Victron Displays of Actual Battery Use

pthomas745

Attempt at answering the perpetual question:  how long will my battery last when boondocking?

I have a 2017 Outback, stock Interstate 70AH battery.  Victron 712 installed.  Have the switches on the TV so it is really off.  Installed the Variable Rheostat mod on the Fantastic fan.

Your mileage and amp use will vary.

Picture 1.  The parasitic drain on the battery with nothing running:  3 watts, or .2 amps  In theory, I should use one amp about every five hours.

Picture 2. About 24 hours later:  The Victron says the trailer has used 5 amp hours over the last 24 hours.  With my 35 available amp hours, the trailer can sit this way for "about" 7 days before I reach 50 percent.  This is what happens when you park your trailer and don't turn the battery switch off.  Come back a few days later, and the parasitic drain is still doing all those little jobs, sapping your battery

Picture 3.  24 hour use of the fridge on propane.  Note that Power and Current are now up to 3 watts and .3 amps, compared to the 2 watts and .2 amps of the parasitic drain picture.  Over 24 hours, this added up to an extra 4 amps on top of the parasitic drain.  At 8 amps a day from my trailer, the battery will last "about" 4 days.  Maybe.

Picture 4.  An example of TV/DVD power use with the fridge running on propane.    I played Star Wars IV...Or, A New Hope, or..the first one...or "The One Where Luke Blows Up The Death Star."  Propane fridge still running.  Now the power use is up to 2.4 amps.  The parasitic drain is still taking its .3 amps, so the TV DVD is taking about 2.1 amps to run the movie.  At a two hour run time (and a few more minutes to replay the Death Star explosion, always a crowd favorite) watching a movie will take up about 4 amps.

BrianZ

Yes, anyone with a Victron battery monitor should do this exercise - it's very enlightening to see & understand what's happening.  I've documented mine in a similar way.
I recently added cutoff switches to both the Alde & Jensen units to eliminate those unnecessary phantom power drains when trying to conserve battery power.

Horigan

BrianZ said:

I recently added cutoff switches to both the Alde & Jensen units to eliminate those unnecessary phantom power drains when trying to conserve battery power.

Do you have more information on how you did this?  Did you use relays or just a switch on the power wire?

pthomas745

And, here is a question:  what is it that the fridge requires amps for while on propane?  The fans were not running, since it was a nice cool day when I did this test.

BrianZ

Yes, @Horigan, please see my multiple messages on page 2 of this discussion showing wiring, etc..

https://tab-rv.vanillacommunity.com/discussion/6415/phantom-drain/p2