ECOHOLICS – Solar Panel Temperatures
Do Not Do This…Unless You Want Magic Black Smoke
You purchased a new Delta Pro and looked up the
specifications – Delta Pro can take up to 1600w/150v/15a of solar input. Then you buy four EcoFlow 400w Rigid solar panels
to plug them in series.
You check the math
37.1v VoC × 4 panels = 148.4v
… just under the 150v Delta Pro solar input limit. The new solar array is right at the watt limit, just under the volt limit, and a little under the amp limit.
You think you are good to go, right?
Wrong!!!
This will likely create black magic smoke from your solar generator on the first cold and sunny day.
This is because solar panel voltages increase as temperatures drop. We see many complaints from newbee EcoFlow customers
who are all excited with their new toy, they proceed destroy their MPPT controller, then complain bitterly on social media about
EcoFlow’s customer support and voided warranty policy. Plugging in four 400w solar panels in series is similar to filling your gasoline powered
car with diesel and wondering why the car manufacturer isn’t replacing your new car.
The Rules When Sizing Solar Arrays
- Stay below the maximum voltage specs of the solar generator
- Stay way below the maximum voltage specs when it gets cold (how far below will be discussed later)
- You can exceed the amperage specs
- In series, volts add
- In parallel, amps add
- With mixed solar panels, the lowest amps in series prevails
- With mixed solar panels, lowest volts in parallel strands prevails
- We cannot stress #1 and #2 enough so it is worth repeating – do not exceed the volts
In order to determine what your maximum VoC of an array can be, use one of the conservative estimate tables below or you
can compute the temperature coefficients precisely if you have the solar panel specs.
Examples
Example 1
- Live in Georgia
- Own a Delta Pro
- Using EcoFlow 400w portable solar panels
You might choose 0°C or 32°F as it almost never freezes in Georgia and the table shows 136.4v as your VoC maximum. The EcoFlow 400w portables have a VoC of 48.0v which means two solar panels in series have a VoC of 96v (Solar Rule #4 above)- well within the 136.4v limit. Three solar panels
in series would exceed the 136.4v limit and result in black magic smoke.
Example 2
- Live in Canada
- Own a Delta 2 Max
- Using EcoFlow 220w bifacial solar panels
Since it gets really cold in Canada you would likely choose -40°C or -40°F and the table shows 48.0v as your VoC maximum at the coldest temperature.
The EcoFlow 220w bifacial portables have a VoC of 21.8v which means you can safely put two solar panels in series (43.6v). Since the
Delta 2 Max has two solar input XT60i ports, you can actually add four solar panels, two strands of two panels per port.
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Published: September 20, 2023
Updated:
- July 15, 2024 – Added DELTA Pro 3
- Novemnber 26,2024 – Added DELTA 3, RIVER 3, RIVER 3 Plus