Battery Bugs, new monitoring tech?
... written for Panbo by Ben Ellison and posted on Mar 20, 2009
Lest you think I'm just about big diesels, check out the good Annie G.'s auxiliary propulsion power system. Years ago I bought the cheapest Minnkoda electric trolling motor I could find (visible on Annie here) and moved the control switch to that battery box where the 'custom' wooden shift/throttle gives me five speeds in forward and three in reverse. None exactly makes the 18' iron-keeled sloop jump, but the rig is handy for getting into the Camden Inner Harbor slip I often use. But I always had a problem knowing if I had enough charge to use the motor as needed. That was neatly solved last summer with the addition of that solar panel and most especially the Argus Analyzer Battery Bug...
Argus makes DCM model Battery Bugs for applications like Annie G, and STM models for batteries used mainly to start engines, and they claim to use innovative testing technologies in both cases. The test for deep cycle use is called Large Pulse Resistance, which an Argus representative told me is similar to load testing the battery every minute (and keeping a history of same), while "Crank-Check captures the voltage profile of the battery during the starting sequence." I don't know enough about such matters to opine on how these truly compare to other battery monitors out there, but my knowledge of, and confidence in, little Gizmo's starting battery and Annie G's solar system was vastly improved by them last season. And both Battery Bugs held up well to my abuse. But they don't make much sense on a bigger boat like the new Gizmo -- which has, God help me, four battery banks all tucked into the inhospital engine space -- because they'd be hard to look at, and I'd never hear the alarms. But I do wonder if the testing technology might become a networkable sensor, and said as much to Argus. Over in the forums, our guy Russ is not happy with his bigger boat battery monitoring, and I'm wondering if any of you are?
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If this little bug works it could be hand if one can gain access to it because the chord restricts placement of the display at a max of 18" from the battery terminals. This means it's probably not viable for most marine applications where batts are placed low, covered and out of sight. This makes sense for some applications however, where fixed mounts would not.
I find the Link20 to be inaccurate for multiple reasons as far as "capacity" and so forth. But I believe the volt meter is quite accurate and probably the ammeter as well.
Batteries are difficult to manage because they have a normal life span degradation and this is affected by environment and how that are used, charged and so forth. A battery is not like a tank of water which you can read it's volume and know how much you need to out back in where you are dealing with a fixed volume etc.
Still waiting for better battery technology.