question

Bonhardt László avatar image
Bonhardt László asked

VRM battery SOC percentage precision.

My VRM dashboard battery percentage only updates at full numbers example "50.0 to 51.0.. 52.0"

in the past i used victron shunt and it updated fine like i had all the precision 50.0 to 50.1 .. 50.2

now the Lynx Shunt i use at the moment seems only reports full numbers to VRM , however in the Victron phone app at the settings where i can set "state of charge" value i can see the correct number with correct scale "50.4%"

Is there a way to fix this so the VRM soc percentage is updated with the correct precision number?

VRMlynx shunt
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JohnC avatar image
JohnC answered ·

Hi @Bonhardt László

I agree with you that SOC should be reported to one decimal point (great for tuning and seeing trends). There's nothing (that I know of) we endusers can adjust to change what we receive in that regard. But your experience is different to mine. I get 1dp on VRM dashboard and hovering on a widget. All good, but Victron Connect has the digits & graphs taking the full digit steps, and that's a stepdown for the graphs, which used to show to 1dp.

I think Victron need to take a closer look at this, not just SOC, but eg. Amps too, which show on VRM to 2dp, but mostly with a lazy zero on the end. Consistency across all the reporting platforms would be a better experience.

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nickdb avatar image nickdb ♦♦ commented ·
With CAN batteries, after some sniffing, I found the SOC broadcast includes a more granular SOC which seems to be ignored by the GX, and thus VRM.

Having created a flow with node red, I was able to display this instead on a node red dashboard. It would be nice, for supported batteries, if we could see 1 decimal point.

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Bonhardt László avatar image Bonhardt László nickdb ♦♦ commented ·

I dig more into this today and found a solution, since the Lynx Shunt is "dumb" after checking the can communication it does not report precise SOC, but it does report a precise consumed amphours number, so instead of working with the reported SOC, modified the batterysoc.py to calculate the SOC based on my capacity / consumedamphours
so now I am able to report a precise number to the VRM :)
1684171540377.png

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1684171540377.png (8.9 KiB)
JohnC avatar image JohnC ♦ Bonhardt László commented ·
@Bonhardt László

If you're using a Peukert Exponent of other than 1.00, then you'd need to allow for that too.

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