Re: Charging from tow vehicle

On Wed, 5 Mar 2025 19:55:25 -0600,
  sticks <wolverine01@charter.net> wrote:

 On 3/5/2025 2:03 PM, Ted Heise wrote:

My thinking was to take a reading from the LiIon battery app
with the battery connected to the trailer and then with the
fridge started (I think it may run off the batt for a minute
or two). Then I would connect the 7-pin to the running TV and
repeat these readings.  Does that seem like a reasonable
approach?

 
 In truth, I think it is pointless in your case.  I think we
 already have agreed now you simply cannot get enough power to
 charge your lithium batteries from the 7 prong.  I would,
 however, like to know if there is power coming in, and going
 out to the trailer.  If there is a power wire hooked up on the
 7 prong on the trailer, where exactly does that power go? 
 Obviously the trailer lights you can easily figure out, and
 they don't use power from the trailer battery.  They draw
 directly from the towing vehicle.  Usually the power tab is for
 trailer brakes, or an accessory of some sort or another.  Were
 you under the impression it somehow went to your battery? 
 Obviously it can't go directly there since it would be
 incapable of charging lithium batteries, so does it go to the
 controller you speak of later?  You need to find out exactly
 where that power goes, and here's why.

Okay, here are some aditional points of information.

I'm positive there is power coming out of the 7-pin connector,
because I've frequently operated the powered lift jack without any
battery connected (i.e., only the 7-pin connected to the trailer).

Pretty sure there is power going into the trailer too, because my
memory (though not certain) is that the interior lights and other
12 V things work in the same circumstance (i.e., no battery
connected, just the running TV).

As I lay awake in bed last turning this over and over in my mind,
I seemed to recall the Acadia had a 110 V outlet in the second row
of seats.  Indeed there is when I checked it this morning.  Rated
at 150 W max, it seems I could use this with my NOCO GENIUS 5
charger (max 75 W draw) to charge the trailer battery in a pinch.
Might could even use it to run the coffee grinder.  ;)

Gotta run to see the cardiologist now, but will come back to this
later today.

--
Ted Heise      <theise@panix.com>       West Lafayette, IN, USA