I Need help with the electrical

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I Need help with the electrical

Postby CaleyAnn » Sun Jan 21, 2018 3:02 pm

I am converting a very small utility trailer into basically a one person camper.

I have figured out that the most amperage I will use at one time is 15 amps. I am figuring that I will use this amount of power no longer than 6 hours a day, with the lrest of the time being only a couple of Amps per hour.

I really do not want to run 120 volts. So far everything I will run is 12 volts.

Since I will only be using 12 VDC I don't think I need a voltage inverter. Is this correct?

What I would like to know is if an AGM deep cycle battery of 100 Ah is big enough.

Based on what I have read, if they authors are correct, I only need 100 watts of solar panels for this sized battery.

What sized controller would I need?

Apparently I will need very heavy gauge wire between the controller and battery. What size, 10, 12 gauge?

From the battery, what size wire do I need to my ON/OFF/Circuit Breaker switches?

And from that to my cigarette lighter power receptacles, what size wire. I read I should only need 16 gauge form my ceramic heater which draws 12 amps.

I also looked into a thread that shows that all the system needs a ground. Just what do I need for equipment, and where do I place the ground?

My entire setup will have one cigarette lighter power receptacle on each wall. The Switch/circuit breaker system will be on the forward wall in the trailer for controlling each receptacle, and the two LED ceiling Lights, and two computer cooling fans I am using to move air. Like I said, all my appliances are 12 VDC. I do not want 120 VAC to foll with, especially since this trailer is just so small. No room for big appliances.

I am totally at a loss to figure out just what equipment I need. That includes the battery, controller, monitor panel, solar cell panels, and what kind of wire I need. Once I know what I need, I can then figure out how I will wire everything, again, with help. All I have figured out right now is that I use less than 15 amps per hour with everything running. I rounded that up to 15 amps. I figure my total power consumption over 24 hours will be about 220 amps, but probably less, as I will probably have some kind of kill switch to cut off power from the battery when I am not in the trailer.

Anyway, I am hoping someone can help me out, as I haven't got a clue. This is totally above my knowledge level. CaleyAnn
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Re: I Need help with the electrical

Postby tony.latham » Sun Jan 21, 2018 3:51 pm

There's a lot of "no's" in my answer. But here goes.

"I really do not want to run 120 volts. So far everything I will run is 12 volts. Since I will only be using 12 VDC I don't think I need a voltage inverter. Is this correct?"

The only reason to invert is for 120v. Me? I'm just a 12V guy. :thumbsup: And I have never regretted it, but we boondock and hate generators.

"What I would like to know is if an AGM deep cycle battery of 100 Ah is big enough."

I was scratching my head on what you were going to be using that would suck 15 amps but I saw the ceramic heater. (I'll address that further down below.) Unfortunately, a 100 AH AGM only has about 60 amps of useable power. If you get any deeper, you'll damage the battery.

"From the battery, what size wire do I need to my ON/OFF/Circuit Breaker switches?"

10 G will be fine. I'd suggest one of these. They make wiring simple:
https://www.amazon.com/dp/B001P6FTHC/ref=sspa_dk_detail_0?psc=1&pd_rd_i=B001P6FTHC&pd_rd_wg=5IPvX&pd_rd_r=RSYEVTZAATYT6BE2EZ29&pd_rd_w=keotB

"I read I should only need 16 gauge form my ceramic heater which draws 12 amps."

And there's the problem. Direct current is a lousy choice for heat. I don't understand why––it's over my pay grade--but it was it is. I had one of those 150W/12A heaters in my first 'drop. I couldn't tell the difference except for the drain on the battery. Perhaps other's have had better luck. (And adding an inverter isn't going to help.)

What works for us is a 12V electric blanket (with a timer) to preheat the bed. Three amps draw and they're cheap. A down comforter draws little juice.


"Based on what I have read, if they authors are correct, I only need 100 watts of solar panels for this sized battery. What sized controller would I need?"

If you ditch the ceramic heater, you're fine with 100 watts of solar. In fact, if you ditch that heater, you can probably downsize to a 35A battery or at least a Group 24 marine. Assuming your 12V outlet can handle 15 amps––and the distance isn't great––I'd use 12G wire.

And frankly you shouldn't need solar unless you are doing something greater than three days.

"Apparently I will need very heavy gauge wire between the controller and battery. What size, 10, 12 gauge?"

12G is fine, depending on the distance. And whatever wattage power for the panels, you need a controller that's rated that high. Folding panels have their own controllers.

"From the battery, what size wire do I need to my ON/OFF/Circuit Breaker switches?"

10G

That's my story and I'm sticking to it.

Tony
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Re: I Need help with the electrical

Postby CaleyAnn » Sun Jan 21, 2018 7:51 pm

Tony, This is great. Wasn't sure anyone would bother answering my odd questions. I've taken my heater off the wish list, and added the heating blanket. Not sure just how well my trailer interior will retain any heat once the door is closed, but that was my major concern when I wasn't in bed in a sleeping bag or whatever I will use to bed down in. I looked at a propane heater, but am not sure there is anything small enough to match my tiny trailer, 4x6 (interior a bit smaller).

I now know that my chosen (wishlist) switch would not have handled the amperage. Each on/off switch is only rated at 5 amps. So eliminating the 12 volt heater, and adding the 4.4 amp heating blanket would be workable. Again, maybe a propane heater rated for indoors would be a smarter choice, which would eliminate the heating blanket also. Any ideas on a propane heater that can work in such a small trailer? I'll see if there is a section on propane in the forum. I found a propane heater, though it is still too big, but I can just shut it off when things warm up. https://www.amazon.com/Mr-Heater-F21510 ... Mr.+Heater . I already have a propane stove with six one pound propane bottles. I believe my heating problems are solved for winter camping

It was suggested I get a folding type solar panel kit that apparently will have everything I need. I'll look into this. I think I will go with this https://www.amazon.com/dp/B074ZR3RNP/_e ... P94C&psc=1 and this https://www.amazon.com/dp/B01N19GOYJ/_e ... P94C&psc=1 They are a matched set. Yes, they are more expoensive, but I am guessing that they will fulfill my reduced power needs, plus a bit more. On top of all that, the battery is lighter. I really cannot lift 100 pound batteries anymore. And the solar system is portable, a lot easier to deal with than other piece together systems. Hopefully this eliminates my confusion, and will be just plug and play.

This is the cutoff switch for my battery https://www.amazon.com/Cllena-Battery-D ... tery&psc=1 CaleyAnn
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Re: I Need help with the electrical

Postby tony.latham » Sun Jan 21, 2018 9:42 pm

Not sure just how well my trailer interior will retain any heat once the door is closed, but that was my major concern when I wasn't in bed in a sleeping bag or whatever I will use to bed down in.


Don't overlook ventilation or you'll regret it. You need two screened windows and some kind of vent. Preferably with a fan in it. Fantastic fans pull about 2 amp hours.

Preheat with that blanket and get a down comforter and you'll be set. With your windows cracked.

:frightened: :thumbsup:

Tony

p.s. If you have to pull your battery, just remove the positive side first and there will be no spark.
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Re: I Need help with the electrical

Postby CaleyAnn » Sun Jan 21, 2018 10:08 pm

The people who sold me the trailer said that if I cut into the roof, I would lose my warranty against leaks.

I was told to install two computer cooling fans, one on each wall at the bottom. I was told to install exhaust vents on each wall at the top. This is supposed to move slightly cooler air in, while the two top vents exhaust the warmer air. Supposedly these fans move quite a bit of air for their size. The person who recommended this said they had done this, and things work well. I want to keep this trailer as intact as possible, with as small of holes as I can do. Though, in addition to the four 2 inch diameter holes for the vents, I will have to drill a hole in the forward bulkhead in order to run my power connector cable in to the battery. I just realized nearly a week later than my hitch bar on the trailer is just that, a big bar, not a V type hitch system. And I only have 10 inches of clear space between the outer bulkhead and the trailer support assembly. That means I cannot mount a battery box outside, or at least I don't think I can. Maybe I need another of your suggestions on how, and where one of those boxes can be mounted.

Since this trailer only has a rear cargo door, I have to install an inner wall. It was suggested I install a teardrop access door into that. If I am not mistaken, those doors have a screened window that I can open.

Hope this air flow will be adequate. CaleyAnn
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Re: I Need help with the electrical

Postby tony.latham » Sun Jan 21, 2018 10:39 pm

That means I cannot mount a battery box outside, or at least I don't think I can. Maybe I need another of your suggestions on how, and where one of those boxes can be mounted.


A photograph is a good 'xplainer.

Sounds like you have the ventilation system figured out.

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Re: I Need help with the electrical

Postby CaleyAnn » Sun Jan 21, 2018 11:05 pm

Thanks for all your help Tony. I will try to remember tomorrow to make all those photos of the trailer I keep trying to do. I keep forgetting because of the volunteer work I do up at the local observatory and nature center. I am the volunteer grounds keeper, which entails trying to repair the damage visitors do, while improving things, including repair of the flood damage that has occurred in recent years due to the Joshua Tree National Park levee breaches. Anyway, most of what I do is heavy, dirty labour, and by the time I am done, I am pooped, not thinking about things like photos. But I will try tomorrow. CaleyAnn
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Re: I Need help with the electrical

Postby CaleyAnn » Mon Jan 22, 2018 3:46 pm

Tony, I managed to get three pictures posted viewtopic.php?f=42&t=69850&p=1222594#p1222594 As you can see, my towing bar is pretty short, and taken up by the original bent piece of metal under the bar in front, with the crank up jack just behind that. That means I need to somehow configure a utility box that straddles things, without interfering with the trailer jack crank, if I want something deeper than 10 inches. As far as I can tell, there are no commercially made utility boxes that will fix in such a tight space. I had been hoping to put the battery in there, as well as the solar system regulator, and various other little electrical things that are needed.

You listed a fusebox type thing in one of your previous posts. Is this needed for my system, or will the ON/OFF switch panel with its own 5 amp circuit breakers be adequate? I ditched the ceramic heater idea because of your insight, and decided to ditch the heating blanket in favour of the small interior propane space heater. That leaves the most power hungry device being my flat screen/DVD player TV, which draws a maximum of 3.3 amps. Everything else is one amp or less. CaleyAnn
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Re: I Need help with the electrical

Postby pchast » Mon Jan 22, 2018 10:26 pm

I hate to be another naysayer but propane inside can be a poor idea.
:thinking:
The ventilation you speak of is minimal to overcome the exhaust from
a combustion heater. Please be careful. Carbon monoxide can kill. It
is heavier than air and care should be taken in locating your ventilation.
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Re: I Need help with the electrical

Postby tony.latham » Mon Jan 22, 2018 10:59 pm

You listed a fusebox type thing in one of your previous posts. Is this needed for my system, or will the ON/OFF switch panel with its own 5 amp circuit breakers be adequate?


If you already have some kind of panel with breakers I suspect it'll work. Those marine fuse boxes with the negative bus bar make wiring so easy. (A negative bus bar is just something to tie all your wires into.)

I responded to your battery issue.

I too recoil about installing an unvented propane heater in such a tiny space. It's a recipe for death in the desert. :thumbdown:

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Re: I Need help with the electrical

Postby CaleyAnn » Tue Jan 23, 2018 8:19 am

OK, I see your point about the propane heating. I need something that warms the air, so I went back to that little 12 Volt 150 watt heater. I also look into the heating blanket, though I am not sure it will help, as I will be in a sleeping bag.

I also put that fuse box on my wish list. I can hook it up to the battery, then run the individual wires to individual switches that are rated 20 amps. I will just have to figure out how to mount the switches so they look nice. The lighted switch, which I had already ordered will just go into a parts box, as each switch is only rated at 5 amps.
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Re: I Need help with the electrical

Postby tony.latham » Tue Jan 23, 2018 11:48 am

I need something that warms the air, so I went back to that little 12 Volt 150 watt heater.


How cold is it down there and what months are you planning on camping?

At 150 watts those heaters draw 12.5 DC Amps as you know. If you want to run one for 8 hours that's 100 amp hours. That means you need 200 Amps hours of deep cycle battery (which equates to two 65 pound batteries). And you would need to recharge the next day for 6.5 hours witha 135 watt panel.

I suggest you spend the $25 on one of these little heaters and play with it before you decide to wrap your electrical system around it. It doesn't make any difference which one you chose, 150 watts is 150 watts and they will all produce the same BTUs.

Here's part of a review from Amazon:

"Waste of money. It does produce heat and the fan does work but does not produce enough heat or fan speed to make any impact. Don't be fooled by the 5 star ratings, I believe they may be made up to sell the product. Best to save your money and fix your vehicle heating. My Jeep's heating worked on my passenger side so I was only looking to provide on the driver's side but no such luck."

And a second:

"The heater in my truck went out so I thought I would grab this one. If you just want something to defrost your window, this may work. If you are looking for an actual heater, this probably is not the unit you want. It puts out very little heat."

And that was my experience with a similar wattage 12V heater in my first teardrop. The 'drop was a commercial Hunter and I think it was a just a selling point. We could hear the fan but it didn't put out enough heat to make any noticeable comfort. It would have been easy and cheap to stick one in #2 but why bother?

Insulation and body heat. And preheat your bed.

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Re: I Need help with the electrical

Postby CaleyAnn » Tue Jan 23, 2018 2:36 pm

Tony, I told you I was totally inexperienced when it comes to electrical stuff. Yes, I will insulate the trailer the best I can with 1 inch thick foam. There will be some gaps, but I think if you tape over those, you won't lose as much of the benefit of the foam. Of course, I am just guessing.

So you absolutely say to strike the space heater, and go with a heating blanket. I will purchase one, though I am not sure how to use a heating blanket with a sleeping bag.

Seems I just keep going in circles about keeping warm during the winter. Of course, about the time I finally get things built well enough, it will be nearly summer, and our summer starts the beginning of May when things usually are in the 90's.

So this means I will not purchase the big circuit breaker panel you suggested, as I will not pull enough amps to need such. The flat panel magnetic circuit breakers should be adequate for all I will be running. And I can always plug the sleeping blanket into the socket which is rated at 15 amps. All this will save me a lot of difficult wiring.

As for summer cooling, I haven't got a clue, other than having the two computer fans exchanging air, while my 12 volt fan unit blows air on me. An A/C is totally ridiculous for such a small trailer. I wonder if there is such a thing as a 12 volt swamp cooler that will not cost an arm, leg and first born. So far I have not found one.
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Re: I Need help with the electrical

Postby friz » Wed Jan 24, 2018 3:17 pm

If I were you, I would start simple. You need a battery, a 40amp inline fuse holder, a marine fuse block for how ever many circuits you think you would need, and a ground bus of some sort. Find a 12v dc wire size chart to determine how large of wire to run on each circuit. This will tell you what size wire you need for each circuit and how long the run can be with that wire size. The longer the run the heavier the wire needed to avoid voltage drop in the circuit. You can probably find one in the stickys at the top of this section.
On the positive side of the battery, use the appropriate connector to attach the 40 amp fuse holder to the terminal. Attach the other end to the fuse holder main post. You can extend this with an appropriate size wire if needed (see chart). Attach the the negative side of the battery to the ground bus with the same size wire as you ran to the fuse holder. Size the fuses in the fuse holder to be as close as possible to the maximum amperage a circuit will carry without going under.
You now have the basis for what ever you want to run. All 12v consumers will have a positive and negative wire. Some you will need to run the positive through a switch, some will have a switch built in. To keep things simple you can use an automotive style battery charger with spring clamps to charge your battery. You can even find solar units with the controller attached to the panels and spring clamps already on the wires to keep things simple.
Keep in mind that you can always add more circuits later.
You might want to camp in your trailer before giving too much though to heating and cooling. I thought it would be a concern, but me and my wife camped about 15 nights in my tear drop over the last year and never needed either. We have found that if we want to be somewhere that the temperature is comfortable in the day time, the night time is good sleeping weather. It helps to have a snuggle buddy.
Good luck and have fun!
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