We have a 420' deep well and no good option for gravity feed, hence the 240V for the soft start Grundfos pump.
That would definitely do it! I plan to put a 240V split phase inverter on the house, mostly because our well pump is 240V as well and I don't like not being able to run that.
We have a power room off the mud room-unheated but in the bermed part of the house so it stays fairly constant temp. We've only equalized once in the 4 years we've had the system and that was during the first year when we hadn't quite figured out how to best manage the system. The batteries were resisting a full charge then and that hasn't happened since we made adjustments. DH knows this stuff better than I.
Constant, cool temperatures are definitely good for batteries. My bank gets warmer than I'd like in the summer, and it's super saggy in the winter, because it's outside in a deck box. Not buried. I've considered building some sort of buried box for them to help stabilize the temperature, but keeping water out would be tricky, and my property is basalt covered in cheatgrass, so digging is always a challenge.
It's definitely good that you've worked out how to maintain the system without equalizing. That's one of those bits of folk knowledge about batteries that mostly solves problems created with incorrect charging settings in the first place. The problem with an awful lot of off grid systems (up until surprisingly recently) was that everyone was using the "grid tied charger" voltages - which work, if you've got 18 or 24 hours to charge a battery. They don't cram enough current in during a typical solar day to fully charge the battery bank, and so people were getting chronically undercharged cells. Equalizing helps with that, though not perfectly. If you've got the charge voltages adjusted up (which it sounds like you do) and current based termination (with evidence that you're dropping into float regularly), there's often no reason to equalize because the cells don't get degraded such that it helps.
For those unfamiliar, equalizing is the fine art of thrashing a lead acid bank with high voltage to shove current through an already "full" bank. It accomplishes several things.
First and most commonly, it helps drive sulfation out of the plates (mostly the negative plate). As the battery bank discharges, the lead (and lead oxide) change to lead sulfate. This is fine when it's the soft sulfate and reverses with recharging, but if a battery sits undercharged for long periods of time, that hardens and becomes harder to get rid of. That hard lead sulfate blocks the plate area and removes sulfuric acid permanently from the electrolyte, reducing the battery capacity (it'll seem full, but not actually be full). Beating on the battery helps drive this out and reverse it, though it can't help a badly sulfated battery. Proper charging, with the proper voltages, should prevent this from being an issue most of the year, and the carbon inclusions help with the winter time when you can't charge fully. The carbon magic somehow helps prevent sulfation from being as hard to remove.
The second feature of equalization is that it helps mix the electrolyte to resolve stratification. If you don't have enough charging current or time to properly charge the batteries (or to charge them fast enough), you'll end up with stratification, in which the heavy (more concentrated) acid is at the bottom, and the lighter (less concentrated) acid is at the top. This is no good, because it's really, really hard on the plates. AGMs don't suffer from this, only flooded lead acid. Equalizing drives the cells well into the gassing region of voltage, and the gas bubbles (from the water in the electrolyte being split) help stir the solution. Again, with a proper sized charging system, properly set, this shouldn't be an issue. This is one reason that lead needs to be overcharged (especially flooded) - the sustained bubbling helps mix things up. Somewhere in the 8-10% overcharge is where everything is properly mixed, per some charts I've seen.
Sorry about all the brain dump here, I've actually been working on a blog post about lead acid maintenance, so this is all on the top of my brain.
We have a 10K watt generator...probably could have gotten a 7K but went with what was recommended. It's a honda converted to run on propane by Central Maine Diesel.
Jealous. Not that my bank could really use that (10kW is about a 0.8C charge rate for me - not that my charger will do that). How happy are you with the propane conversion? Mine is still gas, and I've built an extended run tank for it, but I'm seriously considering doing a propane conversion. I'd need to bring a larger tank down by my office, and the cost of the conversion kit is close to what I paid for my generator, but it should work on other similar generators as well. The ease of starting in the winter would be nice - my generator does not start particularly well when it's below 0F out. Lots of pulling and then I have to let it sit for a while before it will start. On the plus side, it always starts, and I'm nice and warm when it lights off...
I've considered designing a micro-CHP system - combined heating and power. Generally, if I need the generator, I need heat as well, and the generator heating the outside and me burning propane to heat the inside seems a waste. I've considered putting together some heat exchangers to suck heat out of the cooling air and exhaust (this would require building a custom enclosure for my generator) and dumping them in my office. However, the cost to accomplish this would radically exceed any savings I'd ever get in fuel use (I burn 5-10 gallons of gas a winter and 4-7 gallons of propane), so it's one of those "Because I can..." type projects. I'd likely be far better off investing in some thermal storage - a 55 gallon drum of stratified thermal storage, perhaps (useful stratification, in which the top part is always hot and the bottom is always cold). Even then, it's firmly into the realm of "This is an interesting project to reduce my fossil fuel consumption in the winter," and is unlikely to pay off ever. But it'd be neat. And that's often enough for me.
We do plan to install a separate solar water heating system with storage. Thanks for the suggestion regarding East facing panels but we have Southern all day exposure with no trees or interference of any kind. Wouldn't it be best to face them South?
It depends on what you're optimizing for. For maximum raw energy production (kWh/day), yes, facing true south is ideal (in the northern hemisphere, of course). However, for off grid use, raw energy production is seldom useful. A system sized for winter use will overproduce so comically in the summer that you can't use all the energy - or a system designed for the summer will basically be a pure generator system in the winter. For an off grid system, "morning panels" reduce by an hour or two the time you're sucking power out of the battery bank, which helps with longevity of lead - depth of discharge and time of discharge both impact longevity.
Another issue (again, mostly with lead) is that it takes quite a while to fully charge them. You dump as much current as you can into them until you get up to the absorb voltage setpoint (
temperature compensated - I cannot stress enough how important this is for longevity), then you hold that voltage and the current into the pack tapers off as the pack charges. Once you hit your termination current (1-3% of C/20 capacity in amps, though mine is set to 1% for winter - I plan to bump that up to 2% or so in the spring), you drop back to the float voltage. This takes time. Today, my bank took ~5.4 hours to hit that 1% charge rate, though it's quicker if it's fully charged every day (and I was pretty hard on it this morning - I heat with electrons if I expect sun). Starting that recovery 1-2 hours earlier is worth a lot in an off grid system, since it gives you the hours to fully charge it before sundown.
If you're using a lithium pack, it doesn't matter quite as much, so pointing everything south works fine. You can hammer a ton of current into lithium compared to lead, so you can make use of that solar peak and store it. On a sunny day, by solar peak, my bank is full and tapering off.
I literally can't use all the power I generate with my system on a good sunny day, so it's worth it (again, for an off grid system) to spend some panel area to start the recovery earlier. Off grid is different from grid tied in many ways. You don't get to use the grid as your free, ideal battery.
I just checked http://pvwatts.nrel.gov/index.php and the 20 panels we purchased would produce 10k kwh in my location but only 386 in January (the month where we could expect the lowest output). But if we tilted some of the panels up to 30 degrees or more we would get slightly more power in the winter. We might purchase more in order to overpanel and get more power in the winter.
That sounds about right. Solar really is feast or famine. It's rarely balanced. In a reasonable system, you either have a ton of energy you can't use (off grid), or are running the generator. There's very little in between, and what in between you have is mostly "It's cloudy, and I'm choosing not to use much energy today." Finding uses for that summer feast is interesting. I run Folding@Home and BOINC on some spare hardware, because tossing some excess energy at climate simulation and such seems useful (trying to pay back for my filthy power - anyone who tells you off grid power is clean is either clueless or has an agenda, because generators are stupid-inefficient and batteries are pretty bad too).
One thing those simulations don't make clear is just how little panel angle matters on a cloudy day. I can swing my morning panels from east to southwest, and with heavy clouds, where I point them
doesn't matter. Not one bit. I might see 0.1A difference between east and southwest as I swing them around (and generally, peak production has nothing to do with where the sun is, but where the clouds are slightly thinner). It just doesn't matter. Panel area is king.
I've actually been running my upper panel bank nearly vertical this winter. It's less optimal from a power production perspective, but it's better from a snow shedding perspective. Vertical panels shed snow. Angled panels don't. If I have a sunny winter day, I have enough panel that I don't care about optimizing production, if I have a cloudy day, it doesn't matter either, but the vertical angle sheds snow a lot better. My lower bank is
mutter mumble summer angle I really should change that soon. Being able to tilt a bank or two of panels for the winter clearing is nice. If you don't get snow, it matters less.
What I'd suggest, if you have movable panels, is to set them at your latitude for spring/summer/fall (basically, optimize year round production - you'll get more power in the spring and fall when the sun lines up, and the days in the summer are so long that it just doesn't matter), and then set them nearly vertical for winter. You'll get pretty good angle on the winer sun, and the snow clearing is far better than at other angles.
When in doubt, for lead, opt for more panels. You want to fully charge the bank regularly for longevity. If you trust your charge controller at 100% rated power, you can even attach more panels than your controller can deal with - it'll just clip. But that area will help you in the spring/fall/winter when you don't have as much power.
Another quirk of off grid, especially if you have air conditioning: Spring and fall are the feast times, moreso than summer. Nobody really has a feel for how the heat impacts panel production until they live with it. The panel power rating is at STC conditions - panels at 77F. When are the panels at 77F? Well, in the winter, maybe... As solar panels get hotter, they produce less power.
So, with a standard temperature coefficient of around -0.4%/C, what does summer look like? Well, it's 105F out (40C), but the panels are black and in the sun. Let's call them too darn hot to touch, at maybe 65C. What's production? They're 40C hotter than reference, so production is down by 16%. Those 310W panels won't produce more than 260W. Worse, the sky is hazy from the summer humidity - or, if you're in a dry climate, the wildfires. And there hasn't been rain for a month, so the panels are dusty. You might be lucky to see 200W peak out of them in the depths of summer.
Spring and fall, with frequent rain, and clear skies? Cold, happy panels.
And then there's winter. Which mostly sucks. And then you have a vertical panel, snow on the ground, a super cold panel, and bright sun. Wowie powerie! My panels are rated for 9A. My PWM controller is rated at 10A, and will cut off over 11A. How do I know this? Because in those conditions, my morning panels were producing somewhere north of 11A. I don't know how much, because my charge controller wouldn't deal with them and I moved them off-angle pretty far to avoid repeatedly overloading my controller.
So... living within your solar power budget is rather non-intuitive unless you've been doing it for a while.
It's fun, but occasionally frustrating. And you really do need a good generator.