Why will my older iPod charge on my iPod-compatible stereo system but my new iPod not charge? Is there a way around this problem?

The iPod nano 4th Gen (and subsequently introduced iPod nano models) -- as well as all iPod touch and iPhone models -- will not charge via Firewire, and instead only charge via USB.

Many older iPod-compatible stereo systems -- including the Apple iPod Hi-Fi, Bose SoundDock, and SDI iHome -- use Firewire charging, and as a result, will not charge newer iPod models that only support USB charging.

However, it is possible to buy an adapter that converts a Firewire-equipped stereo or other Firewire-equipped charging device to support an iPod model that only charges via USB.

One such adapter is the CableJive (subsequently renamed the dockStubz), which the company explains:

This adapter fixes the charging issue by converting Firewire power to USB, and passes through all other connections.

The adapter is 1.4 x 1.3 x 0.6 inches with a male connector on one end and a female on the other. Plug the male end of the adapter into the bottom of your iPod or iPhone, and then attach the female end to the dock or cable on your compatible accessory.

The adapter doesn't prevent the "accessory not made to work" if this is popping up on your iPhone or iPod when connected directly. Since the charge converter passes through all pins, a device that isn't made to work with the iPhone or iPod will still trigger that message.

It may be best reserved for those with expensive iPod-compatible stereos or custom car audio systems, but it gets the job done with a minimum of hassle.

Those with inexpensive iPod "clock radio" type stereo systems might also consider purchasing a newer iPod-compatible stereo system or alternately purchasing an iPod classic model that still supports charging via Firewire.