Customer Case: INR21700 40Ah 48.1V Battery Pack for Electric Surfboard — High Power 40A Output & Reliable Water-Sport Performance |

Customer Case Study
Li-ion · 13S (48.1V)
Electric Surfboard / Jetboard

Pack: INR21700 · 48.1V · 40Ah

48.1V 40Ah Battery Pack for Electric Surfboard — High Power 40A Output & Reliable Water-Sport Performance

Our customer builds electric surfboards (jetboards) that require sustained power for acceleration and stable cruising.
The project demanded a compact high-energy pack with consistent 40A continuous discharge, controlled impedance,
and production-ready wiring to integrate into a sealed board compartment. PKNERGY delivered a 13S (48.1V) 40Ah
solution based on INR21700 cells, optimized for real water-sport load profiles.

Nominal Voltage

48.1V

Capacity

40Ah

Max Continuous Discharge

40A

Pack Resistance

≤ 60mΩ

What we solved: The customer needed stable high-power output for water-sport acceleration while keeping
a predictable voltage window (54.6V charge cut-off / 32.5V discharge cut-off) and repeatable manufacturing.
We engineered the pack layout and harness to reduce losses and improve integration reliability.

Application Photo

Battery Photo

At a glance

13S 48.1V platform
40A continuous
Low IR ≤60mΩ
XT connector ready

Customer Profile (Anonymous) & Journey

The customer is a water-sports product developer targeting electric surfboards. Their priorities are power delivery,
runtime consistency, and safe integration into a sealed board compartment. They approached PKNERGY to move from
prototype-grade packs to a more production-ready battery solution with stable high-current output.

Application

Electric surfboard / jetboard

Key Requirement

40A stable discharge for thrust

Priority

Repeatable build + safe integration

Customer environment

Challenges (What the customer needed to solve)

1) High-power acceleration demand

Electric surfboards need strong current during acceleration and riding. The pack must sustain high load without severe voltage sag.

2) Sealed compartment integration

The battery must fit precisely and use reliable connectors/harness routing for easier installation and maintenance in a sealed housing.

3) Consistent safety behavior

Protection thresholds and impedance control must be consistent to reduce sudden shutdown risks and improve overall ride experience.

Engineering note

We focused on low pack resistance (≤60mΩ) to reduce voltage drop and heat, and designed the pack to be
integration-friendly for OEM assembly and servicing.

Solution (How PKNERGY engineered the pack)

PKNERGY delivered a 48.1V 40Ah pack based on INR21700 cells for jetboard applications. The solution
balances energy density, high-current capability, and reliable integration. Charging and discharge thresholds
were defined to ensure predictable protection behavior across batches.

40A Continuous Discharge

Designed for sustained thrust demand with stable output current and controlled temperature rise.

Defined Voltage Window

Charge cut-off 54.6V and discharge cut-off 32.5V improve consistency and safety behavior.

Low Resistance (≤60mΩ)

Reduced voltage sag under acceleration and improved overall ride feel.

OEM Harness & Connectors

Production-ready wiring, connector options, and packing method to support batch supply.

Technical Specifications

Parameter	Value
Model	INR21700
Nominal Voltage	48.1V
Nominal Capacity	40Ah
Size	80 × 240 × 195 mm
Internal Resistance	≤ 60mΩ
Charging Cut-off Voltage	54.6V
Discharge Cut-off Voltage	32.5V
Maximum Constant Charging Current	10A
Maximum Continuous Discharging Current	40A
Cycle Life	≥ 300 cycles (80% DOD)
Weight	8650g

Temperature Guidance (Project Reference)

Charge: 0–10°C (0.2C) · 10–35°C (10A) · 35–45°C (0.2C)
Discharge: -20–0°C (0.2C) · 0–10°C (0.5C) · 10–35°C (40A) · 35–60°C (0.5C)

Results & Customer Feedback

Stronger acceleration feel: stable high-current output reduces performance drop under heavy load.
Predictable operation: defined cut-off voltage window reduces unexpected shutdown risk.
Integration-ready wiring: OEM harness and connectors simplify assembly and servicing.
Batch consistency: controlled IR and production process support repeat supply for future orders.

“We needed a pack that could keep up with continuous high power on the water. PKNERGY helped us optimize the battery
for stable discharge and predictable cut-off behavior. The build quality and wiring made integration into our board much easier,
and performance felt more consistent across runs.”

— Hardware Engineer, Electric Surfboard Team (Anonymous)

FAQ — Common Questions

Q1: Why is low internal resistance important for electric surfboards?

Low resistance reduces voltage sag and heat at high current. This helps maintain thrust performance during acceleration and long rides.

Q2: What details are needed to customize a jetboard battery pack?

Voltage platform, peak/continuous current, runtime, space constraints, connector type, and sealing method. Photos of the battery bay
help ensure the pack fits and is easy to service.

Q3: Can you support custom wiring and connectors for OEM assembly?

Yes. We can customize harness length, connector types, labels, and packing method to match your assembly and maintenance process.

Q4: Is this pack suitable for batch orders?

Yes. We design with production consistency in mind — controlled IR, defined thresholds, and repeatable assembly process — to support
pilot builds and scale-up orders.

Building a high-power battery pack for water sports?

Share your voltage, continuous/peak current, target runtime, size limits, and connector preference.
Our engineers will propose a production-ready battery solution.

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Post time: Jan-05-2026