Battery Charging

csonni

Can someone explain here what exactly is taking place with Solar, TV connection and shore power. From what I understand, even when the trailer sits, the solar panel continues to trickle charge the battery. Connecting up the cord to the 7 pin connection allows the TV to charge the trailer battery. When camping, it’s recommended to disconnect the TV so there is no drain on TV battery. The solar continues charging the trailer battery. When connected to shore power, both the trailer battery and TV battery are charged? I’m assuming everything that applies when using shore power also applies when using a generator inverter. Lastly, when is one supposed to use the disconnect switch in the tongue box?

McNutty195

So I'll try to shed some light here.

You've got most of it correct already.

Solar Panel: I don't personally have a factory solar on my T@G, but unless they did something weird, the solar panel should be trickle charging the battery at all times. Even if you are connected to shore power or your tow vehicle, the solar will charge the battery if it is not full. Many times manufacturers hook the charge controller from the panel directly to the battery, so it will charge it even if you "disconnect" the battery from the trailer with the disconnect switch. (Don't know for sure if that's how NuCamp does the T@Gs though.)

7 Pin Connector: This is all correct. When the trailer is plugged into your TV, the TV will charge the trailer's battery with its battery and alternator. Hadn't heard to disconnect when not driving so it doesn't kill your TV's battery, but that makes perfect sense. Edit: I would only work about this during long stops at a campground or such, I don't disconnect the trailer's 7pin at a food or gas stop or anything like that. It doesn't pull that much power

When your trailer is connected to shore power the trailer's built in converter (your fuse and breaker box) converts the 110V AC power to 12V DC to charge the trailer's battery. This will not charge your TV even if it is plugged in as far as I know. Personally, I wouldn't leave the trailer's 7 pin connected to TV if I'm connecting the trailer to shore power. There shouldn't be any back current or anything, but don't see a reason to do it and better safe than sorry. Maybe someone else who knows more can elaborate on this?

A generator inverter essentially acts just like shore power, so yes the same applies as long as you have a big enough generator. A 2000W will easily handle everything this trailer has in my experience.

Finally, the battery disconnect switch is an easy way to "disconnect" the battery from the trailer. This is so that you can avoid running your battery down from Phantom drain from your trailer. Basically, that little blue light on the TV (if you have it) + the stereo + the USB ports + anything else will have a small amount of power drain even when you aren't using the trailer. This can run your battery down over time in storage. Most recommend using the disconnect switch any time you aren't using/are storing your trailer. Personally, I only disconnect it when I know it is going to be a few months before I use the trailer again. We go pretty frequently, so this doesn't happen much. I'd probably recommend you go with the anytime you aren't using it advice, as that's safer, but my way has worked fine for me.

Hope that helps!

zgfiredude

Yes to all the above, with one clarification......the trailer battery needs to be connected when towing.....otherwise the TV will not charge the trailer.

beaky

the charge from the TV to the trailer is a very low charge. in order of charge: 1. shore power 2. passive solar 3. 7 pin

csonni

Thanks for all the clarification. Much appreciated.

Sharon_is_SAM

The battery switch needs to be on or the emergency break away brakes will not work in the event of a complete separation of the trailer from the TV.

csonni

Thats a good one to know!

LuckyJ

@Sharon_is_SAM said:
The battery switch needs to be on or the emergency break away brakes will not work in the event of a complete separation of the trailer from the TV.

That is if you have brake on your trailer.

As for charging the TV battery from the trailer converter, it will charge it unless tge TV as a relay that disconect the charging pin. If not relay exist, the charging pin is connected directly to the TV battery.

Easy way to find out, light test on tge TV charging pin. Electricity is like fluid. If pipes are connected, water will flow either way.

WilliamA

https://teardrop-trailers.vanillacommunity.com/discussion/comment/10172#Comment_10172

That's not entirely accurate.

Passive solar charging is directly related to the wattage of the panels. A 100 watt panel, on a really good day, is going to put out a couple of amps. This is the part of the story where everyone is going to scream that I'm a solar-denyer. Not true at all. I don't use them for two reasons:

1. I rarely stay in the same place for long and don't like spending a lot of time setting up for minimal gain.

2. I have never needed more power than I have, so it's not an issue for me. I've not had issues with keeping my rig going on what I have.

I have read (though I'm pretty sceptical) that output to the trailer harness from some vehicles is reduced from tow vehicle charging output, though I have only my own experience on that. I CAN say that my Rav4, Jeep Cherokee, two Jeep Wranglers and my Jeep Gladiator had unregulated output on the 7 way plug. "Unregulated", meaning that whatever the alternator output was also showed up at the trailer plug. I have tested my tow vehicles extensively for that and my experience is that the 7 way plug provides for fast charging of the trailer battery. I generally get output of 8> amps at the trailer battery "when it's low/discharged". Eight amps for a lead-acid battery is about as high as you'd want to charge one for very long without cooking it. Keep in mind that I have a single lead-acid (grp 27) in my trailer. For folks out there running dual (multiple?) tractor/submarine/forklift batteries or lithium/unobtanium battery combos, your results my vary.

My own WFCO (onboard charger) rarely, if ever, shows as much charging output as my tow vehicle charging line. I have made sure that my wiring is all 10 gauge. Most important, the ground for the 7-way is also 10 gauge, not 16 gauge as is common on new vehicles.

I haven't extensively checked and tested every vehicle on the planet (I'm not Scotty Kilmer) so I can't say for sure, but you'd have a tough time convincing me that any auto manufacturer would build in a completely separate voltage/amperage control circuit just for the trailer charging line. It's just not logical for them to do something like that for the tiny fraction of vehicles pulling trailers.

Keep in mind, the smart (ecm controlled) charging systems on modern autos are programmed to monitor and maintain the vehicle battery/batteries. If the trailer battery has 5 times the capacity of the vehicle battery, it will take 5 times as long to charge it. Accepting ohm's law caveats, (the ecm "see's" both battery voltages as an aggregate/average voltage, then just keeps the vehicle battery within the preprogrammed spec) the ecm is not interested in how well your trailer battery is charged. It's monitoring your tow vehicle battery. It doesn't care how well the trailer battery is charged. The fastest charging system you have is your vehicle.....IF.....your trailer has a similar battery configuration. You don't have to guess at your trailer plug voltage/amperage output.

It's super easy to test it. Then you won't have to listen to me, or Scotty Kilmer....

"One day me and my gal were out walking,

She turned to me and said I must confess,

When you and I get back to where we live,

You'll be at the wrong address"

Or this one:

"She said, I like to argue,

But I disagree"

Cam Waters. From:

"No surprise to me"

WilliamA

csonni

So, if our trailer sits for several weeks without hooking up, should one connect to shore power for some time to charge things up, or is the 100w solar panel enough to keep it topped up?

Sharon_is_SAM

Just make sure you store it with the battery switch off to prevent phantom drain. Solar charging is sun dependent. Best to check your battery voltage to confirm. If in doubt, use a smart charger.

csonni

@Sharon_is_SAM said:
Solar charging is sun dependent.

From what I understand, solar panels also work with cloudy days although not as efficiently. Might be enough to trickle charge a battery, though.

Sharon_is_SAM

I agree that you can get a trickle charge under cloudy conditions. TaB owners have reported solar gain even when they cover their TaB. But, unless you monitor, you are just guessing.

csonni

I remember hearing someone state that, when stopping for an extended period of time (whatever that is), one should disconnect from the TV to keep from draining the TV battery. I did that last night but find it a pain as I use zip ties and/or velcro strap to hold our Curt Echo and trailer wiring tight. Is there a way around this? Is there actually a drain happening even if our trailer battery is charged well?

Bob297

You can also use a diode to prevent draining your TVs battery. I have a park light diode by Roadmaster purchased from etrailer.

csonni

@Bob297 said:
You can also use a diode to prevent draining your TVs battery. I have a park light diode by Roadmaster purchased from etrailer.

I may eventually look into that but, with our trip only a week away, I may have to just put up with it.

LuckyJ

@csonni said:

@Bob297 said:
You can also use a diode to prevent draining your TVs battery. I have a park light diode by Roadmaster purchased from etrailer.

I may eventually look into that but, with our trip only a week away, I may have to just put up with it.

Hum, my plugs hold tgem self together witg some kind of snap on tge cover of my tv plug.