What do I need?

[TheBackRoads]

It wouldn't be THAT difficult to wire up a KD140 panel to a single 55AH battery either.... but I'd rather be able to water when I want vs during the day (at work, cant just let run all day). just my $.02

[concretefire]

Thank you Bill. That certainly cleared some things up. At least math wise. I believe what you were saying there at the end is that it wouldn't make much sense to get the bare minimum panel when the battery bank (even at the minimum just to pump water) is capable of holding so much more power. May as well get a larger panel and make more use out of the battery. Correct?

[Photowhit]

If your 'pushing water' let gravity be your friend and place the water tank as high as possible, 4x4's will hold a lot in compression, just be sure to brace them well, and give them firm footing. If your collecting from a roof 12' high if you get the tank up as high as 7-9 feet, that may well be all the pressure you need, depending on the lay of the land.

Bilge pumps, are typically 'trash' tolerant to some degree, DC, submersible, often cheap and easy to find ratings since small boats often carry small batteries, doubt they would tolerate any back pressure...

...don't ever name your sailboat 'shark bait' it makes calling in for a tow interesting, "This is the sailing vessel sharkbait requesting a tow..."

[BB.]

Sort of--I really was just taking guesses about the amount of water that you will pump from that 150-200 gallon (??) water tank assuming it holds 3-4 days of water for you.

I don't know your garden's water needs and 50 gallons may be way less than required...

Anyway--Yes, such a system would be capable of quite a bit more power than my first pass estimate, which may be a lot more interesting to you as emergency/experimental solar power.

There are other options--You could get a 14 AH AGM battery and run with the smaller panel (7 Amps/14 AH = C/2 discharge rate... Which is certainly possible with many AGM battery). But pushing an AGM at that discharge rate--probably will not last more than 1-3 years.

If you like the single ~135 watt panel, then you could size the battery bank to (12 volts):

• 135 watts * 1/14.5 volts charging * 0.77 panel+charger derating * 1/0.05 rate of charge = 143 AH @ 12 volts maximum battery recommended
• 135 watts * 1/14.5 volts charging * 0.77 panel+charger derating * 1/0.10 rate of charge = 71 AH @ 12 volts nominal battery recommended
• 135 watts * 1/14.5 volts charging * 0.77 panel+charger derating * 1/0.13 rate of charge = 55 AH @ 12 volts minimum battery recommended

I would suggest you look at the MorningStar 300 Watts TSW 12 volt inverter. It is really hard to beat. It has a low power/standby "search mode" (checks for >6 watt AC load every second) and remote power on/off (just use a small switch to turn on/off the inverter).

A ~143 AH @ 12 volt battery bank running a C/8 discharge rate would support:

• 143 AH * 12.5 volt battery bus * 0.85 inverter efficiency * 1/8 rate of discharge = 190 watt average load

The battery will support that for a bit less than 4 hours (to 50% discharge).

And:

• 135 watts * 0.52 system efficiency (with AC inverter) * 4.46 hours of sun minimum = 313 Watt*Hours per day of AC power (February)
• ~313 WH per day (Feb) / 190 watt AC load = 1.65 hours per day (Feb)
• 135 watts * 0.52 system efficiency (with AC inverter) * 5.55 hours of sun (July) = 390 Watt*Hours per day of AC power (July)
• ~390 WH per day (July) / 190 watt AC load = 2.05 hours per day (July)

If you "like" the system and want more energy per day, you can add a second 135 watt panel and ~double the daily production with the same battery.

-Bill

[concretefire]

For ease of conversation, I will just thank 'everyone' for their ideas. Believe me, I have evaluated them. I am not comfortable putting this monster tank up on stilts or 4x4's simply because of the residential area I live in. If I was out in the country.....believe me, way ahead of ya'll on gravity fed water supply. I believe (will have to confirm) that for every 2 foot in drop of height, you gain 1 psi in water pressure. Or maybe it's the other way around but I know that's kind of on the right track. Anyway, since Bill seems to be going above and beyond in trying to help me...I just wanted to let you know Bill that I am digesting what you have said. Saturday, I will be moving the tank to it's final location and I will take pictures and upload them here as an update. I will also take some pictures of the garden to give you a better idea of how big it is and how much water I need and thus how long I would need the pump to run....etc. In other words, a picture says a lot. I think the first example you gave is probably going to be a little overkill. I think 2.5 gallons per minute is on the strong side for what I need. I also think 50 gallons is a LOT, but, on a very hot or dry period, I could see MAYBE using 50 gallon total for that day....but then not watering again for at least 2 days. My garden really is not that big and to be totally honest, I just think this particular project would be perfect for me to understand the basics, basics of solar. On the other hand, I've looked into those solar pond pump kits and they seem very not sturdy enough for my liking. Bill, I also have not ruled out your DC pump with the booster either. Once I have the pictures up, I think we can narrow it down further and YOU can see what I'm talking about. I sincerely appreciate your help and I hope you continue to aid me because I'm just a noob and I AM learning from you. (and others) I would love to be able to finish this project in this thread so that it may help others......all the way from "help" to "finished." I am determined to do this project and see it thru.

[concretefire]

Here are the pictuers. Part 1 is complete. Now comes part 2......the solar pump. As you can see, my garden is very small and not far away from the rain barrel. So now that you can see just how little I have to water and how little I have to travel, perhaps it will be easier to understand what my needs are. I just want to be able to water the garden. High Pressure is NOT a requirement. I would like a good flow though...

Lastly, YES, I understand that adding a solar pump and battery and controller and inverter (maybe all those) is highly NOT EFFICIENT for what I want to do. This isn't about $$. This is about practice and getting my feet wet with solar power. It's practice + just the sheer "neat" factor. So what do you guys think???

[Eric L]

I think 2.5 gallons per minute is on the strong side for what I need. I also think 50 gallons is a LOT, but, on a very hot or dry period, I could see MAYBE using 50 gallon total for that day....but then not watering again for at least 2 days.

O.k., so a very small pump is likely enough, unless you need a lot of head pressure for some reason.

How about an inexpensive 12 volt DC submersible (like this, or similar)? Attach a few feet of vinyl tubing to the output with a little hose clamp, and lower it to the bottom of the tank. The water will come out of the top, but the pressure of the water in the tank will mean the only head pressure the pump is working against is from the top of the water level to the top lip of the tank and then down. Connect the end of the vinyl tubing to a small hose or whatever you plan to use for watering. If it isn't enough, you're only out about $25.

At 12 volts DC, that pump would use about 6 watts to move around 1 gpm, counting a small bit of head. 50 gallons in a day = about one hour (slightly less) x 6 watts = 6 watt hours. If we double that to count for charging inefficiencies, you need about 12 watt hours per day.

For power, keeping it cheap and cheerful: a small charge controller, a small panel in the 30 watt range, and a very small deep cycle battery (35 amp hours would be plenty). Wind-Sun sells all these things. You'd have to rig up a switch and wire and in-line fuse to connect the pump to the battery. The whole thing wouldn't be much more than $200.

If you wanted to build for the future, you could buy a larger panel, controller, and battery; as long as it was a 12 volt system you should be able to use these little DC submersibles.

[BB.]

Will the tank block the window as a fire exit?

-Bill

[tmarch]

Ok, a small solar pond pump doesn't impress you. Something to think about, what of the foreign matter (bird poop, sand etc. ) that gets into your rain barrell? I'd a lot rather try a pump designed for that than try to run a pure water transfer pump. Pond pumps will handle a small amount of sand grit etc. I've seen what asphalt shingle material will do to a pump, it's toast in a short while.

[fix_it_guy]

Ok, a small solar pond pump doesn't impress you. Something to think about, what of the foreign matter (bird poop, sand etc. ) that gets into your rain barrell? I'd a lot rather try a pump designed for that than try to run a pure water transfer pump. Pond pumps will handle a small amount of sand grit etc. I've seen what asphalt shingle material will do to a pump, it's toast in a short while.

He does have a "First Flush" hooked up. But the water will still have some debris in it.