question

ldc avatar image
ldc asked

0w from mppt solar controller in cold conditions?

My two 410W solar panels and mppt 100/50 controller has been working great. This sunny morning, it is reading 0w eventhough the voltage difference is ok and it says it is in the bulk state. (The cerbo shows the inverter in float state and weare hooked up to 30amp shore power.) However. It was really cold last night and now only 1 degrees C. Is there a problem??? Please help.

Thanks!

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solar
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2 Answers
ldc avatar image
ldc answered ·

Some additional info - we have it set for Lithium batteries. Also the blue light on the controller is blinking - "Note (*1): The bulk led will blink briefly every 3 seconds when the system is powered but there is insufficient power to start charging."... But there seems to be plenty of power to start charging. Can anyone please explain???

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Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

If you use the Lithium preset it stops charging below 5°C.

Look at your settings.

Also look at the datasheet of your batteries.

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ldc avatar image ldc commented ·
Thanks! I'll keep an eye on it once the temps rise today. My batteries supposedly charge to 0C. Last night it was a little colder than 0C and they still were charging from the 30 amps/inverter.
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ldc avatar image ldc ldc commented ·

Yep! Thanks so much.

I might need to edit the setting since the batteries say they are good to 0C and it took over half the day to heat up to 5C.

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snoobler avatar image snoobler ldc commented ·

5°C is the default because 0°C isn't really a certainty. It's not like it's a line in the sand and it's fine above and horrible below. There's a gray area. Furthermore, temperature sensors aren't perfect, and placement/conditions can affect the reading.


Cold charging lithium causes lithium to plate on the terminal permanently removing it from being able to deliver charge, i.e., permanent capacity loss. Some cold temperature charging is okay, but it should be done at very low current.


IMHO, heat your battery or insulate it against the cold. Don't charge below 5°C regardless of what the specs say.

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