Shore power / TV power - Montana Owners Club

BB_TX · 08-07-2007, 09:31 AM

I am sure this has been asked and answered, but I could not find it. Are you supposed to disconnect TV cable before connecting shore power? And likewise disconnect shore power before connnecting TV cable? Or does it matter?

kerry · 08-07-2007, 09:59 AM

Doesn't matter

bsmeaton · 08-07-2007, 10:19 AM

For short term it shouldn't matter BB_TX. The only circuit that is actually common between the the two systems is the 12VDC charge wire to the batteries. The rest of the TV connection circuits are completely dependant on the TV and are not affected by the shore power (trailer lights, brakes).

Long term, depending on your TV trailer wiring, your Monty converter may be trying to charge your TV batteries. On my current truck anyway, the 12VDC circuit to the Monty is broken when the ignition is off so back-charging is not a problem.

ols1932 · 08-07-2007, 05:20 PM

No problem. We've left the TV power hooked up many times when we stopped overnight and hooked to shore power. There is no connection between the two.

Orv

dsprik · 08-08-2007, 02:34 AM

Just confirming/clarifying... If the TV umbilical is left connected overnight, AND shore power is not connected, you will drain off your TV batteries? Brad, you mentioned that with the ignition switch off on your truck this connection is broken, though - even though still hooked up?

I always hook up shore before disconnecting the TV.

bsmeaton · 08-08-2007, 04:43 AM

Dave - yes. On my 2006 Ford power to the trailer 12V is OFF when the ignition is OFF.

Not all are that way - my 2001 was "hot" all the time and would drain the TV battery if I was boondocked.

Bill and Lisa · 08-08-2007, 09:11 AM

Many of the newer TVs have what is called a battery isolator which interupts charging via the umbilical when the TV inginition is off. It most likely varies by manufacturer and model. My 2002 TrailBlazer has one, my 2001 Chevy 2500 does not.

Bill

dsprik · 08-08-2007, 03:20 PM

How can you tell? I have a 2002 GMC 2500HD. I guess just get a tester and check the umbilical plug-in when the truck is turned on and then off? Saw a diagram of this plug on MOC a while ago. Can't remember which posts on the plug to check. Does the cutoff also then automatically cutoff the brake magnets?

bsmeaton · 08-08-2007, 07:11 PM

I found out on mine while I had a test light hooked up. Thought I had a fuse out until I learned the key had to be on in the new truck. Does not cut off the brake output.

deadeye · 08-09-2007, 06:23 AM

BB-TX , I think you will find that your hot wire in the wire loop of your tow vehicle goes off when the key is off. I also have a 2001 GMC - 2500HD. That is the way mine is anyway. I think I have also found that that HOT wire does not come off of the alternator to charge the batteries in the 5er. What I am going to do (haven't done it yet) is to come off of the alternator to a starter solenoid switch. Solenoid to be key controlled. Then run extra wire to trailer connector and run through the center prong, which would be the back-up light prong. From there it goes on to the batteries switch in the front compartment of the 5er. This way your batteries are all charging as you are driving and controlled by altenator/voltage regulator when they are charged. I have a Blue Sea Systems High Performance battery switch that you can get from Overton's.com (#70446) for boats to control the batteries. If you need more info, just ask...JB

dsprik · 08-09-2007, 04:22 PM

Deadeye, are you saying that my 2002 GMC 2500HD does not charge the 5ver batteries while I am traveling? Not sure I understand.

ols1932 · 08-09-2007, 05:36 PM

Quote:

quote:Originally posted by dsprik

Just confirming/clarifying... If the TV umbilical is left connected overnight, AND shore power is not connected, you will drain off your TV batteries? Brad, you mentioned that with the ignition switch off on your truck this connection is broken, though - even though still hooked up?

I always hook up shore before disconnecting the TV.

Dave,
You won't drain your truck batteries. I've left mine connected overnight many times without a problem. I have a Ford but I don't think it makes any difference.

Orv

dsprik · 08-09-2007, 05:54 PM

Thanks, Orv. Don't know where I got the idea that if I shut down the engine for a period of time while connected, my truck batteries would discharge.

deadeye · 08-10-2007, 02:01 AM

That is true that you won't charge your batteries while driving on a GM product unless you run an extra wire from the alternator. I think you do on FoMoCo and I don't know about MoPar products. I think that they may have changed it on newer GM's, but I don't know what year. I know my 2001 DOESNOT. That is my project before winter. I had to do this on my 94 Chev. years ago. You will get a 12 volt HOT wire to the 7 prong connector, but it is only 12 volts and not 13.2 to 14 volts that your alternator should put out. Check the rear 7 prong plug with a volt meter with truck running and see what voltage you get...

Bill and Lisa · 08-10-2007, 09:40 AM

Dead Eye,
You reminded me of one of the first changes I made to my truck. I put in the fuse that allows you to charge the battery. Right in front of the driver's postition under the hood is a fuse box. In the top left hand corner is a fuse labeled #1 something - there are only two of this 'block' type in that fuse box. #1 is empty and has some words that allowed me to quickly identify that a fuse in that location was related to charging trailer batteries.

Before installing that fuse readings with a volt meter showed no power between the 12V + and - connectors. After installing that fuse I have 12v DC availabe at those pins on the bargman. Only catch is the voltage is present whether or not my key is turned on so I CAN drain my battery if I am not careful.

Bill

dsprik · 08-10-2007, 11:16 AM

My fuse is in that block...

snfexpress · 08-10-2007, 11:32 AM

In our 2007 GMC (and 2006, as well), yes the fuse needs to be installed. However, your main starting battery will not drain as there is a drain-down protection circuit.

dsprik · 08-10-2007, 02:54 PM

OK... Now I'm just plain confused (or was that "dazed and confused" - Led Zepplin)...

~On Edit: I think I understand. I believe that I have this cut off circuit on my 2002 SLE GMC. I know I have this on my Park Ave. But does that apply to the GMC umbilical cord??? I believe my Park Ave is on a 15 minute timer EXCEPT for the 12v power outlets, which we found out about the hard way on very cold winter night while parked at a hotel with the car electric blanket left plugged in... They are just the Energizer Bunny - they just keep running and running... until they can't run no more. Door locks wouldn't even respond the next morning.

bsmeaton · 08-10-2007, 03:33 PM

Dave,

Use a test light on the receptable and check it out. With the headlights off and foot off the brake - the only prong that should light the test light is the charge line. Once you find it, try it with the ignition off-on-on/runnig and you'll have your answer.

Worst case - it wont light

. Then you either have a blown or missing fuse, or test light from camping world.

Brad

dsprik · 08-10-2007, 04:35 PM

Got it Brad. I will try that tomorrow - with a test light NOT from CW...

I do have that 40 amp fuse in that block in my fuse box, though...

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