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Posted by David Sherman on Thursday, April 23, 2009 at 14:04:54 :
In Reply to: Argus Battery Bug posted by Dan Shockley on Thursday, April 23, 2009 at 12:01:59 :
I too would be interested in first-hand experience. I've worked a fair bit with batteries in portable electronic equipment and it's notoriously difficult to figure out the condition of the chemistry inside the battery based on monitoring external electrical parameters. A hydrometer tells you more than any electrical measurement ever could, which is part of why I like traditional flooded batteries.
For preserving batteries in storage, lead-acid batteries love a constant-voltage charge, and you can put 13.8 volts across a bank of stored batteries forever to keep them fully charged with no damage. No need for any tricky gimmicks that "pulse" them or let them cycle over some range.
It's hard to figure out from the web page just what the Argus does, but from what I can tell, it merely monitors battery voltage and uses a microprocessor to translate the readings into human-readable instructions. They claim it tells you if your battery is overcharging, undercharging, or is "old", the latter presumably meaning that the voltage drops too much while cranking. You can get all that information yourself with a simple ana.log voltmeter ($5 at Harbor Freight) if you know what to look for. It's not that hard to glance at the meter while driving to see if the voltage is too high (overcharging), or too low (undercharging), or while cranking to see if it's starting to drop lower than it did when the battery was new.
To go beyond that, like the battery monitor chips in laptop computers do, requires the the microprocessor know a great deal about the charging and life cycle characteristics of the particular battery being used, and that it monitor not just the voltage but the current in or out of the battery and the temperature of the battery itself.