Originally Posted by brania
Update on Dometic fridge issue. I have added no extra fans. I just went out and plugged in to shore power. The hum occurs on both propane and shore power. Interestingly the hum continued even after I shut the fridge off ( for at least 5 minutes). In any event it sounds like the fridge fan does not draw enough power to drain 2 batteries overnight. I must have another issue.
There are 4 HUGE battery draws.
1) The furnace -> I am pretty sure it is not this as you would notice.
2) Most likely -> Belly tank heaters are on. Look for a switch with a light in it called "tanks" or "tank heat"
3) The Climate Control has not been disabled in your fridge. See the attached manual for how to switch it off.
4) Inverter (if equipped) is powering something 120 VAC (fan, computer, or TV).
there are also 2 "You Did It" possibilities:
1) Your batteries are bad. Have they ever (and I mean EVER) been discharged flat? (zero volts) If so they may need replacing because the plates are most likely very heavily sulphated. It "may" be possible to save them with a 4 stage charger that includes a "De-Sulphation" stage.
2) Your batteries were not fully charged to start with. (my guess)
It takes about 4 days for the on board converter to charge 2 batteries to 100% capacity due to amperage step down as the voltage increases.
It will take about 8 hours with a dedicated 20 amp battery charger running off the generator and will just about never
charge when trying to charge off the tow vehicle's alternator.