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steve-bellis avatar image
steve-bellis asked

MPPT 75/10 Invalid History

Hi,

I have an MPPT 75/10 charge controller managing a 100W solar panel and a 38Ah Battery, running an off grid continuous load. The controller is managing the recharging of the battery correctly, but I have noticed that if I isolate the solar panel for a few days the history tab is still recording a Yield and graphical charging information even though the battery is not being recharged. Conversely the Status tab and Trends tab are both showing the correct information, so the problem is confined to the purely historical data. I have tried both the Smart Solar MPPT 75/10 and a Blue Solar MPPT 75/10 and seen the same problem on both. Any ideas or suggestions?


MPPT Controllers
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3 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

The MPPT determines the passing of days by the light and dark of the solar panel.

By disconnecting the solar panel, you have stopped the clock so to speak. Your MPPT thinks that it is still the same nighttime as when you disconnected the panel, the next day won’t start again until the sun (voltage) returns to the panel.

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steve-bellis avatar image steve-bellis commented ·

I am not sure that can be true otherwise how would be able to log data against a particular date in the extended 28 day history. Also if a panel had failed or become disconnected then if you were remotely monitoring the system if that were true then the first you would know of the problem is when the battery is sufficiently discharged to cause shutdown?

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ steve-bellis commented ·

It is the way it is.

There is no place to set the date or time on the MPPT. 28 day history is relative to the last recorded day, determined by the solar panel getting light, then going dark.

Total panel failure would result in a discharging battery, and that is how you would discover the fault.

The MPPT is mostly limited to Bluetooth/USB connections. So you would observe the solar voltage at 0V, when it should be more in the status display.

The LoRaWAN dongle pushes data to VRM, and then the server is able to time stamp.

The normal Victron remote monitoring solution is a GX device, which does contain its own clock.


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steve-bellis avatar image steve-bellis commented ·

Hi Guy,

Thanks for your explanation, so I guessing that the dates shown in the extended history relate to the phone running the Victron Connect App? There is still one thing that is bothering me, if the MPPT is effectively seeing one continuous "night", why is the data different for each day that the panel isn't active. I would have expected this to be just a repeat of the previous day?

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ steve-bellis commented ·

Today, yesterday, 2 days ago are relative to the last time the MPPT detected a “day” and “night” of solar.

Each new recorded day, those values are pushed along, and the 28th day is dropped.

If there is no solar, there is no day, and the values for the history stay the same as they were.

At that point the “labels” of yesterday, etc are not accurate to the worldly days. And you are looking at the recorded data from the solar days from the MPPT’s perspective.

It’s not typical to be regularly manually disconnecting solar PV from a solar system.

The MPPT is designed to have the solar connected all the time.

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steve-bellis avatar image
steve-bellis answered ·

Hi Guy,

Whilst I appreciate that the MPPT is designed to be permanently connected, I am trying to robustly test this unit as part of a bigger system, which we eventually hope to use in monitoring power cabling in a national transport network. I can understand that with no real time clock the MPPT would see these conditions as perpetual night, but what I can't understand is why during this time differing Bulk, Absorption and Float figures are recorded for each new day. Surely if the registers were effectively "frozen" the same values would be reported for each new day?

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Rod avatar image Rod commented ·
It is quite difficult to understand, why Victron has not added an internal clock chip inside, it is negligible in the cost, but The advantages will be priceless if networking equipment have a time stamp in several functions.


Please seriously consider this improvement.

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kali-the-miller avatar image
kali-the-miller answered ·

Hi Guy Stewart - I am having the same problem:

https://community.victronenergy.com/questions/42069/victron-connect-history-frozen.html

It is clear that the MPPT does not know the time and day - it (probably) does not need to - its just a controller. If any, it needs to be able to sum up a little over time - may be seconds or minutes.

The question here is really about the history display in the VictronConnect app. If the app detects a new day and the MPPT does not show any generation from solar, it should for the new day correctly display zero.

And for my case, if the solar does not drop to zero over night - because I have a hydro application - the app should at midnight start a new day, drop the 29th day off the history and display the power generated after midnight on a new day





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