Don't worry, it won't drain your battery: the caps will draw power to charge themselves up (which isn't a lot of energy compared to the battery) and will keep themselves topped up - but this is only the leakage current of the caps, which is very very small.

The battery icon means "The voltage went below 10v, but the CPU kept running so I turned the screen back on again". Whilst the icon is on the screen powerfail is disabled. It's nothing to worry about, we added the icon as some people had such bad batteries they were running below 10.16v *constantly* and didn't know it :)

Hugo