Re: No solar or refrigerator?
After watching voltages climb to 14.8 during our recent trip only to drop to 12.5 as soon as the sun went down (and knowing nothing about this stuff), I asked a good friend who sells PV systems and has lived off grid for decades to 'splain it to me. Here's my interpretation:
Voltage essentially measures pressure. When there's lots of sun, there are lots of amps heading into the battery so the pipe expands to as much as 14.8 volts before a protective shutoff mechanism kicks in. As soon as the panel stops making electricity, the pressure drops and the voltage pipe shrinks to its standard size, 12.5. If the amperage stored in the battery drops too low to hold that pressure the voltage falls. At 12.2, the reservoir is going dry and can't maintain minimums.
Life and baseball both sometimes are not fair, but it is how you play the hops that counts. —Scott Miller, NYT Sports