Solar and Battery Storage

When we bought our place up here on the mountain there were already two small solar panels mounted to the south side of the house which are charging two 6 volt deep cycle marine batteries which in turn are used to power an electric motor in the basement.

Judging by the look of the solar panels they are nearly as old as the house or around 17 years and severely degraded. While the previous owner told us the panels keep the batteries charged I find that I need to recharge them about once a month, meaning the panels no longer keep up with the electrical draw.

Then again we use all the household systems more than he did so our electrical use is about 20-30% higher than he experienced. We definitely need to rethink what we leave on and what can easily be shut off if we are mindful of the need to do so. You can see the solar panels in the picture at the top of this page.

Now that we have the Generac 17kw standby generator permanently wired into the electrical system to take care of power outages up here on the mountain we want to turn our attention to more long term sustainable solar panel/battery and wind powered electricity generating systems, both to reduce our need to rely on the national/regional electrical grid, but also to move us towards a more self sufficient and self sustainable lifestyle.

We are now in the research phase and are studying various approaches to solar. Wind power will be discussed in more detail on its own page here on Two Ice Floes, but we do understand that we must think about both if we are to incorporate them into the same system either up front or at a later time.

It makes sense to go with both since up here there is always a breeze except in the middle months of the summer when the sun is strongest, and during the winter when the sun is lowest in the horizon the wind is always blowing mostly because we are located on the ridge where the Blue Ridge plateau drops off into southern Virginia and northern North Carolina. So it is obvious the solution is two pronged.

I plan to keep everyone here updated on this project of ours, but I do want and need feedback from all of you. From what I read serious mistakes are often made by novices when selecting and installing these types of systems. I would prefer we do this right the first time so fill up the comment section below folks.

Cognitive Dissonance



5 thoughts on “Solar and Battery Storage”

  1. Let me suggest that you go in the general direction of duping either my own system, or David Knights.
    (He is in Radford, we teach the CCW courses around here together, he keeps chickens, bees, an orchard, a garden, collects
    rain, has full solar, and runs both a jewelry business and a bakery)
    Both are time-tested and sucessful. Mine is totally off-grid – power co wires don’t come within 1/4 mile of here. Dave’s is grid-tie but with all the other features mine has (batteries and inverters, backup generator).

    I’ll soon put up some info on mine – there’s a whole subforum on my site, but it’s kinda cluttered and the good stuff is getting hard to find there.
    Some early tips –
    1. Use poly-silicon panels only, and only from good manufacturers. Judge by weight – the good stuff uses thick glass and stout frames, and it will matter. I’ve got some 35 years old that still put out well over 80% of the original spec.
    Every single other type I’ve tried over the years is failed and out of the system. Don’t be fooled by the hokum of “there’s this new stuff right around the corner that’s gonna be better” – I’ve already bought all that and it all fails in a year. Thin film isn’t where it’s at, and most of the cost is a good frame and glass anyway – check the hardware store – a 250 watt panel costs little more than the same sized window as is. They’re around a dollar a watt now – my first ones (still in use) were closer to $6.50/watt. Don’t fall for the super-expensive but cheaply made aluminum mount rails (sometimes $500/pair), they twist up like pretzels the first windy micro-burst. Dave and I have pioneered a new system of treated wood that has side benefits, along with costing lots less – it creates a convection channel between the roof and panels, keeps the roof cool in summer and warmer in winter if you block it.

    2. Don’t skimp on “cheap” batteries. I use submarine-grade (Rolls-Surrette). With some tricks, you can get the L16-class cheapos to last 8 years, but you get tired of maintaining and pampering them real quick. You need enough, if off-grid, to use only about 10% of the rated capacity a night. If you’d get 1000 full cycles to replacement, you get 10 times as many 1/10 cycles, roughly.
    These aren’t fun to lift or replace – plan accordingly. Further, deep cycle type batteries don’t like huge peaks vs capacity – C/10 is the limit w/o damage – C/15 is better. But don’t make them so large that self-discharge becomes too significant.

    3. Don’t skimp on the electronics. I use Xantrex exclusively now, because everything else (other than the odd home built accessory – but I’m an EE) has failed. The inverters have some pretty “magic” features, like the ability to take power from the grid or your backup generator, auto-distribute it through your home, and keep your batteries charged off any AC source that’s working. I also use Xantrex solar charge controllers, and the batteries seem to really like them – they include temperature compensation for battery temperature, which really matters. You’d like your batteries near top of charge as much as you can manage – but you don’t want them bubbling/gassing – then you have to add water, and contamination never seems to fall out of a battery – and purity matters here.

    Make it bigger than you think you need. Most of this stuff is rated via similar methods to things like BLS statistics.
    Funny how you can run down a 24kwh rated battery in 10kw worth of use…and so on. Panels on the other hand, sometimes (but rarely) put out several times their ratings, when the sun peeks through a hole in bright clouds (cloud-effect). I have a trick for sizing controllers I’ll share in more detail later.

    You’ll learn to adapt to the weather – after awhile, it seems normal and better. So, when it’s sunny, heck, I’m charging my Volt, running my machine shop, welding, running super computers, fusion reactor – whatever. When it’s dark, I can get by on a 10″ tablet or a good book and a small radio, and never have to actually run a generator. But I still do, as all these things can fail, and it’s nice to know before the real emergency, while you can do something about it. If it’s light out at all – you’ll get something, it just won’t be a ton of killowatts. I’ve built a special low power computer just for those days…so I can keep having my kind of fun (programming and staying in touch) no matter what.

    Everything, and I mean everything but my home-defence lighting surprise – is on switched power strips with the power wasting surge supressors removed. Turn it off when you don’t need it. A penny saved…You’d be shocked to find out how much that router, set-top box, microwave, anything with a remote – wastes sitting there “off”. It adds up fast. Is it really worth 250w or so just to have remote control when you’re asleep anyway? If you try both ways, you’ll turn that stuff really off at night at least, and usually, anytime it’s not in use.

    Think total cost of ownership on all this – it’s a fair pain to put up and get going. A lot less fun to have to do over. Do it right the first time. FWIW, I’ve got something over 8 kw worth of panels now – and most people wouldn’t be able to support their lifestyles on that (remember, that’s BLS theory numbers – power at noon time full sun in space). But since I started with only a couple panels, one lamp and one small boombox – it seems like heaven to have this much (and with batteries, 80kw peak loads are possible).

    There are a few videos of some parts of my systems here on my youtube channel under “Alt energy”.

  2. As for in Europe, I did some investigation into solar-power and the answers aren’t easy. The prices of equipment are in Europe substantially higher than in the States and in most places the houses are connected to the grid. A combination of panels and a grid-inverter is therefor the most popular and the cheapest. Good deep-cycle Batteries are prohibitive expensive over here and the price of them thoroughly kills any economic justified picture, if you are connected to the grid.
    If you have no grid, then there is no choice but to go with batteries. Before you invest in batteries, I can highly recommend this eye-opening little booklet;

    BTW; I’m building a 1 kW array complete with a (out of scrap material and self made electronic circuits) solar-tracker. First indications are 30% more power-harvest above a stationary array. A very interesting & challenging journey so far :-))

  3. Another thing I like to add/confirm to what DCFusor said; be very aware of vampire-usage. Before I started my solar-project I went through the house and measured the consumption of every, and I mean every electrical item; down to the milli-Ampere (mA). I was amazed to find out that a seemingly “completely” switched off (that is switched off at the machine) washing-machine still consumed 65 kWh / year. Same counted for the dishwasher. Each Adapter (or wall warts) consumes easily 30 mA standby (which is about 62 kWh/year @ 240V over here in Europe). Even light-dimmers consume when the light is off. Think about a clock-radio, TV, video, telephone etc, etc, etc. A lot of stuff isn’t off, until you pull the plug out of the wall. Another example; the WiFi station (24/7) was consuming 52 mA (108 kWh/y) and I changed the adapter out (adapters which I collected from family / friends, who had “boxes” full of them, ready to be thrown out) and currently it’s using 28mA (58 kWh/y) for the same WiFi-“service”. We mounted wall-switches for the washing machine and dishwasher. Halogen spotlights are changed out for LED, Incandescent bulbs for CFL-bulbs. With all those actions we (2x adult persons household in a free-standing house) consumed last year in total 1.032 kWh. This includes cooking on an electrical ceramic cooker + oven, a freezer (200kWh/y), fridge (100kWh/year), computers etc.
    I would say, that mapping the consumption of each and every item, especially the 24/7 stuff, and remove the excess / switch off / modify, made us a saving of at least 40%. For your info; the current price in Denmark for 1 kWh is 47 $cent.

    1. I have had some early discussions with Mrs. Cog and the child unit about electrical consumption on a daily basis. Neither of them could exist without substantial electrical usage with their present mindset. It is so much more than turning off a few things now and then. It is a mindset of conservation that neither have at the moment.

      There is very little knowledge between them of exactly how much electricity they use. Watts, volts, amps… is a foreign language. I am not being insulting here. Very few people who have lived with electricity all their lives give any thought to it at all.

      To be fair I also waste electricity as well, though I do complain when I walk into a room and the lights are on and nobody is home etc. But the transition would be easier for me because I can switch mindsets easier, having lived a more threadbare life over the last 50 plus years and understand the difference between wants and needs from the ground up rather than looking from the top down.

      In addition I’m not sure we could run a website using an average solar system. We both run computers and several monitors each. They are on while we work, which at this point is 12 hours a day, 7 days a week easy.

      Much thought left here before we even decide if this is the direction we need or want to go in.

      Cognitive Dissonance

  4. @CD
    Fully understood and appreciated. From what I read somewhere else, it seems that you are connected to the grid? There are also systems by which solar power powers the house during the day and excess energy gets stored in batteries for evening/night use. If both are exhausted, the grid (or a generator) takes over. So the hierarchy is solar power / batteries / grid (generator).
    To me, any other “lower” form of energy asks for adaptation in mindset and behavior. Listening to Chris Martenson and others, the question whether we need to, or want to go to a lower form of energy, will be automatically answered.
    Here is a brochure to the system I mentioned above:
    or Martin Lorton on YouTube;

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