Looking for a Solar Generator? These are wonderful power devices that have become popular over the last ten or so years and have come down in price to the point where they are very affordable. They range from smaller sized units such as the Jackery 290wh unit capable of putting out 200-watts of continuous output with a battery that stores 290Wh of power. To know what 200-watts of power will actually support, you must check the wattage of the device you want to power. Let’s take a look at two popular devices that are questioned for being supported by a solar generator.
CPAP Machine
Many folks who use a CPAP machine ask how long they can run their CPAP on some of these solar generators. We will look at an AVARAGE CPAP machine that uses 45-watts, and let’s see how long it will last using two solar generators. The first will be a Jackery 290 which puts out 200-watts of power and stores 290-wh of energy. For the purposes of this article we will assume we have 100% efficiency in converting the power to AC (Which never happens). The second Solar Generator we will examine is my own Inergy Apex 1500 which can put out a sustained 1500-watts of power with a battery that stores 1069-watts of power.
Both of these units can put out the power. The CPAP only requires 45-wh. But for how long? Let’s see.
| Device | CPAP Watts Used/Hour | Battery WH Rating | # Hours of Use |
| Jackery 290-wh | 45-watts/hour | 290-wh | 6.44 |
| Inergy Apex 1500 | 45-watts/hour | 1069-wh | 23.75 |
The calculation us actually just simple division – divide the battery rating by the Watts used per hour for the number of operational hours. This figure does not take into account inefficiencies in the power conversion process of converting the DC power to AC power, so our hours will be less, probably 10% to 15% at least.
Refrigerator Power
What about if we wanted to power something larger – Say our Refrigerator during a power outage. For this, let’s assume an average power consumption of about 150-watts. Many refrigerators consume less, many more. So it will depend on your actual model. Let’s take a look at our same table with this new power value:
| Device | Refrigerator Watts/Hour | Battery WH Rating | Hours of use |
| Jackery 290-wh | 150 Watts/Hour | 290-wh | 1.93 Hours |
| Inergy Apex 1500 | 150 Watts/Hour | 1069-wh | 7.12 Hours |
These numbers now are just for comparison purposes. But – you should get the idea. You need to know what you are going to be powering and understand how many hours of power you will need. And – if using overnight you may have no way to recharge, so once the battery is dead it is dead. No solar panels, and many times we may not be running gas generators overnight for security reasons (So they don’t walk away).
Take the total power of the devices you want to power and add them up. You need to make sure your total will not exceed the output of your Solar generator. Our Jackery can put out 200-watts continuously. My Inergy Apex can put out 550-watts continuously (It can put out 1500-watts for 5 minutes max, then throttles down to 550-watts). Use the max constant power as the value for shopping for a solar generator.
PEAK WATTS? VS SUSTAINED OR RUNNING WATTS?
Many times we have devices that will draw for a very short time – seconds at most – a larger amount of power during startup. This is where your “Peak” power comes in. The Jackery can put out 400-watts of peak power, but it cannot hold that level. It will then put out a lower sustained power level. This is a common value with many battery based and fuel based generators. My Predator 3500 gas generator puts out 3500-watts peak, then only 3000-watts running power. Peak is nice, but sustained/running is what we operate on.
CAN IT CHARGE WHILE BEING USED?
Some can, some cannot. Stay away from any that cannot. With my Apex, I can charge it with up to 500-watts of solar during the day while it is being used. So – If I have drained it low by morning, I can connect the solar panels or other charging option and recharge it while still using it to power my refrigerator. As long as my charge rate is higher than the use rate, it will take a positive charge. This means by adding 500-watts of charging power to it, then while it is putting out 150-watts for the refrigerator it still is charging by 350-watts each hour. In about 3-hours it will be full charged again for overnight use.
CAN IT ACCEPT EXTERNAL BATTERIES?
The Jackery cannot. My Apex can. So – I will attach a 1408-wh external battery to it boosting the total battery to 2477-watts and this will extend my use time to 16-hours – over twice the original 7-hour time limit.
In a future article I will present the idea of building your own battery system out of parts easy to put together. I have build a 420-wh battery box that I use for powering my ham radios, but with a small 300-watt AC Inverter I can easily power a small television, AC devices, even a small portable refrigerator. I have also built a unit that connects a 500-watt AC Inverter to a 1400-watt battery that also can power a number of devices during a blackout. The great thing about a DIY solar/battery generator is the ability to upgrade components or replacing failed components yourself if the need arises.
For more on this topic related to power, look for my book on Amazon titled “Hurricane Ready: Emergency Backup Power”.