DIY: How to Fix iPod Classic Charging Issue?

If your iPod Classic won't charge with a USB charger after replacing the battery with a high-capacity one, check out this article—it might help solve your issue.

There are many online discussions about iPods only charging when connected to a computer and not with a regular USB charger. The answers vary, but the consensus is that Apple designed a special recognition protocol for using chargers with iPods. Testing showed that adding a voltage close to 2V on the D+ and D- data lines allows the iPod to charge with a standard USB charger.

Here's a rough schematic:

Then verify it with a breadboard, and it worked:

Next, make a decoy on a perfboard, roughly like this:

Added a case:

Here's the test: Using an iPad 12W charger, the D+ and D- lines showed 2.6V, and the iPod was not charging:

With the decoy added, the D+ and D- voltage was around 2V (the multimeter shows 1.8V because the voltage drops during charging). The iPod displayed "Charging" with a current of around 300mA:

However, more iPod tests are needed to confirm if this decoy works for all iPods with standard chargers. The iPod Classic and nano 3 passed the test.

Conclusion: Adding a 2V voltage to the data lines is one way to resolve the issue of some iPods not charging with a standard USB charger.

Additional note: If you encounter strange issues, such as the charger still not working, unplug it and connect the iPod to a computer's USB port first, then reconnect the charger. Without detailed observation, it's still unclear what handshake protocol Apple used. More feedback on using this dummy decoy is needed for further analysis.