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All inverters to make solar into 120V AC require a battery in the system, especially to provide the inrush current spin up a pump. If you went with a DC pump, risk of overheating the pump may occur if the panels fail to provide enough voltage to spin it up (the pump will still draw current while sitting still), a likely occurrence many times a day.
All inverters to make solar into 120V AC require a battery in the system, especially to provide the inrush current spin up a pump. If you went with a DC pump, risk of overheating the pump may occur if the panels fail to provide enough voltage to spin it up (the pump will still draw current while sitting still), a likely occurrence many times a day.
This is not true. Grid connected solar systems don't have batteries.
An off grid system without a battery just needs a low voltage lockout relay.
Hazardous to practice engineering without a license.
I'm an engineer, and have designed a few PV systems up to 100 kW. Unless you are far from the electrical grid, it is both better for the environment and your wallet to use the grid as your "battery." The rules vary by jurisdiction, but it is typically referred to as net metering for small grid-tie systems. Electricity flows back and forth throughout the day and year, and the bill is squared up at year-end. If the system produces more electricity than it consumes, the electrical company pays for the difference. In my area of the world they actually pay more for net-metered electricity than they charge for consuming it.
Sorry, but a key parameter here is that the OP wants to try a small DIY solar installation to run a pool pump at night, and that rules out grid-tie setups.
So yes, you'll need to use the solar panel to charge a battery, and a battery to run the pump. There are small "turnkey" systems available to do that. The trick for you will be sizing the system correctly. My advice is to be very conservative in estimating the power output.
Sorry, but a key parameter here is that the OP wants to try a small DIY solar installation to run a pool pump at night, and that rules out grid-tie setups.
So yes, you'll need to use the solar panel to charge a battery, and a battery to run the pump. There are small "turnkey" systems available to do that. The trick for you will be sizing the system correctly. My advice is to be very conservative in estimating the power output.
The OP is experimenting with solar. Those of us who know something about the technology are counselling him on a more cost effective system specification. Charging batteries to run a pool pump at night might be OK for a school science project, but it makes no economics sense. As I and other engineers have said, grid connected without batteries is the environmentally and economically superior design.
If you want to throw money away, just burn it in the BBQ.
The OP is experimenting with solar. Those of us who know something about the technology are counselling him on a more cost effective system specification. Charging batteries to run a pool pump at night might be OK for a school science project, but it makes no economics sense. As I and other engineers have said, grid connected without batteries is the environmentally and economically superior design.
If you want to throw money away, just burn it in the BBQ.
We're all forgetting something. For many people, using solar energy like the OP wants to do is more about personal satisfaction than the economic savings. Lifestyle considerations have a lot to do with the choice to use solar energy for seemingly uneconomic benefits.
There is no benefit to the environment for gird tied solar energy systems and the economic benefits are mostly driven to the utility company, not the end user who installed the system and gets a discount on their electricity.
Most utility companies are under some mandate to generate a certain amount of their energy distribution and generation from solar. They are allowed to count the energy from grid tied systems into the mix. They get money for that. Then, they are still selling the user energy, just at a lesser total cost but that reduction is far less than the benefits they get from having you grid tied to them. The winner is the utility company, not the end user with a grid tied system.
The we have the environmental impacts. That grid tied system has zero impact on the environment as a benefit. The utility companies aren't generating less energy from fossil fuels because of grid tied systems, they just sell that energy to business customers instead and guess who pays for the reduced energy rates utility companies give to business customers? You, the grid tied consumer customer.
A grid tied system also reduces or can eliminate your ability to moderate energy usage from the utility company. In a typical home installation, the amount of energy that is harvested can equal the amount of draw for say the refrigerator, the TV and some other appliances, on a good harvest day. On those days where energy use is high and the utility companies are asking you to limit energy use they are not considering that you are grid tied and therefore probably contributing more than your use. Basically, it is a numbers game and the utility companies have figured out that they can charge you (or someone) for grid tied systems and in the end, they, not you are making money from the investment you made.
The alternative isn't pretty since non-grid tied systems are expensive and also have maintenance costs that go on for the life of the system but as a society, we have allowed the utility companies to run amok when it comes to rates, energy generations schemes and the loser is always the customer, grid tied or not.
You lack both engineering and financial understanding. A grid connected solar system displaces either coal or natural gas generation on about a 115% basis. For every 1 kWh generated by solar you reduce fossil generation by about 1.15 kWh. That's the simple physics of running a grid.
A grid connected system in no way reduces your ability to reduce your load during system peaks, nor would PV impair your ability to sign up for utility sponsored load shedding or load cycling programs. BTW many utilities provide a modest subsidy for PV system generation. The utility makes more money of those who are not using PV to reduce their grid based energy use.
Sorry, but a key parameter here is that the OP wants to try a small DIY solar installation to run a pool pump at night, and that rules out grid-tie setups.
So yes, you'll need to use the solar panel to charge a battery, and a battery to run the pump. There are small "turnkey" systems available to do that. The trick for you will be sizing the system correctly. My advice is to be very conservative in estimating the power output.
One of the reasons for charging a battery for this project is that I thought that it might be more cost effective to purchase a smaller PV panel and trickle charge a battery throughout the day and then use the battery to run the pump when it is fully charged at night. If this is not the most efficient way to do it, that's fine, but this is the information that I really need to know. I don't really care when the pump in running. I just had this configuration in my head as being the most cost effective.
Quote:
Originally Posted by GregW
I suggest buying a complete ready made system and installing it yourself. Then observe the results to help determine what you really need.
This is good advice and pretty much what I planned on doing. I just figured that the pump would be the easiest thing to tap into. As you can see, though, I have no idea what I am talking about.
Quote:
Originally Posted by DCforever
The OP is experimenting with solar. Those of us who know something about the technology are counselling him
It's not that big a deal, but I'm a chick
Quote:
on a more cost effective system specification. Charging batteries to run a pool pump at night might be OK for a school science project, but it makes no economics sense. As I and other engineers have said, grid connected without batteries is the environmentally and economically superior design.
If you want to throw money away, just burn it in the BBQ.
^What type of engineer are you? My son is going to school for mechanical engineering, but is interested interested in solar/alternative energy.
My ultimate desire is to someday be off the grid which is another reason I want to incorporate batteries into the experience. The purpose of finding a "science project" is to understand what is involved and to be able to troubleshoot problems that come along.
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