Autonomie de la batterie domestique : votre batterie peut-elle alimenter la maison toute la nuit ?

Home battery runtime depends on how much usable energy you have and what you run. A battery may keep the fridge, lights and Wi-Fi going until morning. Add electric heating or hours of air conditioning, and the calculation changes quickly.

So, can a home battery power your house overnight? Yes, with enough stored energy and a suitable system. But “overnight” might mean eight quiet hours in one home and twelve busy hours in another.

Here are five checks to help you choose.

1. Start With Your Evening Electricity Use

Before comparing batteries, check your smart meter or monitoring app. Look at consumption between sunset and the following morning across several representative days.

Monthly totals won’t show when you use electricity. Include weekends and colder or hotter periods, when heating and cooling may change the picture.

If you don’t have detailed readings, list the appliances you expect to use. This example covers a few essentials:

These are calculation assumptions, not measured household averages. Cooking, heating, cooling, hot water and other appliances are excluded.

For a refrigerator, use measured energy consumption or an estimate from its energy label. Its compressor switches on and off, so multiplying its running wattage by the whole night can overstate consumption. The US Department of Energy’s appliance guide explains how energy labels help compare appliance use.

2. Calculate Home Battery Runtime From Available Energy

The basic calculation is:

Runtime in hours = energy available to appliances in kWh ÷ average load in kW.

The important part is “available to appliances.”

Nominal capacity is the battery’s rated energy. Manufacturer operating limits, your starting charge, backup reserve and inverter losses affect how much you can use.

For illustration, assume 80% of nominal energy is available for the overnight period and conversion efficiency is 90%:

These are mathematical examples, not Fench Energy test results. They assume no recharging and do not separately account for inverter standby consumption. Temperature, ageing and changing loads also affect results.

If a specification already provides usable energy, don’t deduct the same operating allowance again.

Notre home battery sizing guide explains how to turn your appliance list into a capacity estimate.

3. Check the Appliances That Change the Answer

The refrigerator usually isn’t the whole story.

An appliance averaging 1kW for eight hours uses 8kWh. That single load could outweigh all the essentials in the first table several times over.

Air conditioners and heat pumps vary with weather, settings and building conditions. Measure their consumption where possible instead of assuming they draw their rated input continuously.

Power matters too. kWh describes stored energy; kW describes how much power the system can supply at once.

A larger battery does not automatically mean you can run the oven, kettle and air conditioner together. Check the inverter’s continuous output, appliance starting requirements and battery discharge limits.

A full battery is little comfort if the system cannot support the appliances you switch on.

4. Decide Whether 5kWh or 16kWh Fits Your Routine

A 5kWh-class battery may suit modest evening demand or selected essential loads. A 16kWh-class battery is worth evaluating when you need more overnight energy or a longer backup period.

Fench Energy offers a 5.12kWh wall-mounted battery and a 16kWh range shown in its home storage selection. Compare the exact model’s usable capacity, output limits, installation requirements and documentation.

Also consider how you will refill it. A large battery helps less if your solar system rarely produces enough surplus to charge it. Grid charging may be another option where equipment settings and electricity tariffs support it.

If you’re considering the smaller option, our 5kWh home battery guide covers the main buying checks.

5. Confirm What Happens During a Power Cut

Using stored energy at night and supplying backup during an outage are different capabilities.

Some installations reduce evening grid purchases but do not keep appliances running when the grid fails. Backup may require suitable switching equipment, a dedicated inverter output and selected household circuits.

Ask your installer which appliances will remain powered and whether solar can recharge the battery during an outage. Energy Saving Trust’s battery storage guide provides useful background on storage and backup considerations.

Before ordering, contact Fench Energy with your inverter model, country and overnight electricity use—or a list of essential appliances. Request suitable product specifications and compatibility confirmation, then have a qualified local installer check the complete system.

Home battery runtime depends on how much usable energy you have and what you run. A battery may keep the fridge, lights and Wi-Fi going until morning. Add electric heating or hours of air conditioning, and the calculation changes quickly.

So, can a home battery power your house overnight? Yes, with enough stored energy and a suitable system. But “overnight” might mean eight quiet hours in one home and twelve busy hours in another.

Here are five checks to help you choose.

1. Start With Your Evening Electricity Use

Before comparing batteries, check your smart meter or monitoring app. Look at consumption between sunset and the following morning across several representative days.

Monthly totals won’t show when you use electricity. Include weekends and colder or hotter periods, when heating and cooling may change the picture.

If you don’t have detailed readings, list the appliances you expect to use. This example covers a few essentials:

These are calculation assumptions, not measured household averages. Cooking, heating, cooling, hot water and other appliances are excluded.

For a refrigerator, use measured energy consumption or an estimate from its energy label. Its compressor switches on and off, so multiplying its running wattage by the whole night can overstate consumption. The US Department of Energy’s appliance guide explains how energy labels help compare appliance use.

2. Calculate Home Battery Runtime From Available Energy

The basic calculation is:

Runtime in hours = energy available to appliances in kWh ÷ average load in kW.

The important part is “available to appliances.”

Nominal capacity is the battery’s rated energy. Manufacturer operating limits, your starting charge, backup reserve and inverter losses affect how much you can use.

For illustration, assume 80% of nominal energy is available for the overnight period and conversion efficiency is 90%:

These are mathematical examples, not Fench Energy test results. They assume no recharging and do not separately account for inverter standby consumption. Temperature, ageing and changing loads also affect results.

If a specification already provides usable energy, don’t deduct the same operating allowance again.

Notre home battery sizing guide explains how to turn your appliance list into a capacity estimate.

3. Check the Appliances That Change the Answer

The refrigerator usually isn’t the whole story.

An appliance averaging 1kW for eight hours uses 8kWh. That single load could outweigh all the essentials in the first table several times over.

Air conditioners and heat pumps vary with weather, settings and building conditions. Measure their consumption where possible instead of assuming they draw their rated input continuously.

Power matters too. kWh describes stored energy; kW describes how much power the system can supply at once.

A larger battery does not automatically mean you can run the oven, kettle and air conditioner together. Check the inverter’s continuous output, appliance starting requirements and battery discharge limits.

A full battery is little comfort if the system cannot support the appliances you switch on.

4. Decide Whether 5kWh or 16kWh Fits Your Routine

A 5kWh-class battery may suit modest evening demand or selected essential loads. A 16kWh-class battery is worth evaluating when you need more overnight energy or a longer backup period.

Fench Energy offers a 5.12kWh wall-mounted battery and a 16kWh range shown in its home storage selection. Compare the exact model’s usable capacity, output limits, installation requirements and documentation.

Also consider how you will refill it. A large battery helps less if your solar system rarely produces enough surplus to charge it. Grid charging may be another option where equipment settings and electricity tariffs support it.

If you’re considering the smaller option, our 5kWh home battery guide covers the main buying checks.

5. Confirm What Happens During a Power Cut

Using stored energy at night and supplying backup during an outage are different capabilities.

Some installations reduce evening grid purchases but do not keep appliances running when the grid fails. Backup may require suitable switching equipment, a dedicated inverter output and selected household circuits.

Ask your installer which appliances will remain powered and whether solar can recharge the battery during an outage. Energy Saving Trust’s battery storage guide provides useful background on storage and backup considerations.

Before ordering, contact Fench Energy with your inverter model, country and overnight electricity use—or a list of essential appliances. Request suitable product specifications and compatibility confirmation, then have a qualified local installer check the complete system.