Cloning a Sennheiser BA2015 battery pack

A hobbyist has demonstrated how to clone a Sennheiser BA2015 battery pack by disassembling the original, sourcing cheaper third-party cells, and designing a custom case with 3D printing. This could allow users to produce cost-effective replacements, challenging the high prices of official parts.

The Sennheiser BA2015 battery pack, used in many wireless microphones, contains two NiMH cells and a small NTC temperature sensor. Official replacements are expensive, often costing $80 to $100. The hobbyist disassembled an original pack, noting that the internal cells are glued and friction-welded, and then measured the components to replicate them. Using readily available Panasonic cells and inexpensive NTC sensors, they designed a new case with 3D printing, aiming to produce functional clones at a fraction of the cost. The process involved destructive opening of the original pack, identifying the positive and negative contacts, and understanding the wiring and sensor placement. The custom case was rotated to improve print quality and durability, with some modifications to the contacts and internal structure. The project is still in development, with some uncertainties about the exact sensor specifications and long-term reliability of the clone.

Potential Cost Savings for Wireless Microphone Users

This cloning method could significantly reduce expenses for professionals and hobbyists using Sennheiser microphones, which currently rely on costly proprietary batteries. By enabling DIY replacements, it may extend the lifespan of equipment and lower operational costs. However, it also raises questions about warranty, safety, and compatibility with existing charging docks, which rely on the original sensor and circuit design. The development exemplifies how open-source approaches can challenge proprietary hardware costs, but also highlights technical and legal considerations for end users.

Background on Sennheiser BA2015 Battery Pack Design

The BA2015 battery pack is a common component in many Sennheiser wireless microphones, containing two NiMH cells and an NTC temperature sensor to monitor charging. Official replacements are expensive, and third-party alternatives are available but often lack the integrated sensor and precise design. Hobbyists and technicians have long sought ways to replicate or repair these packs at lower costs, often by sourcing individual cells and designing custom cases. The recent disassembly and reverse-engineering efforts build on this history, leveraging 3D printing and affordable components to create functional clones. The process involves understanding the internal wiring, sensor placement, and mechanical constraints, which are not fully documented by the manufacturer.

“This is one of the cheaper legit ones. The only real reason for these things to exist is to avoid the charging of non-rechargeable batteries since you can put alkaline AA batteries in this microphone and run it for a few hours.”

— Hacker News user

“I managed to destroy the plastic case enough to take it apart and break the glue layer. The two cells are welded together with a metal strip, and the third contact connects to an NTC sensor, which I measured to be around 10kΩ with a beta of 3200K.”

— Hacker News user

Unconfirmed Aspects of Sensor Compatibility and Reliability

It is not yet clear whether the cloned battery packs will reliably mimic the original’s charging and monitoring functions, especially regarding the NTC sensor’s exact specifications and integration with the microphone’s circuitry. The long-term durability of the DIY packs remains untested, and compatibility with official charging docks has not been verified.

Next Steps for DIY Battery Cloning and Validation

The creator plans to assemble multiple clones using the sourced components and test their performance over extended periods. Further research is needed to confirm sensor accuracy, charging behavior, and compatibility with existing hardware. Community feedback and shared testing will be critical to refine the design and establish safety standards.

Key Questions

Can I safely replace my Sennheiser BA2015 battery with a DIY clone?

While technically possible, safety and compatibility cannot be guaranteed. The cloned packs may not have the same safety features or sensor accuracy, which could affect device performance or safety.

Will the DIY clone work with the original charging dock?

This remains unconfirmed. The original dock relies on the sensor and circuit design of the authentic pack, so compatibility with the clone is uncertain until testing is completed.

Is this legal or against warranty terms?

Manufacturers typically advise against unauthorized modifications. Cloning battery packs may void warranties and could have legal implications depending on local laws.

How much could I save by cloning my battery pack?

Using third-party cells and 3D printing, the cost could be reduced from over $80 to under $10 per pack, but savings depend on sourcing parts and your technical skill.

Source: Hacker News