If you are buying the panels online, you also have to consider shipping costs. The big panels can't ship by UPS or USPS, they have to ship by truck. So figure minimum $200 for shipping one panel or 4 panels. If you look at the total delivered price of a couple of 12V panels, PWM, and shipping, it can be much less expensive than a single 20V panel, MPPT, and shipping.

[Sunking]

If you are buying the panels online, you also have to consider shipping costs. The big panels can't ship by UPS or USPS, they have to ship by truck. So figure minimum $200 for shipping one panel or 4 panels. If you look at the total delivered price of a couple of 12V panels, PWM, and shipping, it can be much less expensive than a single 20V panel, MPPT, and shipping.

Betcha a dollar Walmart, Lowe's Home Depot, Sam's, Costco, and Tractor Supply Company says otherwise. The store may not have them in stock, but can get them to the store quickly on their next scheduled delivery truck. No charge. Like I said I will not sell anyone anything at any time and do not make my living from Solar. If you can get low voltage battery panels $1/watt is fine, just do not make the mistake of ever using a PWM controller and parallel panels on systems 200 watts and higher.

Amy I can understand your position. You want to install as many expensive low voltage panels in parallel as you possible can. Lots of racking, wiring, combiners, fuses, more labor, and most importantly mo money for you. That is what a sales person does.

[Amy@altE]

Amy I can understand your position. You want to install as many expensive low voltage panels in parallel as you possible can. Lots of racking, wiring, combiners, fuses, more labor, and most importantly mo money for you. That is what a sales person does.

Quite the opposite, I want to provide the right solution for the customer. There are a ton of places that don't have large solar panels available for local pickup. I'm more than happy to provide balance of system if they can get the panel locally. Ditto with batteries, we often recommend they get the batteries locally so they don't have to pay to ship all that lead. Don't assume everyone is out to screw the customer, despite your doom and gloom, there are good people out there and good companies that want to do the right thing. We'll often do 2 designs, one with 12V, one with 20V, discuss the pros and cons of each, and let the customer decide what they'd prefer. Pain in the neck for us, but often the right thing to do.

[jflorey2]

Don't assume everyone is out to screw the customer, despite your doom and gloom, there are good people out there and good companies that want to do the right thing.

And let me take this opportunity to thank you for all the videos you've made and all the advice you give out online. You've helped educate a lot of people out there with your simple and accessible videos and informative posts - and those posts are made without the sales pressure you see in a lot of posts from people in the solar industry. You're definitely one of the "good ones."

[Amy@altE]

Thanks jflorey2.

[wildduk]

Anyone know a good site to purchase this equipment. Amy, I'm just picking up on the fact that you sell solar systems. Is this correct?

[Amy@altE]

Just answering questions.

[J.P.M.]

Just answering questions.

Amy: I sure don't doubt your intentions, and I've been around here long enough to appreciate the time and selfless effort you've put in on what sure looks like a pro bono basis. To me, those efforts look like a real help, and few could do those things as well or as professionally.

But to say you're just answering questions seems a bit transparent. Two or three years ago, I called out some similar actions by a moderator. As expected, he didn't think much of the stink I made, but, if I remember correctly, he wrote in response to my comments that he would no longer have any input to postings that were from geographical areas where he did business and were related to products or services his company sold. To me at least, that seemed the standup thing to do and worthy of respect.

Bottom line: Even though, IMO only (but probably one shared by most everyone knowledgeable of your input), you've done a sterling job of it, and even though it sucks, it's pretty hard to claim the mantle of objectivity and unbiased opinion when you have skin in the game. This one looks like a plug. Where does the line get drawn ?

As usual, take what you want of the above. Scrap the rest.

[wildduk]

So I'm thinking this system. Maybe upping the panel to 100w vs the 80w it comes with.

mrsolar.com/online-solar-...ng-system-kit/

according to Sunkings numbers,changed to 2 (5w) lights, not 6 (2.5 watt light) I misled him.

i would need a 66.6 watt panel and a 83 ah battery.

it comes with a 80w panel, so upgrade it to a 100w
aslo comes with a 100 ah battery, so should be fine.

Comments??

[Mike90250]

And yes, let's not forget that this Forum is hosted by a solar company http://www.solarreviews.com so please use them and give feedback about your install.

[SunEagle]

So I'm thinking this system. Maybe upping the panel to 100w vs the 80w it comes with.

mrsolar.com/online-solar-...ng-system-kit/

according to Sunkings numbers,changed to 2 (5w) lights, not 6 (2.5 watt light) I misled him.

i would need a 66.6 watt panel and a 83 ah battery.

it comes with a 80w panel, so upgrade it to a 100w
aslo comes with a 100 ah battery, so should be fine.

Comments??

You will still be a little light on charging amps with only one 100watt panel at ~ Imp = 5.5amps for a 100Ah battery. You might want to double the panel wattage to 200watts.