# BESS Calculator > BESS Calculator (iPhone/iPad app by Balasundaram Iyyadurai.) - Source: https://appshunter.io/ios/app/bess-calculator/id6789450533 (this page in markdown: same URL + `.md`) - Developer: [Balasundaram Iyyadurai](https://appshunter.io/developer/1854081775) - Category: Business - Price: $2.99 - Age rating: 4+ - Requires: iOS 15.0 · 24 MB - Languages: American English - Released: 2026-09-02 - Data updated: 2026-10-04 - User reviews in markdown: https://appshunter.io/ios/app/bess-calculator/id6789450533/reviews.md ## What is BESS Calculator? BESS Calculator is a preliminary sizing and financial modeling tool built for developers, EPC contractors, engineers, and investors working on battery energy storage system projects. It turns a rough project idea into structured technical and cost estimates in minutes, so you can move faster into your next detailed feasibility study. WHO IT'S FOR Whether you're preparing an early-stage bid, scoping a site, evaluating a hybrid opportunity, or sanity-checking assumptions before a meeting, BESS Calculator gives you a structured starting point instead of a blank spreadsheet. TECHNICAL DESIGN & CAPEX Enter your target power, discharge duration, and site conditions to get an initial DC capacity estimate, container and inverter sizing, land footprint, and a full EPC CAPEX breakdown covering battery, power conversion, balance of system, substation, transmission, and land costs. Choose between a manual oversizing margin or an engineering-calculated approach that accounts for round-trip efficiency, usable state-of-charge window, and end-of-life capacity targets. DEGRADATION & STATE OF HEALTH Model calendar and cycle-based capacity fade over your project life using configurable degradation rates for different battery chemistries. See projected end-of-life state of health, and choose an augmentation strategy: oversize on day one to guarantee output through end of life, or plan a year-by-year augmentation schedule that tracks the growing top-up capacity, land, and cost required to maintain performance. CHARGING SIMULATOR Simulate charge and discharge cycles, round-trip efficiency losses, and thermal limits to sanity-check your operating assumptions before committing them to a full design. TARIFF-BASED BIDDING & FINANCIAL PAYBACK Work through tariff, revenue, and financing assumptions to estimate payback period, internal rate of return, and net present value. Model both standalone battery storage and solar-plus-storage hybrid configurations, with support for coincident export limits, debt and equity structuring, and combined power transformer sizing. SOLAR + BESS HYBRID SUPPORT Size hybrid projects with configurable DC/AC ratios, combined transformer capacity, and shared CAPEX modeling across the solar and battery components, for consistent comparison. MULTI-REGION, MULTI-CURRENCY Switch between Indian Rupees, shown in Crores, and US Dollars, with region-aware cost bases, interconnection voltage levels, and unit conventions so the numbers match how you actually work, wherever your project is located. INDUSTRY NEWS Stay current with curated renewable energy and battery storage news across India, world, technology, and tender categories, refreshed regularly from multiple sources, right inside the app. SHAREABLE REPORTS Generate a clean, structured PDF report summarizing your inputs, technical results, CAPEX breakdown, and augmentation schedule, ready to download or share with colleagues, clients, or investors. BUILT FOR EARLY-STAGE DECISIONS, NOT FINAL ONES This app is designed for preliminary study, rough estimation, and decision support only. All calculations, sizing results, and financial projections are indicative and depend entirely on the accuracy of the inputs you provide. They are not a substitute for a thorough, detailed engineering, technical, commercial, legal, regulatory, or financial feasibility study conducted by qualified professionals, and should not be relied upon as the sole basis for tenders, bids, contracts, financing decisions, or other commercial commitments. Actual project outcomes may differ materially due to changes in equipment prices, tariffs, regulations, financing costs, and other factors outside the app's control. Use BESS Calculator to explore sizing options, stress-test assumptions, and prepare talking points before your next site visit or design review, then hand the real number-crunching to your engineering and financial advisors. ## Version history (last 5 releases) ### 1.0.4 — 2026-09-28 Updated support and privacy policy links. Minor improvements." ### 1.0.3 — 2026-09-27 • More accurate site land footprint estimates, calibrated to current 5 MWh-class container layouts. Land area and land cost results are now lower and closer to real projects. • Dashboard layout update: Industry News moved up for quicker access. • Stability improvements. ### 1.0.2 — 2026-09-25 NEW: Tariff tab (Capacity-Based Bidding) • Estimate the minimum viable capacity bid tariff (per MW per month) for your plant, directly from your sizing and CAPEX results • Break-even tariff (NPV = 0 at WACC) for Day-1 CAPEX, plus a second figure that also recovers future augmentation costs when Annual Augmentation is selected • Tariff needed to recover CAPEX within your chosen target payback period • Annual availability revenue and simple payback at a glance • Editable financing assumptions: O&M, insurance, debt ratio, interest rate, target equity IRR, loan tenure, inflation and target payback • VGF / incentive grant support, with its impact on the tariff shown • Tariff results included in the PDF report CAPEX improvements • Land acquisition and land development now shown as separate cost lines • Substation costs split into base, IDT (transformer) and PT lines • Updated default cost assumptions Sizing improvements • The DC capacity caption now correctly reflects the selected sizing mode • Added a note explaining why Day-1 DC capacity is lower under Annual Augmentation (degradation is recovered through yearly top-ups instead of an upfront buffer) Fixes • Corrected item numbering in PDF report tables • General stability improvements Tariff results are preliminary estimates for study purposes only and should be independently verified before being used for bidding or financing decisions. ### 1.0.1 — 2026-09-05 Added Benchmark Values and Statistics modules with India/Global BESS cost and capacity data; dashboard layout improvements ### 1.0.0 — 2026-09-02 No release notes. ## More apps by Balasundaram Iyyadurai - [Packzy](https://appshunter.io/ios/app/packzy/id6755930127) All apps by Balasundaram Iyyadurai: https://appshunter.io/developer/1854081775 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-04.*