# question

## Grafana + Venus + Reference Points

Hi,

Could someone tell me what the difference is between :

`solarcharger/Pv/I`

and

`system/Dc/Pv/Current`

I am trying to create a panel that displays the sum of the 2 solar chargers. The issue is that "solarcharger/Pv/I" reports correctly for each instance, but the value retrieved for "system/Dc/Pv/Current" is more than double the cumulative value of the solar chargers?

1598095875384.png (57.6 KiB)

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Peter Buijs - NL answered ·

It looks like the 50A is the Total PV Charging current of a 48V system

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I see in the manual the setting I have chosen is correct.

I have 2 solar chargers, each limited to 45A. This value does change based on the PV power generated but is not ever equal to the output of both chargers. I suspect this value is not reporting correctly.

1598173745127.png (4.4 KiB)
1598173812376.png (54.7 KiB)

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I think you might be confusing PV input current (into the solar charger) with system/Dc/Pv/Current - which is the sum of the output/charge current from the solar chargers.

2573W / 47A = 54.7V, which is a realistic battery voltage for a 48V system (you don't show the battery voltage in your Grafana screen image).

The solar chargers convert power between the PV input and charger output - so the voltage decreases and current increases. Power remains constant, apart from conversion losses.

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Thanks Mark. Yes it is a 48V battery system. I see your point. I'll give this some more thought, thank you.

1598248563463.png (62.3 KiB)
1598248739859.png (62.4 KiB)
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No worries...

Double check the path you have linked to North MPPT 'PV I (in)' - in the screen image above it seems like you may have accidentally linked it to system/Dc/Pv/Current since it is showing the same current as 'Total PV Current (out)' and 113V x 9.9A equals alot more than 310W.

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