Battery longevity with mild cycling (24/7 Fridge + solar)

[JWA]

Were it my fridge going into a period of inactivity the temp control would be set to maintain it's least cold condition, perhaps it cycling on once or twice in a 24 hour period. That would most likely be more than sufficient for longevity.

[boywonder]

Well, due to this thread, I just turned on my fridge in the driveway.....one 120W panel.

The fridge (Truckfridge TF49) is empty and set to warmest setting; we'll see how it goes.....battery was at 12.9V when I closed up the van tonight.

[rockbender]

BW - I don't recall, do you have a battery monitor? If not, I highly recommend it. I like seeing what my battery debt (in Ah) is in the morning and then checking when I get home to see if I've recovered.

I previously had a Trimetric and now am using the Victron Energy. The Victron has more bells and whistles, but I can't help but think the trimetric may have been a little more accurate? I definitely like the aesthetics of the Victron better.

[boywonder]

My solar controller can display total AH, but that's into the battery from the panel, only 1/2 of the puzzle.

I'll add a battery monitor to my wish list.

[Viva]

I have a Victron BMV now, and in past times had a Link. I don't really see how one can be more accurate than another, since it's just a shunt/coulomb counter? I mean, correct me if I'm wrong, as I'm just thinking to myself and can't see how one could be more accurate than another.

(I have to admit though that I can't stand the Trimetric aesthetically, but that's more of a UI thing.)

I think the main area for inaccuracy (which is a biggie) on any coulomb-counter type monitor is that as the battery bank ages and becomes effectively "smaller," unless you adjust for that (and get it right!), the SOC readings become less accurate in the "dangerous" direction (i.e. making things look better than they are). The amps counter should still work correctly though, even without re-adjusting total bank size/capacity, as it's just tallying in and out.

I added a SmartGauge to my "arsenal," and it uses a completely different method to get SOC: I don't totally understand it, but I think it's a combination of super-smart algorithms, and voltage samplings going on thousands of times per second. It does show voltage, but the main reason I have it is to show an accurate SOC (and not need correcting as the bank ages). I also have the Victron, because it is useful too, and does other things such as amps counting.

Yes, it's a bit of cash spent on gauges, but not so hard to rationalize vs. the cost of a bank of AGM's (and I like the information).

[pjpvi]

I leave my fridge on all summer and let solar keep everything happy. I've had great life out of my house batteries. Have only killed them once (last year at Burning Man had dance lights and home stereo running off of batteries into the night. Suddenly everything went dark and quiet. oops). They charged back up fine and have been happy. House batteries were new February 2009 and have done well so far.

I shut down fridge in the winter unless on a trip.

Phil