Sorry for my first post being LONG winded, but perhaps all you pros can offer some insight!
I helped a friend move her horses today. She had been renting a barn in the area but due to personal matters had to move to a friends property.
The long and the short of is that she is looking to minimalize impact on the property owners and one of the goals was for her to stay completely "off the grid" - no extension cords, no need for electricity. There is currently about 10-12 of her horses there and 2 large troughs.
Of course, winter is coming, and the troughs are already starting to freeze over through the night hours. For the time being she has a long extension cord running back to the troughs with traditional electric heaters, but she wants to get some sort of solar system setup ASAP - her goal is to have minimal expenses for the time being and she although I'm sure she could arrange something with the home owners for the electricity, she wants to avoid it if possible.
On a third hand recommendation (questionable, having seen the hardware now) she tentatively purchased a solar panel/battery system that apparently someone had used to provide enough "oomph" to power a 12 volt heating system of some sort.
So, I dug into the box today and found that it has a decent solar panel on the lid - I'd be guessing at the wattage, but the panel is about 2' x 4x and appears to be good quality. Inside there was a solar charge controller indicating green (so the panel was providing power), and a single 12v AGM/Gel battery with an undetermined state of charge, and age. There was also some strange (apparently from France) electric fence controller which used to have an internal battery but seems to be rewired to draw from the AGM battery instead. Nothing more, and certainly nothing that would lead me to believe that if there was any 12v heating hardware included with this package, the relevant hardware was included.
The owner of this setup apparently wants $1500 (!!) for it and I told her that (in my opinion) it's:
A/ Not going to do what she wants to do
B/ Other then the solar panel itself, is of questionable value
C/ Has a battery of questionable age/remaining lifespan
D/ Would need more batteries anyways
So, for anyone who has done this before, what's the best option?
I've considered the following:
- Tell her to return this setup (the purchase is still "tentative" thankfully, so she hasn't doled out any cash) and look at alternatives. If we are going solar for charging, there are lots of good deals on large panels now, and there are better options for batteries then horribly expensive (>$200 each) "special" batteries - WalMart has traditional FLA deep-cycle RV batteries of the same capacity for $99.
- For the heating, there are 12V heating elements out there, but based on what I see we are talking huge amp draw (I saw 50amps quoted in one article) and still questionable effectiveness in severe low temps. With a 50 Amp draw pretty much constantly through the coldest of nights, even a 4-5 bank of batteries are going to suffer, and although I'm no solar specialist, I can't see the solar panel being able to keep up and maintain sufficient charge, especially if there's a few cloudy days, or snow happens to build up on the panels through a daytime snowfall.
- Now, this was another thought I had - a circulating pump, and that's it. There's lots of 12 volt water pumps out there that have a reasonable amp draw (certainly less then 50!) and would keep the water moving. Of course, the old mantra "moving water won't freeze" holds true, but for anyone who has tried this method before, at which point does even that become inadequate?
The advantage here is that a good solar panel coupled with a decent bank of batteries in parallel should run a modest pump (enough to create a swirling current) fairly consistently. I'd have to figure out a way to switch it on and off by temperature so it's not running unnecessarily and gives the solar panel a chance to play catch up through the days where the circ pump can be safely off.
- I've read about bubblers, but it would seem to me that a submerged 12v pump moving water would be better. Is just a large bubbler really sufficient, and do the bubbles bother the horses, especially the skittish ones? Also, when it comes to a pump big enough to make air for a bubble bar, I suspect we'd be talking about a similar amp draw to an actual submersible pump.
- And last but not least, I read about some propane powered solutions but can't seem to find a lot of info on them..and of course, with a 20lb propane tank costing around $10-$15 to fill around here, unless this solution is hugely efficient, the cost of propane would quickly outweigh just working out an electricity arrangement with the house owner.
I'll also be telling her that we're going to have to insulate the tanks, and I've been looking at some of the Do It Yourself passive solar-heating enclosures which could contribute to the whole situation and lessen the need for the circ pump except for overnights.
Anyone speaking from experience, your thoughts are mostly appreciated!