My 2 year old set of iHome speakers were great until one of them stopped charging. They were no longer under warranty and I didn't want to shell out money for another set. The cost of the batteries (via eBay) was $11.99 including shipping for the pair.
The hardest part was finding an appropriate replacement battery. SIZE IS KEY as there is a little battery compartment where the battery fits pretty snug.
iHome comes with a 3.7v 280mAh lithium-ion battery. Dimensions are: 33mm(L) * 20mm(W) * 5.3mm(H).
I ended up using a 3.7v 300mAH lithium-polymer battery with circuit protection. Dimensions: 30mm(L) * 20mm(W) * 4mm(H)
The circuit protection helps to prevent over- charging and discharging.
small philips screw driver (smaller than the standard #2)
soldering iron and solder
replacement 3.7v battery (you may want to replace both batteries at the same time).
Step 1: Disassemble Speaker
If your speaker has the twist lock feature (to expose the added "bass"), untwist the speaker. Tilt the top of the speaker to the side to expose the small screws. There are four screws to remove in each speaker.
Once the screws are removed, be careful not to yank too hard - the speaker wires are very thin and can easily detach from their solder points.
Step 2: Battery Removal/installation
You have two options:
1. Cut the wires now and leave a short length attached to the board
2. Remove the wires during the soldering process (I chose this method)
Attach the PCB to your helping hand.
Tip: use tape to hold the PCB to the speaker housing. The tape will act as a strain relief to keep the speaker wires from detaching.
Use the soldering iron to carefully remove the wires from the old battery.
Tip: tin the tip of the iron - this will ease in removal
Tin the wires on the new battery and solder them to proper spot on the PCB
Step 3: Test Connection
Testing will also ensure that the speaker wires are intact before reassembling. I ran into the problem and had to disassemble and resolder the speaker wire.