I've lost track of the number of xtar chargers that just die on their ass in time. Like yourself, I changed over to the i4 around christmas time so we'll see how long this one lasts. It's a no frills offering where hopefully there's little to go wrong with it. The xtar's just seem to have an inherent weakness round the power connection where cleaning makes no difference, the fault manifests itself in the amp draw dropping all the time resulting in ridiculously long charge times.