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Solar Panels + Cold = A Potential Problem

[snow] Photo Credit: Kevin L @ EcoFlow DELTA Facebook Group

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 &times 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.

[solar]

The Rules When Sizing Solar Arrays

 1. Stay below the maximum voltage specs of the solar generator
 2. Stay way below the maximum voltage specs when it gets cold (how
    far below will be discussed later)
 3. You can exceed the amperage specs
 4. In series, volts add
 5. In parallel, amps add
 6. With mixed solar panels, the lowest amps in series prevails
 7. With mixed solar panels, lowest volts in parallel strands
    prevails
 8. 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 0degC or 32degF 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 -40degC or
-40degF 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.

Related Articles

  * EcoFlow Acronyms
  * EcoFlow Solar Generator & Solar Panel Specifications
  * Temperature Corrected V[oc] Calculator

Related Products @EcoFlow.com

  * EcoFlow River Series
  * EcoFlow Delta Series
  * EcoFlow Portable Solar Panels
  * EcoFlow Mountable Solar Panels

Published: September 20, 2023

Updated:

  * July 15, 2024 - Added DELTA Pro 3
  * Novemnber 26,2024 - Added DELTA 3, RIVER 3, RIVER 3 Plus