Application design case: This example uses Surlon Power's published battery data to show how an OEM can evaluate a power source for a portable test instrument. The equipment brief and runtime calculations below are illustrative, not a reported customer deployment.
A portable test instrument used for equipment inspection needs a battery that fits the enclosure, supplies the electronics and supports a practical working session between charges. For an OEM buyer, the question is not simply which supplier offers a 12V battery. It is which pack can meet the instrument's electrical, mechanical and charging requirements together.
This case explores a custom LiFePO4 battery pack for portable test instruments, using a 12.8V 4Ah reference design. The proposed device has a display, measurement electronics and a data interface. The goal is to define a candidate pack and a useful sample evaluation plan before requesting production pricing.
The Surlon Power 12.8V 4Ah LiFePO4 battery pack uses four 26650 cells in a 4S1P arrangement. Its published reference data provides a starting point for this design review:
| Parameter | Published reference | Why it matters to the OEM |
|---|---|---|
| Nominal voltage / capacity | 12.8V / 4Ah | Starting point for the supply and energy budget |
| Nominal energy | 51.2Wh, calculated | Supports an initial runtime estimate |
| Reference dimensions | 28 × 55 × 135mm | Defines the initial battery-compartment envelope |
| Reference weight | 360g | Contributes to the complete instrument's weight budget |
| Maximum charge current | 2A | One input to charger selection |
| Maximum discharge current | 5A | Needs review against operating demand |
| Instantaneous discharge entry | 15A; duration unspecified | Requires agreed pulse conditions before use |
These are reference values for the listed build. Confirm the ordered specification, tolerances, protection settings and harness drawing before approving a sample or production order.
A nominal 12.8V rating does not establish compatibility with every device labelled 12V. The instrument's input circuit must work across the agreed pack operating range, including charging and discharge cut-off conditions. If the measurement electronics need a regulated supply, the converter becomes part of the battery design review.
Request the full voltage limits and check operation at both ends of that range. For a measurement device, sample evaluation should also check whether converter noise or changes in supply voltage affect readings or data communication.
For this example, assume a 6W average load, a six-hour operating target and 90% conversion efficiency. The nominal calculation is 51.2Wh × 0.90 ÷ 6W, or about 7.7 hours. Applying an additional 20% energy planning reserve gives about 6.1 hours.
The load, efficiency and reserve are design assumptions. This calculation suggests that the pack merits sample testing; it does not prove six-hour runtime. Test the actual instrument with its intended display brightness, measurement cycle, data interface and operating conditions.
The long, narrow reference envelope can be assessed against a compartment drawing before enclosure tooling is finalized. Allow space for cable bends, connector access, mechanical support and assembly tolerances. Avoid relying on the battery wrap as a mounting feature.
The product photographs show red and black leads with a white two-pin connector. The connector series, pinout and lead length need confirmation. A buyer can send a mating-connector drawing or an existing harness specification for review, helping prevent an apparently suitable pack from arriving with incompatible wiring.
The 2A maximum charge-current entry is only part of the charging requirement. Obtain the correct charge voltage, termination conditions and permitted temperatures for the selected build. Do not select a charger from nominal voltage alone.
A useful sample acceptance plan records instrument runtime, startup behavior, temperature rise, charging behavior and mechanical fit. Evaluate any brief load peaks separately from average demand. The published 15A instantaneous entry has no stated duration, so it must not be treated as a continuous rating or an approved startup allowance.
This design exercise turns a broad request for a portable instrument battery into a specification a supplier can review. The OEM has a candidate configuration, a transparent energy estimate, a compartment envelope and a defined set of sample checks. Commercial approval still depends on the agreed specification and actual test results.
For a different enclosure or load, explore the custom LiFePO4 battery pack range or discuss the requirements through Surlon Power's OEM custom battery service.
Developing a portable tester, inspection device or monitoring instrument? Send the following details to help Surlon Power review a suitable configuration and prepare a project-specific quotation:
Request a portable instrument battery quotation, or email market@surlonpower.com with the subject Portable Instrument Battery — 12.8V 4Ah Evaluation. Include the details you already know; unresolved requirements can be part of the technical discussion.
