What are the pros and cons of a solar generator?
Some people use the phrase 'solar generator' to simply refer to solar power generation from solar panels. There is an abundance of information on this and other sites about solar panels and grid-connected residential solar power systems, so I will not repeat this information here.
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What does require explanation is when the phrase 'solar generator' is used to describe an all-in-one power generation and storage solution. A class of product has become common on the market recently, referring to themselves as 'solar generators'.
This article examines these products and provides some warning for those who are considering purchasing them.
What exactly is a solar generator and how do they work?
Products known as solar generators usually contain:
What is a typical voltage for a solar generator to operate at?
Solar generators are typically built for the voltage of the battery bank. Standard voltages are generally 12 V, 24 V or 48 V.
What does the charge controller or solar battery charger do in a solar generator?
The role of the solar charge controller is to do two things:
- Convert the electricity received from the solar panels to the voltage required by the battery bank
- Regulate the flow of power from solar panels to the battery bank to prevent damage to the batteries
What does the battery do in a solar generator?
The battery stores energy so it is available when you need to use it. Solar is an intermittent energy generation source and it may not be generating electricity at the exact moment you need it. Even if it is generating solar power it may not be generating enough to power the electrical devices that you want to use.
What does an inverter do in making a solar generator work?
The electricity that is produced by the solar panels and stored in the battery is produced and stored as DC (direct current electricity). However, most of the household appliances that we want to run require AC power at either 110 volts or 240 volts, depending on where you are.
Inverters in a solar generator are usually pure sine wave inverters. The inverter performs two functions in a solar power generation system:
- Converts the DC power to AC power
- Steps up the voltage from either 12V, 24V or 48V to the required voltage of either 110 volts or 240 volts
Why are there more portable solar generators than fixed solar powered generators?
The evolution of the portable solar generator has come about because in most fixed locations, such as peoples homes and businesses, people have access to grid power at a relatively affordable cost.
Because the public grid supplies non-stop energy and battery storage is expensive, it has not been cost effective to have fixed solar generators (solar panels and battery storage) in most areas.
However, there is an off-grid solar industry to supply the power needs of people who live in areas not served by the grid. These off-grid power systems are essentially larger versions of portable solar generators.
How much electricity do solar generators give you?
Most of the products being sold as solar generators are sold with energy storage capability of 0.1 kWh - 3.0 kWh. To put this in context according to the Energy Information Administration the average American household uses around 30 kWhs per day of electricity.
If we take the Goal Zero Yeti 1000 solar generator we see it has the following specifications:
|Product||Yeti 1000 Lithium Power Station + Build 100 Solar Panel|
|Charge by Wall||18 hours|
|Charge by Boulder 100||15 - 30 hours|
|Battery Capacity||1,045Wh (10.8V, 96Ah)|
|Solar Cell Type||Monocrystalline|
|Kit Weight||60.1 lbs|
|Dimensions of Panel||40.0 x 26.75 x 1.75 in|
What can a solar generator power and for how long?
Using the above example, the unit contains 1,045 Wh (96.8Ah), or 1.05 kWh, of energy when fully charged. A modern refrigerator uses between 1-2 kWh per day. Therefore, this unit could run a full-sized fridge for almost a full day.
However, applications like charging a phone or running lights use very small amounts of energy. These appliances could work for quite a long period of time with a solar generator.
The table belows shows several examples of what the solar generator can power and for how long.
|POV Camera||165+ Recharges|
|32" LCD TV||10 Hours|
What are advantages of solar generators?
The three key advantages of solar generators are:
- Little to no operating noise. This is a large advantage when compared to a typical diesel generator.
- Renewable energy. As long as the sun keeps coming up you don’t need to worry about fuel.
- Clean energy.
What are the disadvantages of most portable solar generators?
The three key disadvantages of solar generators are:
- Slow to charge their battery storage capacity (which is limited in the first place)
- Can only release energy in the form of AC output at a defined rate. Therefore, it’s not very practical to use electrical appliances that have large start up loads like air-conditioners.
- Expensive relative to a fuel-powered generator with the same power output.
Are solar generators suitable for backup power for grid failures?
No. Many appliances connected to the grid will be drawing much more power than what a solar generator could supply instantaneously. Read this article for the best backup power option.
Should you use a solar generator for your boat, caravan or camper?
Probably not. You would be better off charging a battery directly from your boat or car engine. Alternators from an engine can produce far more power than solar, and you can use cheap batteries that offer much more storage capacity.
Will Lithium-Ion battery technology make future solar generator kits more attractive?
Probably. Lithium-Ion batteries offer far higher energy density than lead-acid batteries that have traditionally been used in solar generators.
Author: Andrew Sendy | Home Solar Journalist
Andy is deeply concerned about climate change but is also concerned about cost of living pressures on American families. He advocates for solar energy and solar battery storage only to the extent that they make financial sense for homeowners. He is not affiliated with any particular solar company in the United States.