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303040 3.7V 300mAh Li Polymer Battery CE Certified For Smart Watch

Name: 303040 3.7V 300mAh Li Polymer Battery CE Certified For Smart Watch
Brand: Shenzhen Vats Power Source Limited
SKU: 303040
Price: 0.98 USD
Availability: InStock

Brand Name:	VATS Battery or Neutral
Model Number:	303040
MOQ:	10
Price:	$0.98-1.25
Delivery Time:	7 work days
Payment Terms:	T/T

Detail Information

Product Description

Ratings & Reviews

Detail Information

Place of Origin:

Guangdong, China

Certification:

UL1642//UL2054/CB/KC/PSE/CE/ROHS/UN38.3/MSDS

Voltage:

3.7V

Battery Size:

3.0±0.2*30±0.5*40±2.5mm

Max Charge Voltage:

4.2V

Cycle Life:

500 Charge Cycles

Discharge Rate:

0.5C

Capacity:

300mAh

Packaging Details:

Industrial cartons compliant with air & sea shipping standards

Supply Ability:

Ships in 7 Business Days (In-Stock) / 30 Business Days (Out-of-Stock)

Highlight:

3.7V 300mAh Li Polymer battery

CE certified smart watch battery

Lithium Polymer battery for smart watch

Product Description

303040 3.7V 300mAh Li Polymer Battery CE Certified For Smart Watch

This compact li polymer battery delivers steady 3.7V power for small wearable gadgets. As a reliable lithium ion battery cell, this 3.7v wearable device battery fits tight housings of smartwatches and portable electronics with stable output.

Technical Specifications

Item	Details
Model	HZ303040
Cell Type	Lithium polymer battery
Dimension	3.0±0.2 × 30±0.5 × 40±2.5mm (Thickness × Width × Length)
Nominal Capacity	300mAh (Custom capacity/size/voltage available)
Nominal Voltage	3.7V
Max Cutoff Voltage	4.35V
Standard Discharge Current	0.2C–0.5C
Max Discharge Current	1C
Connector	JST / Molex, customizable
Cycle Life	500 cycles
Certification	CE Certified

Key Features

Compact Form Factor: Thin 303040 footprint saves internal device space while maintaining stable power supply
Reliable 500-Cycle Service Life: Consistent performance over repeated charge cycles for longer usable time
Customizable Connectors & Capacity: Choose JST or Molex connectors, or request tailored sizes to match your hardware design
CE Certified & Shipment Compliant: Passes CE safety tests and meets international air & ocean shipping standards
Manufacturer Direct Supply: No middle markup with sample support available for verification before mass production

Applications

This 3.7V wearable device battery powers a wide range of compact consumer and smart electronics including smart watches, smart bracelets, car recorders, GPS navigators, smart home appliances, massagers, digital cameras, sprayers, dental rinsers, blackhead removers, remote controls, electronic toy guns, electric air pumps, smart trash cans, Bluetooth speakers, fingerprint locks, electric hair clippers, dog trainers, pest repellers, camping lights, robot vacuums, electric toothbrushes, pet water fountains, electric shavers, and mini handheld fans.

Frequently Asked Questions

Can I get samples of this li polymer battery for testing?

Yes, sample testing is supported to validate the 3.7V wearable device battery with your circuit design.

What is the standard lead time for bulk orders?

2–3 weeks for custom orders; 3–7 days for in-stock items.

Can I change capacity, dimension or connector?

Custom size, capacity and voltage are available, including JST/Molex connector selection.

What cycle life can I expect from this lithium ion battery cell?

Rated for 500 charge-discharge cycles under standard discharge conditions.

Is this battery CE certified for export?

Yes, it carries CE certification, and packaging meets international air & sea transport rules.

What is the max continuous discharge rate?

Maximum discharge current reaches 1C; standard working discharge range is 0.2C–0.5C.

What is the maximum cutoff charging voltage?

4.35V, please use matched charge management board to avoid overcharging.

After-sales Guarantee

We provide manufacturer-backed support for this li polymer battery. All units go through pre-shipment inspection and hold CE certification. If quality issues occur under normal use, we coordinate replacements or solutions quickly. Our technical team supports your hardware integration questions. We follow international shipping standards for safe global delivery of this lithium ion battery cell.

Ratings & Review

Overall Rating

5.0

Based on 50 reviews for this supplier

Rating Snapshot

The following is the distribution of all ratings

5 stars

100%

4 stars

3 stars

2 stars

1 stars

All Reviews

Markus K.

Germany May 15.2026

Helpful (45)

Ich war anfangs echt ein bisschen skeptisch, weil man im Netz ja viel zu hören bekommt, wenn es um Li-Polymer-Akkus geht. Aber der originale E66 Akku hier? Junge, Junge... das Teil ist ein Biest! Ich habe die Zelle jetzt seit ein paar Wochen in meinem DIY-Solar-Projekt verbaut und ausgiebig getestet. Was soll ich sagen: Die 66ah sind absolut real, kein Fake-Wert! Die Kapazität ist stabil, die Spannung von 3.7V bleibt auch unter Last super konstant und das Teil wird beim Laden kaum handwarm. Man merkt einfach sofort, dass die Verarbeitungsqualität stimmt und das PCB-Schutzboard ordentlich mitgedacht wurde. Für den Preis kriegt man hier in Deutschland aktuell kaum was Besseres. Versand war auch fix, Verpackung war bombensicher – so muss das laufen! Wer verlässliche Power sucht, kann hier echt bedenkenlos zugreifen. Von mir gibt's eine klare Kaufempfehlung und verdiente 5 Sterne. Daumen hoch!

Robert T.

United States May 13.2026

Helpful (99)

As a veteran engineer in portable audio and smart hardware R&D, I demand the absolute best in battery electrical performance. We sourced this 103048 3.7V 1500mAh Li-polymer battery for a BT speaker project, and its real-world performance has completely blown us away.

Harry

United Kingdom Mar 18.2026

Helpful (90)

I bought these 805050 3.7V 2500mAh lithium polymer batteries to replace the old cells in my Bluetooth speakers, and they work brilliantly. Fit is absolutely perfect, no trimming needed at all. The voltage and capacity are spot on, my speakers now hold charge for much longer than before. Power output is stable, sound quality isn’t affected one bit. They’re well-made and feel really durable. Delivery arrived quickly, items were well packed with no damage. Great value for money compared to local stores. I’ve been using them daily for weeks with zero issues. Would absolutely recommend these batteries to anyone needing replacements for wireless speakers. I’ll be coming back to buy more soon!

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products details

303040 3.7V 300mAh Li Polymer Battery CE Certified For Smart Watch

3.7V 300mAh Li Polymer battery

CE certified smart watch battery

Lithium Polymer battery for smart watch

Overall Rating

Rating Snapshot

All Reviews

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