Bluetooth data different from VE Direct

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johnnyfp asked Mar 27, '23

Bluetooth data different from VE Direct

HI,

We are trying to capture data from a Smartsolar MPPT 100/20 unit via the VE.Direct port over TTL serial and are getting wildly different voltages from the solar battery parameter compared to the App reading the same value.

VE.Direct(Time show is GMT)

Bluetooth(Time shown is NZT)

I first thought that during the day the mppt was pulsing charge, but the above pictures are during the night.

Is the Bluetooth app actually getting the same data but is massively averaged out? Or is the VE.Direct data something different.

The other data from VE.Direct look the same as the APP, like the solar voltage and the current, just this battery voltage is so all over the place.

We've tried replacing the unit and even replace to a different battery make and BMS but are getting the same issue.

MPPT SmartSolar Bluetooth VE.Direct

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Answer 1 · 2023-03-28T00:08:27Z

klim8skeptic answered · Mar 28, 2023 at 12:08 AM

Time periods for the charts are different. Not a valid comparison.

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Answer 2 · 2023-03-28T20:40:15Z

johnnyfp answered · Mar 28, 2023 at 08:40 PM

The graphs are and example of the data got from VE.Direct (IE very spikey up and down) vs the Data shown on the Bluetooth app. If I expand out the app it will be a straight line. But ok, I've included a picture of the same time and it is still vastly different.

Is there a potential difference in the algorithm used by the Bluetooth app vs the VE.Direct data?

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klim8skeptic ♦ commented · Mar 29, 2023 at 08:01 AM

@johnnyfp thanks for the update.

have you measured the battery voltage directly? such voltage dithering would be concerning.

l have a smartsolar mppt and it has never shown such differences between the VC reporting, and reporting via a Venus gx connected via VE direct.

l suspect that you might have a problem with your rs232 adaptor, or perhaps the monitoring device.

measure your battery voltage closely and compare with your recordings.

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