400 battery not charging while towing with frig on DC

jgram2

Good point @Sharon_is_SAM, thanks.

Tundra57

I'll keep everyone posted when I add the new charger. I do have a150amp alternator, I was worng earlier. I did not think the trailer type made any difference to whether or not it can charge. My guess is that the older dumb charge systems maintained 14.5v output and let battery voltage dictate charge. But smart ones monitor current and will drop the alternator output as charge current falls.

The external charger win care as it will boost the charge voltage to the trailer to suit the trailer need. This comes at the expense of higher current draw from the TV so yes the 12v line to the charger needs to be #8 or #6 also I think 20 amps may be a bit much for the trailer plug hence my suggestion of a high current seperate connection.

Thanks to all for your awesome insights as usual. :-)

GatorEgg

Sharon_is_SAM said:

@Tundra, I think an 80 amp alternator is anemic.  I agree with Cbusguy.

I don’t think the alternator capability is all that much the problem.  I think it is in the way these newer vehicles regulate the thing, or power from it.  They’re trying to be smarter than we want them to be.  As I stated above, my 2003 Tacoma towed our T@b thousands of miles and days with the refrigerator on dc with no hint of a problem.  I had wired the brake controller and trailer wiring, including the charge line myself.  It did not run through or interface any truck “systems” except where needed.  I set up my new truck with a plug in pre-made pigtail and just “plug n played”.  Plugged it into the truck’s waiting plug under the dash and off I went.  I have no idea where goes between there and my trailer plug.  As tech laden as this thing is I bet it’s laughing at me while I try to figure out.

Sharon_is_SAM

@GatorEgg - good point.  The new electronics aren’t always so smart!