Please review my wiring diagram

Anything electric, AC or DC

Please review my wiring diagram

Postby Homebrewer25 » Fri Oct 27, 2017 11:27 am

Still in the planning stages. I've got my TTT design mostly figured out, but now I'm doing the planning for the electrical systems.

I'm not a rookie when it comes to electrical work. I've done a fair amount of building and remodeling that included AC electrical work, including running buried cable to a new outbuilding (wood shop) 100A load center. And many years ago I did stereo and television repair work, so I'm familiar with DC as well.

But after many hours sifting thru the info in this section I'm still not 100% sure what I need to do when combining AC and DC circuits. :?
I think I've got it right, but would like those with more expertise than I to review it and comment.

First, since I only have a 4 pin connection, my trailer lighting will be a separate circuit isolated from this camper wiring and powered only by the TV, and is not included in this plan.

This plan is for both DC and AC circuits with shore power using a PD4045 converter and 1 (or 2) deep cycle batteries.
I also plan on using solar panel(s) with charge controller for off-grid recharging.
I will use return wires on each DC circuit back to the controller via a DC negative buss rather than relying on chassis ground.


Now for the questions:
1. Do I still need a DC negative connection to the trailer chassis? I'm thinking that I don't so I can keep the DC negative isolated from the AC ground.
2. If I add an inverter, can I tie the AC output into the same AC outlets powered by the PD4045?
3. Can I connect it back into the PD4045 for the AC supply?
4. Do I need to use separate outlets for the inverter?
5. Recommendations on an inverter to use and how to connect it?

I have not yet worked out the details of the individual DC circuits, but will probably end up using fewer after doing the power calculations.

wiring diagram.png
wiring diagram.png (39.35 KiB) Viewed 484 times


I'm continually amazed at everyone's willingness to help others with their design work, and I greatly appreciate the help I have received. This is one of the best forums I've ever been associated with.
It's 5 o'clock somewhere ... time for a beer :beer:

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Re: Please review my wiring diagram

Postby MtnDon » Fri Oct 27, 2017 1:03 pm

2. If I add an inverter, can I tie the AC output into the same AC outlets powered by the PD4045?
3. Can I connect it back into the PD4045 for the AC supply?
4. Do I need to use separate outlets for the inverter?
5. Recommendations on an inverter to use and how to connect it?


If you have 2 separate AC inputs, they need to be kept separate downstream. No mixing. AC power is cyclical, 60 Hz in north america. If the phases do not match equipment looses its magic smoke and nothing works and you need to buy new equipment. That is one way that AC is very different from DC where we can add things in parallel as long as the voltage is the same.

There are transfer switches that disconnect and reconnect both the hot and neutral legs for a 120 VAC circuit. Some are manual, some are automatic. Search for "RV automatic transfer switch".

Two kinds of inverters; modified sine wave and pure sine wave. Electronics don't like modified sine wave so much. Some things like microwaves don't work at all or at best hardly work and waste most of the input DC. Sometimes you don't know how well the item will work on modified sine wave. In general if the device is strictly a resistance unit... old incandescent lamps or heaters, kettles, they work OK. But with any electronics, it varies. Some items are okay, other smoke or work poorly. In general AC motors will run hot on modicied sine wave. heat shortens their life. How long you expect a motor to work may be a deciding factor. Also, motors that run hot waste battery power.

Connect DC from battery to inverter with a proper size fuse or breaker. Either use a fail safe method of manually switching the AC after the inverter and any other AC sources like shore power, generator, etc. or use a transfer switch. Transfer switches only have a choice of two inputs, so even with an automatic switch sometimes something has to be switched manually. Plug and unplug as long as it can not be screwed up.
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: Please review my wiring diagram

Postby Andrew Herrick » Sat Oct 28, 2017 1:08 am

Just to add a little to Don's' wisdom:

I might be mis-reading your wiring schematic, but you don't need a separate circuit for every DC feature. If you use 14 or 16 gauge wire, you can throw on quite a few fixtures on a single circuit. Obviously, something like the TV should be on a dedicated circuit, but you can put 3 or 4 lights on a single circuit, no problem.
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Re: Please review my wiring diagram

Postby Homebrewer25 » Sat Oct 28, 2017 7:52 am

Thanks for the input.

MtnDon, if I decide to add an inverter, it sounds like pure sinewave is the way to go, along with a manual transfer switch.

Andrew, the number of DC circuits in the drawing is just to show the capacity of the PD4045 (12 DC circuits) and the various DC items that I need to connect. I have not done any calculations on power consumption of each item ... when I do I'll combine circuits where appropriate. It is likely that I'll only need a few.
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Re: Please review my wiring diagram

Postby Socal Tom » Sat Oct 28, 2017 9:33 am

Another thing to consider, the solar charge controller will probably have a load terminal. This allows it to shut off the circuit below a given voltage. That coupled with a small fuse panel could cover the 12v system .


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Re: Please review my wiring diagram

Postby low277 » Sat Oct 28, 2017 5:52 pm

MtnDon wrote:
2. If I add an inverter, can I tie the AC output into the same AC outlets powered by the PD4045?
3. Can I connect it back into the PD4045 for the AC supply?
4. Do I need to use separate outlets for the inverter?
5. Recommendations on an inverter to use and how to connect it?


If you have 2 separate AC inputs, they need to be kept separate downstream. No mixing. AC power is cyclical, 60 Hz in north america. If the phases do not match equipment looses its magic smoke and nothing works and you need to buy new equipment. That is one way that AC is very different from DC where we can add things in parallel as long as the voltage is the same.

There are transfer switches that disconnect and reconnect both the hot and neutral legs for a 120 VAC circuit. Some are manual, some are automatic. Search for "RV automatic transfer switch".

Two kinds of inverters; modified sine wave and pure sine wave. Electronics don't like modified sine wave so much. Some things like microwaves don't work at all or at best hardly work and waste most of the input DC. Sometimes you don't know how well the item will work on modified sine wave. In general if the device is strictly a resistance unit... old incandescent lamps or heaters, kettles, they work OK. But with any electronics, it varies. Some items are okay, other smoke or work poorly. In general AC motors will run hot on modicied sine wave. heat shortens their life. How long you expect a motor to work may be a deciding factor. Also, motors that run hot waste battery power.

Connect DC from battery to inverter with a proper size fuse or breaker. Either use a fail safe method of manually switching the AC after the inverter and any other AC sources like shore power, generator, etc. or use a transfer switch. Transfer switches only have a choice of two inputs, so even with an automatic switch sometimes something has to be switched manually. Plug and unplug as long as it can not be screwed up.


:thumbsup: :) The magic smoke! It's a mysterious, delicate thing!!!!
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Re: Please review my wiring diagram

Postby Homebrewer25 » Sun Oct 29, 2017 8:19 am

Here is a new version with the inverter wired in. I assume that when I'm not on shore power and need AC, I switch the 15A breaker to the converter off and turn the supply transfer switch on. My thinking is that the battery is supplying DC thru the PD4045 directly, and the inverter only needs to power the other 3 breakers (15A and twin 20A).

I would probably use the inverter only for the AC on really hot days.

wiring diagram.png
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Re: Please review my wiring diagram

Postby Socal Tom » Sun Oct 29, 2017 8:28 am

A 5000 btu Air conditioner needs about 800 watts per hour to run. A typical 100 AH 12v battery has about 1200 total watts available, and if you want it to last very long, you will want to use less than 50% , so 600 watts is about what you would have available. That gives you about 40 minutes of run time. You will need a large inverter to handle the surge at start up. You 100 watt panel will probably take 2 days to recharge the battery from a load like that . A better plan is to get a small generator. I run my AC on a
Honda 1000eu , YMMV.
Tom


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Re: Please review my wiring diagram

Postby Esteban » Tue Nov 07, 2017 1:12 pm

Your wiring for the AC circuits shows two colors, black and green. Black for the negative? Green for the ground(s)? You have not shown a positive wire, if I'm interpreting your diagrams correctly.

120 volt AC wires usually have a positive, a negative, and a ground wire, don't they?

Usually AC wires have a black positive, a white negative, and a copper (green) ground wire.

You don't show any 120 volt GFCI outlets.
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Re: Please review my wiring diagram

Postby Homebrewer25 » Tue Nov 07, 2017 3:06 pm

What looks like a space between the black (hot) and green (ground) is the white (neutral) wire. It is tinted a slight gray in the drawing, but it doesn't show very well. All AC circuits will either have a GFCI breaker or a GFCI outlet as the first one in the circuit, with the remaining ones coming off the load side of the GFCI.
I'll not be boondocking very often, so I'm not going to include an Inverter. Most of the time I'll be on shore power, so I may not include a solar panel/charger either. I'll be sure to plan for solar so it will be easy to add it later if I need it.

New Diagram, with green changed to orange (copper), and the background changed so the white wire shows up:
wiring diagram.png
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