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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:I am hoping you would be able to help. I have a teeny tiny very basic system I want to build but with all my research, forum posts etc. no one seems to have a clue how to set up what I want. So the whole idea is to power a fan I have (in my tiny house truck). It uses either 6 D batteries or ac (9v 700ma). I decided the best choice would be to purchase 2 smart battery chargers that charge 4 D cell batteries at once and have 12 rechargeable batteries (6 in the fan, 6 charging). So the battery charger, here( ) has an AC 12vdc port as well as a USB for charging cell phones. I decided a 20 watt panel would be the most versatile choice since I could use it for other things too. However, how do I connect the panel to the charger? Would I need a charge controller when the charger itself stops charging batteries? Perhaps it would be a good idea to buy a charge controller anyway if I want to play around with charging other things. But which controller should I buy for the fastest charge? Also, should the panel be a 6 v,12v, 24v or a 18v???? Does it even matter?


The different voltages of the panel panel would only play a role if you were wiring multiple panels together in either series or parallel. Volts x Amps = Watts. If you are only using one panel, it won't matter, only the wattage does.  According to the information listed with the product, the battery charger itself has it's own controller so as to not overcharge your batteries. If you are running an off-grid system, which I am assuming this is, you will need a charge controller anyway regardless of whether or not you want to add stuff later. At 20 watts, and depending on how much sun hours the panel would get, you could generate anywhere from 60-120 watts if you are in the US. As far as how the system would be setup, your panel array would be hooked up to a charge controller, which is hooked up to a battery bank, which then feeds into the inverter (solar power is generated in DC power, which the inverter converts to AC power). The inverter then sends the newly converted AC power through AC breakers and into your load center, which then feeds into your AC loads. That's the bear bones description of an off-grid system. You can spec out a small off-grid system. You can also look at some of the emergency and backup solar energy kits and also some of our portable modules that may meet your needs for a small home solar panel system.

08-19-2015 by Echo Ring Category: Solar Outdoors

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:Hi, I am an artist looking to use my soldering iron at shows and need to run two @ 25w/120v each, and want a solar generator! Any recomendations? IDeas? I saw a little one but not sure if its 12v will run my guns for hours and at top temp.THanks K


For both soldering irons, you are looking at 50 watts total. You mentioned that you will be running them for hours, so I will assume a full 8 hour day. 50w x 8 hours = 400 watt hours. That means you will need a 400+ watt generator. If you aren't running them for 8 hours (for example, only 5 or 6 hours), you can reduce the number of total wattage by using the formula above, but it never hurts to get a little more wattage than required just to be on the safe side. The extra energy can always be stored, but with a smaller generator, when you run out, it needs to be charged up again, which takes a while. Let's keep it simple and say a 500w generator is what you get. To charge that generator, you could get a single 200w solar panel. Depending on where you are in the world depends largely on how many direct sun hours your array is exposed to and in turn affects how long it will take to charge your generator. With a 200w solar panel and 3-5 hours of direct sunlight, you are looking at 600w - 1000w of energy generated. This is a ballpark because of the unknown factor of just how much sun your array will receive, so you can adjust it as necessary, but this is a basic outline of what you will need. You can spec out a small off-grid system. You can also look at some of the emergency and backup solar energy kits and also some of our portable modules

08-02-2015 by karen Category: Solar Electronics

Q:hello,I got 24V off grid solar systemin my garage.It feeds few LED light in the garage and it is intendent to feed my pool pump for a few hours during the season.So far works well,but my GFCI which feeds the pool pump from the load gdoes not trip when I press the test button.Even when I tested that GFCI with my tester hot against the ground I measure 0 Volts.When I replaced that outlet to house power it worked OK.My power inverter(PWRINV 250024V) is modified sine wave and there is nothing about GFCI in the manual.Is my pool safety?


If the GFCI outlet was not tripping with either the "TEST" button or your GFCI tester, then replacing it is the recommended option. If you replaced it and it is now working, then you should have no other problems. The issue doesn't seem to be with your solar system. You may want to have an electrician come out for an assessment. GFCI receptacles are known to have issues like this for no apparent reason. Like I said, replacing the receptacle (outlet), which you already did, should have fixed the problem and you should be good to go.

GFCI receptacles trip and disable when there is a ground fault present, which is to tell you there is a problem that needs investigating. If the ground fault still exists, no matter how many GFCI receptacles you replace it with, it will trip and disable every time. However, since you changed the receptacle and it is now working, the old one was probably just dead. If there was still a ground fault, the new GFCI receptacle you replaced the old one with would have tripped immediately and disabled. If it is working now with the new GFCI receptacle, then there should be no problem and your pool should be safe.

07-07-2015 by Radek Korec Category: Solar Electronics

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:Do solar power banks charge efficiently in artificial light?


Battery banks do not charge efficiently in artificial light, and we recommend against doing so. You will most likely be using more energy than you are storing because artificial light is far less intense than direct sunlight. It would definitely work; it just isn't a good idea. Even if it is not in direct sunlight, visible light from the sun will still charge a battery bank. It won't be optimal, but it will be more efficient than an artificial light source.

07-07-2015 by Deepak Category: Solar Electronics

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


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