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Q:How many watts do you need to run the average home, appliances, well pump, and in home power. I will be grid tie but want to neutralize the utility bill from my Iowa REC power supplier.


The average annual electricity usage for a residential home in the US is 11,000 - 12,000 kilowatt hours, or 900-1000 kilowatt hours per month. This number can fluctuate depending on how frugal or lavish you are with the your energy usage, but that is the average. It seems like you want your solar system to cover 100 percent of your electricity usage, which means those numbers will be pretty accurate. How much a system like that would cost varies greatly from state to state and home to home, but on average, you can expect to pay around $12,000 for the average solar system described above, however, that is BEFORE the 30 percent federal tax incentive and any other state rebates and incentives are taken off. With just the 30 percent federal tax incentive, that takes the price down by about $3,000 or so. These are just averages and basics, so your situation might not look like this, but this gives you an idea of what you are looking at.

08-19-2015 by Daryl Category: Solar Panels

Q:I am getting bids for a 10K watt grid tied system with micro inverters. I can shop the materials but I cannot compare the labor to install price. There are 40 panels with most going on a metal roof and a few on a comp shingled roof. about 100 ft of trenching to meter connection. is there a general rule of thumb here? Your prompt attention is appreciated.


Prices greatly vary from region to region.  Generally, the average cost for labor and an electrician are about $0.68 per watt; about 23 percent of the total cost of the home solar panel system. The type of roof they are being installed on factors into cost as well, but that depends on the company installing the panels. Metal roofs and comp shingled are pretty standard roof types, which means they shouldn't warrant much extra expense, if any. Spanish tiled, among others, are types that usually come with an extra charge because the tiles are often damaged during installation. Calculating the basic expense, however, $0.68 x 10,000 = $6,800. That's the lowest amount it will cost, going up or down depending on specific labor costs and what their extra charges are.

08-19-2015 by Lance M Category: Solar Panels

Q:Please what size of solar panels, inverter, battery, charge and charge controller for a house with 3tv, 2 fridges, 3fans, 20 bulbs, 1dstv


The size of your array largely depends on the wattage of what you are trying to power requires. The appliances you have listed are large, but I have no idea how much power they need, therefore, I can't give you an exact number. From what I can gather, it seems like you are trying to power at least a few rooms of a house, if not the whole house. The average annual home electricity consumption is about 11,000 - 12,000 kilowatt hours, or about 900-1000 killowatt hours per month. This is an average, of course, and does not reflect your electricity needs personally. It can be higher or lower for you personally. Generally, arrays for residential houses consist of 15-20 home solar panels, a central inverter or multiple microinverters, AGM, gel, or standard lead-acid batteries to store extra energy generated and a charge controller to prevent your batteries from overcharging.  Unfortunately, I can't really be more specific without knowing more about your energy needs. Others questions asked and answered may be of some help and you can find those on SolarTown's ask an expert page, as well as our learning articles in SolarTown's Learning Center.

08-15-2015 by Pam D Category: Solar Panels

Q:I need to put an off-grid system together for a sustainable garden project that our school is doing. We are starting out with 4 water pumps (24 watts, 120vac) running 12 hours day and night (15 minutes on/off). We're located in southern California and the panels would be optimally placed in a sunny, open area. I received a quote for an 800W, 24V, 265AH system w/enclosure and 150 watt inverter for $6,000. I'm new to this but that seemed to be overkill. I'd like to know my solar/battery needs with an idea of general expenses if you'd be so kind.


Depending on where you are exactly in Southern California, your array would receive about 5 - 6 hours of sun per day. When you say 12 hours day and night, I assume you mean 12 hours split between day and night. Also, I will assume each pump is 24 watts, and since there are 4 of them, that makes 96 watts, but we'll call it an even 100 watts. 100 watts running at 12 hours a day equals 1,200 watts. With an 800w solar array and 5 - 6 hours of sun per day, that's 4,000 - 4,800 watts generated per day. I know this sounds like overkill, but it isn't. Generally, when dealing with projects such as these (long operating times of equipment, type of equipment, etc.) it's a good idea to double (or even triple) your energy needs. The reason being is that you never know what can happen. If your array goes down and you are only supplying exactly what you need, you are out of luck until your array goes back up. By overestimating, and by purchasing a battery bank, you can store extra energy for use when/if things like this happen. With the quote you received, it would ensure that you had 2-3 days of energy stored just in case. Having a larger than what is necessary array also ensures that you will have plenty of room to add equipment later should this gardening project get larger and require more pumps or something like that. However, if the 4 water pumps in question equal 24 watts total, and not each like I assumed, then you are looking at 50 watts total, as opposed to 100 watts. If that is the case, then the system size recommended may be slightly larger than what you would need, but not by an extraordinary amount. It also just reinforces what I mentioned above about banking energy and leaving room for growth down the road. Overall, I would say the quote you received was not unreasonable in what would be recommended for the size of your system.

08-04-2015 by Chris Category: Solar Panels

Q:dera sir i want to set up a solar system for 12 horse power submersible pump will you tell me the total cost and best companies which can set up this type of system


First thing to consider is if this is an off-grid system or a grid-tie-in system. If it's an off-grid system, you will need to figure how long you want the pump to be running for. Regardless, 1 horsepower equals 746 Watts. Therefore, your 12 horsepower pump would require about 9000 Watts to run. This equates to an array of 36 solar panels. This also depends on where you live. In the USA, certain areas get more sunlight than others. The northeast region generally receives 4 - 5 hours of sunlight per day, the southeast 4 - 5, northwest about 4 and southwest about 5-7. How much sunlight your panels receive daily will factor into how many solar panels you need. Whether you want batteries to store your electricity for later use or a battery-less system also factors into cost. A lot of factors come into play when configuring cost, but generally you will spend anywhere from $16,000 - $18,000 on a system of this type. The cost will fluctuate most when deciding what brands of parts to buy as well. However, all residential solar system installations qualify for a federal tax credit of 30% (until 12/31/16), which would bring your cost down by about $5,000. Micro-inverters versus central inverters, battery backups, types of batteries, brands of solar panels etc.; all of those parts will affect your total cost.

Installation costs also affect your total price quite a bit as well. A system like the one I described is a pretty easy DIY setup, requiring only about a weekend to install and setup properly. Products purchased from SolarTown are self-install, but other companies sometimes offer free installation when you buy a system with them. It all depends on the company. Install costs generally run about $0.68 per watt, or 17 percent of your total systems cost. So for a 9000w system, you are looking at about $6,120 for install. However, this is factored into the total cost of about $16,000 - $18,000 stated above.

Different companies will tell you different things, and every company will advocate for itself, but the company you go with to install your system depends on the kind of system you go with and ultimately, will end up affecting your total cost.

07-07-2015 by kuldeep Category: Solar Panels

Q:I need help understanding the difference between the Enphase micro inverter and the Solar Edge inverter and how to determine which is the better product for the solar panels I want to install. Thanks for your help!


With an Enphase micro-inverter, each solar panel is optimized separately. With a central inverter, that one inverter will work the entire system. The big difference here is that the micro-inverters allow each panel to operate at its maximum efficiency. This is particularly useful if your system has shady spots. Your system's power output can be about 50 percent lower with as little as 9-10 percent of shade covering your panels using a central inverter. That is the real draw of using micro-inverters over central inverters. Another benefit of using micro-inverters is that if one panel goes down, the whole system won't go down. Micro-inverters also come with longer warranties and are silent compared to central inverters without the need for active cooling. The SolarEdge Inverter is an optimizer for a central inverter. They are designed to increase the power of solar modules. They can be attached to every panel individually - like micro-inverters - or at a two panels to one optimizer ration that lead back to the central inverter. DC optimizers can operate at 98 percent energy efficiency, losing only about 2 percent of efficiency, while micro-inverters hover around the 96/4 ratio. However, micro-inverters and optimizers accomplish the same thing at the end of the day. They both operate to enhance the system in the long run, but in different ways. Using an optimizer will also protect you from shaded areas because they perform maximum power point tracking (MPPT) at module level before sending the DC signal to the central inverter for conversion to AC. You will hear installers argue about which is better, and of course the manufacturers make their own claims. It is very difficult to pick a clear winner, as both systems have no distinct advantage over the other. What it comes down to is cost, ease of installation and safety. In terms of safety, the NEC pins DC safety levels on rooftops below 120. Micro-inverters convert DC power to AC almost immediately, leaving little time for DC power to hang around on your roof and in the system.

07-06-2015 by Anne Category: Solar Panels

Q:I have a solar panel to feed my green house ventilation. At full sun the fan is not cloudy or afternoon sun it runs slowley. At full sun without fan it reads 20 V and 1 ma. ..after connecting fan it reads 0.6 V and the same 1 ma. I tested with different fans and it is the same. Please guide. Thanks, vafa


It seems like you probably need more home solar panels to power the fan you are trying to run. One solar panel might not be generating enough energy to run the fan. It largely depends on the size of the fan you are trying to run, but, generally, 24v+ is needed to properly run a greenhouse ventilation fan.

06-28-2015 by Vafa Category: Solar Panels

Q:I want to setup 3 100w (12v) panels to charge batteries (12v) to run a sump pump. The batteries and sump is in the basement and the panels will be approx 30 ft above them on the roof (3 + stories). Ideally they should be on the opposite side of the house that is another 30 ft away. So I am looking at running cable between 30 and 60ft. What size of cable is needed and will a controller handle the required size?


I figured high to be on the safe side, but with the information you gave, you may want to try an 8-gauge wire at 60 ft., which would produce a loss of 3 percent efficiency. If you are okay with taking a slightly higher efficiency loss (4 or 5 percent as opposed to 3), you can use a 9 or 10-gauge wire. Since you are running a 36v system, you would go with a 48v charge controller. When in doubt, there is no problem (other than a higher price) with using a higher volt and/or amp rated charge controller. In fact, it allows you some room to expand your system later down the road if you so choose. Regardless, yes, a charge controller will handle the cable size you will need.

06-27-2015 by bob m Category: Solar Panels

Q:I am looking for info on the TPM4 mounting hardware. What diameter pole will this fit. can it be mounted at approx. 19' above the ground. What will the angle of tilt need to be in Spokane, Washington. How quick can these ship, I will need 2 of them.


The size of the pole varies based on the square footage of the solar array. You may want to contact us or consult with a pole mounting guide that helps determine the total length and quantity above/below ground for each size. For example, if the module area is 20 square feet, the pole size  should be about 2.5" SCH40 (2-7/8" OD), the length in the ground 34"-40", the height above ground 48"-72", and the hole diameter 10"-14". The tilt for Spokane would be approx 45 degrees.

06-23-2015 by Todd B Category: Solar Panels

Q:Found your website and wondered if you can advise or point me in the right direction or even supply me some. I’m building a small PV system for my shed, nothing fancy maybe, 2 x 25w panels with a Morningstar charge controller and feeding into a basic 9 or 18 amp sealed lead acid battery to run some LED lights for the shed and a USB 5v charger. I understand the importance of using fuses but finding info on what to get is being a task From the looks of it I fast blow fuses. I would assume I need 12v fuses but they seem hard to find and info again on what I really need it hard to find. Do I need 12v fuses? Your advise would be great, I would like to have a inline fuse on every positive line I’m using just in case. Because my panels are not really going to be making more than 2 amp I would assume a 2-3 amp fuse would be all that is required.Again is that correct ? And will 10 awg wire be fine? Do I need circuit breakers on system like this, I dont really see myself using an inverter at this time. I understand you may be geared up for a more pro install than this but i want to be safe.


First of all, you are going to need an off-grid nverter for your system because all solar energy is generated in DC power, and most everything these days is run on AC power, which is what the inverter is going to do. Convert the generated DC power into AC power so it can be used. Unless your LED lights and USB charger run on DC power, you will need an inverter. If you run an off-grid system, you won't need circuit breakers because the system will not be tied into a pre-existing resource. However, if the system is tied into, say, the system for your house, then it will. A circuit breaker can be useful if you want insurance on blown fuses, mainly if you want to stick with lower rated amp and voltage parts to save money, but otherwise, you won't need them. Fuses on the other hand, are a different story. You won't need a fuse on your solar panels unless there are more than two in parallel, which it doesn't seem like there will be. However, if you want to be safe, a 3-amp fuse for your solar panel will do. You should have a fuse for your charge controller, but what size depends on the voltage of your charge controller. You definitely need a fuse between the battery and the inverter, but again, that would depend on the volts of the charge controller. A 10-gauge wire should suffice for your system needs, but you can bump it up to 8-gauge if you want to be 100 percent sure.

06-11-2015 by Ray A Category: Solar Panels


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