---
product_id: 94826253
title: "3500mAh Rechargeable Replacement Battery for Harman Kardon Onyx Studio 1/2/3/4 Wireless Bluetooth Speaker, Real Capacity, Same Quality as Original Battery"
brand: "kratax"
price: "130 zł"
currency: PLN
in_stock: true
reviews_count: 8
category: "Kratax"
url: https://www.desertcart.pl/products/94826253-3500mah-rechargeable-replacement-battery-for-harman-kardon-onyx-studio-1
store_origin: PL
region: Poland
---

# 3500mAh high capacity Includes screwdriver & pry bar Built-in multi-layer safety 3500mAh Rechargeable Replacement Battery for Harman Kardon Onyx Studio 1/2/3/4 Wireless Bluetooth Speaker, Real Capacity, Same Quality as Original Battery

**Brand:** kratax
**Price:** 130 zł
**Availability:** ✅ In Stock

## Summary

> 🔋 Upgrade your beat, never miss a moment!

## Quick Answers

- **What is this?** 3500mAh Rechargeable Replacement Battery for Harman Kardon Onyx Studio 1/2/3/4 Wireless Bluetooth Speaker, Real Capacity, Same Quality as Original Battery by kratax
- **How much does it cost?** 130 zł with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.pl](https://www.desertcart.pl/products/94826253-3500mah-rechargeable-replacement-battery-for-harman-kardon-onyx-studio-1)

## Best For

- kratax enthusiasts

## Why This Product

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

## Key Features

- • **Universal Fit:** Perfectly compatible with Harman Kardon Onyx Studio 1-4 models
- • **Power Up Longer:** 35% more capacity than original for extended playtime
- • **Certified Safety:** ISO9001, RoHS & CE certified with overcharge & short-circuit protection
- • **Plug & Play Ready:** Comes with all tools needed for a hassle-free battery swap
- • **Vibration-Free Sound:** Includes cushioning sponge to eliminate annoying noise

## Overview

The Kratax 3500mAh rechargeable replacement battery delivers 35% more power than the original for Harman Kardon Onyx Studio 1-4 wireless speakers. It includes essential installation tools and cushioning to protect wiring and reduce vibration noise. Certified for safety with built-in protection circuits, this battery ensures reliable, long-lasting performance and seamless compatibility with your speaker.

## Description

desertcart.com: Kratax 3500mAh Rechargeable Replacement Battery for Harman Kardon Onyx Studio 1/2/3/4 Wireless Bluetooth Speaker, Real Capacity, Same Quality as Original Battery : Electronics

Review: So far so good - The tools and the battery are working great. The battery lasts for 4 hours now. I am glad I can take my Onyx 1 whenever I go. The only thing is the battery cord isn't really wrapped by that protector as shown in the photo. Also, the battery capacity is 3200 mAh. It's not a biggie, but I just feel photo and its battery capacity needs to be true to the product.
Review: Wonderful price but even better is the product itself - Great product and price, exactly as described and easy to install

## Features

- High Capacity: 3500mAh Kratax replacement battery has 35% more capacity than the original battery, providing longer lasting performance for your speaker.
- Easy to Use: The package includes the necessary screwdriver and pry bar for battery replacement, which makes it easy to replace the battery. The included cushioning sponge strip is used to wrap the battery to prevent vibration noise when playing music. The sponge of connecting cables can better protect the wiring from damage.
- Hassle-free Purchase: Made with accessories that are equivalent to the original battery and built with the same battery construction for smoother use.
- Applicable models: Compatible with Harman Kardon Onyx Studio, Onyx Studio 2, Onyx Studio 3, Onyx Studio 4 wireless bluetooth speakers.
- Safety Protection: Built-in protection circuits to avoid overcharging, over-discharging, short-circuit protection and charging protection to ensure the safety of the battery and speakers. Passed ISO9001, RoHS and CE international certification.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B07GYXWVTM |
| Batteries | 1 Lithium Ion batteries required. (included) |
| Best Sellers Rank | #1,090 in Portable Bluetooth Speakers #7,712 in MP3 & MP4 Player Accessories |
| Customer Reviews | 4.4 4.4 out of 5 stars (390) |
| Date First Available | August 30, 2018 |
| Is Discontinued By Manufacturer | No |
| Item Weight | 3.07 ounces |
| Item model number | for Harman Kardon Onyx Studio speaker |
| Manufacturer | Kratax |
| Product Dimensions | 4 x 4 x 1 inches |

## Product Details

- **Battery Capacity:** 3500 Milliamp Hours
- **Battery Cell Composition:** Lithium Ion
- **Brand:** Kratax
- **Number of Batteries:** 1 Lithium Ion batteries required. (included)
- **Recommended Uses For Product:** Suitable for Harman Kardon Onyx Studio speakers

## Images

![3500mAh Rechargeable Replacement Battery for Harman Kardon Onyx Studio 1/2/3/4 Wireless Bluetooth Speaker, Real Capacity, Same Quality as Original Battery - Image 1](https://m.media-amazon.com/images/I/71dhN9-JwyL.jpg)

## Questions & Answers

**Q: Has anyone been using this replacement battery for more than a year?  Is it holding up well?  Does it hold a charge well after a year or 2 of use?**
A: Don't worry! Until now, we have never received any complaints from customers about the performance of battery was deteriorated gradually after one year's use.

**Q: Will the charger for the 2600 work with the 3500?**
A: If the batteries are the same style(work for Harman/Kardon Onyx Studio or Onyx Studio 2), the charger can be used for 2600mAh battery or 3500mAh battery. 
Please feel free to contact us if have any future questions, thank you!

**Q: Would this work on a Studio 3?**
A: We have received responses saying that the battery can work on Studio 4. We can assure that it can work on Studio and Studio 2, but Studio 3 we cannot be 100% sure of the compatibility.

**Q: Is this the most powerful, longest lasting best battery available for the hk onyx studio 4 bluetooth speaker please?**
A: Sure, our battery uses the same material and craftsmanship as the original battery. As long as you carefully replace it according to the video on YouTube, you will get a new speaker. If you have any problems after purchase, you can also full refund or replace it at any time.

## Customer Reviews

### ⭐⭐⭐⭐⭐ So far so good
*by H***T on March 8, 2026*

The tools and the battery are working great. The battery lasts for 4 hours now. I am glad I can take my Onyx 1 whenever I go. The only thing is the battery cord isn't really wrapped by that protector as shown in the photo. Also, the battery capacity is 3200 mAh. It's not a biggie, but I just feel photo and its battery capacity needs to be true to the product.

### ⭐⭐⭐⭐⭐ Wonderful price but even better is the product itself
*by C***K on January 10, 2026*

Great product and price, exactly as described and easy to install

### ⭐⭐⭐⭐⭐ Decent kit, flawed speaker charging needs addressed
*by T***3 on March 25, 2024*

Kit is ok, I've used 3 of them now in a Onyx 2 and two 4's. Battery is smaller than the OEM cell but regular 18650's can in theory have the advertised 3500 capacity. I haven't been using them long enough to verify, but they are basically drop-in, charging works as normal, and the speakers work as normal again. The problem is if you leave them plugged-in all the time, the Onyx is just going to kill the battery again over time because there's no good shut-off behavior for charging while plugged-in. This is what is killing the battery, and it'll just happen again. What I've done is wired a simple switch into the positive battery lead and mounted it in the bottom of the carry handle recess. Charge the battery up, flip this switch off, and now you can leave the speaker plugged-in all the time without killing the battery. If I'm going to use it on battery power, switch the battery back on, top it off if need be, and unplug and go. Self-discharge of the battery is slow with it unconnected like this. I'm not sure if this is really worth the effort because the battery life is short no matter what, but I didn't see the point of even bothering with replacing the battery knowing it would just get killed again. The 2/3/4 are really great speakers and short of this battery issue mine have all held up for many years with nothing really beating them for the size/performance. If you regularly run yours off the battery then it is definitely worth the effort.

## Frequently Bought Together

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*Product available on Desertcart Poland*
*Store origin: PL*
*Last updated: 2026-03-17*