31 votes
Accepted

Why am I offered a 5 kW inverter with a 6.6 kW solar installation?

It could be that the system will spend such little time providing above 5 kW, once shading and losses are taken into account, that it's not worth the cost of getting the next-largest inverter. ...
410 gone's user avatar
  • 14.7k
20 votes

Why am I offered a 5 kW inverter with a 6.6 kW solar installation?

Standard Test Conditions vs Real life Photovoltaic panels are rated at "Standard Test Conditions" (STC): Irradiance = 1000 W/m² Cell temperature = 25°C Air Mass = 1.5 Those conditions are achieved ...
Eric Duminil's user avatar
14 votes

Why am I offered a 5 kW inverter with a 6.6 kW solar installation?

Solar systems are rated at peak power. It's normal for inverters to be rated less since you will very rarely have ideal conditions to reach peak power. For example, my inverter is rated at 80% of peak ...
WhiteFang34's user avatar
9 votes

Which battery is best for solar power?

There is no "best battery." There are different kinds of batteries for different applications. Here are some things to consider, What voltage do I want? (Most DIY projects pick 12V because they want ...
Maxfield Solar's user avatar
9 votes

Why is solar energy so expensive?

It is not, necessarily The initial capital cost of a plant is not the same thing as its lifecycle costs. The best way to analyze the cost impact of an energy source is to look at the total expected ...
kingledion's user avatar
  • 1,077
9 votes

Why am I offered a 5 kW inverter with a 6.6 kW solar installation?

There already are some answers addressing the fact that you probably will not reach or will rarely reach the rated power of your panels. That explains why you don't need a higher rated inverter. Now, ...
AVee's user avatar
  • 191
8 votes

How does the solar industry fund itself?

Your first sentence is incorrect, as per the very chat discussion you've referenced: the sales price for panels is more than the cost of the panel's components. The second sentence is also incorrect: ...
410 gone's user avatar
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8 votes
Accepted

What is the amount of silicon in a 1kw panel?

Fthenakis has published more on the subject than anyone, to my knowledge. His LCA lists a whole bunch of factors, but it's roughly 1.5kg of silicon in the PV itself. But a module also has 16.1kg of ...
410 gone's user avatar
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8 votes
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Can 140 square miles of solar panels power the US?

Summary No, that's way too little. I think "140 miles square" has got mangled into "140 square miles". Running the numbers Following on from one of Elon Musk's presentations, which ...
410 gone's user avatar
  • 14.7k
8 votes

Angle of solar panels on flat roof

Oh yes it could be worth arguing about, but only if you have huge roof area and very few panels. With roof fully covered by panels, they should be flat. Generally, if production is limited by panel ...
juhist's user avatar
  • 5,020
7 votes

How can I cheaply evaluate how much solar energy I can collect?

A simple short term test like the one you are thinking about will reveal little information. Many factors affect the output of photovoltaic cells. Results from a cloudy day will differ those for a ...
Fred's user avatar
  • 3,507
7 votes

How much irradiation from the sun is required to generate solar power?

Solar Irradiance The amount of energy striking the earth from the sun is about 1,370W/m2 (watts per square meter), as measured at the top of the atmosphere. This is the solar irradiance. The value at ...
LShaver's user avatar
  • 11.9k
7 votes
Accepted

Are there solar panels that can survive extreme temperature changes?

Effects of extreme temps on solar panels This answer on Chemistry.SE lists the three major factors which lead to solar cell degradation: Temperature UV exposure Mechanical damage ...
LShaver's user avatar
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6 votes
Accepted

Is a solar cell phone charger a sustainable choice?

The best article I could find which addresses this question is "Life‐Cycle Assessment of Solar Charger with Integrated Organic Photovoltaics". Their conclusion: Because of the complicated ...
LShaver's user avatar
  • 11.9k
6 votes

Is Tesla Powerwall a good investment?

No it is not. Your calculations of 13year ROI is based on the assumption that charging the power wall is free during the day time. It is not. Depending on your locale, either you need to factor in ...
Aron's user avatar
  • 380
6 votes

Pros and cons of solar panels over a parking lot?

Yes, from a sustainability point of view it's better to place solar panels over parking lots because You save trees that can continue to absorb CO2 and provide a home for insects and possibly other ...
THelper's user avatar
  • 14.5k
6 votes

Why am I offered a 5 kW inverter with a 6.6 kW solar installation?

In some jurisdictions (like Flanders, Belgium), you have to pay a fee based on the maximum power your inverter can deliver to the grid. As EnergyNumbers notes, slight undersizing won't necessarily ...
AI0867's user avatar
  • 161
6 votes

Any way for microinverter PV array to power a house when the grid is down?

tl;dr: Because of how the grid and your inverters work, it's unlikely that there is a solution for your current system. You will either need to set up a communication network with your microinverters ...
LShaver's user avatar
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6 votes
Accepted

What is the most economical and convenient house battery type?

Lithium-Ion electric car batteries would do the job, but they are too expensive and I am not sure about their lifetime. A pack of ordinary lead acid car batteries seems to be a more affordable ...
juhist's user avatar
  • 5,020
6 votes
Accepted

Do solar panels generate more electricity in hot or cold climate?

If the amount of radiation stays the same, solar panels produce more energy when they are cooler. Heat causes efficiency to suffer. However, this is assuming the radiation amount is the same. Usually ...
juhist's user avatar
  • 5,020
5 votes

Fusing a Solar (PV) Panel

There is no benefit to having an extra fuse at the solar panel. The fuse at the charge controller end is recommended (an in some jurisdictions a requirement). From https://www.boats.com/how-to/solar-...
John's user avatar
  • 203
5 votes

How can I cheaply evaluate how much solar energy I can collect?

You are much better off using one of the "solar calculators", specifically one that uses actual data from installed systems. You might get lucky and find one of the tracking sites has an install near ...
Ⴖuі's user avatar
  • 1,307
5 votes

Is it cost effective to use a solar panel in an apartment if I have a low electricity bill?

The amount of power you consume/power costs are surprisingly unrelated to the cost effective-ness of solar power. To be more accurate, they are "slightly" related. When you install a solar ...
Migz's user avatar
  • 191
5 votes

Can solar panels be recycled?

Yes, solar panels can be recycled -- in Europe this is required by law, and technology exists and is quickly being improved to facilitate this. Legal requirements In Europe, recycling of solar ...
LShaver's user avatar
  • 11.9k
5 votes

Is solar energy the best renewable source of energy?

The validity of your assumptions depend very much on your location and on the amount of energy you want to generate. Some small-scale solutions do not suffer from the same drawback as large-scale ...
THelper's user avatar
  • 14.5k
5 votes
Accepted

How to attach more sources of energy to your charge controller

If you have a single-string MPPT charge controller, then you should not even think of trying to combine your two generators (i.e. PV array and wind turbine) onto a single input and feeding that in. ...
Tim's user avatar
  • 2,824
5 votes
Accepted

Cost benefit analysis of a PV array with racking to set optimal angle, vs a larger array

According to the New Zealand Ministry of Business, Innovation, and Employment (pdf), the average home in New Zealand uses 7,046 kWh per year, and pays a rate of $0.2879/kWh (NZD). I used this as a ...
LShaver's user avatar
  • 11.9k
5 votes

How to consume all my photovoltaic electricity locally?

Maybe my answer is naive, but have you thought about a battery like the Tesla Powerwall? Storing energy during daylight and using at night increases dramatically the auto-consumption rate (~98%).
Aubrey's user avatar
  • 608
5 votes

Solar charging an e-bike's lithium battery while riding

Before you worry about charging, consider this: It takes about 85W to propel a 75kg cyclist at 20km/h under ideal conditions. Thin film (i.e. flexible) solar panels have an efficiency of ~9% and when ...
Tim's user avatar
  • 2,824
5 votes

Is there a difference between DC \ PV cable and AC cable?

The phenomenon that leads to all of this is called the "skin effect". Basically, DC current flows through a wire evenly, whereas AC current tends to want to flow along the outer edge (the "skin") of ...
Tim's user avatar
  • 2,824

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