3.7V 500mAh Li-Polymer Battery for a U.S. Smart Wearable Wristband

BATTERY APPLICATION CASE

3.7V 500mAh Li-Polymer Battery for a U.S. Smart Wearable Wristband

CUSTOMER MARKET United States	APPLICATION Smart Wearable Wristband	BATTERY MODEL LP503035 500mAh 3.7V
NOMINAL ENERGY 1.85Wh	PACK DIMENSIONS Max. 5.5 x 30.5 x 40.0 mm	PROJECT STATUS Customized specification completed

 

Challenge

The U.S. customer needed a rechargeable battery for a compact smart wearable wristband. The product had limited internal space and required a thin, lightweight power source with stable low-current output.

Because the battery would be worn close to the body, the project also required integrated electrical protection, temperature monitoring, and a miniature connector suitable for repeatable assembly.

Our Approach

PKNERGY developed an LP503035 3.7V 500mAh lithium-polymer battery with maximum dimensions of 5.5 x 30.5 x 40.0 mm. The pack uses a 20 +/- 5 mm UL1571 30 AWG lead and a reverse Pico-EZmate (MX 1.2) connector.

The protection design integrates a PCM, 10k ohm NTC temperature sensor with B=3435, and a 1A PTC. Electrical limits were matched to the low-power wearable load: 4.2V charge cut-off, 3.0V discharge cut-off, up to 250mA charging, and 100mA maximum continuous discharge.

Solution Outcome

The finalized 1.85Wh solution provides a thin rechargeable power module with defined protection, thermal sensing, and connector details. It gives the customer’s engineering team a ready specification for mechanical fit checks, charging validation, and wearable prototype testing.

Key Highlights

• 7V nominal voltage, 500mAh typical capacity, and 1.85Wh nominal energy
• Slim form factor with a maximum thickness of 5.5 mm
• Integrated PCM, 10k ohm NTC, and 1A PTC protection components
• Maximum 250mA charging current and 100mA continuous discharge current
• Compact Pico-EZmate (MX 1.2) connector with 20 +/- 5 mm lead length
• Cycle life specification of at least 300 cycles with defined capacity retention requirements

Customer Value

The customized pack helps preserve a slim wristband profile while improving safety integration and assembly consistency. The defined cable, connector, and protection components reduce engineering work and support a faster transition from prototype evaluation to volume production.

TECHNICAL SOLUTION SNAPSHOT

LP503035 Smart Wearable Wristband Battery

Reference assembly drawing from the approved battery specification.

Key Technical Parameters

Nominal Voltage	3.7V	Typical Capacity	500mAh
Nominal Energy	1.85Wh	Charge Cut-off	4.2V
Discharge Cut-off	3.0V	Max. Charge Current	250mA
Max. Discharge Current	100mA	Cycle Life	>=300 cycles
Charge Temperature	0 to 45 C	Discharge Temperature	-20 to 60 C
Maximum Dimensions	5.5 x 30.5 x 40.0 mm	Connector / Lead	Pico-EZmate MX 1.2 / 20 +/- 5 mm

Why This Solution Fits the Application

· A 5.5 mm maximum thickness supports a compact and comfortable wristband enclosure. · PCM, NTC, and PTC components provide layered electrical and thermal protection for a body-worn device. · The miniature connector and defined lead length simplify assembly and improve production consistency.