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Q:my electric show for jan 418 kWh, feb 393 kWh and mar 390 kWh should i use a 2x 250 panels b ok


Based on this information, we can assume that, on average, you use about 400 kWh per month, or 400,000 watts per month. Two 250 watt panels are not going to generate that much energy (assuming you are trying to cover 100 percent, or close enough to that, of your energy needs through solar). Seeing as how I have no idea how many sun hours your system would be exposed to, you will need a system of anywhere from 2.5 - 5.4 kW (or 2500 - 5400 watts) to produce that much energy. (Note, those numbers are assuming you live somewhere in the United States. If you live in another part of the world, these numbers can change.) So, at about 250 watts per panel, you will need an array of 10-22 panels large (again, depending on how many sun hours you get).

03-19-2015 by Richard Category: Solar Panels

Q:I would like to know what sort of panel and battery I would need to run a 70 Watt LED overnight (12 hours) for a solar powered streetlight to be used in Haiti. I currently have it worked out as being 840 wh/day. I would also like to try and account for 2 days battery holdover. I would assume this would run on a 12 volt system but I could be wrong! Thanks!


In terms of panels, each panel runs about 250 watts or so. It depends on where you are in Haiti, but you can assume you will get anywhere from 7 - 8 sun hours per day. So a 250watt panel would give you about 1750 - 2000 watts from 7 - 8 hours of sun. If you want to have batteries for 2 additional days of storage, this should suffice. At 840 wH/d, you will have about 910 - 1160 of watts leftover to charge the batteries per day, which will take about 2 days or so to charge them. Make sure you get a charge controller so your batteries don't overcharge. Look for a 30 - 40 amp charge controller just to be safe from any random spikes in additional energy production.As far as batteries go , your best bet would most likely be a gelled lead acid battery. They must be charged at a slower rate than, say, AGM solar batteries, but are well suited for systems that have less than severe discharge rates. Since the batteries won't be discharging often, these batteries may suit this project well.


03-12-2015 by Simon B Category: Solar Lights and Garden

Q:I want to create a 24/7 water feature that calls for a 400GPH submersible pump with vertical lift of less than 5 feet. What charge controller, pump, battery and PV panel combo do I need? I'm thinking sealed batteries for no maintenance.


At SolarTown, any submersible pump we sell would get your GPH. Our lowest rated pump pulls 22 gallons per minute, which equates to about 1300 GPH. At 5 feet, it should be more than enough. Depending on the type of soil that you are pumping the water from depends on what kind of pump to buy. It also depends on if you are pumping from a well or not, but if the water you are pumping contains any dirt, sand, sediment or is high in minerals, the Helical Rotor pump is recommended. All other situations can be handled by a Centrifugal. If you are running the pump 24/7 and don't have the ability to do manual maintenance or simply would rather not, sealed batteries would work fine, but you should go with AGM batteries, as you will probably be using battery power a lot since you are running the pump at all times. Wattage vastly depends on what kind of pump you get. Pumps can run anywhere from 20 - 1400 watts, not including what you will lose from cords and other system losses (you should generally have an additional 15 - 25% extra watts for just such occasions. It also depends largely on the panels. Panels are generally 200 - 250 watts per panel. Best case scenario your system receives 8 hours of sunlight per day (but if you are in the states, you will only get 5 - 6, again, depending on where you live). However, since you plan on running it during the 16 hours that the sun is not giving your system power, you will need to make sure your system is generating enough power to bank and get you through those 16 hours. Whatever system you would normally get for 8 hours of sunlight (again, at best. It depends on where you live.), you should triple it - and maybe even quadruple it - in order to run it 24/7. For example, if your watt needs total 500 at the end of everything, you should really aim for 1500 - 2000 watt generation.

02-28-2015 by Norman H Category: Solar Outdoors

Q:What is the amount solar energy required for running a fan and light.


There are several factors that come into play when answering this question. For starters, what type of fan and light and how many watts does each require? To make it simple, let's just say the fan is 200 watts and the light is 50 watts. Together, that makes 250 watts. The next thing to consider is how long you want your light and fan to run for. Again, let's just say you want them to run for a total of 8 hours a day. You must now find out of how many sun hours your house receives in a day. In the US, it is generally anywhere from 3 - 6, but in other parts of the world, it can be as high as 8. We will say your house receives 5 hours of sun per day. There are many other parts and factors that go into this, but since you are asking simply about solar energy, I will keep it as simple as possible. So you can go out and buy one 250 watt solar panel, and that will allow your light and fan to operate for those 5 hours of sunlight, but once you lose that direct sunlight, your fan and light won't run. Since you want them to run for 8 hours, you need to accommodate with more panels and batteries. So instead, you should buy two 250 watt solar panels, which will generate enough to run the light and fan, and will allow you to bank the extra power generated in batteries to run the light and fan later when the sun is not out. How much solar energy is needed exactly depends on many things, but hopefully this example gives you a good idea.

02-26-2015 by Ramu Category: Solar Electronics

Q:My Monthly energy consumption is 800 kWH in Peak month... and 400 kWH the lowest... The average in the last 24 months is 600 kWH. I want to start little and grow as I go. I'm willing to pay to the utility company as much as the first 450 kWH per month, and the rest should be provided by the solar panels. Accordingly to my calculations, I would need 4 solar panels (250 w), right? My peak sun hours are from 4.5 to 5 hours. So, with these 4 panels, what's the size of the inverter that I need? It is a Grid-tie for sure! but should I buy the 1kw inverter or 4 micro inverters? Since I want to grow I suppose that micro inverters are the way to go... Can you lead me? And in the other hand, should I buy Cristalline or thin-film? The installation is going to be made on the roof... I look forward to your advise. Thanks!


Let me educate you a bit on your questions: Thin film is an expensive and sometimes an ill-fitting option compared to a polycrystalline panel. If you plan on putting the modules on your roof, then yes, you will need racking. Most people think that a roof mount is the most convenient and efficient, but there are many reasons that people choose other options, such as if your roof is small, unstable, or in the shade. Other option include mounting the units on the ground or on a pivoting stand. Many permit offices will not give you a permit if the racking approach does not have a civil engineer's stamp of approval, so check with your local office for regulations and rules regarding solar panels and racking. Solar racking is available here at SolarTown depending on what kind of racking or mounting you are looking for. Now lastly, for your solar inverter(s), you must remember that the main difference comes down to the idea of one central inverter (otherwise known as a string inverter) for the entire array or an individual micro inverter connected to each module. The single central inverter is still very popular among homeowners. One reason why is because economically, they are less expensive than micro inverters. Another positive is that in case of any problems, central inverters also have only central point of failure, as opposed to finding the problem through each individual inverter. The drawback is that if you want to expand your solar array system and add on some more panels, you may exceed the capacity of your current central inverter, which translates to big bucks for another central inverter just for these additional panels. In the event that shade is covering a part of your array, micro inverters minimize the issue of that shade affecting the entire array, as opposed to one panel. If just one panel is partially shaded, that is the only panel loosing efficiency and will not reduce the output of the other modules that are part of the solar energy system. Another plus many people like is that with micro inverters, a homeowner can relatively easily increase the size of his or her array, and with the latest technological advancements, the new micro inverters being developed will be able to harvest 5-20% more energy than central inverters over their lifetime. Micro inverters do cost more, but not significantly. I hope this helps answer your questions.

12-11-2014 by jorge Category: Solar Panels

Q:I would like to know the parts I would need for a single 300 watt poly solar panel system to mount on top of my RV. I would like the system to be expandable to a total of 600 watts. I will need to run a laptop for up to 10 hours per day and an Engle 12volt refrigerator/freezer @ 3 amps per hour. And a few L.E.D. lights.


The parts you'll need are a 300 watt solar panel, and a mounting system for the panel, an inverter, charge controller, and additional batteries. What we would strongly recommend is that you take a look at our RV solar kits. If you click on that link you should find our offerings such as the Go Power! Solar Elite kit which looks like it will suit your needs. That particular RV solar kit includes a 320 watt kit that you can expand up to 480 watts. The kit comes with everything except additional batteries. Let us know if we can be of any further assistance.

06-10-2014 by Brian Category: RV and Marine

Q:In our wooded backyard with only indirect sunlight, can I get a battery charged up enough to run 'Christmas lights' in the summer on a few lawn ornaments?


Solar panels need, you guessed it, sun, and the more sun the better. If you don't get direct sun any part of the day, the solar batteries attached to your solar powered garden light will not charge all of the way, and the lights will not work very well. The panels will pick up some of the ambient light but probably not enough for a full charge. Some of our solar lights come with wires between the light and the panel. If you want to put the light under a tree where there is not much direct light, you can still install the panel several feet away in an area that does get direct sunshine. Please contact us if you need any more information.

06-04-2014 by pat g Category: Solar Lights and Garden

Q:How many solar panels will I need for 4 hps lights that are 1000watts each ?


You may want to consider our solar power lights.  If you have 4 lights, each rated at 1,000 watts, you will need a total of 4,000 watts of power. Depending on how often you intend to run the lights, you may need more power generation than that, however. For example, if you intend to keep these lights on for most or all of the time, you will need excess capacity to store in a battery bank for night-time use. If you only intend to use the lights at night, you'll still need a battery bank, but you'll need fewer panels. All in all, a 4,500 to 5,000 watt array of fifteen to eighteen 300-watt panels would be needed to power these lights.

06-03-2014 by Isaiah Category: Solar Lights and Garden

Q:I have an irrigation tube well of 20 HP solar submersible pump, and want to operate for about 8 to 10 hours. How many Solar panel will be required, what should be the total surface area of solar panel. I am from hot area of pakistan.


Solar water pumps are a good way way to manage some off-grid applications for farmers, ranchers and others. You will find that many of our customers at SolarTown, after they hear the cost of batteries, decide that they will use the solar water pumps without a batter-backup. Your 20 HP pump is out of the range for a smaller solar installation. Remember that 1 Horsepower is equal to 746 Watts - both are units of power. Your 20 HP pump therefore at any given time would presumably need about 18,000 watts to run. This would in turn require an array of roughly 70 solar panels in order to consistently run the pump and store electricity in a large battery bank (at least 20-30 large AGM or gel batteries) to be used in the morning and evening. You may want to consider an application without the battery backup.

05-29-2014 by Khan Category: Solar Water Pumps

Q:I have over 20 solar lights in my garden of the Malibu battery/solar panel type. The power cords are too short to reach from the solar panels in the sun light to the dark areas where I want to put the solar lights. First, how do I extend the power cords to 50 feet or more. Second, is there a large solar panel made that could power the 20 or more lights and have the proper outlets to plug them in? Having one large panel rather than 20 would be a lot easier to site and put up. Thanks.


Unfortunately, the Malibu solar lights are pre-wired and cannot charge each other, not to mention that their small panels wouldn't be able to charge up two batteries fully every day. Solar outdoor lights are generally designed to use their own panels built into the solar light or installed a few feet away rather than drawing from a single larger solar module. If you want a larger system to run off of solar panels,  you would need to design it as an off grid system. You'll need to look at a charge controller and inverter, as well as a battery for storing energy.


05-26-2014 by Frank Category: Solar Lights and Garden


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