Electrical Charging System

[NH Horseman]

I have a 25SB Zinger and wondered about the electrical hook-up system between the Camper and the Tow Vehicle. Are there isolation diodes that prevent the Camper from draining the vehicle battery if dry camping while still hooked up to the tow vehicle? I know the tow vehicle charges the camper battery (at least I assume it does) and wondered about the camper draining the tow vehicle battery when camping while hooked up. Is there any combination that is not recommended?
For example: Hooked up to AC power while still connected to Tow Vehicle while vehicle is running or shut off. Just wondering if the tow vehicle charging system would be fighting the camper converter charging system.

While on the subject; I've been told the Camper Converter is not enough to charge a discharged battery but only keeps one charged up. Is that right? The specs seem to say the converter draws 8 amps. That's a lot of draw at 110 volts (880 watts) and one would think it would be able to charge up a good but discharged battery as well as power the internal lights and other 12 volt appliances.

[casmith]

Hi Jim,

My Tow Vehicles have a factory relay that cuts the 12V connection to the trailer connector when the truck is off. This isolates the two, keeping the TT from draining the truck when stopped.



Craig

2011 35RL

2011 F350

[Lloyd]

I think most vehicles work the way casmith stated.
As far as your on board charger, that should recharge a good battery.
I don't know how many amps the converter draws, I suppose it would depend on how much work it was doing. You're right, 8 amps is a big draw. A furnace fan is about 8.5 amps, and on a cold night it can kill the battery.

[rock1424]

I have always unplugged the trailer from the TV because I have always thought that leaving it connected would drain the TV Battery. I guess I don't know for sure if that's true or not, but I've never had a reason to leave it plugged in and figured better safe than sorry.



Also, your converter has a 3 stage battery charger that will output different voltage depending on the charge state of your battery(s). So yes it will charge a discharged battery, that's what it's made to do.



<TABLE border=0 cellSpacing=0 cellPadding=0 width="100%"><T>

<T>

<TR>

<TD vAlign=top width="23%" ="arialblack12bold">Output Ranges</TD>

<TD vAlign=top width="2%" ="arialblack12bold">:</TD>

<TD vAlign=top width="75%" ="paddingbottom">- Nominal (Absorption Mode) 13.6 Vdc (includes charging and load)
- Boost (Bulk Mode) 14.4 Vdc
- Trickle (Float Mode) 13.2 Vdc (after 48 hrs.)</TD></TR></T></T></TABLE>On edit: I am assuming you have a WFCO 9800 series converter like the one in my rig.

If so here is a link to the spec sheet for it.Edited by: rock1424

[NH Horseman]

Thank you Rock. I printed a copy of the spec sheet on the converter and will check to see which model I have. It was inconceivable, to me, that it would not charge a low battery. It would be foolish to assume that but that's not the only thing I was told when given the "tour" when I picked up the camper.

On leaving the camper hooked to the T.V.; if parking overnight at a rest stop, WalMart, Sams Club, Cracker Barrel, Flying J; etc., I would leave the camper hooked up and wondered about draining the T.V. battery.

[NH Horseman]

Checked my converter and it is a Model WF 8955.

[happycampers]

ca smith and old farmer... thats interesting how you say that your 12v is cut off when the truck is off because mine is always live. I don't know if it makes a difference but I don't plug my 7way in when its on shore power. And since mine is always live I unplug it when we dry camp.

[NH Horseman]

We are getting different scenarios here. If the electrical system is properly designed, it should allow the vehicle to charge the battery but NOT allow the camper to drain the vehicle battery. There should be an isolation diode in the line. That was the reason I asked the question, just to make sure. If there isn't, I would certainly install one in my camper. The way to check that is this: Disconnect the camper battery, don't plug the camper into shore power, see if the 12 volt items work. If they do, they are drawing on the vehicle battery. I suspect they will all be dead.

[Lloyd]

Originally Posted by happycampers

ca smith and old farmer... thats interesting how you say that your 12v is cut off when the truck is off because mine is always live. I don't know if it makes a difference but I don't plug my 7way in when its on shore power. And since mine is always live I unplug it when we dry camp.

I guess I should have been more detailed and specific.
If your TV plug is wired correctly, The spade at 1 o'clock as you face it should be---"auxiliary power lead" going to the aux. battery. Most if not all vehicles now days come with and aux. battery,and a battery specific for the TV. With the TV plug wired such, there should never be a dead/drained battery when you go to start your TV, just because you left it plugged into the RV.
I don't leave my rig plugged into the TV when the land line is plugged in either. Whether it would hurt it or not---I don't know.


And yes, that spade is hot all the time.


Edited by: Old Farmer

[casmith]

The only reason I know this is because on my 2009 F150, I could not get battery charging power from the TV to the TT until I went to Ford and bought a relay and a fuse to complete the circuit. Of course, my luck, a year later, I was cleaning out my glove box to trade it in and there was a fuse and a relay in a plastic bag.



I'm certainly no expert on the TV to TT connector wiring or pin-out but have experienced the relay thingy and summized that the relay would deactivate when the TV was powered off thus opening the charge circuit.



Sorry if I misled anyone.



Craig

2011 35RL

2011 F350

[happycampers]

I will have to further investigate my TV when I bring it back home in the spring. Years ago, my dad had rigged up an aux. battery with an isolator in one of his trucks to work exactly how you describe it and I never really understood the purpose-- now it starts to make sense...

NH Horseman; thats a good idea to test it -- that I will definitely try in the spring.