Off Grid - Small system for corral

[MountainXBGL]

Looking for some help/suggestions.

The problem I am solving for: Livestock corral has a water tank that freezes frequently during winter and sometimes 2+ weeks of sub-freezing temps make it a daily challenge to keep water available.

What I have currently (not assembled into any type of system) : the tank, when I purchased, I installed a 12vdc resistance element that I can connect either 600W or 300W
I have purchased 4 - 275W ~40V panels
I have a 24v to 12v converter
I have a 2000W inverter ( I know the element is dc and will not work with this, however, I also have a 1500W 110v resistance element that I currently run off generator to thaw tank)
What I would like to accomplish as quickly as possible: Assemble panels to direct feed 600W element in tank - I understand this will only work during daylight (sun) but my thinking is that during the day, the element can thaw tank and heat water helping to keep it from freezing so thick during night and next day, not as much work to do to thaw (what I currently do with generator and works pretty well)
My long term goal Array feeding into a controller, with battery bank of maybe 4 - 6V 200Ahr (12v system)
inverter giving availability of 110v for hand tools and water pump
Lights for at corral (12v LEDs and/or 110V LEDs)

Sorry for length, but I wanted to give as much info as I could. I am learning solar systems and have not grasped everything yet, like what gauge wires need to go from where to where? how big a controller I would need? do I need combiner box?, can I simply run panels into my 24v to 12v converter direct to my element if I parallel my panels?

Again, solar beginner here but I am very experienced in low voltage systems (do it professionally for alarm, cctv and access systems) so I am familiar with current/electrical practice.

[organic farmer]

I do not believe that your 600w heater is going to have any noticeable effect on the water in the trough.

If you were to use a fish aquarium air pump, you could make it blow bubbles in the water trough, and that make stop it from freezing.

[Mike90250]

Stop Buying stuff.

first, there is some cowboy trick about filling a gallon milk jug with salty/brine water and a bit of air, and let it float in the tank. It won't freeze and can be bumped out of the way by a horses nose to get to the water. I've not tried it, no idea if it works.

Now, there are 2 ways to power a stock tank heater
gasoline generator for $700 for a med size generator that you fuel up

Solar power station, that will likely cost $5K before it's all done with.

Lets start with the tank - is it insulated or bare metal ?

You have a 1500w heater, Would a 600w heater work as well, just to keep a hole open, not to make a hot tub out of it ?

Say it's a 600w heater, on 110VAC. Cycle time is 50%. So in a 24 hour day, it would consume 7,200 watt hours That's about what my off grid ranch uses, with house, lights, 3 fridges, pumps, filters and all the goodies. Wow. Step the estimate up to $10K at least.

You will need batteries large enough to store twice the daily usage, and if it's cloudy, you are out of power. A battery for 15kwh
( notes, a 6v 200ah, $110 golf cart battery contains 1,200 wh, Eight of them wired for 48V would be 9,600 wh (9.6kwh) would not be enough)
so upping the batteries to 8, size L-16 floor scrubber batteries (6v 380ah, $250 each) would give you 18,240 wh, which would work.
Solar to charge that ( harvesting about 10 kwh in 5 hour day ) would need to be at least 3,000 watts of panels, which actually output 2,250 under great conditions.
Then you need racks or a pole mount, a shed of some sort to put the batteries, charge controller, inverter into to keep the water off it all. Couple lbs of heavy wire to connect it all up, fuses, electrical panels and all the little stuff, Now thats a project and some real money.

How much to rent a trencher and lay electrical cable from the house ??

This will not easily work with a DC heater, as the thermostat cannot handle DC

And the battery needs to not go below 50% charge or it can freeze. Li batteries are even worse, they must be shut down at 33F.

Freeze point Pb battery.jpg

[MountainXBGL]

I do not believe that your 600w heater is going to have any noticeable effect on the water in the trough.

If you were to use a fish aquarium air pump, you could make it blow bubbles in the water trough, and that make stop it from freezing.

I forgot to mention a couple other things I have waiting for my long term solution - I have a thermostat relay that I can set kick on and off temps which will trigger the element to run and I also have a circulation pump that will also kick on. I am feeding the tank from 250G water tote. Once I have power setup, the relay will kick on at say 40F and run element as well as the pump which will feed water from livestock tank back into tote which gravity feeds back into livestock tank. The tote will be housed in small shelter to help keep it from freezing so in effect, it will feed warmer water back into livestock tank, which is getting warmed and feeding back into tote (warm water cycle)..

edit add - the thermostat and relay are dc - the relay output from thermostat is going to trigger a 50A relay to throw power at element

[MountainXBGL]

Mike - the corral is 3/4 mile from my house with no grid lines near. Would have to pay big construction costs to get a pole up there. and also, I am not necessarily looking to power the element 24hr a day. For quick solution, I was hoping I could get 4-6 hours per day direct feed from panels.

And your cowboy trick - I have read that as well. Haven't tried it yet but I believe I will. I will let you know.

[J.P.M.]

Looks like you did a "ready, fire, aim" approach to the application.

Before I embarked on designs/methods for an application that required keeping a tank from freezing, I would want and need to know what the worst (greatest) - not average - expected heat loss from the water before I started a design or looking for solutions. That's called the design duty and will include not only the most severe (greatest) heat loss rate to the environment the water will see, but also its time duration and something of the pattern of cold snaps - how long they can last for example. You haven't mentioned any design heat loss for the tank. It's a necessary piece of information.

If PV is one of the solutions under consideration for freeze prevention - and it seems the only one at this time anyway - some consideration will need to be given to how you'll keep the water from freezing for several days when the sun doesn't shine during a cold snap with no/insufficient time coincident sun to provide power to a heating element. Then there's the consideration of whether or not battery storage is needed - which sounds likely.

Insulating the tank bottom and sides will reduce the heat loss and so the duty, and so quite possibly reduce the size and cost of any heating method, but perhaps not the complexity of, say, a PV solution. But, even with insulation, usually half the heat loss (or more) from open top tanks is from evaporation, more so at windy sites, so a good part to the heat loss remains even after any insulation measures. Still, insulation will lower the heat loss in predictable and measurable ways and that will always make meeting the duty easier and probably less expensive but perhaps not necessarily less complicated or more reliably.

As Mike writes, between the PV, (likely) batteries, racking and construction costs, I might consider insulating the tank. Then, get a conservative estimate of the duty to keep the water at/above the freezing temp. after the insulation. Then, size heating elements to meet that duty and check/update/size the gas fired genny to meet the electrical load required by the heating elements. Or alternately, consider a propane fired water heating system with a thermostat and a bubbler or small water circulation system that together would keep the water from freezing.

I've also not dome the cowboy trick exactly. I like the milk jug idea but I'd use fresh water. I've frozen milk jugs and left about 10 % of the volume as air to handle the ice volumetric expansion with no leaks. I'd not add salt to the jug water for your application and only fill the jug maybe ~ 50 % or so. The increased air pressure from the free volume decrease due to the water to ice volumetric expansion will not be a problem for the jug. However, the e plastic will deteriorate with UV and the jug will leak. I'd not want to brine up the tank water when the jug leaked.

As you learn more about solar and PV you may come to see that as perhaps not the best solution for your application. Most likely, other solutions will be less costly than a PV system and most likely a lot less troublesome than babysitting a bunch of batteries that, depending on your climate, may need their own heating system as well.

Solar is a great way to meet energy requirements for many tasks, but in spite of what solar peddlers, and their media and treehugger shills would have the solar ignorant believe, it ain't a panacea for every application.

If it were you, I'd keep what I bought only until I found a better solution. Then, I'd put all of it on Ebay.

Welcome to the neighborhood and the forum of straight(er) talk and few(er) illusions.

[MountainXBGL]

Thanks JPM. TBH, the purchases I have made were not specifically for the "water tank" solution. I have need to have power available at my corral, which my goal is to have a PV system that will give me abilities for lights, plug in use of hand tools, etc. The "water tank" problem, I realize is a very difficult one to solve for especially with solar. My hope is that I can find a creative way for solar to play an assist role in a solution that doesn't require gassing a generator daily. I am playing around and exploring ideas that could involve geothermal, timed circulation between exposed and non-exposed water banks, ways to insulate both exposed and non-exposed water banks, etc.

I appreciate the responses. We have had a run of really cold weather with several more days of it predicted. I have a working solution now with the generator and the 1500W element. It is working for now. Just exploring ideas to implement before next years cold season that would be more efficient.

I am getting the impression that some are feeling as though I have blown through a bunch of money and will have to spend a bunch more for something that isn't going to get me where I need to be. I understand that sentiment. My current out of pocket is less than $800 for items that I will use for a PV solution to give me power at the corral. The water tank....well.....hopefully I can find a creative mesh of ideas/technologies to solve....if I can't, well, can't say I didn't try. I like to tinker.

[SunEagle]

Thanks JPM. TBH, the purchases I have made were not specifically for the "water tank" solution. I have need to have power available at my corral, which my goal is to have a PV system that will give me abilities for lights, plug in use of hand tools, etc. The "water tank" problem, I realize is a very difficult one to solve for especially with solar. My hope is that I can find a creative way for solar to play an assist role in a solution that doesn't require gassing a generator daily. I am playing around and exploring ideas that could involve geothermal, timed circulation between exposed and non-exposed water banks, ways to insulate both exposed and non-exposed water banks, etc.

I appreciate the responses. We have had a run of really cold weather with several more days of it predicted. I have a working solution now with the generator and the 1500W element. It is working for now. Just exploring ideas to implement before next years cold season that would be more efficient.

I am getting the impression that some are feeling as though I have blown through a bunch of money and will have to spend a bunch more for something that isn't going to get me where I need to be. I understand that sentiment. My current out of pocket is less than $800 for items that I will use for a PV solution to give me power at the corral. The water tank....well.....hopefully I can find a creative mesh of ideas/technologies to solve....if I can't, well, can't say I didn't try. I like to tinker.

A real simple calculation will help you determine how much you might have to spend for a solar / battery system.

Anytime you want to run a load without grid power you can expect to spend about $1500 for each kWh your loads will use. So first determine what your water heater is going to use each day and then you can determine the size of the battery and panel wattage needed.

You might be able to run the heater directly from a panel but you have to understand that when the sun is not out (cloudy or at night) your heater will not work and will require another power source like a battery (very expensive) generator (somewhat expensive) or the grid (maybe expensive) to work.

[J.P.M.]

Thanks JPM. TBH, the purchases I have made were not specifically for the "water tank" solution. I have need to have power available at my corral, which my goal is to have a PV system that will give me abilities for lights, plug in use of hand tools, etc. The "water tank" problem, I realize is a very difficult one to solve for especially with solar. My hope is that I can find a creative way for solar to play an assist role in a solution that doesn't require gassing a generator daily. I am playing around and exploring ideas that could involve geothermal, timed circulation between exposed and non-exposed water banks, ways to insulate both exposed and non-exposed water banks, etc.

I appreciate the responses. We have had a run of really cold weather with several more days of it predicted. I have a working solution now with the generator and the 1500W element. It is working for now. Just exploring ideas to implement before next years cold season that would be more efficient.

I am getting the impression that some are feeling as though I have blown through a bunch of money and will have to spend a bunch more for something that isn't going to get me where I need to be. I understand that sentiment. My current out of pocket is less than $800 for items that I will use for a PV solution to give me power at the corral. The water tank....well.....hopefully I can find a creative mesh of ideas/technologies to solve....if I can't, well, can't say I didn't try. I like to tinker.

You're welcome. Not trying to wet blanket your enthusiasm, just share some of what I think I might know.

Good luck.

[MountainXBGL]

Very much appreciated and no worries about raining on the fire. Was hoping for something that could be applied quickly to help, which is why I asked about direct solar with no batteries. It would only help during daylight and then only as much as what sun was available. Always understood this wasn't the long term but if it could assist, that would be of value to me.

[bcroe]

Get the tank insulated. Seems like some kind of automatic propane heat
system would be an answer. Just how big the propane tank needs to be
depends on your demands. good luck, Bruce Roe