Why does the battery drain when the house or business appears switched off?

What you will see

• Battery percentage falls overnight while everyone is asleep.
• A closed shop or office still shows a small load.
• Charge drops even though the main appliances are off.
• The displayed percentage changes suddenly without an obvious matching load.

Why it happens

Some electronics consume standby power when they appear switched off. Routers, security equipment and other devices may also remain deliberately active. Automatic appliances, including refrigeration and pumps, should be included when describing what was left running.

The solar equipment itself uses energy. Solis documents that inverter and battery-management consumption can continue when a battery seems idle. The amount and source of that consumption depend on the equipment and operating state, so there is no universal “normal overnight percentage drop.”

A percentage change is not always a direct measurement of energy delivered to appliances. State of charge is estimated, and some systems correct that estimate as they obtain better information about the battery.

That is why the timeline matters. A gradual decline accompanied by recorded discharge should be investigated differently from a sudden percentage jump. Describe the observed pattern without assuming either one proves a defective battery.

Diagram

What is still running

Wi-Fi routerCCTVRefrigeratorAutomatic pumpStandby electronicsInverter and BMS’s own use

Gradual decline, discharge recorded

Real energy use. Find the loads.

Sudden jump, no matching load

Often a correction to the charge estimate. Keep the timeline.

What you can check yourself

• List equipment left connected overnight, including CCTV, internet devices, refrigeration and automatic pumps.
• Record the starting and morning battery readings with their timestamps.
• Save battery-discharge and property-load graphs covering the same period.
• Note whether the grid was available and whether a timed discharge period was active.
• If safe, turn off nonessential devices using their normal controls and record the effect on the displayed load.
• Do not interrupt security, refrigeration, medical or other essential equipment just to make the reading reach zero. Tell us which loads must remain running.

What not to do

• Do not disconnect battery cables, operate unidentified breakers or open a distribution board to hunt for a hidden load.
• Do not repeatedly reset the battery percentage or change its capacity setting.

When to call us

• Contact us if the decline is unusually large compared with previous similar nights, displayed load remains unexplained, or abrupt charge changes repeat. A review can separate appliance consumption, system consumption and reporting behaviour.

Overnight checks in Faisalabad and Lahore

Shops and offices in Faisalabad and Lahore often leave CCTV, routers and refrigeration running overnight. Tell us which loads must stay on, and our team will separate them from system use and reporting.

Send us

The inverter and battery models, overnight graphs, devices left running, grid-availability details, and your city and area.