question

raymiller avatar image
raymiller asked

VRM Dashboard- secondary Battery Monitor BMV Widget Displays: NaN:NaN

In the VRM Dashboard, I have three widgets activated to monitor the system voltage. The BMS on the Pylontech UP2500 takes the prime spot with the BMV712 monitor has the bottom panel, it displays this message "NaN:NaN" not sure what this is supposed to mean?

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VRM
1633206734922.png (52.6 KiB)
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6 Answers
Sebastiaan Adamo avatar image
Sebastiaan Adamo answered ·

Same issue here with the BMV-700 running on VenusOS v2.84:victron-nan-bmv.png


victron-nan-bmv.png (21.0 KiB)
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cotje avatar image
cotje answered ·

Same here... and I think it should display the Time-to-go. Guess we are missing a setting or state for this to happen. Not sure which though!

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jeroen-kuijf avatar image
jeroen-kuijf answered ·

Good morning,

I have 3 BMVs, 2 a with victron direct cable and 1 with an usb to a Cerbo.

The 2 with the direct cable show this message (NaN:NaN) on VRM, the usb one shows just charging/discharging and time to go.

Quite annoying as the text is constant moving when consumption and solar are almost equal.

I hope they can solve this one day, as it is like this already some years now.

Regards, Jeroen Kuijf.

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Alex Pescaru avatar image
Alex Pescaru answered ·

Probably a variable that is missing or not properly collected and when sent to VRM and computing that field, the resulting value is out of range.

NaN (Not a Number) is the result of an operation that was supposed to return a number, but couldn't because of an error or undefined/empty value.

Could also be a divide by zero error...

Alex

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jeroen-kuijf avatar image
jeroen-kuijf answered ·

Good evening,

A couple of days ago we got a VRM software update, still the same, Aaargghhh.

The same as the 49.9-50.1Hz switching indication and never showing 50.0Hz, but that is already in the BUS to the GX, other topic.

What to do?

Greetz, Jeroen.

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dognose avatar image
dognose answered ·

NaN means "Not a Number" and typically is the result of some code dividing "null" (not to confuse with 0) through anything.

(Divisions by zero would result in +inf)

I think it should display "hours:minutes" (time-to-go) there, which means the equation is "remaining_capacity / discharge", where remaining capacity is typically total_capacity * soc.

So, big chance, that the capacity can't be read from the bms, hence that value is null, causing the computation of NaN values. My Pylontech is displayed as 70Ah, but I remember that I entered that value somewhere during the setup process (of the inverter). So not sure, if the BMS is supposed to report that on it's own at all.

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