---
product_id: 436345015
title: "DC 3.7V 800mAh 603040 Rechargeable Lithium Polymer Replacement Battery for DIY 3.7-5V Electronic Products with Built-in 2-Wire Battery Replacement"
brand: "hxjnldc"
price: "€ 32.70"
currency: EUR
in_stock: true
reviews_count: 9
url: https://www.desertcart.fr/products/436345015-dc-3-7v-800mah-603040-rechargeable-lithium-polymer-replacement-battery
store_origin: FR
region: France
---

# 0.8A max current output Compact 6×30×41mm size 800mAh high capacity DC 3.7V 800mAh 603040 Rechargeable Lithium Polymer Replacement Battery for DIY 3.7-5V Electronic Products with Built-in 2-Wire Battery Replacement

**Brand:** hxjnldc
**Price:** € 32.70
**Availability:** ✅ In Stock

## Summary

> 🔋 Power your passion with precision and protection!

## Quick Answers

- **What is this?** DC 3.7V 800mAh 603040 Rechargeable Lithium Polymer Replacement Battery for DIY 3.7-5V Electronic Products with Built-in 2-Wire Battery Replacement by hxjnldc
- **How much does it cost?** € 32.70 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.fr](https://www.desertcart.fr/products/436345015-dc-3-7v-800mah-603040-rechargeable-lithium-polymer-replacement-battery)

## Best For

- hxjnldc enthusiasts

## Why This Product

- Trusted hxjnldc brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Safe & Smart:** Built-in Seiko IC protects against overcharge, overdischarge, overcurrent, and short circuits.
- • **Power Up Longer:** 800mAh capacity delivers extended runtime for your DIY gadgets and electronics.
- • **Reliable Warranty:** Backed by a 1-year replacement guarantee for worry-free performance.
- • **Compact & Lightweight:** Slim 6×30×41mm design and just 16g for seamless integration without bulk.
- • **Universal DIY Friendly:** Includes heat-shrink tubing for easy wire splicing—perfect for custom connector setups.

## Overview

The DC 3.7V 800mAh 603040 Lithium Polymer battery is a compact, rechargeable power source designed for DIY 3.7-5V electronic devices. Featuring a high-capacity 800mAh cell, a robust 0.8A max current, and advanced Seiko IC protection, it ensures safe, long-lasting performance. Its universal 2-wire connector and included heat-shrink tubing make it ideal for custom installations, backed by a 1-year warranty for dependable use.

## Description

Buy HXJNLDC DC 3.7V 800mAh 603040 Rechargeable Lithium Polymer Replacement Battery for DIY 3.7-5V Electronic Products with Built-in 2-Wire Battery Replacement: 3.7V - desertcart.com ✓ FREE DELIVERY possible on eligible purchases

Review: Using for my outside driveway sensors. - These batteries were what I needed for my outside sensors. The end fitting did not fit so I cut the old battery end fittings off and spliced them to the new batteries. They are working perfectly.
Review: Nice fit to Anki Cosmo - I have used this battery to update Anki Cosmo robot as described various guides which used 503040 600 mAh. 603040 fits perfect and 800 mAh is much better for endurance - kids tests Cosmo for 2 hours and still very well changed, so I may assume resulting runtime will be 2.5 - 3 hours.

## Features

- This battery is applicable to electronic products with DIY 3.7-5V less than 2.96Wh 800mAh.（★Not suitable for power tools and model aircraft）
- Please compare the connector specifications and polarity according to the display diagram before purchasing,★the red wire is the positive "+" and the black wire is the negative "-"，Do not reverse-charge or reverse-connectreverse. The primary battery of some products has no plug or mismatched plug or mismatched polarity. It doesn't matter, you can cut and solder the plug directly or use our heat shrinkable insulating sleeve to connect the same color wire.
- 603040 rechargeable lithium ion polymer battery, nominal voltage 3.7V, full charge voltage 4.2V, capacity 800mAh, power 2.96Wh, ★size 6×30×41mm(0.236×1.181×1.614inch）(T*W*L), Weight:16g(0.564oz)，Maximum current:0.8A。 It can prevent overcharge, overdischarge, overcurrent, and short circuit.
- It‘s consists of of large-capacity A+ lithium battery, Japanese Seiko IC overcharge and overcurrent short circuit protection board, 3302-26 high temperature resistant silicone cable, and genuine JST Pitch1.25mm ★2 wire connector module.
- If there are any quality issues within a year,★ please feel free to contact us via email for replacement.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B09YQ2C1KR |
| Amperage | 0.8 A |
| Antenna Location | GPS, Power Tool, Watch |
| Battery Capacity | 800 milliamp_hours |
| Battery Cell Composition | Lithium Polymer |
| Battery Cell Type | Lithium Polymer |
| Battery Weight | 13.7 g |
| Best Sellers Rank | #267,341 in Health & Household ( See Top 100 in Health & Household ) #327 in 3.7V Batteries |
| Brand | HXJNLDC |
| Customer Reviews | 4.3 out of 5 stars 230 Reviews |
| Item Dimensions | 1.61 x 1.18 x 0.24 inches |
| Item Weight | 18.7 g |
| Manufacturer | HXJN |
| Model Name | 603040 |
| Model Number | 603040 |
| Number of Batteries | 1 C batteries required. (included) |
| Recommended Uses For Product | GPS, Power Tool, Watch |
| Reusability | Rechargeable |
| UPC | 754525114512 |
| Unit Count | 1 Count |
| Voltage | 3.7 volts_of_direct_current |
| Warranty Description | 1 |

## Product Details

- **Number of Batteries:** 1 C batteries required. (included)
- **Brand:** HXJNLDC
- **Battery Cell Composition:** Lithium Polymer
- **Battery Capacity:** 800 Milliamp Hours
- **Recommended Uses For Product:** Power Tool, Watch, GPS

## Images

![DC 3.7V 800mAh 603040 Rechargeable Lithium Polymer Replacement Battery for DIY 3.7-5V Electronic Products with Built-in 2-Wire Battery Replacement - Image 1](https://m.media-amazon.com/images/I/61OCFCtcXgL.jpg)

## Customer Reviews

### ⭐⭐⭐⭐⭐ Using for my outside driveway sensors.
*by J***E on August 9, 2026*

These batteries were what I needed for my outside sensors. The end fitting did not fit so I cut the old battery end fittings off and spliced them to the new batteries. They are working perfectly.

### ⭐⭐⭐⭐⭐ Nice fit to Anki Cosmo
*by L***M on May 11, 2025*

I have used this battery to update Anki Cosmo robot as described various guides which used 503040 600 mAh. 603040 fits perfect and 800 mAh is much better for endurance - kids tests Cosmo for 2 hours and still very well changed, so I may assume resulting runtime will be 2.5 - 3 hours.

### ⭐⭐⭐⭐⭐ Stuff
*by Z***S on October 24, 2025*

Worked fine. Exactly what I needed. Thank you.

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*Product available on Desertcart France*
*Store origin: FR*
*Last updated: 2026-09-06*