Connection to TV

[Sparky0]

RV - 2005 Trillium
TV- 2008 Pathfinder
Battery - 2 x 6v US battery 2200 (232 AH)

So... this weekend I charged up the batteries and headed out on a 2.7 hour drive to our campsite. When we arrived I discovered that I had 70% charge left (69 AH taken from the battery).

When I get home I fully charge the batteries to the controllers 14.6 target. Next I plug in the TV and instead of charging like it usually does, it was drawing 4 amps from my panels and god knows how many amps from the battery. The voltage dropped from 14.6 to 13.2 immediately and went back up to 14.6 when i disconnected the TV.

When the TV is disconnected, the batteries hold a charge perfectly.

Has anyone ever had this happen? I would think if I had a short somewhere, i would have a blown fuse, not a constant draw.

Any ideas?

[Markz]

Sounds like you need a battery isolator. Does your vehicle's battery maintain a charge when not connected? I would also recheck your trailer's umbilical wiring for a short.

[Sparky0]

Originally Posted by Markz

Sounds like you need a battery isolator. Does your vehicle's battery maintain a charge when not connected? I would also recheck your trailer's umbilical wiring for a short.

Yes, the battery on the TV maintains charge when not connected.

I'll be testing the amp draw on the 12 volt "charging line" on the 7 pin tomorrow.

What I'm wondering now is, if the battery in the TV is charging to 13.5 or so and the RV battery is at 14.6 (solar charging).... wouldn't the charge reverse and send voltage and current from the RV to the TV?

No sure... but as far as I know a High volt battery drains to a low volt battery. Just two different charging profiles may be doing this?

[ehoepner]

14.6 volts is over charging your battery. That high voltage boils the battery dry and burns it up.

Your truck voltage of 13.2 is correct, no problem with your truck, the problem is in your converter. The factory installed converters over charge the battery if left connected to long.

[Byron Kinnaman]

I wonder if the power to your Television is backwards.

[Sparky0]

The solar controller (3 stage) charges the deep cycles up to 14.6 and then stays at 14.6 for 2 hours during the absorption cycle and then goes down to 13.6 for float.

The 2.45 (x6 cells)= 14.7 absorption phase is actually in the spec sheet for the US Battery 2200 6v.

Which still puts my RV battery at a higher voltage than my TV battery.... and thus, possibly, the current going the other way.

I've added about 2 cups of water to the battery bank in the last 60 days.

It's only 5 amps going in through the solar on bulk and 2 amps (Would like to get another panel to get from 2 to 6 amps) on absorption, so not much boiling going on.

[Sparky0]

Originally Posted by Byron Kinnaman

I wonder if the power to your Television is backwards.

TV= Tow Vehicle.

[John in Michigan]

Would be very interested in knowing the root cause. Is it possible that the solar charge controller is actually keeping the TV battery above the voltage at which the voltage regulator activates the alternator? In that case the solar charge controller would be supplying current to the TV instead of the alternator.

I suppose its possible that this could be happening at least part of the time that the TV is running/towing.

[Sparky0]

Originally Posted by John in Michigan

Would be very interested in knowing the root cause. Is it possible that the solar charge controller is actually keeping the TV battery above the voltage at which the voltage regulator activates the alternator? In that case the solar charge controller would be supplying current to the TV instead of the alternator.

I suppose its possible that this could be happening at least part of the time that the TV is running/towing.

I think this might be exactly what's going on. I'm heading out to the RV storage with a hand full of test leads and a multimeter.

My first order of business is to find out if the draw is coming from the pins for e brakes, running lights, turn signals (possible short). If they check out ok, then it must be the charging line. If the charge wire is drawing back into the TV battery, I'm just going to disconnect it, as I already have solar charging as I'm driving.

I'll post what I find out.

Thanks everyone for the input.

[Sparky0]

OK, so here's what I discovered...

The charging wire voltage at the TV 7 pin connector is 14v.

If I plug in while the RV solar controller is sitting at less than 14 volts, everything is fine and the TV is sending amps to the RV.

If I plug in the TV while the RV batteries are at more than 14 volts (like 14.6), the charge goes in the reverse direction. RV to TV.

Once this happens, even if the trailer voltage drops below 14 volts, the current direction doesn't correct itself. The RV keeps feeding the TV.

It's like the TV alternator is sensing the difference in voltage, turns off, and won't reset when circumstances change.

To me it's not worth having the charging line on the 7 pin if the two systems are confusing each other.

I snipped the charging line on the TV and put an inline waterproof fuse holder without a fuse... in case I ever want to activate by putting in a fuse.

Note: non of the other systems in the 7 pin connector were drawing excessive amps... so no shorts.

Thanks again for everyone's input.

[John in Michigan]

Originally Posted by Sparky0

If I plug in the TV while the RV batteries are at more than 14 volts (like 14.6), the charge goes in the reverse direction. RV to TV.

Once this happens, even if the trailer voltage drops below 14 volts, the current direction doesn't correct itself. The RV keeps feeding the TV.

It's like the TV alternator is sensing the difference in voltage, turns off, and won't reset when circumstances change.

I had read that a TV voltage regulator will "turn off" the alternator when the battery voltage exceeds 14.5 volts. THEN the TV voltage regulator won't "turn the alternator back on" until the battery voltage goes below 13.5 volts.

[Sparky0]

Originally Posted by John in Michigan

I had read that a TV voltage regulator will "turn off" the alternator when the battery voltage exceeds 14.5 volts. THEN the TV voltage regulator won't "turn the alternator back on" until the battery voltage goes below 13.5 volts.

That sounds close to what's happening.... in my case the RV was showing 13.2 and still sending current to the TV, so the "turn Back on" for the alternator might be less than 13.2 for the Pathfinder"

[Markz]

What is running off your battery bank while you are towing?

I only run my refrigerator from the TV but can flip a switch and use the TV to charge the RV battery if needed. If my battery is fully charged when I depart i have no reason to switch on the battery. I use two 3-way switches to isolate the solar and battery as desired. I also use a relay connected to my running lights to assure my refrigerator is only pulling power when my running lights are on, which would only be while driving.

[Franswa]

all of that is way too confusing for my little brain.....

"To me it's not worth having the charging line on the 7 pin if the two systems are confusing each other."

I came to tat same conclusion as soon as I started "playing" with solar....and decided to keep the two (TV, trailer) completely seperate.....except for the ball, chains and trailer lights of course

and I don't watch TV when I'm camping....good one Byron...

[Sparky0]

Originally Posted by Markz

What is running off your battery bank while you are towing?

I only run my refrigerator from the TV but can flip a switch and use the TV to charge the RV battery if needed. If my battery is fully charged when I depart i have no reason to switch on the battery. I use two 3-way switches to isolate the solar and battery as desired. I also use a relay connected to my running lights to assure my refrigerator is only pulling power when my running lights are on, which would only be while driving.

I've got the battery shut off to the rv during travel. The draw is coming exclusively from the tow vehicle.

[Joe Romas]

Could your Nissan be like 09-14 Fords F150?
It seems Ford has a better idea and your truck be similar.
Here's at least one thread of many I found, you may find it interesting.
https://www.f150forum.com/f118/trail...arging-298371/

[Sparky0]

Originally Posted by Joe Romas

Could your Nissan be like 09-14 Fords F150?
It seems Ford has a better idea and your truck be similar.
Here's at least one thread of many I found, you may find it interesting.
https://www.f150forum.com/f118/trail...arging-298371/

I don't know. What I do Know is that i installed the required tow package relays under the hood to accommodate the 7 pin connector and brake controller.

Side note, I did some traveling this week and found there to be little to no difference between running with the panels alone and running with the charge wire connected. I think I'll just keep the charge wire out of the equation and throw a fuse on it if I find that I need it. Rainy day traveling and such.

Thanks for finding that info though. Interesting.