13.6 volts as charged by IOTA indicates full charge and in float mode. How long after the fridge ran before you checked voltage & found 12.5 volts?So I have a dec 2016 build camper (so you know the battery age)
Dual exide option, 150ah of power
I have charged the battery to 13.6 v as read on a meter
After 12 hours overnight, with only the fridge set to 5, it's at 12.5v
The math doesn't add up. Everything else is turned off, and from what I can find with the 2ah (two way 85 fridge) the fridge takes, there's no way it should eat up that much voltage.
Thoughts before I spend 500 on two 6 volts?
I am going to pull both batteries and have them tested at camping world, who is an exide dealer, to rule that out, but that seems like far too much of a rapid discharge for the small load.
Thoughts?
I have seen my voltage with fridge running indicate 12.4v and 20 min after stopping show 12.7 volts. It is normal for the battery to recover some voltage after being under load. That is why the Trimetric is so informative. It is measuring current consumed or added over time rather than guessing by measuring voltage. That gives a truer picture of the state of charge of the battery.
Another issue to confuse things is marketing talk. If a fridge consumes 4 amps while running but runs for a total of 30 minutes per hour in average conditions, it consumes 2 amp hours per hour or an average of 2 amps. So if you know the running current consumption of the fridge and track the actual number of minutes the fridge runs in one hour, you can multiply the running current by total minutes run time in an hour then divide by 60 minutes per hour, you will know how many amp hours your fridge consumed from your batteries.
Do some tests and calculate what is actually happening in your system before assaulting your wallet. You may be better off buying additional solar panels and a Trimetric battery monitor rather than new GC2 batteries. Even with the larger capacity batteries, you just extend the run time before the batteries are depleted if the solar is insufficient to replace the energy consumed per day. Hang in there to better understand your system.
$500 is not an insignificant investment. $400 for a Trimetric & another panel may serve your needs better. In a couple of years, LiFePO4 batteries may be near as cheap as two GC2 batteries and much lighter. Be patient, Grasshopper.
Paul
Edited by PaulT, 27 July 2017 - 05:35 PM.