 # Queries for calculate the energy with integral function

Hi all!
I’m a newbie of influxdb, and start to test influxDB with Grafana (latest version of both).
I’ve a data series of instant DC power (Watt) that flow in a rechargeable battery.
The power has positive value when battery discharge and negative value when battery charge.

I want to calculate the energy (Watt hour) for charge and discharge phase.

For do this, I’ve used the integral function using clause WHERE, and create these 2 queries in Grafana:

_cumulative_sum(integral(“value”)) / 3600 FROM “Battery_Power” WHERE (“value” > 1 ) AND timeFilter GROUP BY time(_interval)

_SELECT cumulative_sum(integral(“value”)) / 3600 FROM " Battery_Power " WHERE (“value” < 1) AND timeFilter GROUP BY time(_interval)

Often the query work fine, and show a chart as I expected, other times, on chart I not see a data of integral, but the value seem have an offset.
Someone has same issue, or I’ve completely wrong my query syntax?
Thank you!

Hi, not sure if you solved this issue, but another attempt would it be to create sub-queries. I’m currently measuring the current power of an UPS, but if I want to have Wh, I need to first sum the instantaneous value for each phase, and then get an average estimate for that stream of data. Below a query with an example:

`SELECT mean("sum_xupsOutputWatts") FROM (SELECT sum("xupsOutputWatts") AS "sum_xupsOutputWatts" FROM "telegraf"."autogen"."xupsOutputTable" WHERE time > now() - 1h AND ("xupsOutputPhase"='1' OR "xupsOutputPhase"='2' OR "xupsOutputPhase"='3') GROUP BY time(:interval:) FILL(null))`