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antonio1968 avatar image
antonio1968 asked

Victron 100/50 Watts fluctuations

Hello, I just installed my brand new mppt smart 100/50, every day, at the same time, if it is sunny and clear, around 2 pm, the app show me a fluctuating wattage, reaching around 700 Watts then falling down on 0, going ahead for 30 minutes, constant voltage but fluctuations in current. Then stable on 130/140 Watts, till the evening, where, against the logic, I have back 250/260 Watts.

My panels array is providing 1100 Watts (ideally) i also checked all the wiring, everything it seems working.

Anyone knows the possible reason? I am gonna damage my battery pack, thanks in advance to you all.


MPPT Controllersbattery charging
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5 Answers
klim8skeptic avatar image
klim8skeptic answered ·

your mppt will do a scan every 10 mins or so to search for the highest power
(watts) output.

you will notice the mppt's solar current reducing/increasing, while the mppt searches for the maximum power yield.

interesting to watch, with no major power loss.













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antonio1968 avatar image antonio1968 commented ·

Thanks for your timely answer, however, your logic is coherent, but can you consider on the fact, that the peak of wattage is around 750 watts, then stabilized on 130, it is so faraway a mid value, anyhow, couldn't be lower than the sunset, where instead, it is stable around 250 watts.

Thanks.

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therealroland avatar image therealroland commented ·
So, the fluctuations happen every couple seconds. In my case going from 220w to 0w and back up every few seconds. Happening perhaps to close to full batteries (but how would I know for sure?)
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mtbcol avatar image
mtbcol answered ·

I have a similar problem on the first day of instal 330watt mono panel, 100/20 controller in afternoon sun not overhead controller showed a constant 20 watts being harvested. The next day, cloudless sky sun directly overhead, charger constantly going from 0 to 135 watts of harvest.??

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PURescape avatar image
PURescape answered ·

I'm also struggling with the same issue. Like mtbcol, my 525 watt array is only returning about 125 watts in the App at full sunlight. And then falls to under 50 even in times of high and direct sun. Is there a setting that may be able to increase the overall watts being harvested? Also, would this indicate that I can increase the total wattage of my Solar Array (add more panels) given that there is less actual wattage moving through the MPPT

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Matthias Lange - DE avatar image Matthias Lange - DE ♦ commented ·
Maybe your batteries are just full?
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therealroland avatar image
therealroland answered ·

Same here. 100|50, connected to 2x 100w series, 2x 100 parallel, 4x25 parallel, charging 2 100 Ah batteries. Thought one or more panels malfunctioning when I saw this, but doesn't look like it. So this just happens when batteries (nearly) full? If so, please confirm, so I won't keep checking my cables :-)

Btw, this happened on a clear, cold day, almost no clouds in the skies, batteries discharged from full to about 12.6v - so the set of panels picked up peak 210w, but then started fluctuating.

The next 'day' depending on when you powered up the charger, it almost immediately goes to float.

Related to that, does the wattage harvested shown in the app is just that, i.e. what the batteries can suck up, or the wattage total generated from the panels at that time?

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kevgermany avatar image
kevgermany answered ·

To answer your last question first, wattage is what goes comes out if the 100/50. If there is no load, there's no wattage as no current flows.

You appear to have quite a few different panel types. Please give more info - panel specs and how wired, the wiring details you give lead to guesses. Also the configuration settings in the 100/50 and battery details.

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