How the Battery Rated Capacity Tester Works
A battery’s nameplate says 100 Ah. Your formation line ran correctly. The OCV is within range. And yet the battery will fail at 68 Ah in the field — six weeks after it left your plant.
This gap between rated capacity and actual delivered capacity is the most common, most costly, and least visible quality failure in lead-acid battery manufacturing. It cannot be caught by a voltage check. It cannot be predicted from a 10-minute high-rate discharge. It is only confirmed by a full constant-current discharge at the specified C-rate — down to the correct end voltage — with the total Ampere-Hours counted to 1% accuracy.
ELIND’s Battery Rated Capacity Tester (RCT) does exactly that. It discharges a 6V cell or 12V battery at a settable constant current — from 0.5A to 100A depending on model — until the user-defined end voltage is reached. The PLC tracks battery voltage, discharge current, test time, and total Ah discharged at every point in the cycle. When the test ends, the actual Ah delivered is displayed and logged.
This is not an extrapolated estimate. This is the measured Ah at the specified C-rate, under IS 1651, IS 5154, IS 15549, IEC 60095-1:2018, or IEC 60896-11 test conditions — whichever standard governs your battery’s application.
That result is the number a QA head can sign off. The number a procurement manager can submit to an OEM. The number that protects a battery manufacturer against a warranty claim that begins: ‘The battery was below rated capacity from day one.’
Battery Rated Capacity Tester — Technical Specifications
| Parameter | Value |
| Input Voltage | Single Phase AC, 200–240V |
| Input Frequency | 50 Hz |
| Battery Type Supported | 6V cell or 12V lead-acid battery (SLI, VRLA, Tubular, Traction) |
| Discharge Mode | Constant Current (Electronic Load Bank) |
| Discharge Current Range | 0.5–5A (RCT 12-05) | 1–10A (RCT 12-10) | 2–20A (RCT 12-20) | 3–30A (RCT 12-30) | 5–50A (RCT 12-50) | 10–100A (RCT 12-100) |
| Current Accuracy | ±1% from 10% to 100% of full-scale range |
| Voltage Accuracy | ±1% |
| AH Measurement Accuracy | ±1% |
| AH Measurement Range | 0.1 AH to 999 AH |
| End Voltage Setting | 4V to 15V (user-settable) |
| Display Parameters | Battery Voltage | Discharge Current | Test Time | AH Discharged |
| Data Recording | 25,000 rows | USB 2.0/3.0 compatible | Windows 7/10/11 |
| Data Output Format | Spreadsheet (CSV) at pre-set log interval |
| Enclosure | MS enclosure, powder coated |
| Dimensions (approx.) | 250mm × 450mm × 450mm (varies by model) |
| Weight (approx.) | 50 kg |
| Operating Temperature | 0–65°C |
| IP Rating | IP20 |
| Efficiency | >90% |
| Multi-Channel | Available on request — configure to order |
Compliance Standards
The Battery Rated Capacity Tester is designed to execute capacity tests as specified under the following Indian and international standards. Confirm the applicable standard with your QA team before specifying the test parameters.
| Standard | Requirement |
| IS 1651, Clause 12.5 | Capacity at 10-hour rate (C₁₀); discharge to 1.75V/cell at 27°C — for SLI and stationary lead-acid batteries |
| IS 5154 | 20-hour rate capacity (C₂₀) for automotive batteries at 25°C ±2°C |
| IS 15549, Clause 12 (Part 1) | VRLA cell capacity test to rated Ah |
| IEC 60095-1:2018, Clause 9.1 | 20-hour capacity check (Cₑ) at 25°C ±2°C; discharge to 10.50V — for lead-acid starter batteries |
| IEC 60896-11, Clause 7 | Capacity at 10-hour rate at 20°C — for stationary VRLA batteries |
Pre-Dispatch Testing
Every Battery Rated Capacity Tester is tested against ELIND’s internal verification standard before it leaves the Peenya campus. The pre-dispatch checklist covers:
- AH measurement accuracy verified at three current setpoints across the model’s full range — confirmed against a reference load and calibrated current meter.
- Constant current regulation verified throughout the discharge cycle — the current must hold steady from test start to end-voltage cutoff without taper.
- End-voltage cut-off confirmed — discharge stops within tolerance of the set end voltage. No under-discharge or over-discharge of the test battery.
- Data logging and USB export verified — all four display parameters (voltage, current, time, AH) record correctly at the set log interval and export cleanly to spreadsheet format on Windows 10/11.
- Display parameter accuracy confirmed — on-screen readings cross-checked against reference instruments for voltage and current.
No unit is dispatched without passing all five checks.
Applications of the Battery Rated Capacity Tester
1. Incoming quality inspection at UPS and inverter OEM manufacturers
A UPS manufacturer sourcing lead-acid batteries from multiple suppliers cannot assume every incoming batch meets the rated Ah. Substandard cells entering the assembly line surface only when the finished UPS fails a runtime test — at which point the cost is disassembly, replacement, and a production schedule disruption. The RCT gives the incoming QA team a definitive C₁₀ discharge result per IS 1651 before the cells enter the line. Batteries below rated Ah are returned at the supplier’s account. Manufacturers supplying at the scale of Luminous Power Technologies and Amara Raja run incoming capacity checks as standard practice. The RCT is the instrument that makes this operationally practical.
2. Scheduled capacity assessment of telecom tower battery banks
TRAI backup power guidelines require telecom operators to maintain battery banks at a minimum of 80% of rated Ah. A battery bank that reads correct OCV and passes a basic discharge check can still be at 65% capacity — and will fail during a prolonged grid outage. The RCT runs a scheduled full-discharge capacity test per IEC 60896-11, identifies which batteries are below the 80% threshold, and generates the test record needed to justify replacement to the maintenance manager and audit the bank against TRAI compliance. Telecom operators and tower companies including BSNL and Indus Towers use periodic capacity testing as the primary tool for planned maintenance.
3. R&D validation of new battery chemistry and plate formulations
When a battery R&D lab validates a new plate formulation or separator material, the fundamental performance question is capacity versus temperature: how does the battery deliver Ah at 0°C, 27°C, and 45°C? The RCT’s settable end voltage and constant current discharge allow repeatable capacity mapping across temperature points. The USB data log records each test cycle’s voltage profile and Ah reading in spreadsheet format — the data format that R&D engineers at labs including Amara Raja and HBL Power need for analysis and charting without manual transcription from a display.
4. Conformance testing for railway and defence procurement
RDSO tender specifications for lead-acid batteries require capacity certification per IS 1651 or IS 1652. DRDO and Defence PSU procurement processes have similar requirements. The RCT generates a complete test record — start voltage, discharge current, test time, total Ah, end voltage — in spreadsheet format with a log interval that produces a full discharge curve. This record is the documentary evidence the procurement authority requires for tender acceptance. Generating this test data in-house, on calibrated equipment, eliminates dependence on third-party testing labs for routine conformance verification.
5. Grading of refurbished and second-life batteries
The second-life battery market — solar storage, e-rickshaw swap stations, telecom backup — grades returned batteries by remaining capacity: Grade A (>90% of rated Ah), Grade B (80–90%), Grade C (<80%, recycle). Manual grading from visual inspection and static voltage is unreliable. The RCT runs a controlled C-rate discharge on each returned battery, records actual Ah, and produces the grading data automatically. The data log links each test result to the battery’s serial number — creating the audit trail that a solar storage operator or second-life integrator needs to certify the battery grade to their own customers.
Why Battery Manufacturers and Test Labs Choose ELIND
Electronic load bank — constant current that does not drift
Resistive load discharge testers are cheaper. They are also inaccurate. A resistive load draws less current as battery voltage falls during discharge — which means the test is not conducted at the specified C-rate, and the Ah reading is not comparable to a standard-compliant result. ELIND’s RCT uses an electronic load bank that actively regulates discharge current throughout the test cycle. The current holds at the set value from the start of discharge to the end-voltage cutoff. This is the only way to generate an Ah result that stands up to IS or IEC compliance verification.
Actual Ah at specified C-rate — not a short-test extrapolation
Some testers run a partial discharge and extrapolate full capacity. That approach has one problem: the Ah delivered in a real discharge is not linear, and the extrapolation error compounds at the end of the discharge curve — which is precisely where a below-capacity battery diverges from a healthy one. The RCT runs the full discharge to the end voltage specified by the applicable standard. The Ah count is direct, not calculated from a shortened test. The result is the number the standard requires.
PLC-based controller — industrial-grade, not lab-grade
The RCT is built for factory floor and lab environments where duty cycles are continuous and operating conditions are not controlled. The PLC-based controller handles repeated daily use without calibration drift between test cycles. There is no software licence to renew and no vendor dependency to manage. Parameters are set directly on the controller. Operators with no programming background can set up and run a test in under two minutes.
25,000-row data log with USB export — the format your QA function already uses
Test data is logged at a pre-set interval and exported directly to a USB drive. The file opens in Excel on Windows 7, 10, or 11 without conversion. Each row records timestamp, battery voltage, discharge current, and cumulative Ah. For a standard C₁₀ test, this produces a full discharge curve with 600+ data points — enough to identify capacity fade, mid-discharge voltage dip, and end-of-discharge behaviour. This is the data format that QA managers, procurement reviewers, and RDSO auditors already know how to work with.
Multi-channel configuration — available on request
For battery manufacturers or test labs running high-volume capacity checks, multi-channel RCT configurations are available on request. Each channel operates independently. Channel count and battery voltage are confirmed at order stage. Specify your test volume and battery type when enquiring.
Battery Rated Capacity Tester — Available Models
Six standard discharge current ratings are available. All units are built to order. Lead time: 3–4 weeks from confirmed order and advance receipt.
| Model | Discharge Current Range | Typical Application |
| RCT 12-05 | 0.5A – 5A | Small VRLA cells; R&D lab testing |
| RCT 12-10 | 1A – 10A | 12V/7Ah to 12V/100Ah VRLA; UPS replacement batteries |
| RCT 12-20 | 2A – 20A | Medium VRLA and tubular batteries; telecom backup |
| RCT 12-30 | 3A – 30A | Inverter and solar storage batteries; second-life grading |
| RCT 12-50 | 5A – 50A | Large VRLA / SLI / industrial batteries; IS 1651 C₁₀ at higher Ah |
| RCT 12-100 | 10A – 100A | High-capacity stationary batteries; traction; RDSO / defence testing |
† Model designation: RCT 12-50 = Rated Capacity Tester, 12V battery, 50A maximum discharge current. Multi-channel configurations available on request.
† Minimum order quantity: 1 unit.
Battery Rated Capacity Tester — Configuration Options
| Parameter | Options |
| Discharge Current | 5A | 10A | 20A | 30A | 50A | 100A maximum (model dependent) |
| End Voltage Setting | 4V to 15V — user-settable on controller |
| Channel Count | Single channel (standard) | Multi-channel (configure to order) |
| Data Logging | USB 2.0/3.0 | Spreadsheet (CSV) | 25,000 rows | Windows 7/10/11 |
| Log Interval | Pre-set by user — confirmed at order stage |
| Applicable Standard | IS 1651 | IS 5154 | IS 15549 | IEC 60095-1:2018 | IEC 60896-11 |
Get a Quote or Technical Datasheet for the Battery Rated Capacity Tester
Share your battery type (VRLA, SLI, tubular, or traction), rated Ah, required discharge current, applicable test standard, and whether you need single- or multi-channel capability. Send us an email or call us / drop us a message on WhatsApp for more details. A configured technical proposal will be returned within 48 hours.
Frequently Asked Questions
Q1: What is the difference between a Battery Rated Capacity Tester and an HRD Tester?
This is the most common question from battery plant QA teams, and the distinction matters operationally. A Lab HRD (High Rate Discharge) tester discharges a 12V or 24V battery at a high constant current — typically 300A to 3000A — for 6 to 10 minutes, to determine the battery’s cranking capacity (CCA). It tells you whether the battery can deliver the short-burst high current that an automotive engine or a UPS switchover demands. It does not measure Ah capacity.
The Rated Capacity Tester runs a full constant-current discharge at the specified C-rate — typically over 10 or 20 hours for a C₁₀ or C₂₀ test — and counts the total Ah delivered. It tells you the actual energy storage capacity of the battery against the rated figure. It does not test for welding defects or high-current cranking performance.
In a battery manufacturing plant, both instruments serve different gates: HRD testing is the end-of-line structural quality gate; capacity testing is the Ah compliance gate. They are not interchangeable.
Q2: How do I choose the correct Battery Rated Capacity Tester model for my battery type?
The C-rate is the discharge current expressed as a fraction of the battery’s rated Ah capacity. C₁₀ means the battery is discharged at a current equal to one-tenth of its rated Ah — so a 100 Ah battery tested at C₁₀ is discharged at 10A over 10 hours. C₂₀ halves that rate: the same 100 Ah battery at C₂₀ is discharged at 5A over 20 hours. The C-rate is not a choice — it is fixed by the applicable standard. IS 1651 Clause 12.5 specifies C₁₀. IS 5154 and IEC 60095-1:2018 Clause 9.1 specify C₂₀. IEC 60896-11 for stationary VRLA batteries also uses C₁₀, but at 20°C rather than 27°C. Testing at the wrong C-rate produces a different Ah result and does not satisfy the standard, regardless of what the display reads.
RCT model selection follows directly from the C-rate calculation. The one rule: the required discharge current must fall between 10% and 100% of the chosen model’s full-scale range — that is the band where the ±1% current accuracy specification applies. Share your battery’s rated Ah and the applicable standard with ELIND’s technical team and they will confirm the correct model.
Q3: What test standards does the RCT support, and do I need to specify this at order stage?
The RCT is designed to be standard-agnostic — the operator sets the discharge current, end voltage, and log interval to match the requirements of whatever standard applies. The applicable standards include IS 1651 Clause 12.5, IS 5154, IS 15549 Clause 12, IEC 60095-1:2018 Clause 9.1, and IEC 60896-11 Clause 7. You do not need to specify the standard at order stage unless you require a test report template pre-formatted for a specific standard. Confirm this requirement at the enquiry stage if applicable.
Q4: What does the data log contain, and is it suitable for RDSO or NABL audit purposes?
Every test cycle records battery voltage, discharge current, elapsed test time, and cumulative AH discharged at a pre-set log interval — typically every 1 or 5 minutes. This produces a full discharge curve from start voltage to end-voltage cutoff, with 25,000 rows of storage capacity before the log requires clearing. The data exports directly to a USB drive in spreadsheet format compatible with Windows 7, 10, and 11. For RDSO tender acceptance or NABL-accredited lab documentation, the discharge curve and final Ah reading from this log constitute the primary test record. If your lab requires a specific report template or additional fields, confirm this at order stage and ELIND’s team will advise on data export options.
Q5: Can the RCT test a 6V cell rather than a full 12V battery?
Yes. The end voltage is user-settable from 4V to 15V, which covers both 6V cell testing (typical end voltage 5.25V per IS 1651 for a 6V battery, or 1.75V per cell) and 12V battery testing. When testing a 6V cell, confirm the end voltage setting against the applicable clause of your test standard. The discharge current range and AH accuracy specifications are unchanged.
Q6: What is ELIND’s service arrangement for plants outside Bengaluru?
ELIND’s service function operates from the Peenya campus in Bengaluru. For the Battery Rated Capacity Tester, most service requirements — parameter setup, calibration queries, data export troubleshooting — are resolved remotely. ELIND built the equipment and can guide your operator through any operational issue over a call or video session without an on-site visit in the majority of cases. Where a physical visit is required, ELIND arranges this on a case-by-case basis at an additional charge. Lead time for on-site support is confirmed at the time of the service request.