Simplest way to run minimal 12v in a trailer (1 Viewer)

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Hi Folks,

The wife would like to go to Tetons/Yellowstone in October, which means we'll need an electric blanket for her camper (small teardrop).

Ideally I'd like the trailer to live independently of the vehicle as I've only got 4-pin wiring now and would rather not re-wire (old truck with a lot of half-assed DIY wiring throughout). If that's just stupid and I must go 7-pin, please let me know. We also don't plan on doing a lot of driving with the camper in tow aside from there and back, so not much charging time from the vehicle.

Will a big deep cycle battery run an electric blanket for 3-4 nights on one good charge? If so, how do I wire a 12v blanket to the battery? Fuses needed? Or would it be better to get an inverter and run a 110v blanket?

Side note: eventually we may do a more complex wire-up with solar panels on the camper and maybe some 110v and USB, but there's no way in hell I'm getting that done in the next few weeks :hillbilly:

Honestly, clueless, please explain things like I'm 5 years old. Thank you.
 
Depends on your electric blanket setting. Typically about 50 watts, so in 8 hours that 400 watt hours or at 12 volts 33 amp hours. There are 12 volt electric blanket so you don't need an inverter. So this could work with a deep cycle battery but to maximize the life of the battery, I'd count on getting at least a 60 amp hour battery.

And of course, you should fuse it, unless you know the blanket has a fuse. I'd fuse it in any case.
 
I'm still working on understanding the conversion math. Like I said, clueless.

But if I interpret your reply correctly, a 60 amp hour battery would reliably run the blanket for one night. That's not gonna be enough, we'll need probably 3-4 nights (in cold weather), without charging in between.
 
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I'm still working on understanding the conversion math. Like I said, clueless.

But if I interpret your reply correctly, a 60 amp hour battery would run the blanket for one night. That's not gonna be enough, we'll need probably 3-4 nights (in cold weather), without charging in between.

For 3 nights, you need 200 Amp hour battery. That's pricey and huge! You could use a smaller battery but will stress your battery more since you'll be deep discharging more frequently. For more than one night, you should get a gas or solar generator to charge you battery.
 
We camp in winter weather quite often.
We use a down comforter and it works great. It is cold getting up though.
We warm up the bed with hot rocks from our campfire.

I would use a gas heater in your circumstance.
 
You've never met my wife. I'd be OK tent camping down to 20* night time temps, but she is a totally different story. We have a little buddy but it doesn't fit into the floorplan of the teardrop very well and we're also concerned about carbon monoxide.

Ultimately, we want a good solar-charging setup, but maybe putting off this trip till next year or renting a camper van would be a better option. :(
 
Here's another dumb idea:

Put a basic dual battery setup in the truck so the second battery can charge while I drive around for the day... then when I get back to camp, pull the battery out of the truck and put it in the trailer. Thoughts?
 
Here's another dumb idea:

Put a basic dual battery setup in the truck so the second battery can charge while I drive around for the day... then when I get back to camp, pull the battery out of the truck and put it in the trailer. Thoughts?

Watch your back. Those batteries are heavy. I'd go with the generator, or three down blankets.
 
I don't mind the heavy lifting--I do that recreationally anyway :eek: The 50-60AH batteries are around 40lbs, so not bad at all. Generator is definitely a no go. We despise camping anywhere near someone with a generator and we definitely don't want to be "that guy."

And what I'm after here is a solution that involves a 12v source in the trailer, not more blankets. My wife does not generate body heat--no amount of insulation will keep her warm :eek:

Aside from the fact it's clunky and dumb, is there any reason the battery swapping method would not be feasible?
 
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Easy to run power back to the trailer. Just run a wire from the battery to a solenoid and from the soleniod back to a plug for the trailer. Use a power source hooked to acc on key to activate the solenoid so it only charges when the vehicle is running. Need an inline fuze between the battery and solenoid.
 
Battery swapping will work if a bit PITA. I'd leave the batteries in the truck wired up as a regular dual system, and plugged the trailer into the truck during the night, when you do need the warmth.
 
OK, thanks for that suggestion--that does sound easier :) I was starting to get a little frustrated because my needs are evolving as I think this through and I'm probably not communicating all that clearly. :eek:

So let's hit the restart button on this thread:

What is the best way to charge a house battery without risking the start battery? ACR or isolator? Do I need to manage the charge to the house battery to make sure I don't over-charge it? Again, sorry for all the dumb questions--I swear I've tried to read up on this stuff but for whatever reason, electrical info just flies right over my head. Thanks for humoring me.
 
If you are just using your alternator to charge the battery while the vehicle is running you wont over charge anything. If you leave the trailer plugged into the vehicle it wont drain the starting battery because the circut is open due to the solenoid.
 
Just found this, which was super helpful for a dummy like me:
How to make a cheap isolated dual-battery setup for $50

I like pictures :)

So going off that schematic, I would then just run positive and negative wires from the yellow battery out to the trailer with a fuse in line for the blanket?
 
I did that trip last year, same time of year....It's simply awesome, but I would plan running a wire from the truck to the trailer to charge. We ran into some really cold weather and that taxes batteries also. My truck charges the second battery in the truck and also the trailer battery when driving. I run an ACR so if the truck is plugged in, the trailer uses 2nd truck battery (deep cycle) and the trailer battery without affecting the starting battery. IMO, don't fear the 7pin plug, it's worth the effort. It allows you to charge the trailer battery, run reverse lights, etc.

Also, depending on where you plan to drop the trailer, there may be power and you could charge it that way.

BTW - you will love that trip. - and sorry for hijacking with pictures, but I loved our trip.

yell.jpg


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We went in early September last year and left early due to the crowds. :eek: Which is why we're trying for later in the year :) No shore power where we're going, and in our general usage.
 
We went in early September last year and left early due to the crowds. :eek: Which is why we're trying for later in the year :) No shore power where we're going, and in our general usage.

Understood, I was in Tetons and Yellowstone early/mid Oct last year. Crowds were nearly gone, but one or two visitor centers and things were open. Well worth waiting a little later in the season.
 
You will need to think through this more. If the 50 watt figure is accurate, than the 33 amp hours in a night's use is about right. That's a huge draw. And since a normal deep cycle can't go below 50% charge without permanent damage, you are cutting things pretty close. You would need a 100 amp hour battery(About the biggest practical "normal" 12 volt deep cycle battery) fully charged to start each night. Diving around all day could easily handle charging it back up but all that battery moving and swapping sounds like a pain. But you do need to consider how you're going to charge it. An ACR could manage it pretty well, but then you'll need to install a second tray for the battery and install and swap a 75 pound battery every evening. Sounds like a pain in the ass.

Why not do a dual battery install, and just park close enough to run some 10 gauge wire from the truck to the trailer? That should be able to easily handle the 4-5 amps you're talking about.

But for the win, I agree the down comforter, and some good wool blankets and you'll be plenty warm, and if it's really going to be that cold, stay in a hotel.
 
Better solution: Small Webasto, Espar or Propex with a small battery for the fan and be done with it. Any of the three and you'll be crying to open the door on the coldest of nights in your teardrop...

I've done the 'convert DC to heat via heated mattress pad' and anyway you look at it, for more than turning it on for a couple hours to pre-heat the bedding, you're looking at big lead-acid type batteries (yes, plural), LiFePO4 (expensive) or a generator to power it.
 
Just for a point of reference, when we were there last October, we saw 15-20 at night a couple of times, and while sleeping with some nice down bags was warm enough, it absolutely sucked being outside in the early am or after the sun went down.
 

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