How to Compare Home Battery Quotes in South Carolina

The best way to compare home battery quotes is to make every installer price the same outcome, then compare the complete installed system rather than the battery name or headline capacity. Two proposals can use the same battery enclosure and still deliver different usable energy, output power, backed-up circuits, outage behavior, electrical work, monitoring, warranty support, and financing cost.

Start with a one-page design brief. Give each bidder the same critical-load list, documented running and starting demands, backup priorities, reserve preference, existing-solar details, utility account, and expansion goal. Then require each proposal to state what the system will do, what equipment and work are included, what is excluded, and what evidence you receive at completion.

This guide is for South Carolina homeowners comparing installed battery proposals. It does not rank products, supply a generic battery count, or promise a runtime. Those answers depend on the home, loads, system design, weather, operating settings, and exact equipment.

A battery quote is a system quote, not a box price

A home battery project may include much more than battery modules. Depending on the design, it can require a bidirectional or hybrid inverter, gateway or system controller, automatic isolation or transfer equipment, current sensors, disconnects, overcurrent protection, backed-up-loads panel, load controls, communications hardware, conductors, conduit, mounting work, plans, permits, inspections, utility submissions, commissioning, and monitoring setup.

That is why a low price beside a product name tells you very little. It may be a complete installed backup system. It may be storage for bill management without outage backup. It may exclude circuit relocation, panel work, permitting, a required controller, or a difficult installation location. It may also be a financed amount presented after an assumed incentive rather than the gross cash price.

Sunburst’s battery storage service can cover new solar-plus-storage projects and battery additions to existing solar, but the right proposal still depends on a site-specific load, compatibility, electrical, and approval review.

The National Renewable Energy Laboratory’s residential battery storage model separates battery energy, battery power, inverter, balance-of-system, labor, engineering, permitting, and other project components. Its model is not a South Carolina price sheet, but its structure illustrates an important buying rule: the battery pack is only one part of a functioning installed system.

Use this comparison order:

1. Confirm that each proposal is designed around the same loads and goals.
2. Compare energy and power on the same basis.
3. Define exactly what remains powered when the grid is down.
4. Compare the full equipment and installation scope.
5. Verify compatibility, approvals, controls, and monitoring.
6. Separate product warranties from labor and service responsibility.
7. Compare gross cash price and total financing terms before incentives.
8. Define what proves the project is complete.

If a quote fails one of the early technical gates, a polished monthly payment does not make it comparable.

First, make every installer use the same design brief

Battery proposals often differ because installers are solving different problems. One may assume refrigeration, lighting, internet, and several outlets. Another may assume nearly every circuit in the house. One may preserve a high reserve for outages. Another may plan to cycle more of the battery for daily bill management. Those designs should not be judged as if the only difference is price.

Before requesting revisions, assemble the facts each bidder should use:

• the purpose of storage: outage backup, time-based energy management, solar self-consumption, or a defined combination;
• the circuits and equipment that must operate during an outage;
• verified running demand and motor or compressor starting demand;
• the loads expected to run at the same time;
• the desired outage scenario and reserve setting;
• whether solar recharge during an outage is required;
• any loads that can be automatically shed or manually deferred;
• the exact existing solar inverter, modules or module-level electronics, monitoring, and ownership status;
• the serving electric utility and current program;
• the electrical service, main panel, subpanels, and known site constraints; and
• a specific expansion goal, if expansion genuinely matters.

Use the South Carolina solar battery sizing guide to develop these pre-quote load, power, energy, reserve, and outage inputs. This article begins where that sizing work ends: checking whether each seller actually documents and prices the same result.

Do not accept a generic whole-home label in place of this brief. “Whole home” might mean the entire panel is connected behind backup controls while software manages high-demand loads. It might mean most circuits are connected but not expected to run together. It might mean every circuit except a few excluded loads. Those are materially different outcomes.

If the proposals began with different assumptions, ask each bidder to revise the design table before comparing totals. A bid that clearly says it cannot meet part of the brief is more useful than one that quietly changes the brief.

Compare usable energy and power separately

Battery proposals commonly feature kilowatt-hours, but energy capacity alone does not establish backup capability. The U.S. Department of Energy’s storage basics distinguishes energy capacity, measured in kilowatt-hours, from power capacity, measured in kilowatts.

• Energy in kWh describes how much electricity can be stored and delivered over time.
• Power in kW describes how fast the system can deliver electricity at a moment.

A system can have substantial energy but insufficient output for a large starting load. A system with strong output can start demanding equipment but still use its available energy quickly if many loads remain on. Both numbers must fit the same load plan.

Ask each bidder to complete these fields for the exact proposed configuration:

Comparison field	What the quote should state
Battery model and quantity	Exact manufacturer, model, revision or product family, and number of units
Nameplate energy	Total published energy before any operating or reserve limitations
Usable energy	Energy available under the quoted operating assumptions and the source for that figure
Backup reserve	Proposed minimum state of charge, who can change it, and how it affects the modeled result
Continuous output	Sustained output for the complete configuration in the proposed operating mode
Starting or surge capability	Output, duration, conditions, and manufacturer documentation used for motor-start assumptions
Derating or limits	Temperature, state-of-charge, grid status, inverter, phase, or configuration limits material to the design
Warranty basis	Whether time, throughput, cycling, retained capacity, operating conditions, or connectivity affect coverage

Do not add the ratings of individual components unless the manufacturer documents that the proposed configuration combines that way. A battery module, inverter, gateway, and entire installed system can each have a different limiting value. On-grid and off-grid output may also be described differently in product documentation.

Avoid dividing price by a single advertised kWh number and declaring a winner. That shortcut ignores power, reserve, backup equipment, circuit work, usable-energy definitions, installation conditions, warranty coverage, and financing. It can make a storage-only proposal look equivalent to a complete backup system when it is not.

Replace “whole-home backup” with a circuit and load schedule

A useful proposal should name the electrical boundary. Ask for a panel schedule or load list showing:

• every circuit that will be backed up;
• every circuit that will not be backed up;
• loads controlled by a smart switch, relay, contactor, or energy-management system;
• the priority and shed/reconnect logic for controlled loads;
• expected simultaneous loads used in design;
• large motors, compressors, pumps, heating elements, vehicle charging, pool equipment, and other high-demand loads;
• any manual steps the homeowner must take; and
• the measured or documented demand behind the sizing decision.

Then ask the installer to show how the proposed continuous and starting output supports that schedule. A circuit being electrically connected to a backed-up bus does not prove every connected load can operate at the same time. Likewise, a load-management device does not create more stored energy. It controls when certain loads may run.

The proposal should also state what happens when demand exceeds the available output. Does the system shed a lower-priority load, stop supplying the backed-up bus, retry automatically, or require homeowner action? The answer must come from the exact equipment design and manufacturer documentation—not a general statement about batteries.

Runtime depends on usable energy, starting state of charge, changing household load, conversion losses, equipment limits, solar production, reserve settings, and weather. Ask bidders to show their assumptions and scenario method. Do not compare an optimistic sunny-day scenario from one quote with a conservative no-solar scenario from another.

Verify that the quote actually includes outage backup

A battery can be proposed for time shifting or self-consumption without providing the outage experience a buyer expects. Standard grid-connected solar normally shuts down when utility power fails. DOE’s solar resilience guidance explains that independent operation requires a properly configured inverter and storage system.

Ask every bidder to answer these questions in writing:

1. Does this exact proposal provide backup power when the utility grid is down?
2. What device safely isolates the home or backed-up circuits from the utility?
3. Which device establishes the local electrical reference needed by the system?
4. Which circuits receive power, and which are outside the backup boundary?
5. Can the solar array operate and recharge the battery while the system is islanded?
6. If it can, what inverter, controller, firmware, production, load, and battery-state conditions apply?
7. What happens when solar production exceeds the loads and charging capability?
8. What happens when the battery reaches the reserve or shutdown threshold?
9. How does the system recover when grid service returns?
10. What homeowner action, internet connection, or service call may be required?

The South Carolina Energy Office’s battery-backup overview identifies islanding protection, emergency-load wiring, metering, controls, and interconnection as parts of a solar-plus-storage system. Treat its diagram as consumer context, not as the design for every product.

“Solar recharge included” needs particular care. The array may be large enough to recharge under favorable conditions but still be limited by clouds, shade, season, storm debris, inverter output, battery state, load consumption, or control behavior. Some configurations curtail or stop solar production under particular islanded conditions. The quote should state supported behavior and assumptions, not promise indefinite operation.

Compare the architecture and complete equipment list

Every quote should include an equipment schedule and a simplified one-line diagram. At minimum, identify:

• battery modules or enclosures;
• battery inverter or hybrid inverter;
• existing solar inverter and whether it remains;
• gateway, system controller, or transfer/isolation equipment;
• backed-up-loads panel, smart panel, or load-control devices;
• disconnects, breakers, fuses, relays, and other protection;
• meters, current transformers, and energy-measurement hardware;
• communications devices, gateway, antenna, network connection, or cellular service;
• required rapid-shutdown or module-level equipment;
• mounting brackets, pad, bollards, enclosure, or other site work;
• conductors, conduit, trenching, penetrations, and restoration; and
• service-panel or meter-equipment changes.

The proposal should label the system as AC coupled, DC coupled, hybrid, or another manufacturer-defined architecture and show the energy and communication paths. That label is not enough to choose a winner. Its value in quote comparison is to reveal what each bidder assumes, which existing equipment remains, and which components must work together.

For a battery added to existing solar, request model and serial information for the installed inverter and module-level electronics, current firmware where relevant, monitoring ownership, original contract, warranties, and the interconnection record. Our guide to adding a battery to existing solar explains the retrofit feasibility checks in detail.

For the quote comparison, require a direct answer to four questions:

1. Which existing components remain, and which are removed or replaced?
2. What manufacturer document supports the proposed combination and communication path?
3. Who accepts responsibility if the old and new equipment do not commission together?
4. How does the work affect the existing equipment warranty, monitoring, and service relationship?

A phrase such as “compatible with most solar” is not evidence. Compatibility can involve voltage and current ranges, grid-forming behavior, frequency response, rapid-shutdown equipment, meter/CT placement, firmware, communications, product listings, battery controls, existing ownership agreements, and utility settings.

Normalize the balance of system and site work

Many quote differences live outside the battery data sheet. Create an inclusion table and mark each line as included, allowance, excluded, or pending inspection:

Scope category	Details to normalize
Backup equipment	Controller/gateway, transfer/isolation equipment, backed-up panel, load controls, circuit moves
Electrical	Breakers, conductors, conduit, disconnects, meters/CTs, protection, grounding/bonding, panel or service work
Site	Equipment location, mounting surface or pad, weather/flood exposure, clearances, access protection, trenching, wall/roof penetrations, finish repair
Solar integration	Retained/replaced inverter, solar controls, rapid shutdown, firmware, communication, monitoring integration
Design and approvals	Site survey, engineering, plans, one-line diagram, permit, inspection, utility filing, revision work, fees
Digital setup	Network connection, account creation, device provisioning, firmware/configuration, alerts, owner permissions
Handoff	Commissioning, functional tests, owner training, manuals, warranties, registrations, as-built records, support contacts

An allowance needs a defined basis. “Electrical upgrades if needed” can become a significant change order if the contract does not say how need is determined, what is included, how additional work is priced, and whether the homeowner can cancel if the revised scope changes materially.

Site location is also a technical and commercial issue. Battery equipment may have manufacturer installation restrictions and local code requirements involving clearances, protection from impact, environmental exposure, access, and placement. Ask the bidder to identify the proposed location and cite the applicable installation instructions and filing-date requirements. Do not compare a garage-wall design with an exterior-pad design as if their labor and materials are identical.

UL Solutions explains that UL 9540 addresses energy-storage systems and equipment, while UL 9540A is a fire-propagation test method. A claim that cells were tested, or that a document mentions UL 9540A, does not by itself prove the complete installed configuration has the required system listing or local approval. Ask for the listing/certification basis for the exact battery, inverter, controller, and configuration proposed.

Put South Carolina permits and utility work in the contract

Permitting and utility treatment can vary with the design, jurisdiction, serving utility, and whether a grid-connected system is new or being changed. The South Carolina Energy Office says the utility reviews grid-connected systems for electrical safety and its program requirements and directs consumers to the actual provider for current procedures.

Each quote should identify:

• the authority having jurisdiction for the property;
• who prepares and submits plans;
• who pays permit, review, and inspection fees;
• whether engineering or other documentation is included;
• who responds to corrections or resubmittals;
• the serving utility shown on a current bill;
• whether a new, amended, or other interconnection submission is expected;
• what export, operating, inverter, meter, or program assumptions the design uses;
• who supplies the single-line diagram and equipment documents;
• who pays utility processing or equipment fees; and
• what approval or authorization is required before normal operation.

The South Carolina LLR Building Codes Council publishes the codes and modifications in effect. Because adoption and local procedures can change, a quote should not rely on an undated claim that a certain battery “meets South Carolina code.” The installer should identify the applicable code path, manufacturer instructions, listed configuration, permit process, equipment location, inspection, and labeling for the project when filed.

Utility procedures are not interchangeable. Dominion Energy South Carolina, for example, publishes a residential process that requests system information and a single-line diagram. That does not establish the process for a Duke Energy, Santee Cooper, electric cooperative, or municipal customer. Use the bill to identify the provider, then consult its current materials. Sunburst’s South Carolina utility guide helps locate the relevant provider and program.

Ask what happens if the AHJ or utility requires a design change. The contract should say whether ordinary revisions are included, what can trigger a change order, whether substituted equipment needs homeowner approval, and what happens if the approved project cannot deliver the originally stated backup scope.

Compare monitoring, controls, and account ownership

Monitoring is part of the system, not a decorative app. The quote should say what the homeowner can see and control, what the installer or manufacturer can access, and what connectivity the system needs for operation, updates, alerts, or warranty support.

Compare these fields:

• monitoring platform and supported operating modes;
• homeowner account owner and administrator;
• installer or manufacturer access permissions;
• battery state, solar production, grid flow, home load, and backed-up-load visibility;
• alert delivery and who responds;
• reserve, time-based, storm, or other control settings available to the owner;
• internet, Wi-Fi, Ethernet, cellular, gateway, subscription, or data requirements;
• subscription or connectivity fees now or later;
• firmware and grid-profile responsibility;
• historical-data access and export;
• account transfer when the home is sold;
• privacy and participation terms for any utility or virtual power plant program; and
• the commissioning evidence that proves sensors and energy-flow directions are correct.

Do not assume that an app showing a green status proves the backup controls, load schedule, solar charging, or metering are configured correctly. Ask for a commissioning review that compares displayed solar, grid, home, and battery flows with the installed measurement hardware.

Current manufacturer libraries demonstrate why the exact documentation matters. Enphase’s storage documentation center separates product data sheets, supported components, installation information, software, troubleshooting, warranties, and labor terms. Tesla likewise publishes separate owner documents for Powerwall. These are examples of document structure, not product recommendations. Require the current U.S. documents for whatever exact system is quoted.

Separate product warranty from installed-service coverage

“Ten-year warranty” or “industry-leading warranty” is not a complete service plan. A battery project can involve several warranties and several responsible companies:

• battery product warranty;
• inverter or power-conversion warranty;
• gateway, controller, meter, and load-control warranty;
• manufacturer software or monitoring terms;
• installer workmanship warranty;
• electrical, roofing, mounting, or penetration coverage;
• performance or capacity-retention terms, if offered; and
• financing or third-party service obligations.

Build a responsibility matrix before signing:

Event or cost	Manufacturer	Installer	Homeowner	Written evidence
Initial diagnosis or truck roll
Remote troubleshooting
Product replacement
Removal and reinstallation
Shipping and return freight
Return-material authorization
Second visit or access equipment
Electrical-system troubleshooting
Firmware, gateway, or monitoring work
Replacement-product warranty term
Support if the installer closes

Read the warranty for the exact model and document revision. Check when coverage begins, who may claim, whether registration or connectivity matters, which operating conditions apply, whether cycling or energy throughput matters, how retained capacity is evaluated, what remedy the manufacturer controls, and which costs are excluded.

Manufacturer examples show why headline summaries are risky. Enphase publishes an exact U.S. IQ Battery limited warranty alongside separate labor terms and product resources. Tesla’s product documentation can include connectivity-related warranty conditions. Those terms apply only to the cited products and documents. They do not prove what another manufacturer covers or what a South Carolina installer includes.

Use Sunburst’s warranty guide to organize product, workmanship, monitoring, and service questions. The signed installer contract should resolve any gap between a manufacturer’s remedy and the labor needed to diagnose, remove, ship, reinstall, commission, and return the system to service.

Test every future-expansion promise

“Expandable later” is useful only if the proposal defines later. Ask for:

• the exact compatible battery models or generations;
• the maximum supported quantity and energy for the proposed controller and inverter;
• whether mixed ages, capacities, or product generations are allowed;
• whether added units change output as well as energy;
• reserved wall or floor space and required clearances;
• available panel, breaker, conductor, gateway, communications, and service capacity;
• whether a future addition needs another controller, inverter, panel, or load device;
• software, warranty, or product-availability dependencies;
• permit, inspection, and utility work expected for expansion; and
• whether the original warranty term, a new term, or different terms apply to added equipment.

Do not pay a premium for an undocumented expansion claim. A product family may technically support more modules while the present panel, location, communications, inverter, utility configuration, or discontinued generation prevents the simple addition a salesperson described.

The most defensible contract language identifies the currently approved system. Future expansion is a planning condition, not a guaranteed price, product supply, approval, or labor scope years from now.

Compare price without letting financing or tax assumptions hide it

First ask for the gross cash installed price before any tax credit, rebate, or assumed future savings. That becomes the common starting point. Then compare:

• exact included equipment and labor;
• allowances and excluded work;
• taxes and fees;
• permit, inspection, engineering, and utility charges;
• service-panel, circuit, trenching, or site contingencies;
• deposit and milestone schedule;
• change-order rules;
• equipment-substitution rules;
• cancellation and refund terms; and
• completion and final-payment conditions.

For financing, record the cash price and financing terms separately:

• amount financed;
• annual percentage rate, not just an advertised interest rate;
• term;
• lender, dealer, origination, or other charges;
• total of payments;
• required down payment;
• payment changes or re-amortization assumptions;
• prepayment terms;
• ownership, lien, or security-interest provisions; and
• effect on warranty or service if the lender or installer changes.

A monthly payment is not a project price. A low payment can reflect a longer term, larger total finance charge, temporary payment assumption, or different scope. Compare the same equipment and work using both gross cash price and total financing disclosures.

When the proposals also include a new photovoltaic array, apply the broader equipment, production, roofing, and contract checks in the solar quote comparison guide before isolating the battery portion.

Treat tax benefits as a separate homeowner question. The IRS’s current Residential Clean Energy Credit page, reviewed in July 2026, states that the federal Section 25D credit is not available for property placed in service after December 31, 2025. A battery project completed in 2026 should not be compared using an assumed federal 30% homeowner credit.

If a proposal shows a federal credit in a 2026 “net cost,” ask for a corrected gross-price and financing presentation. Any state, utility, or other incentive should be itemized with the legal basis, timing, responsible claimant, eligibility assumptions, and current source. Have a qualified tax professional apply the rules to your facts. An installer can document the project; it cannot guarantee a tax result.

Use a same-scope battery quote worksheet

Copy the following fields into a spreadsheet. Give each quote its own column. Use documented, allowance, excluded, or missing rather than guessing.

Design and performance basis

• Storage objective and operating priority
• Backed-up circuit/load schedule
• Verified running and starting demand used
• Expected simultaneous-load assumption
• Battery manufacturer, model, quantity
• Nameplate and usable energy basis
• Reserve/minimum state-of-charge assumption
• Continuous output in proposed mode
• Surge/start capability and conditions
• Islanding and transfer equipment
• Solar operation and recharge while islanded
• Load-control hardware and sequence
• Limitations, exclusions, and recovery behavior

Equipment and installation

• AC/DC/hybrid architecture
• Retained and replaced existing equipment
• Battery/hybrid inverter
• Gateway/system controller
• Backed-up panel or smart/load controls
• Disconnects, protection, meters, CTs
• Rapid-shutdown or module-level equipment
• Communications/network hardware
• Conductors, conduit, trenching, restoration
• Mounting, pad, impact protection, location work
• Panel, service, meter, or circuit changes
• Equipment listing and compatible-component evidence

Project administration and handoff

• Site survey, design, engineering, one-line
• Permit and inspection responsibility/fees
• Utility and interconnection responsibility/fees
• Correction and revision responsibility
• Commissioning and safe functional testing
• Monitoring setup and homeowner account ownership
• Owner training, manuals, labels, warranty registration
• As-built drawing and model/serial schedule
• Support route and response commitments

Commercial and risk terms

• Gross cash price before incentives
• Allowances, exclusions, and change-order triggers
• Deposit and milestone schedule
• Financed amount, APR, term, fees, total payments
• Incentive assumptions shown separately
• Product, workmanship, and service warranties
• Labor, shipping, RMA, access, and follow-up responsibility
• Schedule and delay terms
• Substitution approval
• Damage, insurance, cancellation, and dispute terms
• Definition of substantial completion and final payment

A blank cell is not automatically a disqualifier, but it is a question that must be resolved. A bidder may need a site survey before finalizing panel work or equipment location. The important distinction is whether the contract states how uncertainty will be resolved and priced.

Battery quote red flags

Pause before signing when a proposal relies on any of these patterns:

• one battery name and one total with no equipment schedule;
• advertised capacity without a usable-energy basis;
• no continuous-output or starting-load analysis;
• whole-home backup without a circuit/load schedule;
• backup promised without identified islanding or transfer equipment;
• solar recharge promised without an exact supported configuration;
• existing-solar compatibility asserted without model numbers or documentation;
• gateway, panel, circuit, permit, utility, or site work left unpriced and undefined;
• product warranty presented as if it includes all labor and service;
• expansion promised without a documented maximum and compatible configuration;
• a monthly payment shown without cash price, APR, fees, term, and total payments;
• a 2026 net price reduced by an assumed federal 30% homeowner credit;
• incentives described as guaranteed;
• equipment substitutions allowed without homeowner approval and an equivalent-or-better definition;
• final payment due before inspection, utility status, commissioning, monitoring access, or records are complete; or
• pressure to sign before you receive the contract, warranty documents, and design assumptions.

Red flags do not always mean misconduct. A preliminary estimate may intentionally defer details until a site survey. But a preliminary estimate should be labeled as such, and unresolved items should not disappear when it becomes a binding contract.

Define completion before work begins

A battery attached to a wall is not necessarily a completed project. The contract should state the acceptance package and who signs off on it.

Request, as applicable:

• approved and as-built one-line diagrams;
• final panel/circuit schedule and backup boundary;
• equipment model and serial schedule;
• permit and inspection record;
• utility/interconnection status or authorization relevant to the project;
• configured operating modes and reserve setting;
• commissioning report;
• safe transfer/islanding functional-test result;
• verification of the supported loads or load-control sequence under the agreed test conditions;
• verification of solar, battery, grid, and home-flow metering;
• homeowner monitoring login and permissions;
• alert and support routing;
• manuals, shutdown information, and owner training;
• manufacturer registration or warranty evidence;
• installer workmanship warranty and service contacts; and
• open-item list, correction deadline, and final-payment trigger.

Testing must follow manufacturer instructions and be performed by qualified personnel. A homeowner should not open energized battery or electrical equipment, defeat disconnects, change grid profiles, bypass protective devices, or create an outage by unsafe means.

If you want help turning competing proposals into the same technical and installed scope, request a battery storage assessment and bring the bids, a recent utility bill, circuit priorities, existing-solar records, equipment photos, and warranty documents. Sunburst can review the site and goals before recommending a project scope; an assessment is not a promise that every quoted product or requested load plan will fit.

Questions to ask each battery installer

Use these questions in the same order with every bidder:

1. What exact load and outage assumptions did you use?
2. What are the configuration’s usable kWh, continuous kW, and supported starting-demand basis?
3. Which circuits are backed up, excluded, or controlled?
4. What happens if connected demand exceeds system output?
5. Does the proposal include grid-outage backup, and what equipment creates the safe island?
6. Can solar operate and charge the battery while islanded in this exact configuration? Under what conditions?
7. Is the design AC coupled, DC coupled, or hybrid, and what existing equipment remains?
8. Which manufacturer document supports component compatibility?
9. What battery, inverter, controller, panels, protection, meters, communications, and site work are included?
10. What permit, inspection, engineering, utility, and revision work is included?
11. Who owns the monitoring account, responds to alerts, and maintains communications?
12. What does each product and workmanship warranty cover, and who pays labor, shipping, RMA, and reinstallation?
13. What exact expansion is supported, and what future work or approval would still be required?
14. What is the gross cash price before incentives, and what are the complete financing disclosures?
15. What documents and tests establish completion before final payment?

The quality of the answers matters more than the number of promises. A careful installer may identify conditions that require a site survey, AHJ decision, utility response, or manufacturer review. That transparency is more credible than an unconditional answer that ignores the home and design.

Judging Sunburst by the same worksheet

This article is only useful if you apply it to every bidder, including us. Ask Sunburst Solar Solutions for the same things: the exact battery and inverter model numbers, usable energy at the stated conditions, continuous and surge output, a circuit-by-circuit backup schedule, the permit and utility interconnection responsibility in writing, and the commissioning tests we will run in front of you before final payment.

A few facts you can verify about us rather than take on trust: we are based at 500 Seven Farms Drive on Daniel Island and work across South Carolina; the team brings 30+ years of combined experience and roughly 450 combined installs; and our lifetime full-system and roof-penetration warranty is published rather than described verbally. Our battery storage service page lists what is included in a standard scope, and battery installation by city shows where we work, including Columbia and Lexington in the Midlands.

If your quotes disagree on size rather than price, the difference usually traces back to load assumptions — work through the sizing gates before you decide who is right. Book a free assessment when you want a fourth quote written to this standard.

Frequently asked questions

Is price per kWh a good way to compare home battery quotes?

Not by itself. First verify that the denominator is usable energy for the same operating assumption and that the quotes include comparable power, backup controls, circuits, electrical work, approvals, monitoring, warranty, and service. Price per advertised kWh can hide major differences in the installed system.

Does a larger kWh number mean a better battery quote?

No. More energy may support a longer or larger load scenario, but output power, starting capability, backup boundary, controls, site fit, compatibility, warranty, and price also matter. A larger system that does not support the required loads or installed configuration is not automatically better.

Does a home battery always work during a utility outage?

No. Outage operation requires a supported design with safe grid isolation, compatible power conversion and controls, and a defined backed-up load path. A battery configured for grid-connected energy management may not provide the outage behavior the homeowner expects.

Will solar always recharge a battery during an outage?

No universal promise is credible. The proposed solar, inverter, battery, controller, and protection must support islanded operation together. Recharge also depends on available sunlight, load use, system limits, state of charge, and controls. Require the bidder to document behavior for the exact configuration.

What does whole-home battery backup mean?

There is no useful comparison without a circuit and load schedule. It may mean an entire panel sits behind backup equipment while controls limit large loads, or it may describe a broad but incomplete set of circuits. Ask which loads can run simultaneously and what happens when demand exceeds output.

Should permits and utility work be included in a South Carolina battery quote?

The quote should state which permits, inspections, plans, utility submissions, revisions, and fees are included or excluded. The actual requirements depend on the jurisdiction, utility, and project configuration. Do not assume every utility or town uses the same process.

What battery warranty detail matters most?

There is no single field. Verify the exact covered product, start date, time and throughput or cycle terms, capacity-retention method, operating/connectivity conditions, exclusions, remedy, shipping, labor, removal/reinstallation, RMA process, and replacement coverage. Separately verify the installer’s workmanship and service promises.

Can I use a federal 30% tax credit when comparing 2026 battery quotes?

The IRS states that the Section 25D Residential Clean Energy Credit is unavailable for property placed in service after December 31, 2025. Do not reduce a 2026 installed battery quote by an assumed federal 30% homeowner credit. Have a qualified tax professional review any other incentive under current rules and your facts.

How many battery quotes should I get?

Multiple proposals can expose different design assumptions, but the count is less important than comparability. If three bids solve three different load plans, their totals still do not answer which installer offers the best scope. Normalize the design brief and require missing fields before deciding.

Sources

• U.S. Department of Energy, Solar Integration: Solar Energy and Storage Basics
• U.S. Department of Energy, Solar and Resilience Basics
• National Renewable Energy Laboratory, 2024 Annual Technology Baseline: Residential Battery Storage
• South Carolina Energy Office, Battery Back-up
• South Carolina Energy Office, Interconnection
• South Carolina LLR Building Codes Council, Building Code Adoption
• UL Solutions, Energy Storage System Testing and Certification
• Internal Revenue Service, Residential Clean Energy Credit