Solar Generators: How Big, How Much?
Two of the most common, and justified, questions I hear during my normal day are, “How big of a solar generator do I need to run xyz?”, and “How much does a solar generator cost?”
Let’s define what a solar generator is (or isn’t).
The questions of “How big” and “How much” are important, and anyone considering the purchase of a solar energy unit needs to understand how to determine what the answer to both should be, but to make sense of that, there needs to be an understanding of what exactly a solar generator is. Don’t worry, this isn’t going to be science lesson
Are you ready for this? In the strictest of technical terms there is no such thing as a solar generator. The term “Solar Generator” has been applied to power stations as a means of categorizing these devices in a way that consumers can easily identify with. Most of the devices which get labelled as “Solar Generators” are in fact Power Stations. These are units which control the inflow of energy, store that energy, convert that energy into usable current (DC to AC most often) and safely control the output of that energy. While it is true that solar panels can be used to capture solar energy (capture mind you, not generate) and that captured energy can be used to charge a Power Station, wind powered turbines, water turbines, a simple cord plugged into a DC outlet, another generator or just about any other energy source that produces a DC current can also be used to charge the Power Station. For the sake of not throwing too much at you at once, lets just keep calling a unit that includes solar panels a “Solar Generator” and a unit that does not include solar panels a Power Station.
So on to the first of the two big questions: How Big
Unfortunately, the answer to “How Big” is not one that can just be looked up or posted on a website. Most manufacturers will provide estimates of how long various units will operate common appliances, such as the one below provided by Nature’s Generator. While these may be helpful for comparing units against each other, they do not do a good job of indicating the unit’s ability to meet your individual needs for power delivery; for that you need to do a little fact gathering and, as much as you dread it, a little math.
Let’s talk about some of the important solar generator specifications. Here is what you need to look for, and why:
1) Running Watts or Output Continuous Power
This number indicates the watts that the inverter in the unit will send out as standard AC current. This is one of the most important specifications to consider when evaluating the appliances that you need the solar generator to run. It doesn’t matter how much battery capacity (Wh) the unit has, or how many watts are being fed into the unit, the Output Continuous Power is the maximum total watts that can be run at a continuous rate. To determine the running the watts you want to look for, you will need to make a list of the appliances that the solar generator will power simultaneously. Most appliances will have a plate or a label that shows energy requirement in watts or amps. If the energy requirement is in amps, you can multiply the amps by the voltage requirements to get the wattage needed to run the appliance. IE: a refrigerator that requires 15A, and 120V would mean it uses (15x120) = 1800 Watts.
2) Peak Watts
So now you have your list, and you have added the wattage requirements of all the appliances up and it totals 3600 watts, so all you need to do is grab a solar generator with 3600 Running watts, right? Well, not quite. Many appliances require a significant amount of energy to start up, well beyond their continuous running demand. A refrigerator may take as much as seven times its normal demand to start up its compressor for example. This is where peak watts come in. If you plan to run appliance that have a heavy start up demand, then you will want to make sure that you have and Output wattage that will run all of the normal demand AND a peak wattage that is equal to the normal demand plus the expected start up demand. If you are not certain of the start up demand, doubling the running watts is a good rule of thumb.
3) Capacity or Watt hours
Great! Now that the power requirement is understood it’s off to the sales floor! Oh, no, wait a minute. It’s great that there is enough power to run the mini fridge and have lights on, but how long can you keep the bulbs lit up once the sun goes down? Right. So, let’s talk about capacity. Many Solar Generators/Power Stations are expandable, meaning that additional capacity can be added in the form of power packs, additional batteries, etc. Expanded or not, total capacity is going to determine how long you can keep the lights on. Listed as watt hours (Wh). Watt hours indicate how many hours it would take to use all the energy in the system if one watt was used per hour. A practical example would be a power station that had a capacity of 4800 Wh and was running appliances which required a total of 480 watts could sustain those appliances for 10 hours before needing to be recharged.
Next Question Please: How Much?
Wattage and capacity are just the basics that will help with the buying decision when considering a solar energy solution. Other factors can impact cost can include:
· Type of transfer switch
o Some are manual, some are automatic, allowing nearly instance switching from public utility power to solar backup units for uninterrupted power during storms or other black out events.
o Amp capacity
o Number of circuits
· Hybrid systems that harness both solar power and wind power via small home wind turbines.
· Control and monitor modules to monitor power levels, control output, and that are even Wi-Fi enabled.
· Battery type and life cycle.
· System portability
For this conversation let’s just focus on the correlation between wattage and cost, and watt hours and cost to give very high-level expectations. Across the leading manufacturers and suppliers of solar generators the average cost runs about 48 cents per running
watt up to 4500-watt hours. For units with more than 4500-watt hours expect to pay 48 cents per running watt, plus an additional 40 cents for every watt hour over 4500). If you are looking to expand the capacity of the system you can expect to pay an average price of 40 cents per watt hour for battery expansion pack, power pods, etc. So, a practical example would be:
A solar generator that provided 3600 watts and 2400-watt hours should run around (3600*.48) = $1,728.
If you wanted to add a power pack to the system to get the watt hours up to 4800-watt hours, it would cost an additional (2400*.4) = 960 for a grand total of $2,680
**These are just averages based on industry prices and not in any way an offer of a sales price for any specific product
Is a $1,728 Solar Generator going to power your whole home? No. This is an example of a portable solar generator that would be used as a backup power option for black outs, or for off-grid power needs like RVs, camping, remote job sites, work sheds and garages, or even backyard parties.
A whole home system might look like this:
A solar generator that provided 10,000 watts and 10,500 Wh at (10,000*.48) plus (6,000*.40) = $7,200
You might consider adding an extra battery to 10,500 Wh ($4,200)+$7,200 = $11,400
**These are just averages based on industry prices and not in any way an offer of a sales price for any specific product
Conclusion
Hopefully you’re not left more confused than when you started reading. There are a lot of factors to consider when shopping for the best solar energy option, but with careful thought, a good solar generator can provide you and your family with peace of mind during inclement weather, offer extra freedom when planning those big road adventures, and lower the monthly shock of your electric bill each month. You can buy a full system, ready to hook up and turn on, no contract, no hidden fees, no stress.
