Balmar Smartgauge vs Trimetric

[Back2PA]

Just coming back from a nice visit on a buddy?s boat in the BVI?s. Talk turned to systems and he?s using the Balmar unit to monitor his batteries - he says it?s a favorite amongst boat owners.


The unit supposedly performs the same function as the Trimetric, but does so using a simple connection to the battery bank along with proprietary algorithms rather than a shunt and ?in/out calculation.? Cost is roughly the same as the Trimetric. He?s running solar plus large genset and about 800AH battery bank, all integrated into a very sophisticated system. Comments?

 

[kdbgoat]

Personally, I would trust the shunt more.

 

[Back2PA]

Personally, I would trust the shunt more.

That was my first thought also, but we?re talking $1M+ boats here, so thinking they haven?t made the decision without researching the best possible options, which is why I?m hoping someone knows something about the Balmar

 

[Lou Schneider]

Without a shunt, the Balmar Smartgauge is unable to measure current flow and relies solely on voltage measurements to determine the battery's state of charge.

By contrast, the Trimetric does measure the actual current flow in and out of the battery using a shunt and uses this to keep track of the battery's SOC.

The problem is even small amounts of current being drawn out of the battery can affect the battery's voltage enough to make this guesswork at best.  The age of the battery is also a factor as older batteries tend to lose more voltage as they discharge than newer batteries.

Balmar's state of charge accuracy is rated at +/- 5% "after a few cycles".  That's nowhere near what you can get using a shunt that actually measures the current going in and out of the batteries.

Boats tend to have larger battery banks than RVs, so possibly the effects of random loads affecting the battery's voltage are less than in an RV.

But from what I can tell, and the feature they promote, is ease of installation, not accuracy.  The main selling point is not having to install a shunt in the main line coming out of the battery. 

 

[Harry B]

This design has been around for a while abroad. It was designed in England and it is standard equipment on British military equipment where battery state of charge info is required.
I imagine it has been well tested before the military commuted to it.

 

[bigbillsd]

Why not just plug one of the volt meters into the dash 12v outlets, has to be just as accurite.  You will get the same information, voltage of a battery being discharged or charged.  I went for a year going by voltage alone.  I installed a Trimetric https://amzn.to/2IPJcHH back in December and can't imagine going back to something that try's to analyze battery voltage.  In my RV there is always a draw on the batteries or they are being charged.  Meaning the voltage isn't accurate.  Even the BMK from Magnum uses a shunt. 

-Bill