Battery
A battery represents a home storage system. Power Insight tracks charge and discharge power, which sources charged the battery (grid vs. solar), and the levelized cost of storage. If you have multiple batteries, add one device each.
Add it with Add device → Battery.
Settings
Name
For example "Rooftop" or "Heat pump". Used in the device and sensor names.
Power sensor
Sensor with this device's power in W, kW or MW. Positive = discharging, negative = charging.
Invert power sign
Turn on if your sensor uses the opposite sign.
Exports to the grid
Turn on if this device can export power to the grid.
Default: off for batteries.
Export compensation per kWh
What you are paid per kWh exported to the grid. Required for savings, financial return and export compensation sensors.
Asked for whenever the battery exports to the grid; enter 0 if you are not
paid for it. Both this and Exports to the grid can be changed later under
Reconfigure, and a new rate applies from then on.
Power sources / Charges from
Whole mix — the power comes from all sources in proportion to what they supply.
Specific devices — only from the sources you select below, e.g. a battery that charges from solar only.
The sources this battery charges from. Only used with Specific devices.
This drives the battery's blended charging cost and its charging-source-share sensors. Batteries are never selectable as a charge source for another battery.
The selection describes what you expect your energy manager to do, not a hard
limit. If the battery charges from elsewhere — say it is set to solar only but
tops up from the grid at night — that power is still counted, as coming from
your other sources, and the watts show up in the restriction_deficit
attribute of its operating-cost sensors. See
When a device draws from outside its sources.
When you add or remove a grid or PV device, Power Insight raises a repair issue asking you to reconfigure each battery so its charge-source list stays correct.
Lifetime production / Lifetime cost / CO₂ footprint
These behave exactly as for a PV system. Together, lifetime cost ÷ lifetime throughput gives this battery's LCOS. Changing them later applies a correction factor.
CO₂ footprint has no effect yet — CO₂ sensors are not implemented.
Already accumulated
Optional, in two sections, one per route. Energy (kWh): Charged, Discharged and any grid charging, and optionally its own export to the grid and its own average grid tariff (else the grid's). Amounts: the savings and export compensation your app shows, taken as they are. See Carried-over history.
Sensors
Turn these on in the integration's Options → Battery sensors. The choice applies to every battery, and each one gets its own set of sensors.
Power flow
Where the discharge goes
Splits this battery's discharge by where it goes: your appliances, charging a battery, the idle draw of other energy equipment, or the grid. The ratio sensors give the same split as a percentage of this battery's own discharge — Discharge to grid ratio at 40 % means 40 % of it is exported.
- The grid sensors need Exports to the grid on.
- The batteries sensors only exist when another battery is allowed to charge from this one, which is rare.
| Sensor | Unit | Turn on with |
|---|---|---|
| Discharge to home consumption | W | Power split (W) |
| Discharge to batteries | W | Power split (W) |
| Discharge to system standby | W | Power split (W) |
| Discharge to grid | W | Power split (W) |
| Discharge to home consumption ratio | % | Power split (%) |
| Discharge to batteries ratio | % | Power split (%) |
| Discharge to system standby ratio | % | Power split (%) |
| Discharge to grid ratio | % | Power split (%) |
This battery's share of the home
How much of the whole home's consumption, battery charging, standby and export this battery covers right now. Compare with the ratio sensors above: a ratio divides by this battery's discharge, a share by the home's total.
| Sensor | Unit | Turn on with |
|---|---|---|
| Share of home consumption | % | Share of home totals (%) |
| Share of battery charging | % | Share of home totals (%) |
| Share of system standby | % | Share of home totals (%) |
| Share of grid export | % | Share of home totals (%) |
What charges the battery
One sensor per source the battery may charge from, named after it — for example Charging share from Rooftop. Together they show the current mix, such as 70 % solar and 30 % grid. With Power sources set to Specific devices, only the sources you selected get a sensor.
| Sensor | Unit | Turn on with |
|---|---|---|
| Charging share from <source> | % | Charging sources (%) |
Cost, savings and earnings
Every money sensor comes in two flavours, chosen per section in the options:
- Standard values electricity at your live grid price; your own stored solar power counts as free.
- Levelized also counts what your hardware cost, spread over every kWh it delivers (LCOS, see How it works). Needs Lifetime production and Lifetime cost.
Each sensor ending in rate is money per hour right now; the matching Total adds it up and keeps counting across restarts.
Operating cost
What charging the battery costs: grid power at the grid price, solar power for free (Standard) or at the PV system's LCOE (Levelized). Its standby draw is included.
| Sensor | Unit | Turn on with |
|---|---|---|
| Operating cost rate | EUR/h | Cost method: Standard |
| Levelized operating cost rate | EUR/h | Cost method: Levelized |
| Total operating cost | EUR | Total costs |
| Total levelized operating cost | EUR | Total costs + Levelized |
Avoided cost
What this battery's power kept off your grid bill: the power it put into your home, valued at the grid price. This is the saving before its own operating cost is taken off.
| Sensor | Unit | Turn on with |
|---|---|---|
| Avoided cost rate | EUR/h | Savings method: Standard |
| Total avoided cost | EUR | Total savings |
Cost savings
The net saving: avoided cost minus operating cost. The levelized variant also subtracts the battery's LCOS, so it shows whether the hardware pays off. Export earnings are not included — see Financial return.
It goes negative while the battery charges from the grid and positive while it discharges — that is expected.
| Sensor | Unit | Turn on with |
|---|---|---|
| Cost savings rate | EUR/h | Savings method: Standard |
| Levelized cost savings rate | EUR/h | Savings method: Levelized |
| Total cost savings | EUR | Total savings |
| Total levelized cost savings | EUR | Total savings + Levelized |
Export compensation
What this battery earns by exporting, at its Export compensation per kWh.
| Sensor | Unit | Turn on with |
|---|---|---|
| Export compensation rate | EUR/h | Export compensation rate |
| Total export compensation | EUR | Total export compensation |
Only when Exports to the grid is on.
Financial return
Everything this battery brings in: cost savings plus export compensation. The levelized variant also counts what producing the exported energy cost, so it can be lower than the levelized savings while you export for less than the LCOS. See Why is my levelized financial return lower…
| Sensor | Unit | Turn on with |
|---|---|---|
| Financial return rate | EUR/h | Financial return method: Standard |
| Levelized financial return rate | EUR/h | Financial return method: Levelized |
| Total financial return | EUR | Total financial return |
| Total levelized financial return | EUR | Total financial return + Levelized |
Only when Exports to the grid is on.
Levelized sensors are only created once Lifetime production and Lifetime cost are filled in on this device's Reconfigure page.
Reading the battery's totals
A battery does not produce energy. It buys energy when it charges and replaces grid energy when it discharges, and its totals split those two sides up:
| Total | What it adds up | Counts up when |
|---|---|---|
| Total operating cost | What charging cost: grid energy at the grid price; energy from your PV systems counts as free | charging from the grid |
| Total levelized operating cost | The same, with PV energy priced at that PV system's LCOE, its lifetime cost per kWh | charging from anything |
| Total cost savings | Grid electricity it replaced (discharge into the home × grid price), minus the operating cost | discharging; it goes down while charging from the grid |
| Total financial return | Savings plus what exports earn, if the battery may export to the grid | discharging, and exporting |
- The operating cost is already inside the savings. Do not subtract it again: the savings are the battery's net result, what discharging saved minus what charging cost.
- Charging from PV is free in the standard totals and costs the LCOE in the levelized ones. A battery charged only from PV has a Total operating cost near 0 but a real Total levelized operating cost: what the PV energy it stored cost to produce.
- Financial return equals savings for most batteries. It only adds export compensation, and a battery that may not export to the grid earns none.
- The battery's own lifetime cost (its LCOS) is in neither operating cost. It is charged when energy leaves the battery, so it lowers the levelized savings and levelized financial return instead.
Example. The battery charged 2,500 kWh from PV and discharged 2,200 kWh into the home; a kWh from the grid costs 0.34, the PV system's LCOE is 0.10 and the battery's LCOS 0.15.
| Total | Calculation | Value |
|---|---|---|
| Total operating cost | 0 kWh from the grid × 0.34 | 0.00 |
| Total levelized operating cost | 2,500 kWh × 0.10 | 250.00 |
| Total cost savings | 2,200 × 0.34 − 0 | 748.00 |
| Total financial return | 748 + 0 export | 748.00 |
| Total levelized cost savings | 748 − 2,200 × 0.15 (LCOS) − 250 (PV energy at its LCOE) | 168.00 |
Had 500 of the 2,500 kWh come from the grid instead, the operating cost would be 500 × 0.34 = 170.00, and the savings 170.00 lower: 578.00.
Because some of its draw did come from the grid, as far as the meters can tell. Whenever the battery's power sensor shows it drawing power and the PV systems it may charge from produce nothing — at night, for example — that draw can only have come from the grid, and it is booked at the grid price. Small amounts like this usually come from the battery's own consumption (its battery management and inverter in standby), or from short top-ups by its energy manager.
If the battery is set to Specific devices, its Operating cost rate
shows the watts drawn from outside its sources in the restriction_deficit
attribute. The Total operating cost attributes show whether any of the
total was carried over from your app (carried_over) or counted by Power
Insight (tracked): carried-over history only adds operating cost for what
you entered under Of which from the grid.