Solar panel working correctly? 100/30 MPPT

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quimbola asked Sep 25, '22

Solar panel working correctly? 100/30 MPPT

Renogy 175 working correctly, help?

Hi all,

Looking for some help. I just installed a renogy 175 w, Victron 100/30 MPPT smart controller, 15’ of 12 AWG wire, 30 amp breaker between Battery and MPPT. At 1:00pm today in Colorado with no clouds in the sky here is my Victron reading.

This seems low. I have the Victron set to AGM battery and kept the default settings.

Do I have a bad panel, or is this what I should expect? What else can I check?

Thank you in advance!

-Josh

Solar Panel

1664139408085.png (386.8 KiB)

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Answer 1 · 2022-09-25T22:36:53Z

Sarah answered · Sep 25, 2022 at 10:36 PM

It is possible that you are getting a voltage drop across the cables that is impacting the power output. Measure the voltage at the battery to see what is going on. Also is it possible to test the install with a shorter cable run to the battery?

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Answer 2 · 2022-09-25T22:50:07Z

quimbola answered · Sep 25, 2022 at 10:50 PM

I checked the voltage right out of the panel and it read 19.9, same as the app.

Anything else I should check?

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Sarah commented · Sep 27, 2022 at 09:54 AM

@Quimbola Check what the voltage is at the battery and see if that matches the app. This will be indicative of voltage drop between the MPPT and battery.

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Answer 3 · 2022-09-27T14:29:42Z

quimbola answered · Sep 27, 2022 at 02:29 PM

Hi Sarah, they match.

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Answer 4 · 2022-09-27T14:35:35Z

nickdb answered · Sep 27, 2022 at 02:35 PM

At 21.6V that isn’t a lot of panel given the battery and the +6V requirements.

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Answer 5 · 2022-09-28T12:45:35Z

Sarah answered · Sep 28, 2022 at 12:45 PM

@Quimbola not sure what is happening. The panel only just exceeds the +5 volt requirement so this could be a problem, Check to see that all your connection are tight and that there are no stray wires that could be shorting any of the connections. Also double check the default AGM settings compared to the battery manufacturers recommendations.

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nickdb ♦♦ commented · Sep 28, 2022 at 01:52 PM

Max panel voltage is 21.6 according to the specs, so it was never going to be a good idea to have just one.

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klim8skeptic ♦ nickdb ♦♦ commented · Sep 28, 2022 at 02:38 PM

You have a valid point.

The Renogy 175 panel consists of 32 cells.

Below Victron's recommendations for panels having 36 cell requirement to charge a 12v battery.

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Answer 6 · 2022-09-28T14:33:24Z

quimbola answered · Sep 28, 2022 at 02:33 PM

Checking the voltage directly at the solar panel gives me the 19.9v, do you think it is a bad panel?

These are the panel specs:

Max Power at STC: 175W
Open Circuit Voltage: 21.6V
Short Circuit Current: 10.62A
Opitmum Operating Voltage: 18V
Optimum Operating Current: 9.73A

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Sarah commented · Sep 29, 2022 at 10:05 AM

The problem may well be that you are not getting sufficient voltage out of the panel to operate the mppt charger - you need at least the battery voltage plus 5 volts. If this is the problem having two solar panels in series would solve it.

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