BCM Community

Somebody told me that before I started messing around with serious solar power I needed to install one of these  (http://www.bogartengineering.com/trimetric.htm) monitors.  So before we left Florida I bought one and had it shipped to Melbo.  Then we tripped over it for 2 months until finally a couple of days ago I got busy and installed it.  I am SO impressed.  I spent most of yesterday playing with it and so far have learned that my battery bank, which I previously thought was toast maybe isn't so bad after all. 

I installed an automotive digital volt meter several years ago.  There's probably 30 feet of various sized wire between it and the batteries but we have been pretty religious about not letting the voltage on it get below 12.  Based on how quickly we reached that number I had concluded that our batteries (3 x Lifeline AGM 8Ds) were not in good shape.  However yesterday I ran a test using the Trimetric to figure out what my battery capacity really was and I got to over 300 amp-hours with the Trimetric still reading 12.2 volts at the batteries.  It turns out that when I have a load on the batteries my cheapo volt meter reads as much as a full volt lower than the Trimetric.  When the batteries are charging the two seem to read relatively the same number but the difference under load is dramatic. 

If anybody is looking for a super cool, relatively inexpensive toy to add I can strongly recommend this one.

Bob,

The best way to wire a voltmeter is directly to the batteries, through a relay operated by the run switch. Most folks just find 12 volts in the dash somewhere, and that is picking up the voltage drop of what ever loads there are on that circuit.

Eagle buses are wired that way from the factory, makes a lot of sense to me.

Yes Bob I have a trimetric also and I rely on it to keep my batts up to speed.

Melbo