A solar generator is the term for a power station that uses solar panels to capture energy from the sun and store it in batteries for later use. It’s an efficient, clean and renewable source of energy for off-grid living and activities like camping and tailgating.
There are plenty of choices in the market, so here I evaluate among which solar generators I would select for off-grid living and for emergencies.
| Key takeaways: • LFP batteries are heavier, but are more stable and last 15-30% more charge cycles than Li-ion batteries • A pure sine-wave inverter is most compatible with home appliances • Look for batteries systems that are expandable |
Solar generators include:
Solar Panels
The main number to look for is wattage, which represents the solar panel’s power output. Naturally, higher wattage is better than lower wattage.
Another number that is frequently given is the solar panel’s efficiency. At present the best sunlight to electricity efficiencies hover at about 24%. The stated power output assumes a top efficiency. In reality, the angle of the solar panels, weather conditions, time of day, and other factors can all affect efficiency.
Power outputs vary from 60W to 400W for many commercially available panels, however, when selecting a high wattage panel, or purchasing multiple panels, you will want to ensure that your battery and charge controller can handle that load.
Some panels are foldable and come with handles and stands making them easier to transport and adjust for optimal sunlight.
Most solar panels come with MC-4 connectors which allow them to be strung together and plugged into the battery.
Solar Battery
Batteries come in all sizes. They’ll have a stated power output, like 2400W, which tells you how many of your appliances they can manage at once, and they’ll have a stated capacity, given in Watt hours (Wh) which tells you how much energy the battery can store.
For example, if a lightbulb is 60W and your battery has a capacity for 1000Wh, you can expect your battery to be able to power the lightbulb for 1000 / 60 = 16.7 hours at full charge.
To charge that same 1000Wh battery from empty using a 200W solar panel, you can expect it to take 5 hours.
1000Wh battery / 200W solar panel = 5 hours
Note that this charging calculation would be accurate only under ideal conditions.
Multiple Outlets and Ports
I would also expect to have USB and USB-C ports, AC outlets, and an easy-to-read dashboard that shows battery vitals.
Battery Chemistry
The two usual choices for battery composition are between LiFePO₄ (Lithium Iron Phosphate) and Li-ion (Lithium ion). I prefer LFP batteries, as they last for 15-30% more charge cycles and are more stable in both performance in high-temperature and in storage than Li-ion batteries. The drawback is that LFP batteries are 30% to 60% heavier than Li-ion, however this isn’t a concern since the battery will be mostly stationary.
Battery Expandability
I would also like a battery that can be chained to other batteries to increase capacity. Ideally, I would like the capability to expand to a 10,000Wh system. That would be able to power the average home for a whole day.
Powering the Home
In 2020, the average home used 10,715 kWh of electricity. Dividing that by 365 days gives us 29.3 kWh / day or 29,356 Wh / day.
In an off-grid scenario, by being parsimonious with power – refraining from using power-hungry appliances like the microwave, dish washer, electric stove and oven, and coffee maker, for example – you should easily be able to stay under 10,000Wh for the day. To put it in perspective, the average refrigerator would require just 1,500 to 2,000Wh for the whole day.
This is important because you will probably only receive 5 hours of direct sunlight from about 10am to 3pm. In order to charge a 10,000Wh battery from empty to full, it would require 10,000Wh / 5 hours = 2,000W from solar panels.
A common size of portable panel is 350W. In the above scenario, you would be able to charge your battery every day with 6 x 350W panels.
Inverter Type
Inverters convert DC power stored in the battery to AC power, which many appliances use. There are three types of inverters. Pure Sine Wave, Modified Sine Wave and Square Wave inverters. Pure Sine Wave inverters create a smooth sinusoidal waveform that closely resembles the power from the electrical grid. This is best for sensitive electronic devices like computers, TVs, medical equipment and refrigerators. The other two are more suitable for less sensitive devices. If possible, select a battery with a Pure Sine Wave inverter for best compatibility with your devices and appliances.
EcoFlow vs Bluetti vs Pecron Solar Batteries
Here is a comparison of three popular solar batteries that can be chained to provide sufficient power for your home.
| EcoFlow Delta Pro | Bluetti AC300 | Pecron E2000 LFP | |
| Power Output | 3600W 7200W Surge | 3000W 6000W Surge | 2000W 4000W Surge |
| Capacity | 3600Wh | 3072Wh | 1920Wh |
| AC outlets | 5 | 6 | 5 |
| USB outlets | 4 | 5 | 6 |
| Battery Chemistry | LFP | LFP | LFP |
| Inverter Type | Pure sine wave | Pure sine wave | Pure sine wave |
| Expandable > 10 kWh | Yes | Yes | Up to 8 kWh |
| Price | $2,995 | $2,599 | $899 |
| Price / Wh | $0.83 | $0.85 | $0.46 |
EcoFlow vs Bluetti vs Pecron Portable Solar Panels
| EcoFlow 400W | Bluetti PV350 | Pecron PV300 | |
| Power | 400W | 350W | 330W |
| Portable | Yes | Yes | Yes |
| Price | $999 | $849 | $539 |
| Price/W | $2.5 | $2.4 | $1.6 |
Both EcoFlow and Bluetti, two of the largest manufacturers of home backup batteries and solar generators have comparable prices at around 83 cents per Wh for batteries and $2.4 per Watt for solar panels.
Both would be decent choices, however, if you think you can do with a maximum capacity of 8kWh, you might consider the Pecron E2000 LFP which is almost half the price of the other two.