Trying to be helpful, that's all.
I currently have 24kwh worth of submarine batteries in my system, that cost me $6k installed (well carried in and wired up, I had to build the shed). They have a 25 year warranty, and are made in Canada by Rolls-Surrette. Right now, there's not really anything better out there, though these are expensive per kwh. I'd almost kill for the tech that's in my Volt, it's less lossy, lasts longer, and only getting better with time. Too bad they won't sell them without a core you return, or I'd be running those.
L16's (6v/385 ah) are fairly cheap, and if you take real good care of them - last about 10 years. A minimal 24 system needs 4, I used 8 on my lower-draw building. Since lead-acids are heavy, they are cheapest usually at the nearest distributor - those babies cost to move around long distances.
Battery life has more to do with cycles, and sub-cycles. For example, if a battery lasts ~700 full cycles (typical for a good deep-cycle type), it'll last 7000 1/10th cycles (about 20 years?). If you just float them and never charge/discharge them (just keep them at float volts with only takes a few milliamps) they last longer than a human lifetime - it's cycling the kills them. Luckily it's proportional. Constantly charging and discharging, except for a little near the top of charge is not good for any battery tech currently existing.
I am personally fortunate that I did all this incrementally. First off - the stuff cost a lot more back in the day, so I really had to learn how to conserve (and Dollar cost averaging worked out well - factor of 6 since I began) - I started with 4 50w panels, one light, and one boom box - that's it. Got used to it, everything else is gravy.
The first major upgrade brought in the smallest top-loader freezer I could find, and total panel power of 600w, but I started needing a backup generator some more. I jiggered the thermostat to run it warmer than normal, just a little below freezing. We used that to freeze 2 liter pop bottles full of water, and used quality Coleman coolers as refrigerators with 2-3 bottles apiece in them - sometimes they'd go 2-3 days without melting all the way. That was one cool trick (pun accidental). The thing is, you could then exchange the bottles in the AM on sunny days, and have the freezer run (it was in a storage shed, sheltered from the sun, unheated, in the woods) only when you had the extra power - this avoided cycling the batteries any extra - straight from panels to freezer in that mode. Worked that for about 10-12 years with 8 L16 (big golf cart) batteries, with a little trick - we put a couple of cheap 12v trolling motor batteries across those and those, believe it or not, took the pounding and kept the L16's from having to deliver a lot of peak current - either direction, which is what kills them.
Even those "tiny" 100 ah troling batteries across an ~800 ah pack made the L16's last 12 years (most people get 4-8). Yes, we had to change them about every two years - but those are cheap, easy to lift, and you get a return credit at WalMart. Even though they are much smaller, they actually have more plate square area than the big guys - lots more thinner plates. That's why they die (thin plates warp and fall apart faster under use), and why they naturally take the peaks better.
An electrical engineer would instantly recognize this as using a "bypass capacitor". That's more or less the function of those things.
Then we did the thing depicted here and it's almost like being on the grid. I have a real fridge (dorm room size), electrically heated hot water (with a new trick I'll describe later), all the amenities - even air conditioning, and sometimes electric supplemental heat when there's extra power - may as well use it once the main batteries are full. And that electric car, which I run down about every two days - it's the main power user now (used to be the fridge, and then this big computer - 4 24" hd displays and all the goodies) that I have on all day most days. But I've upgraded the big 'puter to LED displays, an i5, and SSD's and now that whole rig comes in under 150w - with all 4 hd displays going.
But conservation was and is key. Every single thing around here is on a power strip - the type that DOES NOT have a surge protector - no need for that, and it wastes power even with the thing off.
You'd be astonished how much that cuts your use when all those 5-20 watt "vampire loads" are gone from running 24/7 when you don't need them. Things like soft-on TV's, microwave ovens, cable boxes, and the filters in home entertainment systems all draw a bit, and it adds up to a couple hundred watts even here where I took care to buy the right ones. But...they spend almost all their time fully powered down, and I only hit the power strip on when I need whatever that thing is.
That's a lot of kwh a day - .2x24 is half a kwh that I don't cycle through my batteries, even though I do indeed have the panel power to make up for that - I'm conserving battery life here and rarely use more than about 10% of a charge to make them live longer - and they are showing signs of living "forever" - no noticeable degradation in about 6 years so far. If anything, they act a little better than new with the new charge controllers, they seem to like that.
So the upshot is, there's a lot of up-front cost to doing it the way I do, but then, nothing for long periods. I've got panels 30 years old that are still 70% of new output. The other cost was learning to conserve, "walk lightly on the earth" which isn't really a cost after you get used to it, it kind of feels good, like you're doing the right thing.
I have never had an unplanned power failure, ever. We shut things down for about 2 min once to do some battery work. That's it - since 1979. This is the best UPS system ever!
aperbag:
