I BOUGHT THIS LAST YEAR TO KEEP A VEHICLE BATTERY CHARGED FOR AN EXTENDED PERIOD DURING MY ABSENCE. WHEN I RETURNED, I FOUND A TOTALLY DEAD BATTERY. THIS THING IS A VERY POOR DESIGN BECAUSE IF THERE IS A POWER INTERRUPTION THE MICROPROCESSOR RESETS AND STOPS CHARGING. GIVE ME THE GOOD OLD PRE-MICROPROCESSOR CHEAPIES THAT JUST TURN BACK ON WHEN THE POWER RETURNS. WHAT A DUMB DESIGN. DUH! I WOULD RECOMMEND A CHARGER FROM CTEK, SUCH AS THE US3300, WHICH IS POWERED FROM THE CAR BATTERY ITSELF AND MAINTAINS ITS SETTINGS DURING A POWER OUTAGE (WHAT A GOOD IDEA!)