Off Subject. Solar for my house.

[V8Cobrakid]

so i called up a few guys from SMA to answer my questions.

it comes down to this:

buy the Sunny Island. it will invert the power of the panels and charge the batteries, keeping the SOC in an optimal range.

buy or magically find an inverter that is 200vdc to 120ac. i can plug the AC into the sunny island. the sunny island will distribute the power as needed.

I was thinking it would be pretty awesome to as on a second "gas cap" so i can install an electric plug into it.

[RobH]

I think the 200 VDC to 120VAC inverter you might use is called a Windyboy. I looked briefly at the manual, and it looks like it might work. The SMA people aren't prepared to recommend it, but the specs look promising. You'll need to figure out the amount of power that the Prius can put out in order to choose the proper size Windyboy.

Note also that you'll need a charge controller. It's a device that manages the solar panels, and outputs 48 volts that looks like a battery. I don't think the Sunny Island has a built in charge controller. Outback has a good PPT (Power Point Tracking) unit, and I assume that there are several others by now.

[V8Cobrakid]

this is the same idea i had.. windyboy.. hmm...

the gentleman from SMA said the sunny Island is a charge controller.

[V8Cobrakid]

while reading up on the pdf file for the windyboy.. i'm learning it may not work. there are certain peramiters you can set.. but the way they are giving examples.. you need at least 300vdc or the unit shuts off.

[V8Cobrakid]

nevermind.. i found a model that's programable to run between 150 and 250vdc input. maxed at 15amp.

All the diagrams i'm finding still tell me that i'll have to use a sunnyboy along with the sunny island. the island is a charger and central distrubuter of the power. the sunnyboy is still needed to take the panels DC and turn it to a usable 120ac. the 120ac from the sunnyboy, along with the 120ac from my prius, get managed by the sunny island.

[RobH]

There are three basic connections to the Sunny Island. They are 48V IN/OUT, AC IN, and AC OUT.

A 400V string of solar panels must be connected to a high voltage inverter such as a Sunnyboy. The high voltage inverter output connects to the AC IN of the Sunny Island.

The Prius 200VDC would be connected to a Windyboy, with output to the Sunny Island AC IN. You need to select a Windyboy that limits its load to whatever the Prius can produce.

An AC generator would connect to the Sunny Island AC IN. The Sunnyboy/Windyboy inverters will drop out whenever a mechanical generator is connected. If you connect the AC generator to AC OUT, then the Sunny Island will drop out.

Multiple 48V strings (actually about 65V) must be connected to a charge controller, which is then connected to the 48V IN/OUT.

The battery array is connected to the 48V IN/OUT. The Sunny Island charge controller manages the battery array. I think you need some advise from SMA about the dueling charge controllers. Which charge controller should provide battery maintenance (equalization charge)?

And of course the AC OUT is what you connect your loads to.

[V8Cobrakid]

thanks for the tips. this is kinda what i figured after reading pdf after pdf... the sunny island has sensors so it can keep a proper SOC for the batteries... but!....i would have to run the panels through an inverter and in through AC1 or else the sunny island will not have a chance to maintain the batteries on it's on... or so i assume.. unless it's smarter than i'm thinking.

if the system is only clocking the voltage comming in.. then it won't matter.. when the array drops out it will clock the battery voltage and try to maintain... so if it has the option i assume i twill stop pulling from the DC and pull from any available AC ( if a generator is plugged in .. or prius. or other AC source that can "feed" the sunny island so it can distribute between current needs and storing energy for later use.

what i assume anyways.. and it seems to be what the guys at SMA are trying to tell me. i assume diodes will take care of the panels any any other voltage drain there may be.

[V8Cobrakid]

I've already talked about solar for my parents house. I want to go into Hydro Electric options.

This is going to be my project (no family involvement) and Im looking to build my own hydro-electric system.

I've read many pages on several different designs.

What I'm wondering is: Can i take an AC pump i currently have and turn it into my generator?

How about a wheelchair motor?

I wanted to stay away from car alternators.. unless i run it through a set of bike gears.

Let me lay out the property. We own 62 acres of mountain side. there are a few streams that join together at the bottom of the property. the incline is fairly steep and there are no fish.

I wonder if i have enough water. I'm headed out to the property this week. I'll bring a five gallon drum to see how long it takes to fill. it would be nice if it landed on that 1 minute mark. I have enough of a drop to counter the lack of water.

[V8Cobrakid]

bringing an old subject to life again...

we are thinking of purching a used system. the pure sine wave inverter provides 2400 watts has a build in charger and transfer load.. disconnects, solar inverter, and panels that produce about 1000 watts per hours of sunlight...

my question is.. these systems are over 12 years old and have been sitting for 3 years with dead batteries... seeing we'll have to buy 3 grand in batteries to make use of the daytime charge, is this a decent deal for 3 grand? i've read panels don't fail.. but do lose voltage over 10 to 20 years. how often do inverters fail?

it's odd seeing non cased in panels up close.. the solder points in the back are kinda corroded.. one has become disconnected. i'm hoping i could solder it back on.

i'm also thinking it's a better place to start seeing i can always add on panels and add batteries... if i really need more inverter power we could purchase a second inverter and run a separate disconnect and panel box for it.

ideas? warnings?

the other way i see it.. this system new would cost 4k for panels, 2k for the inverter, and 500 for the solar charge controller.. plus various hundreds for cables, disconnects, wire, and mounting hardware... i don't count the batteries because i'll have to buy new ones with this system or without it.. then again.. a new system might last me 20 to 30 years, while this one might fail (inverter or charge controller.. and corroded connections on the back of the panels... and discoloration on the front of the panels)

which bring me to my OTHER question... copper like discoloration on the front of the panels.. is it coper in the panel showing though with age? or are they "burnt up" (which i looked up but fail to understand... but i guess everything has it's limits to amperage that can pass though it without things eventually electrifying)

[RobH]

The first thing that strikes me is the combination of copper colored panels and a sine wave inverter. That's rather like a Model T with SKS. That inverter sounds a lot more modern than the panels. The largest source of copper colored panels was probably an experiment with ordinary panels out in the desert with optical concentrators multiplying the amount of light on each panel by something like 2X or 3X. That much light is ok, but the heat did major damage to the panels. The experiment ended, and a flood of those fried panels hit the used market.

Age is not kind to exposed solder connections or to the large capacitors used in inverters. There is a reason modern solar panels are encapsulated between a mounting board and some special high-transmission glass.

The old panels are probably down quite a bit in power, and also by different amounts. You would do well to individually rate the panels, and only put similar ones in series. There may well be a few that just don't even belong in service.

As for the cost effectiveness of a used system, you're going to have to measure what you've got, and then decide if it's worth it. A panel that puts out 1/2 rated power, but costs 1/10 of new cost would be a real deal. Assuming no space constraints. A modern MPPT charge controller will suck about 1/3 more power out of the panels as an older design non-MPPT controller. Think of MPPT (Maximum Power Point Tracking) as a continuously variable transmission, instead of a direct drive.

A high quality, well maintained battery system will last 20 years easily. A poorly maintained battery system of any quality can be killed in 6 months. One of the standard recommendations is to install a fairly cheap battery system as a learning project. Then after you learn what's really necessary, throw it away and install a high quality system. Don't waste your learning curve on an expensive system, since you'll probably kill the first one regardless of quality. Just the scuttlebutt from guys who've been there.