Substitute Marshall Willen (or Nearly Any Bluetooth Loudspeaker) Battery

Did you Bluetooth speaker stop working? Is it not charging at all or very briefly?

In this guide you'll see how to check, source for the battery and change it. Let's go!

Please note:

1. these instructions are made for the Marshal Willen, but other bluetooth speakers may be fixed on the same way, just check the proper battery, as instructed below.
2. these instructions imply the handling of Li-ion batteries that must be careful or can damage equipment or harm you or others. Do this only if you know what you do.

For this fix you'll need:

Compulsory (once checked the step 1):

1. Substitute battery.

Optional supplies if necessary (check step 2):

1. Cutting pliers.
2. Soldering iron.
3. Heat shrink tubing.

The first thing to check is that the speaker has not suffered any major issue that make it unusable anymore.

Then check whether the speaker is still usable is to follow the manufacturer's instructions. Normally it implies pressing for 10-15 seconds both buttons ON+Connect (or what the manufacturer says) at the same time, until the speaker makes some noise.

Connect it to a proper charger to see whether it charges or not.

If it starts charging but stops after some seconds, then the battery is dead. It needs to be changed.

The screws are not evident. You will need to:

1. Remove the back strip at the back from one side.
2. Remove the torx screw either with the proper screw driver, or with electronics tweezers.
3. Remove the rubber band that cover the speaker's side.
4. Then remove the front grid, gently. It normally gets out with a bit of pull from a side.
5. Remove the screws, after that, you will see the inside of the speaker.

Once you have speaker is open, you'll see the battery, check its characteristics: voltage and capacity. If possible, the brand and model of the battery.

In this case, it is a C406A5. Li-ion battery.

It has 3.7V, 11.1W, and a capacity of 3000mAh.

It's also important the connector type and wiring: three wires. But the connector is secondary: you can use the one from the old battery, as you will see latter.

Search in internet for the new battery. It's specially important the voltage, if different, it can damage the speaker or make not work it at all.

I found it in Amazon, but other trusted providers are good too.

In my case, the new battery has a much bigger connector than the old one: it won't connect.

The only way is to cut both connectors, and use the connector from the old battery with the new battery, this is the procedure:

1. Cut the cables from the old battery, one by one and isolate each end so they don't short-circuit, otherwise it can explode or harm you or others. The old battery must be disposed according to local rules. Keep the old connector.
2. Cut also the new battery cables one by one, also protecting each end wire for safety.
3. Cables are normally Red, White/Yellow and Black. Where Red is positive, White/Yellow is the signal one, and Black is ground.
4. Now solder each cable with the same between the new battery and the old connector, one by one, and protect each with the heat shrink tubbing also the three of them.

Once the battery is ready, connect it to the speaker's board connector. Test the speaker by turning it on.

The battery may be half full, and the speaker will show that. You can now connect the speaker to a device like a smartphone and test the speaker. Congratulations!

Once the speaker with the new battery is tested successfully, you can close the speaker by reversing the steps of Step 2.

If this instructable was useful, or you have any questions, please let me know in the comments.