A commercial battery only pays its way when it is sized to your data and controlled for your tariff. Use these questions to test supplier proposals on demand data, control strategy, incentives, warranty, siting and monitoring. A commercial battery can cut demand charges, store surplus solar for evening trading and keep critical loads running during an outage, but only if the proposal is built on your real usage data and a clear control strategy. The quickest way to separate a well-designed proposal from a sales pitch is to ask specific questions and expect specific written answers. Put the questions below to every supplier and compare their answers side by side.
Questions about your data and the business case
Business bills often include charges that household bills don't, such as demand charges based on your highest usage in a single half-hour. A battery's value depends on which of those charges it can reduce. Ask:
- What data did you use? Expect 12 months of 15 or 30-minute interval data, not a single bill.
- Which charges will the battery reduce? Demand charges, peak usage charges or both, and by how much in each month.
- How big and how long are our peaks? A short spike needs power (kW); a long peak needs energy (kWh). Sizing for one and not the other is a common flaw.
- What happens on the worst day? One missed peak can set a monthly demand charge, so ask how the design copes with several hot days in a row.
- What are the savings with and without incentives? The project should still make sense if incentive values move before installation.
- What is the payback in a conservative case? Ask to see the assumptions, including tariff changes and battery degradation.
If a supplier can't show you the half-hours that set your demand charge, the savings estimate is a guess.
Questions about control strategy
Two identical batteries can deliver very different savings depending on how they are programmed. Ask the supplier to explain in plain English:
- whether the battery prioritises peak shaving, solar shifting or a backup reserve, and how it switches between them;
- how it predicts peaks, for example from schedules, weather forecasts or learned patterns;
- how much capacity is held back for outages, and whether you can change it;
- whether it can join a virtual power plant or demand response program, and how that interacts with peak shaving;
- who can change the settings, and whether updates are included after installation.
A battery that discharges for a grid program just before your own site peak can cost more than it earns, so the priorities must be written down.
Questions about incentives
From 1 September 2026, NSW offers incentives for eligible business batteries, from 20 kWh up to large commercial and industrial scale. NSW indicates the incentive can be around 30-40% of battery installation cost for eligible combined solar-and-battery installations, depending on circumstances, with the value set by the certificate market. Ask:
- Are our site and the proposed battery eligible, and what does eligibility depend on?
- What incentive value have you assumed, and is it shown separately from the price?
- Who handles the paperwork and certificate process?
- What happens to our price if the certificate value changes before installation?
- Would adding or expanding solar at the same time change eligibility or value?
Confirm the current rules on the NSW Government business energy page before signing, and read our overview of NSW incentives for background.
Questions about warranty and lifetime
| Ask about | What a clear answer looks like |
|---|---|
| Warranty length | A number of years, plus any energy throughput or cycle limit that can end it sooner |
| Retained capacity | The percentage of original capacity the manufacturer commits to at the end of the warranty |
| Operating conditions | Temperature range, ventilation and use patterns that keep the warranty valid |
| Claims process | Who you claim through and what local support exists |
| Inverters and power electronics | Their warranty terms, if different from the battery modules |
| Workmanship | The installer's own warranty on the installation work |
Peak shaving can cycle a battery harder than household use, so check that the warranty's throughput limit suits the proposed control strategy. Our warranty guide explains the difference between product, performance and workmanship cover.
Questions about fire safety and siting
Battery location is a safety decision, not just a space decision. Requirements depend on battery size, chemistry, building type and the relevant Australian Standards, and larger systems can involve fire engineering or fire authority input. Ask:
- Where will the battery go, and why does that location comply?
- What clearances, ventilation and barriers are required, including protection from vehicle impact?
- Does the location keep exits and escape routes clear?
- What is the battery chemistry, such as LFP, and which safety certifications does the product hold?
- Will an outdoor cabinet, enclosure or fire-rated room be needed, and is it priced?
- Are signage, emergency shutdown procedures and site documentation included?
Design and installation must be carried out by accredited installers and licensed electricians. Check each supplier's credentials with our installer vetting guide.
Questions about monitoring and reporting
- Will we see site demand, battery state of charge and solar output in real time?
- Does the system send alerts for faults or missed peaks?
- Will we receive monthly reports showing the demand charges avoided?
- Who owns the monitoring account and data if we change service provider?
Reporting is how you check the savings promised in the proposal, so make it part of the contract rather than an optional extra.
Red flags in a battery proposal
- Savings based on an average day, with no mention of the monthly peak that sets your demand charge.
- A battery size chosen to maximise the incentive rather than to match your load profile.
- No written control strategy, or settings that only the supplier can see.
- Siting, enclosure or switchboard work listed as "to be confirmed" with no allowance in the price.
- Pressure to sign quickly because an incentive is "about to end", without evidence from the official source.
None of these automatically rules a supplier out, but each deserves a clear written answer before you commit.
Next steps
Collect your interval data and bills before requesting proposals, so every supplier works from the same numbers. For a proposal for your site, request a free assessment from Blue Energy Solar. The energy market lists a Commercial Battery (BESS) 20-200 kWh from $24,900 for a 20 kWh system installed before incentives, a Demand-Charge Analysis from $690 and a Peak Shaving System from $14,900. These prices are indicative and are confirmed after a site assessment.
Frequently asked questions
Should a business install solar before a battery?
In most cases solar comes first, because it lowers daytime usage and gives the battery low-cost energy to store. A battery on its own can still reduce demand charges by charging at off-peak times and discharging during peaks, where the tariff rewards it. If you plan both, ask for a combined design, since combined solar-and-battery installations can change the NSW incentive picture.
How long does a commercial battery project take?
It varies with size. A smaller system involves data analysis, design, network application and installation, typically over weeks to a few months, while larger systems can need grid connection studies, fire engineering and staged works that take longer. Ask each supplier for a written timeline with every approval step listed, and check how equipment lead times could affect incentive values.
Can a commercial battery provide backup power during an outage?
It can if the system is designed for it, but backup is not automatic. It needs backup-capable inverters, a changeover arrangement and a decision on which circuits are essential, because a battery sized for peak shaving may not run the whole site. Ask which loads will be supported, for roughly how long, how fast the changeover is and how much capacity is reserved for backup.
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