The battery in my Sharp GX30i mobile phone now only lasts for about a 20 minute call. This battery is a replacement from Power Mart aka Topscope Pty Ltd, purchased in August 2009 for $19.95, plus $4.50 delivery. The original battery with the phone lasted more than four years, so the replacement only lasting about 20 months is disappointing. However, this is within the expected life of a Lithium Ion battery.
The company Battery Charger are offering a replacement for the SHARP XN-1BT30 battery, at only $7.69 (assuming they still have them). The catch is $10 for Australia Post registered delivery. While I am at it I might as well order another battery for a Motorola U9 as well (for $9.22). The company gets a positive mention in the Whirlpool forum.
I did consider a new smart phone, but the old 2G phone has worked reliably (being dropped many times) and carries out the main function of making phone calls. Also it would be a shame to create more e-waste by throwing out a functioning phone. Also there is an new range of higher function low cost smart phones about to come out, such as the HTC Wildfire S. That should cause the price of existing units such as the Huawei Ideos u8150, to drop to under $100.