TV not charging batteries

Hi. We have recently purchased a 2002 3124KB. We have been on two camping trips so far. The first one was close by with full hookups. The second one was boondocking. We left home after being hooked up to shore power and had full battery charge. When we arrived a few hours later, the batteries were almost drained. The refer had been running on battery power during the drive. We thought the TV's alternator would have kept the batteries charged. On the way home from camping, we left with batteries pretty much drained. The refer was off and nothing was pulling battery power that we know of. When we arrived home, the batteries were still drained. Again, we expected a charge from the TV. The batteries do charge fully when connected to shore power. Any help from the experienced owners out there would be much appreciated!

Diane and Rich

Search will be your friend for this topic. There is a lot of discussion about charging and power loads while towing. You may need to add or upgrade wiring, or as in the case of my Ford, add a relay for charging to occur.

[tentcamper]

It sound like either you have two issues or you are not charging the battery.

Here are my 2 thoughts on your issue:

1 - When your getting ready to leave home you have shore power plunged in and are running off 12v. When you hit the battery test button it reads good. But if you are plugged into shore power, even without a battery connected it will read good or max. Did you check you battery voltage when you were not connected to shore power?? If this is the case and the battery voltage is low after disconnecting from shore power. You have a issuer with the battery connection or ground between the converter and battery. The same wire and ground are used by the TV to charge the battery when running down the road.

2 - When you travel you stared with a full charge battery?? How did you check it was full charged? I will assume you check the voltage with a volt meter when the camper was disconnected from shore power and the TV (7 pin connection is disconnected) and know the converter has charge the battery? You travel for a few hours without running the fridge. When you arrive the battery is discharged. The issue has to be at lease two problems: First you are not getting any voltage to the battery from the TV. Second, you either have a very poor battery or an exceptional drain of the 12 in the camper 12V system when the camper is closed.

Test the TV charge line; using my volt meter with the camper closed, shore power disconnected, 7 pin connector connected to the TV. Disconnect the meter to the battery plus lead and measure the voltage between the the disconnected battery plus line and the neg terminal of the battery you should see something like 12.7 to 13.3 v dc. This will be the voltage of the TV battery.

Test the drain of the camper: with shore power disconnected, 7 pin connector to TV disconnected all lights off in the camper, the camper closed, and fridge off. Read the ohms between the disconnected battery plus lead and the battery neg and wait until the ohms stop changing or rising, which could take about 30 to 60 seconds. I would use ohms law to calculate my amps draw (amps = volts/ohms) use 13.3 volts for and the reading you get from the meter for this calculation.

[Bill]

Some good stuff in Tentcamper's reply. I would suggest that you try the following, similar to his suggestion.
1. Disconnect shore power.
2. Disconnect the positive (+) post from the TM battery.
3. Plug the TM's Bargman connector into the tow vehicle.
4. Start the tow vehicle engine.
5. Measure the voltage between the disconnected TM battery cable and the TM battery negative (-) post.

You should see something over 12 volts. I bet you will see 0 volts. Assuming this is true, possible causes are
a) Most likely - TM main battery fuse is blown. It is right there in the TM + battery cable, about 6 inches from the battery connector. Open up the fuse case and see if the fuse is blown. If not, go to b).
b) Much less likely - Bargman connector is bad. While you watch the voltmeter in step 5 above, have someone unplug and replug the Bargman several times, while shaking the cable. If no sign of life, go to c).
c) Every tow vehicle has a fuse in the 12-volt charge line that runs back to the trailer. Some vehicles also have a relay. And in some vehicles, neither the fuse nor the relay is installed by the factory. Pull out your vehicle's Owner's Manual, that dusty old tome, and find the section on fuses. There will be a description of where to find the fuse box, and a pictorial diagram of the various fuse locations within the box. Look for one that says something like "trailer charge line". Then open the fuse box and see if there is a fuse in that location.

Let us know.

And Mr. P is right. Your best friend for this question will be the Search function.

Bill

[tentcamper]

If you still have a glass fuse? You can not just look at the fuse, you need to test the holder and fuse together. I had a glass fuse holder in my 03 that was defective, it had very high resistance. I have read on this form that many other people have had issues with the glass fuse holders. I replaced the holder with a blade fuse type holder and a 30 amp fuse. I got the fuse holder at the auto parts store.

Some tow ready vehicles have the 12V line wired to the Bargman connector, but do not install the fuse for it in the fuse box. In a few rare cases, the 12V line is connected to the Bargman but not to the 12V source. If no 12V on the connector, check for this.

[SCBillandJane]

I have a similar problem of not having power after starting with a charged battery, running the refrigerator on battery while traveling, and not having enough battery power to use the power jack to raise the trailer off the hitch ball when setting up in the campground. I am totally ignorant of electricity. On Tuesday I went to the TM factory for a tune up. I asked them to check the trailer to see if the problem with the refrigerator was with the trailer. I was assured that their tests showed no problems with the trailer.
Today while getting the trailer for storage, I measured the battery unhooked from all power sources. Volts were 12.55. I hooked up to the tow vehicle power without starting it. Volts were 12.55. I started the tow vehicle and the volt meter jumped around anywhere from zero to 12.9 seemingly at random. I unhooked from the tow vehicle and connected to house current and volts steadied to 13.9.
I have a volt meter but don't understand how to use it. Can you help me test stuff so I can show a Toyota mechanic or camping world or whoever what needs to be fixed. Should I follow the steps you have already given?

Try setting volt meter to a range greater than 14 V ( most likely 20V) DC. One scale will have a ~ the other will have a -- symbol Choose the -- scale. Plug red lead into the Bargman connector in the 1:30 position. Plug black lead into 7:30 Position and start TV. TM not connected. You should see about 13.8V steady. If the voltage was changing rapidly as you stated, you may have a loose connection. If you have an auto circuit breaker in the fuse box, you could have a short and the breaker is resetting ( assuming it is resettable). However once you get it corrected, unless you rewire the 12V line with heavy wire, you will never have good luck running fridge on battery while driving as it draws a lot of current and will either not charge the battery or drain it at some rate. Lots of discussions here, just search. I suggest you add items like drinks etc to the fridge the day before traveling the run fridge on shore power until you hook up. It should do a good job of holding the cold and you will not have to worry about draining the battery.

[Padgett]

"I started the tow vehicle and the volt meter jumped around anywhere from zero to 12.9 seemingly at random."

I'd be looking very closely at the TV wiring. If the TM is wired right then the problem needs to be with the TV. Jumping around a lot with everything else OK sounds like a bad ground. Though it could be either the power or the fround wire in the bargman.

With the battery connected you should see 12v both on the trailer connector and on the TV connector. 12v and ground are the large contacts diagonally oposite on the connector. With engine running you should see over 13v on the TV side.