ShiftCharge.ioLearn · 9 May 2026
Should I charge my home battery overnight?
When overnight charging is the right call, when it costs you money, and how a smart-tariff planner picks for you.
Join the betaIt sounds obvious — electricity is cheaper at night, fill the battery overnight. The reality is more nuanced, especially if you have solar or are on a half-hourly tariff like Octopus Agile.
The simple answer
On a flat overnight rate (Octopus Go, Intelligent Octopus) and no solar, charging overnight to cover the next day is almost always the right move.
On Agile, on Cosy, or with significant solar, "always overnight" is the wrong rule and will cost you money on bright days or when off-peak prices spike.
When overnight loses money
On Agile, some nights are not the cheapest part of the day — the cheapest hour can be early afternoon when wind generation is high.
On a sunny forecast, charging overnight wastes capacity that solar would have filled for free.
How to decide each day
Look at tomorrow’s prices, the solar forecast, and your typical demand shape, then ask: what is the cheapest combination of import slots that covers the day?
A battery scheduler does this every evening once Agile prices publish so you do not have to.
Common questions
- Is it bad for the battery to skip an overnight charge?
- No. Modern lithium batteries are happy at any state of charge. Cycling the battery less when you do not need to is, if anything, gentler on it.
- Should I top up overnight in winter even if Agile prices are middling?
- Often yes. Solar in winter is small enough that you cannot rely on it to refill the battery, so a partial overnight charge to cover the morning peak is usually the right call.
Want this running in your home?
ShiftCharge is in private beta. Join the waitlist and we will reach out when there is a slot open for your hardware and tariff.
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