From: theise@panix.com   
      
   On Thu, 6 Mar 2025 17:56:09 -0600,   
     sticks  wrote:   
   >  On 3/6/2025 7:54 AM, Ted Heise wrote:   
   > > On Wed, 5 Mar 2025 19:55:25 -0600,   
   > >    sticks  wrote:   
      
   > >>   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).   
   >   
   >  It looks like the PD 4000 power controller you have only does   
   >  one thing that I can tell, that being to convert AC power into   
   >  DC power.  It operates when it is plugged into shore power and   
   >  charges the batteries, but will also provide power for the DC   
   >  power outlets without the need for the battery.  So you can   
   >  rule out using this controller for charging from the DC   
   >  supplied power from the 7 prong plug.   
      
   I think that's probably correct.  Here is the (typical) exterior   
   wiring diagram from the manual...   
      
   https://panix.com/~theise/wp-content/uploads/2025/03/Lance-1475-   
   xt-wiring-traced.pdf   
      
   This shows that the 7-pin does connect to the battery, and seems   
   consistent with the trailer manual statement that "Normally the   
   battery will be kept charged by either the tow vehicle charging   
   system while on the road or by the AC/DC power convertor when   
   plugged into AC service."  It looks like the TV is wired directly   
   to the battery and not by way of the PD4000 load center (though   
   it's also wired into the load center).   
      
   From some sites I've looked at while trying to figure this all out   
   (can't remember where) I've gotten the sense that the Acadia would   
   be trickle charging the trailer battery.  And of course the car's   
   system is designed for lead acid chemistry, so isn't going to be   
   very (or at all) effecive for charging the trailer's lithium   
   battery.  I also have the sense that the fridge must draw more   
   than the Acadia supplies and be drawing the difference from the   
   trailer battery when towing.   
      
   The Lance manual also says, "The 30 amp main circuit breaker   
   located on the chassis in the car connector junction box will not   
   allow power into the trailer or the battery(s) to be charged when   
   an overload or short circuit occurs."  That said, I'm not sure   
   this junction box warrants further investigation so long as the   
   trailer is getting power.  Stil need to double confirm the trailer   
   is in fact getting power from the Acadia, and will try to get that   
   done tomorrow morning.   
      
      
   >  So you do have some AC outlets in the unit I believe, and these   
   >  most likely only work when the shore line cord is plugged in.   
   >  There might be a disconnect switch somewhere, but it probably   
   >  just has a bank, or something like a electrical box that ties   
   >  in all the AC outlets to the shoreline somehow.   
      
   Yes, correct, there are AC outlets in the Lance.  Looks like the   
   power goes from the shore line to the outlets by way of the load   
   center...   
      
   https://panix.com/~theise/wp-content/uploads/2025/02/Lance-schematic.jpg   
      
      
   >      ...To get AC power without being plugged in, you would need   
   >  an additional inverter that would change the DC battery power   
   >  into AC for use at those outlets.  So far, you have not said   
   >  you have such an inverter.   
      
   Pretty sure there is no inverter in the trailer (though it seems   
   there must be one in the Acadia to run its low power AC outlet).   
      
      
   >  I think you're ability to use the lift jacks off the 7 prong is   
   >  interesting.  I think it is probably wired mainly for trailer   
   >  brakes, although it looks like the dry weight of your unit is   
   >  around 3,000 lbs and 4,000 is the legal requirement for trailer   
   >  brakes.  Do you have a brake controller in the Acadia and use   
   >  trailer brakes on your Lance?   
      
   Yes, there is a brake controller in the Acadia, installed by the   
   RV dealer I got the Lance from.   
      
      
   >  How else it could be wired into the Lance's volt system is an   
   >  interesting question. You say you think you also get lights.   
   >  Sounds like there must be some other kind of control box then   
   >  if this is true, and I would certainly follow the power lead   
   >  off the 7 prong to find out where it goes.  Mainly, because it   
   >  should NOT be going directly to the battery since it is a   
   >  Lithium.  You simply cannot charge a Lithium battery properly   
   >  from the alternator of a modern vehicle on it's own. It would   
   >  never charge the Lithium, and it could harm the alternator.   
   >  That capability requires the addition of the DC to DC   
   >  generator.   
      
   So the diagram I posted shows the power does go from the Acadia to   
   the Lance battery.  Is that a problem?  I don't think there's any   
   other kind of control box, unless it's in the junction box under   
   the Lance tongue (or maybe in the Acadia's tow system).   
      
      
   >  You say you get these lights "without any battery connected."   
   >  I'm assuming you mean you either have a disconnect switch, or   
   >  you have the battery cable actually disconnected.  You see what   
   >  I'm getting at?  If the interior DC circuits have no access to   
   >  the battery, how is it they are getting power from the 7 prong.   
   >  Where does it get hooked into the system?   
      
   Yes, the interior lights go on with no battery in place (or with   
   it and disconnected), I think the wiring schematic shows it goes   
   into the load canter.   
      
      
   > > 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   
      
   [continued in next message]   
      
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