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How Much Battery Do I Need for My Brisbane Home?

Author : Andrew Colley | Published On : 25 Feb 2026

You've sorted your solar panels and now you're looking at batteries wondering if 10kWh is enough or if you need something bigger. Every Brisbane solar expert gives different advice, and battery quotes range from $11,000 to $18,000 without clear explanations of what size actually makes sense for your home.

Here's what matters. Your evening electricity use between 5pm and midnight determines battery size, not your total daily consumption. Most Brisbane families run 8-15kWh during those peak hours, and that number tells you whether you need a 10kWh battery or something larger. Get it wrong and you'll either overspend on unused capacity or keep buying grid power every night.

We've been installing batteries across Brisbane since 2018 with top solar installers Brisbane, and the pattern is clear. A 10kWh battery suits most homes perfectly, while 13.5kWh batteries work for larger families or those planning electric vehicle additions. Anything bigger only makes sense for specific situations most households don't actually have.

 

Understanding Battery Sizing for Brisbane Homes

Battery sizing isn't about storing your entire daily electricity use. It's about covering the gap between when solar stops producing and when you go to bed, plus overnight essentials.

Your solar panels generate power roughly 5am to 7pm in Brisbane, with peak production 9am to 3pm. Most families use minimal power during those peak hours while solar pumps excess into the battery. Then everyone comes home around 5pm, and electricity demand spikes just as solar production drops.

That 5pm to midnight window determines your battery size. If you're running 10kWh during those hours, you need a battery with 10kWh usable capacity. Solar power providers Brisbane often recommend batteries based on total daily use, but that creates oversized systems because it ignores consumption timing.

Depth of discharge affects usable capacity. Modern lithium batteries discharge to 10% remaining charge safely, giving 90% usable capacity. A 10kWh battery delivers 9kWh actual storage, while a 13.5kWh battery provides 12.2kWh usable. Budget for usable capacity when sizing, not the headline rating manufacturers advertise.

Brisbane's consistent solar resource helps battery sizing work better than southern states. You'll get reliable solar charging most days, even in winter when production drops to 60-70% of summer output. This consistency means you can size batteries tighter to actual needs without worrying about cloudy days.

How to Calculate Your Evening Electricity Use

Grab your last three electricity bills and find your daily average consumption. Most Brisbane households sit between 15-30kWh daily depending on home size and appliance use. That total doesn't tell you what battery you need, but it's the starting point.

Check your smart meter data through your electricity retailer's portal. Most Queensland suppliers provide hourly usage graphs showing exactly when you consume power. Look for your typical 5pm-midnight usage over a week that's your target battery capacity.

No smart meter data? Estimate based on appliances you run between 5pm and midnight:

  • Air conditioning (cooling): 1.5-3kWh per hour

  • Cooking (electric stove/oven): 2-4kWh for dinner

  • Hot water (electric): 2-3kWh for evening showers

  • TV and entertainment: 0.3-0.5kWh per hour

  • Dishwasher cycle: 1.2-1.8kWh

Add up what you typically run 5pm to midnight. Most families hit 8-14kWh during this window. Brisbane solar installers recommend measuring across a full week including weekends when usage patterns differ from weekdays.

Consider seasonal variation too. Winter usage drops 20-30% because air conditioning demand falls. Summer evenings spike higher with cooling loads. Size for summer patterns if you want year-round coverage, or accept some grid power on peak summer evenings.

Battery Sizes: What Works for Brisbane Solar Installers

10 kWh Batteries (9 kWh usable) -

This size suits couples, small families, or energy-efficient homes using 15-22 kWh daily. You'll cover evening cooking, lighting, air conditioning for 3-4 hours, entertainment, and overnight baseline loads. Total coverage: 9-14 kWh.

This battery fully charges from a 6.6kW solar system by 2pm on most days. You'll still use some grid power if you run a dryer or extended air conditioning on hot nights. Cost installed: $11,000-$13,500.

13.5 kWh Batteries (12.2 kWh usable) 

This capacity suits larger families, homes with pools, or properties planning electric vehicle charging. You'll cover extended cooking, air conditioning for 5-6 hours, pool pumps, standard entertainment, and overnight loads with reserve capacity. Total coverage: 14-21 kWh.

Pair this with an 8-10 kW solar system for adequate daytime charging. Cost installed: $14,000-$17,500. This size makes sense for homes using 25-35 kWh daily, where evening consumption regularly hits 12-16 kWh.

15-20 kWh Batteries

Large capacity batteries suit specific situations: electric vehicle charging overnight (8-12 kWh), commercial or home office loads, backup power for rural properties. Cost: $18,000-$26,000 installed. Most Brisbane homes don't need this much storage unless running significant equipment or multiple EVs.

When to Choose Bigger Batteries

A 13.5 kWh battery costs $3,000-$4,000 more than 10 kWh. That extra storage saves you $1.05 daily or $383 annually at Brisbane electricity rates. Payback on the upgrade takes 9-10 years, and you won't achieve full payback before the 10-year warranty expires.

Go bigger when:

  • You own or plan to buy an electric vehicle within 2-3 years

  • Your evening usage regularly exceeds 12kWh (verified by smart meter data)

  • You're adding a pool, upgrading to ducted air conditioning, or converting to electric hot water soon

  • You work from home with heavy daytime loads reducing solar available for battery charging

Affordable solar systems Brisbane now include battery-ready configurations where solar is sized for future battery addition without installing batteries yet. This lets you start with solar, see actual consumption patterns, then add the right-sized battery based on real data.

Conclusion

Battery sizing for Brisbane homes centres on one measurement: electricity use between 5pm and midnight. Most households run 8-15kWh during peak evening hours, making 10kWh batteries the practical choice for typical families and 13.5kWh suitable for larger homes or electric vehicle owners.

The decision requires measuring real consumption patterns using smart meter data showing exactly when you use power. We've been working with commercial solar installation Brisbane projects and residential systems since 2010, and we've seen that accurate sizing beats guesswork every time. The right battery size for your home depends on your specific evening loads, not generic estimates based on house size.

Want accurate battery sizing for your Brisbane home? Book a free energy assessment where we'll review your smart meter data, analyse evening consumption patterns, and recommend the right capacity for your actual needs. Contact Halcol Energy or book online. Our Brisbane solar experts provide honest advice about what size makes financial sense for your household's usage patterns.

FAQs

Q1: What size battery does a typical Brisbane home need?

Most Brisbane homes need a 10kWh battery providing 9kWh usable storage to cover evening electricity use of 8-12kWh between 5pm and midnight. This suits families using 20-25kWh daily with standard appliances. Homes using 25-35kWh daily need 13.5kWh batteries. Battery sizing depends on evening consumption specifically, not total daily usage.

Q2: How do I know what battery capacity I need?

Calculate battery capacity by measuring electricity use from 5pm to midnight using smart meter data from your retailer's portal or by adding up evening appliance consumption. Brisbane homes average 8-15kWh during this window. Add 10% buffer and choose a battery with that usable capacity. For example, 12kWh evening use requires 13.2kWh minimum, pointing toward a 13.5kWh battery.

Q3: Is a 10kWh battery enough for a 4-bedroom house in Brisbane?

A 10kWh battery suits most 4-bedroom Brisbane homes using 20-25kWh daily with typical loads. This covers evening consumption of 8-12kWh from 5pm-midnight for families of 3-5 people. Larger families running extended air conditioning or pool equipment need 13.5kWh batteries. Bedroom count matters less than actual evening usage patterns.

Q4: Can I add more battery capacity later?

Adding capacity later depends on your system. Modular batteries like Sonnen Eco allow expansion by adding modules. Tesla Powerwall requires installing complete additional units. Solar power installation Brisbane experts recommend planning for future expansion when initially installing use inverter capacity for larger banks but start smaller, then expand when needs clarify.

Q5: What battery size works with a 6.6kW solar system?

A 6.6kW solar system in Brisbane produces 24-28kWh daily in summer, supporting a 10kWh battery comfortably with excess solar for daytime use. This combination suits most homes using 20-25kWh daily. Larger 13.5kWh batteries require 8kW solar systems minimum for reliable charging, especially in winter.