Quote:
Originally Posted by nhinze
This trailer came with a small solar panel on the roof. I'm guessing less than a 100W probably. The trailer was built in 2006. The voltages I'm reading are from the "Solar Regulator" screen. It also has a "Battery Charge Indicator".
When plugged into shore power and the fridge on it says it is charging the battery at 14+ V. Removing shore power and connecting to the vehicle with the engine on, the charging voltage drops to 12.5V.
I don't have a TV in there. Essentially only the fridge, lights, and radio are 12V.
Is this whole setup ignoring the vehicle charge line and defaulting to the solar panel? That tiny panel cannot keep up with the demands on the fridge in 12V mode.
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The tow vehicle charge line, solar, and built in converter/charger all work together if they are all "on". They do not switch "in", "out", or "default. The highest voltage provides the most current. Lowest voltage provides the least current.
Most late model absorption refrigerators work on propane or 120 volts. They only use a small amount of 12 volt current to run control circuits. A few models use a large amount of 12 volt current to power the heater in the boiler.
Assuming yours uses 12 volts to power the heater in the boiler, expect that heater to use a lot of 12 volt power. The built in converter charger can probably provide enough current to satisfy the refer and charge the batteries. This explains the 14.4 volts you see when plugged into shore power.
The small solar probably does very little to help the refer run when not connected to shore power. A 100 watt panel may provide 6 to 8 amps in direct sun when it is new. A smaller, older panel may provide a lot less. Battery terminal voltage would be expected to drop slowly.
A tow vehicle charge line may provide a little or a lot of 12 volt current. It depends on how it was installed. The limiting factor is typically the size of the 12 volt power wire and the size of the negative ground wire. A small alternator can also limit.
Many smaller tow vehicles use 10 gauge wire for the 12 volt positive. I have seen some that use smaller 18 gauge ground wire or no ground wire at all. In this case the tow vehicle cannot supply enough current to fully power the refrigerator. Battery voltage will slowly drop. That would explain the 12.5 volt reading while connected to the tow vehicle.
I installed an 8 gauge charge line and short 8 gauge ground wire, and a bigger self resetting circuit breaker in my Nissan Pathfinder. I get much better charging from my tow vehicle now.
I run my refer on propane while driving. I check to see it is still lit whenever I stop. The wind sometimes blows to fire out.
I wish you good luck and happy trails ahead!
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