wiring help

Anything electric, AC or DC

wiring help

Postby Firesniper » Fri Aug 14, 2015 11:38 am

Hello everyone i am currently building a camper and i am no where near am electrical person. I'm sure someone has asked this question but i couldn't find it please help. i need a wiring diagram for a camper. i would like a setup where i can run a electric blanket and some lights and a small fan with 2 outlets for an extended period of time 4+ days in areas of no electricity no cell phone service ect. i plan to have 2 deep cell batteries and a portable solar charging system- 120 watts from teardropshop.com. I'm not sure what all I'm going to need. Any help with this will be greatly appreciated. :worship:
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Re: wiring help

Postby DrewsBrews » Fri Aug 14, 2015 12:57 pm

Depends on what type of power your lights, blanket and fan use. 120v, 12v, or a combination of 120v and 12v?
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Re: wiring help

Postby Gladtobehere » Fri Aug 14, 2015 1:57 pm

I also believe that heating anything using 12v is hard on your batteries. I use 1500btu catalytic propane heaters when AC is not available. Keep your 12v for LED lighting and fans.
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Re: wiring help

Postby Firesniper » Fri Aug 14, 2015 2:06 pm

i was to do a combination of 120 and 12v. the blanket will operate on less than 25 volts and the lights will be some 12v leds and for a fan just a simple small 12v fan to circulate air.
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Re: wiring help

Postby MtnDon » Fri Aug 14, 2015 2:55 pm

Heating electrically with a battery or two as the power source is generally a lousy plan unless the duration is short.

It sounds like you are planning to use lead acid batteries as most of us do. You may or may not be aware that lead acid batteries should never be discharged more than 50% if one is interested in reasonable length of service. Even if the battery is listed as a deep cycle battery.

So, look at the battery specs and find the amp hours (AH) measured at the 20 hour rate. If you can not find that rating don't use that battery. There are batteries that are called deep cycle but are not truly deep cycle. A true deep cycle [url]will[/url] have the 20 hour rate info listed. Once you have the AH rating, divide it by half and then multiply by the nominal battery voltage. For example, if the 20 hour AH rating is 130....
130 AH / 2 = 65 AH.
65 x 12 = 780 watt-hours
780 watt-hours is the amount of energy you can safely withdraw from that battery.


Look at the specs for the heating blanket you want to use. Is it a 12 volt DC blanket or is it a 120 volt AC blanket? (120 VAC is the common US/Canada household voltage). IF the blanket is a 100 watt blanket the battery would, theoretically, be able to power it for 7.8 hours (780 watts / 100 watts = 7.8 hours. However because it would need 120 VAC there would need to be an inverter to make AC from the battery DC and that will cause a loss of 10 - 20% of the battery power.

For best results you should get the specs on everything you want to use, volts, AC/DC, and the amps or the watts it is rated at. Also the number of hours you want to use each item. Make a little spreadshett if you can.

Then you can plan from there and we can offer better advice.
Our 6x12 deep vee nose cargo trailer camper conversion... viewtopic.php?f=42&t=58336

We have a small off grid cabin we built ourselves in the NM mountains; small PV solar system; 624 watts PV, Outback CC & inverter/charger ... http://countryplans.com/smf/index.php?topic=2335.0
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Re: wiring help

Postby DrewsBrews » Fri Aug 14, 2015 7:56 pm

The wiring can vary depending on the task at hand and how integrated you want it to be. 120v inverters for instance can be remote mounted out of the way and have wiring run to outlets, this looks nice and integrated, but inverters use power while they are turned on (even when nothing is plugged into it) so some folks opt to have the inverter right there in the cabin area and plug 120v items directly into it so they can turn it on/off as needed to not waste battery power.

And not wasting power is the name of the game.. The less you drain the batteries down each time before recharging the longer the batteries will last you before needing to be replaced. 50% is the max you want to drain it and expect to have any amount of longevity. If you only drain 20% or 30% each time before full recharge you could potentially extend the life by years if you also treat them right in the off season.

12v wiring is pretty straight forward, run a + and - wire to each item and put a fuse on each run as close to the battery as is possible within reason (for safety sake). Often a fused bus box( also called a fuse block or power distribution block) is a worthwhile purchase to easily split out the one battery connection into many fused connections. Here is an example https://www.bluesea.com/products/5026/ST_Blade_Fuse_Block_-_12_Circuits_with_Negative_Bus_and_Cover/featured. If you keep the 120v inverter in the cabin area then it is essentially just another 12v appliance to run wiring to. Though the size (thickness) of the wire and fuse would be increased for higher power draw items such as that. Also with low voltage the shorter the run (length of wire) the better. Often times the required wire size for a certain power draw can be decreased if the length of the wire is shortened enough. So where you mount the batteries can help/hurt the situation.

For the solar side I found this page : http://www.chromolywally.com/?p=188 that has a diagram nearly identical to the solar setup you are describing.
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Re: wiring help

Postby Firesniper » Sat Aug 15, 2015 10:51 pm

Thanks everyone for the advice it looks like its going to be very helpful
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Re: wiring help

Postby nonewtaxes » Fri Sep 18, 2015 12:02 pm

Thank you for posting that OP, I am in the same situation however I am still very confused due to not fully understanding what needs to be run and where.

I just received my 1000 watt inverter (the portable type not the hard-wired type), I have an 8 circuit fuse block similar to what you recommended in your response, I have a ground block and here is what I need to power with all that:

- 2x 110 outlets inside the front cabin
- 1 switch which controls the outdoor "porch" 12v LED light
- 1 shore power outlet (I am absolutely clueless where this should connect to power my electrical components once plugged into shore power)
- 1 12 v interior LED dome light
- 1 Fan-tastic exhaust fan which I understand can be operated on 12v.
- 1 outdoor 110 outlet for plugging in cell phones, etc outside
- 1 110 outlet in the galley for anything needed such as small griddle or whatever else for cooking

I have purchased 14 gauge stranded wire but based on the mixture of recently deciding to add shore power AND implementing an inverter which I wasn't planning before, I don't know what should be run where. Any help would be greatly appreciated. I have spent soooo many hours reading posts, googling, etc and either I'm slow or I'm trying to do something that should never be done.

The link you provided (viewtopic.php?f=30&t=63874&p=1137763&hilit=wiring+diagram#p1137763) to the wiring diagram is helpful but it doesn't seem to match what I'm planning
To piggy back off from the OP's questions (in order of my greatest lack of understanding)
- Do I NEED a converter?
- What gets wired to my fuse block? According to the diagram you provided the link to
- When I install the shore power what does the back side of that outlet get wired to?
- I think I understand that none of the 12v stuff does NOT need to go through the inverter which begs the question how do I power the 110 outlets when there is only 2 standard outlets on the front of the inverter? I've read (here: http://www.doityourselfrv.com/rv-inverter-install-diy/) that is possible to do if you have a "dedicated" outlet which is not usable. How do I accomplish that, the article didn't describe how to wire it.

Thank you a ton in advance for any help. I'm hoping to complete my electrical this weekend so I can begin putting in the spars for my roof (this project has gone on waaaaay too long haha).
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Re: wiring help

Postby tony.latham » Fri Sep 18, 2015 12:36 pm

I'm a 12V only camper (thankfully I don't live in the southern U.S. where A/C is a must).

Here's your first need. 12V marine fuse block with a bus-bar ground:

Image

You can find 'em on Amazon.

We use a 12V electric blanket that has a 40/45 minute timer to pre-heat the bed. It works well and sucks about 4 amps if I recall. They're about $30 on Amazon. We haven't found a queen-sized one but they work fine.

I hope this helps.

Tony
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Re: wiring help

Postby DrewsBrews » Fri Sep 18, 2015 1:46 pm

Unfortunately using all these power options in one install is going to bump up the complexity. IMO your best bet is to look at each power source (shore, inverter and 12v) as a separate system and isolate them from each other as much as you can or else risk frying parts, your tear and/or yourself.

If you want to wire the inverter and/or shore power to outlets then it is handled much like home wiring. In that case I'd suggest looking up how-tos for home wiring on outlets, ect. If your needs are simpler than that, some folks just run short extension cords and/or power strips within the tear.. because those items they are more familiar with using and it is easy, quick, and cheap to implement.

Then there is the question of how to handle the two different 120v power sources (shore and inverter). There are two ways to go about this:

Running in tandem: This would mean dedicating some outlets to shore power only and other outlets to inverter power only. it would keep 120v items that you would not want the inverter running totally separate: for instance, it would make no sense to run a120v battery charger off the inverter to charge the same batteries the inverter is running from. You can split a standard "single gang" outlet into 2 independent outlets (in an electrical sense). There are little tabs that you break off to do this. That may allow you have one for shore and one for inverter power if you don't want to have 4 total outlets in each location. In that case though the grounds would require being tying together (which may be advisable anyway) but it is another thing to look into. Doing this approach means both shore and inverter power can operate independently and you choose which source you use by plugging your appliance into one or the other.

Switching between: Tying both shore and inverter power into the same system of outlets is an option, but it would require implementing a cut over from one power source to the other. That way power never tries to "backfeed" to the other power source, and items you don't want running off the inverter get isolated by staying on the shore-side circuit when you switch the outlets to inverter power. I'm not sure if a switch exists to do this specific task, but it could be as simple as just having a plug (that feeds all outlets) you unplug from the shore side circuit and plug directly to the inverter.

Though, like I said this adds complexity and can be dangerous if not done properly. Unless you have a firm grasp of how it all works together I'd suggest consulting an electrician before you get too far into it.
Last edited by DrewsBrews on Fri Sep 18, 2015 1:50 pm, edited 1 time in total.
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Re: wiring help

Postby jss06 » Fri Sep 18, 2015 3:03 pm

You want a power transfer switch to control the power from the shore power/inverter. They make automatic ones for home use with gensets. Next I would make everything 12v you possible can
Including you phone chargers. They make 12 to 5 volt USB outlets. Way more efficient then going through an inverter to 120v AC then back to 5v DC.

I have something very simular to what you are describing exempt I don't have an inverter. I only have 120v when I have shore power.
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Re: wiring help

Postby MtnDon » Fri Sep 18, 2015 10:21 pm

Yes to the ATS. Google ' rv auto transfer switch' . One of those simplifies the AC when there are mutiple sources.
Our 6x12 deep vee nose cargo trailer camper conversion... viewtopic.php?f=42&t=58336

We have a small off grid cabin we built ourselves in the NM mountains; small PV solar system; 624 watts PV, Outback CC & inverter/charger ... http://countryplans.com/smf/index.php?topic=2335.0
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Re: wiring help

Postby nonewtaxes » Sun Sep 20, 2015 11:51 am

Thanks a ton for the replies. You've helped me change my plan a bit for simplicity's sake. I am going to go ahead and run wires for 120 to the galley but install these for my outlets:
ISWEES Dual USB Car Cigarette Lighter Socket Splitter 12V Charger Power Adapter Outlet https://www.amazon.com/dp/B00RJVJJCI/re ... .vb9VXP8E7

My new question is since there are two separate 12 v leads on the back of these outlets, can I join them together and only run one pair if wires for each outlet.

Another question (sorry, I'm an idiot when it comes to electricity), can i daisy chain one of the outlets to the overhead light inside camper and daisy chain the other outlet to the fantastic fan?

Thanks again for all your help everyone, the more input the better.
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Re: wiring help

Postby tony.latham » Sun Sep 20, 2015 12:10 pm

My new question is since there are two separate 12 v leads on the back of these outlets, can I join them together and only run one pair if wires for each outlet.


Yep. Just make a .... I'll call it a splitter so that your two-wire feed turns into a two-grounds and two-hot wires. It'll work fine. I just looked for a photo from my builds, but don't see one.

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Re: wiring help

Postby nonewtaxes » Fri Sep 25, 2015 7:19 am

Thanks again. My outlets are here and I plan on hopefully putting them in this weekend. We'll see what happens. I've decided to go with a strictly 12v system as suggested for simplicity. If I need AC power I have my portable inverter to plug in to my new shiny outlets.
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