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DJW · 07-12-2015, 09:45 PM

Hiya, Not sure what subgroup this crazy question might belong in, so...

We are NEVER in the AS without being hooked to power. For the first time we are spending 3 nights in a NP campground with no electricity, etc. We will be very careful with our power use, but not sure we'll make it without a re-charge. Our trailer just isn't set up to be real energy efficient since we never use it away from shore power.

What if.... I connect the trailer, through the pigtail, to my '07 Tundra and just let the truck idle for an hour or so? Will the alternator on the truck see the lower voltage and charge the trailer's house batteries? Would it be better to use jumper cables from the truck battery to the trailer batteries? Or, is this just stupid?

Thanks!

Don

drboyd · 07-12-2015, 09:51 PM

A lot of people do just that. Between that and generally being careful with your electricity usage, you'll be fine.

Just make sure you've got plenty of gas in the Tundra.

BoldAdventure · 07-13-2015, 07:25 AM

Opinion, yes that will work. But I don't think anyone in the National Park campground is going to appreciate listening to your Tundra idle for an hour or even a half hour. We're in Devils Tower (right now as of this posting), and it's peaceful and quite here.

tjdonahoe · 07-13-2015, 07:38 AM

Quote:

Originally Posted by BoldAdventure

Opinion, yes that will work. But I don't think anyone in the National Park campground is going to appreciate listening to your Tundra idle for an hour or even a half hour. We're in Devils Tower (right now as of this posting), and it's peaceful and quite here.

Hi there I spent several years in that area , glad you like It, if you get to billings, we could have a spot for you....

AWCHIEF · 07-13-2015, 07:39 AM

Last summer I was parked next to a red neck idiot with an old diesel monster truck that did this. The winds was blowing his putrid exhaust directly into my trailer. Thankfully the next morning him and his two friends were raided by the state police and carted away for stealing from trailers in the park.
So two lessons in this: #1 have some consideration for others and #2 keep a low profile if you behaving in a criminal manner.

rwnash · 07-13-2015, 08:20 AM

I have never had much luck getting a trailer to charge off the tow vehicle; the wiring is just too long and is typically not very large in diameter. Also, the voltage difference between the vehicle alternator and the trailer battery is probably only a couple of volts at best - not an ideal situation. Obviously, it depends on your particular situation and if you know wire sizes and distance you can use Ohm's law to calculate how much charging will occur.

However, based on my experience I suspect for three days you will be Ok if you are careful about how much electricity you use. We rarely are plugged in and can go several days without any problem on one battery; 4th of July we were down to 12.4 volts after 5 days.

One thing to check is the "anti-sweat" switch on the refrigerator; I found out the hard way that it consumes a great deal of power.

Good luck,

Whit Nash

Melody Ranch · 07-13-2015, 08:23 AM

Charging from the truck is to weak to recharge the battery. Be careful about leaving the truck connected to the Airstream overnight or all day. You can drain the truck batteries dead....then, your SOL if your boon docking.

DJW · 07-13-2015, 08:24 AM

Thanks all. Please know we'll be respectful of the folks around us in the camp. We're going to be part of an AS group, some of which will be running generators during the day to re-charge. The plan is , if we need to do anything, to run the truck at the same time as others run their generators. I think our Tundra makes about as much noise as a Honda E2000. Maybe we won't need it at all.

Don

Foiled Again · 07-13-2015, 09:06 AM

If you're part of a rally or group of Airstreamers, some of whom have generators - I'm sure someone will be willing to let you charge your batteries from their generator. I have a Honda 1000 which I carry JUST in case I need to (A) fill a tire with air or (B) recharge a battery either on the coach or the truck.

I've lent it out on occasion to help fellow RVers.

It's also good to run a fan or two which always helps when boondocking.

Paula

Wingeezer · 07-13-2015, 09:38 AM

I believe that the tow vehicle will charge the trailer but at a pretty slow rate.

Like you, we seldom are at an RV park without power, but we do sometimes overnight at Flying J's and similar on snowbird trips south.

Mainly for that reason - plus the odd stop at a park with no electricity - I decided to buy one of the Honda 2000 watt genius.

At a Flying J stop, we will run the generator in the evening, locked to the trailer tongue, in order to use the furnace, tv, appliances, etc. then at bed time I put it away in the truck so it doesn't "grow legs and walk" overnight - even though it would be locked!

If we get a really cold night, then running the furnace overnight can take a lot out of the trailer batteries and so I may start up the gennie again for an hour or so in the am while we have breakfast. The built in charger in the AS has a max charge rate of 40 or 50 amps I think so that should ensure our batteries are back up to snuff.

The small gennie has proven handy around the house too for the odd power failure, and sometimes I take it to the trailer which is in a storage yard to run power tools if doing small jobs on the AS. I could even run a small Lincoln Mig welder that I have with it.

I got a pretty good deal on the Honda with free shipping, (As I recall, it was $850 maybe four years ago.) and I think there is always an excellent resale market for them if ever I no longer need it. It has been a good purchase for me.

Might be something to consider.

Brian.

m.hony · 07-13-2015, 10:24 AM

Seems like on my Toyota there is no power to the umbilical unless the truck ignition switch is on-

Gnorts · 07-13-2015, 10:34 AM

Quote:

Originally Posted by DJW

Thanks all. Please know we'll be respectful of the folks around us in the camp. We're going to be part of an AS group, some of which will be running generators during the day to re-charge. The plan is , if we need to do anything, to run the truck at the same time as others run their generators. I think our Tundra makes about as much noise as a Honda E2000. Maybe we won't need it at all.

Don

Take a long extension cord and an adapter, and plug into a neighbor's outside receptacle...just be sure heavy loads like water heater and air conditioner are off, and it should work fine. Probably a faster recharge than from your truck's alternator.

dannydimitt · 07-13-2015, 10:48 AM

this is a great way to charge the battery in the trailer , till your able to get on the road . We also plug the cord into the truck every time we are parked some where with no electrical outlet. The Two huge batteries in the truck supplement the single little battery in the trailer . Have never come close to sucking enough juice out of the truck batteries to interfere with starting the diesel in the morning.
ps. if it ever did , could fire up the generator and the inverter in the trailer will charge the truck batteries as well as the trailer battery.

c177tx · 07-13-2015, 11:23 AM

I learned the hardway about leaving the trailer plugged into the TOw Vehicle overnight. Woke the next morning and had to get a jumpstart. Was running both fans all night long. Camping on the beach with no wind that night, figured the two house battieries would handle it, but they were the original battieries and several years old Be sure to check the health of your batts before the trip

timhortons · 07-13-2015, 11:26 AM

If things are set up properly you should be able to charge at about 10A or ~100WH per hour when connected with the vehicle running.

There's a diode that is supposed to prevent reverse drain on the TV battery for the safest results, disconnect the TV at night.

Radio/Fan/Fridge Fan/LED Lights/Water Pump,Tablets/Phones ... with and solar and TV top ups you can live without Shore Power, indefinitely or beyond water capacity anyways.

I prefer this to carrying a generator and gasoline around.

Wolf Alaska · 07-13-2015, 11:28 AM

I use a portable PVC array that folds & can be carried like an attache case. It provides 120 watts or 8.3 amps of 12 VDC all day. I put a 12 VDC outdoor receptacle on top of the battery box. I plug the powercord into that.
Quiet recharging power & the battery is fully charged at the start of each evening.
Let's Roll !
Wolf

leedav · 07-13-2015, 11:43 AM

my dealer assured me that the battery was isolated. Never trusted that enough to leave the trailer connected to the TV

xrvr · 07-13-2015, 12:41 PM

Should not drain the TV batterys on any pickup I've had. Chevy, dodge and ford van.

m.hony · 07-13-2015, 01:02 PM

I seldom ever disconnect the trailer umbilical from the tow vehicle. It has never killed the battery, but I put the switch in the trailer on "store" so nothing but the propane detector and tongue jack would be connected. I don't think there is any juice going from the tow vehicle to the umbilical until the ignition switch is on.
The electric tongue jack runs faster after starting the vehicle, but that may be because the alternator is charging.
I wonder too if the tow vehicle is like my Harley- after the battery drops to a certain voltage the theft deterrent system stops working to stop draw on the battery to keep it from going dead.

Sent from my iPhone using Airstream Forums

Al and Missy · 07-13-2015, 02:15 PM

Quote:

Originally Posted by timhortons

If things are set up properly you should be able to charge at about 10A or ~100WH per hour when connected with the vehicle running.

There's a diode that is supposed to prevent reverse drain on the TV battery for the safest results, disconnect the TV at night.

Radio/Fan/Fridge Fan/LED Lights/Water Pump,Tablets/Phones ... with and solar and TV top ups you can live without Shore Power, indefinitely or beyond water capacity anyways.

I prefer this to carrying a generator and gasoline around.

If there were a diode in the 12V connection from the truck, it would have to be in the direction to prevent current flow from the trailer to the truck or the truck would be unable to supply power to the trailer. What SOME trucks have (my F150 did, my Ram does not) is a relay that supplies 12V to the trailer only when the engine is on.

Tim Hortons is correct about the 100 WH per hour, but a group 27 battery is about 100 Amp- hours so it would take 10 hours or more to fully charge it from zero or about 5 hours from 50%, which is the recommended limit for discharge.

Al