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Joined: Dec 2002
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Some of the best equipment (costly but worth it in my opinion) I have found is from Outback Power. They manufacture both grid interactive and standalone inverters with a wide range of inputs. They have UL listed built solutions you can almost just hang on the wall. Whta I really like is the wide range the solar to battery chargers can handle, it allows for a build up over time of your system.
Trace and others are acceptable. I use them when there solution is the best fit. Be careful to ensure compatibility, some equipment is positive ground only while other is negative ground, at time poorly documented until you find the installation instructions. The good thing is most companies have the installation instructions online.
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Joined: Jul 2004
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Tie all of your panels onto a DC buss. Then hang your battery string off of the DC buss, along with a grid tie and non grid tie inverter.
You will end up with solar to PoCo system, along with an independant system to power up the pool pump and charge your batteries. When the PV panels output more than what the batteries and pump can take, the excess will go to the PoCo. Pump the cool pool water thru heatsinks mounted behind the PV panels to increase their output. A transfer switch to switch on the non grid tie inverter when the PoCo goes away and you are all set.
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Joined: Jul 2004
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Since Todd pointed out the solar rebate program is broke I am on my own again so I will be going with a scaled down system. At this point, if I can pump my pool water and keep my golf cart charged I will be happy. I am probably looking for a 120/240 inverter that runs off of 36v. I assume somebody makes one. This has really been pushed to the back burner tho.
Greg Fretwell
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Joined: Dec 2002
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36 volts is an odd duck. I can not look things up for I am at home and do not want to use up my neighbors generosity in bandwidth. Outback may have a charger that could be set at 36 volts, but I a fairly certain the inverters won't do. I could be pleasantly surprised. You may need to look at a specialty place like Atkinsons. I am unsure if they have anything, but they do engineer things like 3-wire starters for generators.
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Joined: Jul 2004
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I wondered about that. I know there is a lot of 36v on ships (old war ships) but that was 400hz. The reason I chose 36v was that is what my golf cart is and I don't want any extra batteries around if I can avoid it. If 36 is a non starter, maybe 48 is better. Then it becomes a question, is it cheaper to buy a 36v inverter from some specialty house or convert the golf cart to 48v. (several hundred bucks). The up side of that is you get a very fast/powerful golf cart but I am really not in that big of a hurry. As I said, when the Fla rebates are not in the picture this is not as important to me so I have time to shop around and see what I can do on the cheap. I assume the feds will still honor their 30% rebate since they don't care if they are out of money. edit The top hit on a google search was this http://www.powercomplete.com/36VoltInverterwithCharger/TrippLiteAPS3636VR.htmlI am not exactly sure how I would integrate this into a solar system but, at least, 36v equipment is available.
Last edited by gfretwell; 04/07/10 01:17 PM. Reason: add a comment
Greg Fretwell
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Joined: Jul 2002
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I recommend an inverter type generator, often called a low speed generator, where the AC output frequency is created and has nothing to do with the speed of the motor. They save on fuel as the generator can slow right down and save fuel under low and no load situations. How does that work? Through most of an electricians training, we are taught that the output frequency of an alternator is based upon it's rotational speed, could be 50Hz, could be 60Hz, but the prime mover still has to be moving at a constant speed to achieve that frequency, all the time, not speeding up and slowing down.
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Joined: Dec 2002
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Trumpy, You are correct for the standard generator. A an inverter generator can use a DC generator (see http://micro.magnet.fsu.edu/electromag/java/generator/dc.html ) or an unregulated AC generator with a full bridge rectifier (half bridge does not make economical sense as you would only get half the available power out). This output is then inverted to AC using a timer for the frequency (same as a stand alone solar inverter). Yamaha, Kawasaki (I think), and Honda (if they still manufacture there own generators) should have one. I have not looked for one above about 10KVA so I don't know if large ones exist. It seems unlikely as a DC generator, but maybe as the dual conversion AC style. I don't often find myself above the 30KVA size where I am looking at standard generators. An advantage to these styles is that they can be easily paralleled. One serving as the master providing the frequency for the others to follow.
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Joined: Jul 2004
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I am really avoiding getting a generator. That is just one more engine that won't start in an emergency and if the outage lasts for more than a few days fuel becomes a problem. My friends up in Punta Gorda (ground zero for Charley) called it "feeding the monster". They had to go out on a foraging trip every day looking for an open gas station and hauling cans of gas back to the house. In recent years, more people get killed by generators than by the actual storm. The other option is a propane powered generator but once you empty that tank you are stuck until the propane supplier comes back around. In a disaster situation, that might be a while.
Greg Fretwell
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Joined: Jun 2004
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I found that the economically critical element is pre-existing south-facing collection space.
In my neighborhood only about 1 in 8 homes are suitable.
Lacking this attribute one must accept a great plunge in performance, so much so that the numbers don't work even with the subsidy.
Because of life safety issues none of the current generation of inverters is suitable during outages. Installing a back-up plant just for outages is brutally expensive since it's utility is so low. Our Poco is too reliable to back-up. Way up in the hills, that's another matter.
BTW the nasty weather that leads to outages is normally the type that is a stinker for solar collection, too.
Hence, I'd also recommend using a gen-set.
I get away from using a UPS for my Mac by using a Laptop. UPS is built-in at the factory and the load is so low that any gen-set is untroubled.
Tesla
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Joined: Jul 2004
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I suppose it all depends on where you live and what the weather actually is. After a hurricane we usually have sunny days for at least a week because it blows all the weather away. (water is cooler etc) The guy I was talking to was guaranteeing his collector system up to 150 MPH. I do have the south facing roof on my addition and I put an extra membrane under the shingles to mitigate problems with mounting collectors. This is not intended as "life safety" just quality of life.
Greg Fretwell
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