Some customers notice that their battery still shows a small amount of grid import overnight, even when the battery has charge available and the home is only using a small amount of electricity.
This can look confusing at first. If the battery has energy stored, why is the home still using anything from the grid?
The simple answer is that this can be normal operation for a grid connected battery system.
Your battery is constantly balancing power
A home battery is always trying to balance three things:
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The power your home is using
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The power your battery is supplying
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The connection to the electricity grid
This balancing happens automatically in the background. When your home load is very low, especially overnight, the system may allow a small amount of grid import to help keep everything stable and responsive.
Another reason this can happen is that the household load may be very small. At very low loads, it may not always be efficient or practical for the battery inverter to discharge continuously. In simple terms, the system may decide that drawing a very small amount from the grid is better than cycling the battery for tiny loads.
A good way to think about it is cruise control in a car.
When cruise control is set, the car does not hold the exact same speed every second. It makes small adjustments to keep the drive smooth. A battery system works in a similar way. It constantly adjusts its output, but it may not hold the grid meter at exactly zero at every moment.
Why it is easier to notice at night
This is usually more noticeable overnight because household usage is lower and more stable.
During the day, larger appliances, solar generation, cooking, heating, cooling, hot water or EV charging can hide these small movements.
At night, when the home is mostly idle, even a small grid import can stand out in the app.
Does this mean the battery is faulty?
No. A small overnight grid import does not usually mean your battery is faulty.
In many cases, it is simply the inverter managing very small loads while staying connected to the grid. The system is still designed to prioritise your solar and battery energy where available.
What does it cost?
In most cases, the actual amount of energy involved is small.
Overnight electricity rates are often much lower than peak rates, commonly around 20 c to 25 c per kWh depending on the retailer and plan.
That means a small overnight import is usually a low cost item, even though it may appear clearly in the app.
Final takeaway
A small amount of grid import overnight can be normal behaviour for many grid connected battery systems.
It is part of how the inverter keeps the home, battery and grid connection stable, especially when household usage is very low.
For most households, this does not indicate a system fault. It is simply the battery system making small adjustments in the background while continuing to prioritise stored energy where available.