Blue Solar MPPT - history recording during night time

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thomassolar asked Sep 14, '19

Blue Solar MPPT - history recording during night time

I know that when it comes to measuring voltage and deciding absorption time, the MPPT starts a new day when the solar voltage raises in the morning above 5V more than battery voltage.

But what about the history from the "dark hours"?

An example:

Let´s say the battery voltage is 28,25V when it is getting dark in the afternoon and the MPPT stops charging.

During the night the battery has a minimum voltage of 27,50V at 3 o clock a.m. because of heavy load

When the MPPT powers up the NeXT morning, the voltage of the battery is 27,90V

When I open the history screen the coming day, will I then:

a) See the minimum of 27,50V on YESTERDAY?

b) See the minimum of 27,50V on TODAY?

or c) Not see the minimum of 27,50V at all because it happened during night when the MPPT had no solar Power?

MPPT Controllers voltage

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thomassolar commented · Sep 16, 2019 at 06:09 AM

Nobody knows.??

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Modifications Space

Node Red Space

Answer 1 · 2019-09-16T08:18:04Z

klim8skeptic answered · Sep 16, 2019 at 08:18 AM

Hi Thomas,

BlueSolar Mppt with rev 1 hardware are powered from the solar panel.

BlueSolar Hardware rev 1.5:
⦁ Powers itself from the battery instead of from PV: to enable load shedding / streetlight functions. Note that the rev 1 types of 75-15 and rev 1 100-15 already powered themselves from the battery.
⦁ Programmed with rev1 firmware files.
⦁ Software reports these products as rev1

I have both a rev 1 and rev 2 mppts.

I looked at todays history, the rev 1 unit reported a min 12.65v, the rev 2 unit reported 12.45v.

It looks to me the rev 2 unit recorded the voltage drop before dawn from boiling the kettle.

YMMV.

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thomassolar commented · Sep 16, 2019 at 11:21 AM

Thank you for responding :-)

I have a rev 2 hardware Blue solar 100/50

From what you experienced this morning, it seems like it starts the "today history voltage recording" before dawn.

But then we still don´t know exactly when during the night it changes from "yesterday" and to "today" when it comes to minimum and maximum voltage in the history screen.

I will do some test myself the next time I spend a night in the cabin, or maybe someone else has tested?

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mtadao thomassolar commented · Sep 19, 2019 at 08:01 PM

I have monitored the behaviour today (Kenyan time) and it changed to a new day at between 10.31pm and 10.51pm on 19/9/2019 as per attached screenshots

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screenshot-20190919-223507.jpg (377.4 KiB)

screenshot-20190919-225128.jpg (367.5 KiB)

Answer 2 · 2019-09-19T06:51:43Z

thomassolar answered · Sep 19, 2019 at 06:51 AM

Then I have been able to do some testing myself:

- Lowest (or highest) voltage is recorded in the history screen also if the peak happens during night time when the MPPT is not charging (off-state)

- A New day (when it comes to history) starts before dawn. It is diffucult to understand exactly when. Maybe when the PV voltage starts to rise slightly above 0V, but at least way before it reaches the battery voltage+5V which starts the charging.

(This topic is just something I have been wondering how works, I hav NOT had problems with it, and there is NO bug)

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mtadao commented · Sep 19, 2019 at 07:47 AM

My 75/15 charger seems to start a new day around 11pm with the new update unlike before when it started a new day after waking up.

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thomassolar mtadao commented · Sep 19, 2019 at 08:41 AM

Yes, it seems to happen sometimes in the middle of the night. If there was an ordinairy 24h clock in the MPPT, I would of course expect it to happen at 24 (12p.m.) o clock.

So exactly what "triggers" a New day is still a mystery. But at least we now know that it happens at some time during the night, and we also know that the history screen records the lowest voltage peak even if it happens during night time. And that is good :-)

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mtadao thomassolar commented · Sep 19, 2019 at 10:07 AM

Seems its a mystery even to victron energy

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Answer 3 · 2020-02-15T07:40:23Z

mtadao answered · Feb 15, 2020 at 07:40 AM

Has Victron determined when the solar chargers see "a new day" and why as my blue solar 75/15 changes sometime before 11pm? but when i bought it in May 2019, a "new day" started just before dawn. Am just curious. .

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