Your first bill after the battery: what to check

Verified 16 October 2026

A battery changes what shows up on your bill. Some lines shrink, some stay exactly the same, and a few can look odd in the first month. Here is what to look at.

Start with the dates

Look at the billing period at the top. If the battery went in part way through, that bill is a mix of before and after. It won't show what a normal month looks like now. Wait for the first bill that falls fully after the install.

The lines to read

• Supply charge. A fixed amount per day for being connected. A battery doesn't change it. If it didn't move, nothing is wrong.
• Usage, by time band. This is the power you bought from the grid. Plans with peak, shoulder and off-peak bands show a line for each. After a battery, expect the peak line, usually the evening, to fall the most.
• Controlled load. If you have a separate hot water circuit, it appears on its own line. The battery doesn't usually touch it.
• Feed-in credit. The kWh you sent to the grid, and the rate per kWh. The battery fills first, so the kWh figure is often lower than before. That is the battery doing its job.
• Any credit from a virtual power plant (VPP). If you joined a VPP program, the credit may show as its own line or arrive on a later bill. If you expected one and can't find it, ask your retailer when it will appear.
• Discounts and fees. Check that any sign-up discount or credit you were promised is still being applied.

Common surprises

• The bill is not zero. A battery lowers what you buy. It rarely removes it, and you still pay the daily supply charge.
• You bought more in some hours. If your battery charges from the grid overnight, or in free hours, you will see more power bought at those times. Check the rate for those hours. It should be one of your cheapest.
• Exports dropped and the feed-in credit shrank. Expected, as above. Look at the total bill rather than that one line.
• The season is different. A winter bill set against last summer's tells you very little. Compare like with like where you can.
• An estimated reading. Look for the word estimated next to the meter reads. The next actual read corrects an estimate.

Write down five numbers

Keep these from each bill so you can compare later: the billing dates, the kWh you bought from the grid, the kWh you sent out, the daily supply charge, and the rates on your plan.

When to check again

• After your first full bill that falls entirely after the install.
• When the seasons change. A battery behaves very differently in January and July.
• When your retailer tells you prices or plan terms are changing.

Is this still the right plan?

The plan that fitted your home before the battery may not fit it now. Here is how to tell. PowerLens reads a recent bill and says Stay or Switch, and checking is free. If you want the half-hourly picture too, add your meter data file (NEM12) later. Where to get it.

Watch is optional. Each month it checks the plans on offer against your saved usage and emails you when the answer changes. See what it costs.