Don't rely on this Exdee, mine shows bright blue, 'battery ok', the battery tester however says call the cardiac arrest team cos the battery's dead. There's a marked improvement in the crank 'speed' now, 1/2 second to start as opposed to 1 - 2 seconds
Yeah you are probably right. It looks like a very simple and non-technical indicator. I doubt it has any significance. Probably indicates battery life based on the water or something..