Outdoor solar setup?

paperfist

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Hey guys,

I want to setup a solar panel, a battery or two to power a fountain water pump and some accent lights for trees.

Can any of you offer advise or point me in the right direction?

The panels I see that come with the pumps look kind of junky. I don't really know how to size the two together. And I'm not even sure if I can use the battery(s) to store power for after when the sun goes down. The primary reason I want to do that is so the two pond liners I have don't freeze.

Thanks!
 

Red Squirrel

No Lifer
May 24, 2003
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Basically you need the panel, charge controller, and battery, and if the pump does not use the same voltage as the battery, some kind of converter (DC-DC, inverter if it's 120v etc). To avoid killing the battery perhaps a micro controller with a relay that turns off the pump if the battery voltage is too low. The solar panel connects to the charge controller, which then connects to the battery. The charge controller ensures the battery is getting the proper voltage to charge correctly, as solar panel voltage varies a lot, it's a constant current device and not constant voltage. So at this point you have a battery that will always be kept charged. Then you connect your load (the pump or other accessories like the micro controller) the the battery. The load will run off the battery and the solar, and when the solar is not producing, only run on the battery. Basically you can think of the battery as a capacitor to smooth out the ripples of the solar as it will vary based on clouds etc.

For sizing, you want a battery that has enough amp hours to last at least the whole night, but I'd double that since you don't want to keep discharging it fully. You also have to account for days where it's not sunny. The panel itself also has to be sized so it can charge the battery fast enough and run the pump at same time. I've experimented with small panels and found that a 30w panel actually outputs 15w at the very best so keep that in mind, that the rated wattage is the absolute max it can produce with the ideal conditions they created at the factory to test it. Everything from sun angle to atmosphere conditions can affect it.

Keep winter in mind too, very short days and very long nights. Not sure if you want to run this all year round or not but if yes it's something to account for.
 

Blain

Lifer
Oct 9, 1999
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Hey guys,

I want to setup a solar panel, a battery or two to power a fountain water pump and some accent lights for trees.
Tell us the model numbers of the pumps and if the lights are LED or not, we can go from there.
 

paperfist

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Basically you need the panel, charge controller, and battery, and if the pump does not use the same voltage as the battery, some kind of converter (DC-DC, inverter if it's 120v etc). To avoid killing the battery perhaps a micro controller with a relay that turns off the pump if the battery voltage is too low. The solar panel connects to the charge controller, which then connects to the battery. The charge controller ensures the battery is getting the proper voltage to charge correctly, as solar panel voltage varies a lot, it's a constant current device and not constant voltage. So at this point you have a battery that will always be kept charged. Then you connect your load (the pump or other accessories like the micro controller) the the battery. The load will run off the battery and the solar, and when the solar is not producing, only run on the battery. Basically you can think of the battery as a capacitor to smooth out the ripples of the solar as it will vary based on clouds etc.

For sizing, you want a battery that has enough amp hours to last at least the whole night, but I'd double that since you don't want to keep discharging it fully. You also have to account for days where it's not sunny. The panel itself also has to be sized so it can charge the battery fast enough and run the pump at same time. I've experimented with small panels and found that a 30w panel actually outputs 15w at the very best so keep that in mind, that the rated wattage is the absolute max it can produce with the ideal conditions they created at the factory to test it. Everything from sun angle to atmosphere conditions can affect it.

Keep winter in mind too, very short days and very long nights. Not sure if you want to run this all year round or not but if yes it's something to account for.

Thanks! Didn't even know there were DC to DC converters. Will have to re-read a few more times.
 

paperfist

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Tell us the model numbers of the pumps and if the lights are LED or not, we can go from there.

I don't have anything picked out. I keep searching for pump and panel and the results are all over the map from something that can supply water to a house (well pump) to stuff that looks like a toy pump and panel setup ala Harbor Freight.

I'm not really sure what to use.
 

natto fire

Diamond Member
Jan 4, 2000
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I'm assuming the main reason to go this route is because bringing premise wiring to the site is cost prohibitive?

A mains wired pump will provide much lower maintenance over a battery/paneled one.

If the pump has to run 24/7, then you can size the battery and panel you will need accordingly.
 

paperfist

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I'm assuming the main reason to go this route is because bringing premise wiring to the site is cost prohibitive?

A mains wired pump will provide much lower maintenance over a battery/paneled one.

If the pump has to run 24/7, then you can size the battery and panel you will need accordingly.

Yes and no. The run would be about 200' to the electrical box. So it would be convenient to just go solar. Plus the cool factor.

Can you tell me how to size it?
 

natto fire

Diamond Member
Jan 4, 2000
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Yes and no. The run would be about 200' to the electrical box. So it would be convenient to just go solar. Plus the cool factor.

Can you tell me how to size it?

Since you are not in an ideal solar zone you will have to oversize the batteries a bit, to account for 2 to 3 days of not receiving energy from the panel. You might meet in the middle by oversizing the panel a bit too, but it is a fine knife in the cost department.

Do you have a pump picked out? I would pick the lowest wattage DC pump I could find for proper flow requirements, and then size the electrical parts from there.
 

paperfist

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Hey guy I've been doing a little research.

I'm looking at this panel:
http://www.amazon.com/Renogy-Watts-...d=1448698730&sr=8-3&keywords=100w+solar+panel
Renogy 100 Watts 12 Volts Monocrystalline Solar Panel

and this pump:

http://www.amazon.com/gp/product/B0...rue&ref_=ox_sc_act_title_1&smid=ATVPDKIKX0DER
Little Giant 33BPLA 12 VDC In-Line Utility Pump

which is supposed to be a 2 AMP submersible.

I'll add a marine deep cycle battery. If I add 2 it will turn it into a 24 volt system, right? Not sure how to manage that...

What else would I need?
Would the panel be sufficient to run the pump 24/7 along with the battery?

Thanks!
 

Red Squirrel

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May 24, 2003
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You need a charge controller too, you don't want to connect the panel directly to the battery as it will over charge it. A 12v panel will generate in the 20's of volts when the sun is at full power. Charge controller will ensure the battery is getting the proper charge voltage.

Actually this kit might work, it looks like it's the same panel except with a charge controller:

http://www.amazon.com/Renogy-Watts-..._UL160_SR160,160_&refRID=1WQTHG555Z8J0C0BAXGQ

It's just a pwm one though, you typically want MPPT (Maximum Power Point Tracking) but I think for your application pwm should be ok as well. MPPT is more expensive and more important if you're off grid and really need to squeeze every watt you can.
 

natto fire

Diamond Member
Jan 4, 2000
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Hey guy I've been doing a little research.

I'm looking at this panel:
http://www.amazon.com/Renogy-Watts-...d=1448698730&sr=8-3&keywords=100w+solar+panel
Renogy 100 Watts 12 Volts Monocrystalline Solar Panel

and this pump:

http://www.amazon.com/gp/product/B0...rue&ref_=ox_sc_act_title_1&smid=ATVPDKIKX0DER
Little Giant 33BPLA 12 VDC In-Line Utility Pump

which is supposed to be a 2 AMP submersible.

I'll add a marine deep cycle battery. If I add 2 it will turn it into a 24 volt system, right? Not sure how to manage that...

What else would I need?
Would the panel be sufficient to run the pump 24/7 along with the battery?

Thanks!

2 amps @ 12v is 24w. If you got two "average" sized deep cycle batteries with a capacity of 35 amp-hours each, you would have a capacity of 840 watt-hours. Basically, you would be able to run that pump for roughly 35 hours with ZERO sunlight. Of course, even on cloudy days, the panel will output some energy. Also, you would only get 24v if you hooked the two batteries up in series. If done in parallel, you will get the cumulative capacity of the batteries at 12v, with 12v batteries.

As Red Squirrel said, you will still need a charge controller to avoid overcharging the batteries. Charge controllers can be had for pretty cheap. The one I linked also provides overcurrent protection, so that if the pump motor locked up, it would trip the OCPD, instead of toasting your batteries. It does have a fairly weak IP rating, which means it is weather resistant, but if it will be installed in the elements and you get severe weather, you might want to think about a more robust enclosure, or look for a charge controller with a higher IP rating.

Not sure what your plans for lighting are, or what capacity batteries you are looking at, but for the pump alone, I would think this panel should be more than adequate.
 
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paperfist

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You need a charge controller too, you don't want to connect the panel directly to the battery as it will over charge it. A 12v panel will generate in the 20's of volts when the sun is at full power. Charge controller will ensure the battery is getting the proper charge voltage.

Actually this kit might work, it looks like it's the same panel except with a charge controller:

http://www.amazon.com/Renogy-Watts-..._UL160_SR160,160_&refRID=1WQTHG555Z8J0C0BAXGQ

It's just a pwm one though, you typically want MPPT (Maximum Power Point Tracking) but I think for your application pwm should be ok as well. MPPT is more expensive and more important if you're off grid and really need to squeeze every watt you can.

Thanks for the info! The MPPT one is only about $80 more. Are they that much more efficient?
 

paperfist

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2 amps @ 12v is 24w. If you got two "average" sized deep cycle batteries with a capacity of 35 amp-hours each, you would have a capacity of 840 watt-hours. Basically, you would be able to run that pump for roughly 35 hours with ZERO sunlight. Of course, even on cloudy days, the panel will output some energy. Also, you would only get 24v if you hooked the two batteries up in series. If done in parallel, you will get the cumulative capacity of the batteries at 12v, with 12v batteries.

As Red Squirrel said, you will still need a charge controller to avoid overcharging the batteries. Charge controllers can be had for pretty cheap. The one I linked also provides overcurrent protection, so that if the pump motor locked up, it would trip the OCPD, instead of toasting your batteries. It does have a fairly weak IP rating, which means it is weather resistant, but if it will be installed in the elements and you get severe weather, you might want to think about a more robust enclosure, or look for a charge controller with a higher IP rating.

Not sure what your plans for lighting are, or what capacity batteries you are looking at, but for the pump alone, I would think this panel should be more than adequate.

Thanks for breaking that down into something I understand.

I'm not sure if the MPPT controller that Red Squirrel linked too would have those protections.

The lighting I guess I'm going to hold off on for now. Primarily I want to drive the pump so if there's juice left I'll do some lights too.

I'm thinking a battery like this: http://www.amazon.com/gp/product/B00KQX5FPQ?psc=1&redirect=true&ref_=oh_aui_detailpage_o05_s00 or 2...
 

paperfist

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So that panel I select says on a perfect days it outputs 500 watt hours per day.

If I had 2 - 33ah batteries (66ah) x 24 (hours) = 1584 ah.

Does that mean in perfect conditions I'd only be able to charge those 2 batteries to roughly 1/3 capacity per day?
 

natto fire

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Jan 4, 2000
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So that panel I select says on a perfect days it outputs 500 watt hours per day.

If I had 2 - 33ah batteries (66ah) x 24 (hours) = 1584 ah.

Does that mean in perfect conditions I'd only be able to charge those 2 batteries to roughly 1/3 capacity per day?

Well, to get the amp-hours from the watt-hours, you need to do some extra calculations.

Your 500 Wh solar panel setup will output roughly 41 Ah at 12v. If you put the batteries in series, you would be looking at 20 Ah, at 24v for roughly the same 500 watt-hours. There will be losses of course, but when going from DC to DC, they are actually pretty minimal. So basically, your 500 Wh solar panels would be able to charge your battery bank in a few hours of good sunlight.

Any solar or electrical experts feel free to chime in, I know you are dime a dozen on this forum, but I am still hesitantly thinking you are overkill on your panels.
 

Carson Dyle

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Jul 2, 2012
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Since you are not in an ideal solar zone you will have to oversize the batteries a bit, to account for 2 to 3 days of not receiving energy from the panel. You might meet in the middle by oversizing the panel a bit too, but it is a fine knife in the cost department.

Why would you need to worry about extended sunless periods for something that is strictly ornamental? Ideally, maybe you might, but it doesn't sound terribly important.
 

mizzou

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Jan 2, 2008
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I imagine after all the time and money you spend on setting this up, it will not be as cost effective as having it wired into your main utility power.

Sounds like a fun project though :)

I would like to set up a solar array at some point, my roof is perfect for about a 250-500 watt setup. Have it wired into a battery bank that I can tap into for electric heat or other misc. things like a electric golf cart
 
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Red Squirrel

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Also keep in mind that you don't want to always deep cycle your batteries even if they are advertised as deep cycle, as it's still harder on them. So when making your calculations I would actually divide the rated amp hour in two. Given the price of the battery you posted you're probably better off paying more, and getting a 100AH marine battery locally. Not sure what is the equivalent to Canadian Tire in the states, but that's where I get my batteries for my UPS, it's about 120 bucks for a 100AH battery.

When I was playing with a 30w solar panel, I never got more than like 15w out of it as well, I imagine you need extremely good conditions to squeeze the max rating of panels. This was in June/July which is peak sun here.

Actually that reminds me I need to charge those batteries, they've been sitting in storage for a while. I'm actually curious to see how much more efficient solar panels are when it's cold out, I'll have to play with them some time again.

Though since this is not for something that is super essential, you could save money by not oversizing it as much, but instead just add a microcontroller circuit to check voltage and turn off the load if voltage goes below 11 volts. Then it's running JUST the micro, and once voltage is higher, it can turn the relay back on for the load. The controller would always be connected and so would the micro, so there is a chance that if you get a super long period of no sun the micro will run the battery down but I doubt it, they use a ridiculous small amount of power, basically you'd treat it like a car, where there are some accessories that are always on such as the auto starter.
 
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paperfist

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Well, to get the amp-hours from the watt-hours, you need to do some extra calculations.

Your 500 Wh solar panel setup will output roughly 41 Ah at 12v. If you put the batteries in series, you would be looking at 20 Ah, at 24v for roughly the same 500 watt-hours. There will be losses of course, but when going from DC to DC, they are actually pretty minimal. So basically, your 500 Wh solar panels would be able to charge your battery bank in a few hours of good sunlight.

Any solar or electrical experts feel free to chime in, I know you are dime a dozen on this forum, but I am still hesitantly thinking you are overkill on your panels.

Thanks.

I didn't think anyone was going to answer anymore so I went ahead and ordered the stuff a week or so ago. I went with the 100 watt panel, a MPPT charger controller, a 33ah battery to go along with one I already have and of course the 2 amp pump.

So for about $300 I'll get my solar feet wet. If I have to tweak anything at least I won't loose my shirt.

So
 

paperfist

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Why would you need to worry about extended sunless periods for something that is strictly ornamental? Ideally, maybe you might, but it doesn't sound terribly important.

I think because for my purpose at least in the winter I don't want the 2 pond liners to freeze and render all that damn digging for naught :)
 

paperfist

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I imagine after all the time and money you spend on setting this up, it will not be as cost effective as having it wired into your main utility power.

Sounds like a fun project though :)

I would like to set up a solar array at some point, my roof is perfect for about a 250-500 watt setup. Have it wired into a battery bank that I can tap into for electric heat or other misc. things like a electric golf cart

Yeah, but my yard is tricky. I think the electrical run would be at least 150', probably closer to 200' since I'd have to snake the wire around the driveway and then down into the basement, through all the floor joists to the electrical panel in the front. Digging for the pond liners and a 15' tree I installed was enough hard labor to last me a few years :)

Plus, like you said it's a fun project. I'm really interested to see what kind of output I can get from the panel. I always wanted to do my whole roof, but where I live there's a lot of cloudy days. So wasting $300 is easier on my wallet then the $6-7k it would take for the whole house.
 

paperfist

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Also keep in mind that you don't want to always deep cycle your batteries even if they are advertised as deep cycle, as it's still harder on them. So when making your calculations I would actually divide the rated amp hour in two. Given the price of the battery you posted you're probably better off paying more, and getting a 100AH marine battery locally. Not sure what is the equivalent to Canadian Tire in the states, but that's where I get my batteries for my UPS, it's about 120 bucks for a 100AH battery.

When I was playing with a 30w solar panel, I never got more than like 15w out of it as well, I imagine you need extremely good conditions to squeeze the max rating of panels. This was in June/July which is peak sun here.

Actually that reminds me I need to charge those batteries, they've been sitting in storage for a while. I'm actually curious to see how much more efficient solar panels are when it's cold out, I'll have to play with them some time again.

Though since this is not for something that is super essential, you could save money by not oversizing it as much, but instead just add a microcontroller circuit to check voltage and turn off the load if voltage goes below 11 volts. Then it's running JUST the micro, and once voltage is higher, it can turn the relay back on for the load. The controller would always be connected and so would the micro, so there is a chance that if you get a super long period of no sun the micro will run the battery down but I doubt it, they use a ridiculous small amount of power, basically you'd treat it like a car, where there are some accessories that are always on such as the auto starter.

I could have gotten some 'blem' deep cycle batteries, but I already had 1 33ah one for a window cleaning system I have. I know you don't want to continuously charge a battery over and over, but I think this tricky charge way shouldn't damage them too much.

Even with the MPPT controller I bought I still need the microcontroller?
 

Red Squirrel

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You don't NEED the micro but it's just an added bonus so you can monitor voltage and control a relay to turn the load off if the voltage is too low. You could try without it, and just monitor it to see how it works out.

Edit: out of curiosity I googled to see if there are premade products that do this, and looks like there is. Probably easier than setting up a circuit yourself:

http://www.ebay.com/itm/12-volt-bat...954223?hash=item4af4a3c82f:g:R8IAAOxysE5Sa4Ly
 
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natto fire

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Jan 4, 2000
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Thanks.

I didn't think anyone was going to answer anymore so I went ahead and ordered the stuff a week or so ago. I went with the 100 watt panel, a MPPT charger controller, a 33ah battery to go along with one I already have and of course the 2 amp pump.

So for about $300 I'll get my solar feet wet. If I have to tweak anything at least I won't loose my shirt.

So

Good to know. There was quite the delay in response, and I would have done the same thing. We are all armchair experts here (my electrical work is mainly in commercial 'LV'), so I would rather you update with your results and prove me wrong or right, over the thread dying and nobody learns from it. Hope the setup works good for you, and please report back!
 

SilthDraeth

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Oct 28, 2003
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I have learned a few things from this thread. Paperfist, definitely update us once you have it all setup.