Boondock 12 volt charging for RV battery with a Tesla.
Just a heads up for those towing RV trailers with Teslas. The 12 volt charge line on the 7 pin connector deactivates shortly after the drivers seat is vacated. This means that the RV will not draw off the Tesla to charge its 12 volt battery. That’s pretty much normal operation with any tow vehicle now.
However, if one has run their RV battery down after a few days of camping an emergency go to procedure has always been to just connect the trailer to the tow vehicle and get a charge so one can run the furnace etc. This is not possible with the tesla as the 7 pin 12 volt charge line goes dormant when the driver gets out of the car.
The alternative is to use the ACC aux socket in the trunk of the model Y (and probably X, assuming it has one). Make a cable with a female 7 pin receptacle and a cigarettes' lighter plug on the other end. Hook up the two appropriate pins (see any 7 pin diagram for the right pins). You MUST leave the Tesla in sentry mode. Then the ACC aux plugs stay active.
We made a jig using a cheapy tool box to monitor the current and voltage and observed about 13.3 volts and 5 to 7 amps of current leaving the Tesla although the trailer battery wasn’t very run down at the time so it didn’t take much of a charge. It also has a cheapy renogy 9 amp DC to DC isolation converter in line which limits the amount of current drawn from the 12 volt acc plug in the Tesla as it has a 16 amp current limit.
Anyway. Hope this helps someone freezing in their trailer because the RV furnace motor won’t spin fast enough to open the sail switch and enable the furnace. Been there. In our trailer it’s an ALDE hydronic heat and hot water system but same idea. Needs 12 volts for the circulation pump etc.
Heads up. Cameras don’t play nice with LED displays so they appear to be displaying gibberish in the pictures, but in the real world are a nice indicator of what’s happening. Also first pic is a bench test pic using a booster pac as a source. Important for a geeky guy like me. ??.
Cheers.
John.
And just a gratuitous purdy campground picture from last week. :)
However, if one has run their RV battery down after a few days of camping an emergency go to procedure has always been to just connect the trailer to the tow vehicle and get a charge so one can run the furnace etc. This is not possible with the tesla as the 7 pin 12 volt charge line goes dormant when the driver gets out of the car.
The alternative is to use the ACC aux socket in the trunk of the model Y (and probably X, assuming it has one). Make a cable with a female 7 pin receptacle and a cigarettes' lighter plug on the other end. Hook up the two appropriate pins (see any 7 pin diagram for the right pins). You MUST leave the Tesla in sentry mode. Then the ACC aux plugs stay active.
We made a jig using a cheapy tool box to monitor the current and voltage and observed about 13.3 volts and 5 to 7 amps of current leaving the Tesla although the trailer battery wasn’t very run down at the time so it didn’t take much of a charge. It also has a cheapy renogy 9 amp DC to DC isolation converter in line which limits the amount of current drawn from the 12 volt acc plug in the Tesla as it has a 16 amp current limit.
Anyway. Hope this helps someone freezing in their trailer because the RV furnace motor won’t spin fast enough to open the sail switch and enable the furnace. Been there. In our trailer it’s an ALDE hydronic heat and hot water system but same idea. Needs 12 volts for the circulation pump etc.
Heads up. Cameras don’t play nice with LED displays so they appear to be displaying gibberish in the pictures, but in the real world are a nice indicator of what’s happening. Also first pic is a bench test pic using a booster pac as a source. Important for a geeky guy like me. ??.
Cheers.
John.
And just a gratuitous purdy campground picture from last week. :)
