This is a completely (almost) revamped version of the previously posted heart battery icons. This version should be good on both light and dark colored notification bars, where before it was hard to distinguish the dark red when used on a dark bar. Also the heart icon now grows smaller instead of being hollowed out as in the previous version.

Get it at XDA, as always: http://forum.xda-developers.com/showthread.php?t=764792