Please review my wiring diagram.

[Jcondon]

Originally Posted by Serf27

I don’t have one. The old system was some type of small converter or breaker box and had a standard small extension cord on it.

I still need this piece:
Shore Power Inlet 125V 30 Amp RV Adapter Great Replacement for Trailer RV Camper Van NEMA L5-30R - 30 Amp RV Receptacle Twist Lock Connector with 3 Stainless Steel Pins and Screws https://a.co/d/7cmgb0f

I also need the wire that goes between that piece and the breaker box so I can run that wire to the breaker box and just install the connector when I get one.
Inside the trailer, I have 12/2 Romex for the receptacles.

Good, we are on the same page. From the power inlet to the breaker panel you can use 10/2 Romex if it’s inside the wall or 10/2 MC Cable if it is exposed outside the wall. The MC provides the physical protection required. Home Depot can cut you a piece of either. Carry on. The AC side is squared away. Now let’s take a look at that DC?

[Serf27]

The wires between the connector and breaker box will be in a custom battery box I built. The box is outside but the actually cable is inside the box and I’ve weather sealed it.
I’m guessing I can use either MC/2 or Romex 10/2.

Thanks for the help. Almost there.


I think I’ve got the 12v system ready, with the help from this thread.
This is the diagram for it.
Ignore the breaker box. I drew this up a few months ago when I first asked. Now I’m running the wires and hooking it all up.

I need to add a + bar to the diagram.
I also added a switch panel that will feed off of the + bar.
I’m still trying to figure out if the 10g Red wire on the 7 way connector for the truck will charge the batteries at idle or only while driving.
I don’t have the DC to AC inverter.

[Jcondon]

Originally Posted by Serf27

The wires between the connector and breaker box will be in a custom battery box I built. The box is outside but the actually cable is inside the box and I’ve weather sealed it.
I’m guessing I can use either MC/2 or Romex 10/2.

Thanks for the help. Almost there.


I think I’ve got the 12v system ready, with the help from this thread.
This is the diagram for it.
Ignore the breaker box. I drew this up a few months ago when I first asked. Now I’m running the wires and hooking it all up.

I need to add a + bar to the diagram.
I also added a switch panel that will feed off of the + bar.
I’m still trying to figure out if the 10g Red wire on the 7 way connector for the truck will charge the batteries at idle or only while driving.
I don’t have the DC to AC inverter.

If you can see it it should be MC. Your call. MC is not expensive.

[Serf27]

I’ll only see it when I open up that box. Won’t be visible when driving or camping.
Maybe the MC for a cleaner look.

I re did the grounds on the 2 metal boxes.
1 box at the end of the circuit: I used a scrap piece of ground wire, screwed it into the box. I used some type of connector(I don’t know the name of it) to crimp it to the Romex ground cable and screwed the timer ground cable onto the receptacle.

For an outlet/box that feeds another receptacle:
I used the metal crimp to connect both Romex grounds. 1 Romex wire then went to the box ground and the other Romex ground went to the receptacle.

99% sure this is correct, yes?
First pic is the box at the end of the circuit, second pic is box that feeds another receptacle.
It’s a little hard to see the metal crimps because of lighting and their color.

Is the 30amp connector I linked from Amazon sufficient to be used?
Is a surge protector recommended?

Thanks.

[richard5933]

Originally Posted by Serf27

I’ll only see it when I open up that box. Won’t be visible when driving or camping.
Maybe the MC for a cleaner look.

I re did the grounds on the 2 metal boxes.
1 box at the end of the circuit: I used a scrap piece of ground wire, screwed it into the box. I used some type of connector(I don’t know the name of it) to crimp it to the Romex ground cable and screwed the timer ground cable onto the receptacle.

For an outlet/box that feeds another receptacle:
I used the metal crimp to connect both Romex grounds. 1 Romex wire then went to the box ground and the other Romex ground went to the receptacle.

99% sure this is correct, yes?
First pic is the box at the end of the circuit, second pic is box that feeds another receptacle.
It’s a little hard to see the metal crimps because of lighting and their color.

Is the 30amp connector I linked from Amazon sufficient to be used?
Is a surge protector recommended?

Thanks.

I'm not seeing a plastic cable connector (or any other type) on the Romex in your first picture. It appears like the wires are just pushed through an opening in the box. Is there one there that I'm missing or did you skip this?

[Jcondon]

Originally Posted by Serf27

I’ll only see it when I open up that box. Won’t be visible when driving or camping.
Maybe the MC for a cleaner look.

I re did the grounds on the 2 metal boxes.
1 box at the end of the circuit: I used a scrap piece of ground wire, screwed it into the box. I used some type of connector(I don’t know the name of it) to crimp it to the Romex ground cable and screwed the timer ground cable onto the receptacle.

For an outlet/box that feeds another receptacle:
I used the metal crimp to connect both Romex grounds. 1 Romex wire then went to the box ground and the other Romex ground went to the receptacle.

99% sure this is correct, yes?
First pic is the box at the end of the circuit, second pic is box that feeds another receptacle.
It’s a little hard to see the metal crimps because of lighting and their color.

Is the 30amp connector I linked from Amazon sufficient to be used?
Is a surge protector recommended?

Thanks.

The crimp connector is called a crimp sleeve. You may find its easier to just take the ground from the Romex and wrap it around the ground screw leaving a pigtail for the receptacle. No crimp at all unless you are also splicing. If this is the case then we use Greenies. The ground wire from the Romex goes through the hole to the device and the nut splices the others. They work great. The surge suppressor is not really needed with your very simple system. As you add electronics you may get a portable surge suppressor. Or get it now if you want?

[richard5933]

Whether you need a surge protector or not really depends on where you'll be plugging in once you start traveling. If you'll be at campgrounds there is always a chance that the power will be less than stable.

My recommendation, if you choose to get something to protect your 120v system, is to get an EMS device and not just a surge protector. Surge protectors will help protect if there is a high-voltage event. An EMS will also protect against low-voltage events and a few other potential problems on the pedestal.

Like Jcondon said, you might not need one now. You'll have a converter to protect, but it doesn't sound like too much more at first. But if you start adding things like an a/c unit it makes more sense to add one.

A portable EMS can be added at any time. This is one which is commonly used. There are also others out there.

https://www.campingworld.com/progres...E&gclsrc=aw.ds

[Jcondon]

Originally Posted by Serf27

The wires between the connector and breaker box will be in a custom battery box I built. The box is outside but the actually cable is inside the box and I’ve weather sealed it.
I’m guessing I can use either MC/2 or Romex 10/2.

Thanks for the help. Almost there.


I think I’ve got the 12v system ready, with the help from this thread.
This is the diagram for it.
Ignore the breaker box. I drew this up a few months ago when I first asked. Now I’m running the wires and hooking it all up.

I need to add a + bar to the diagram.
I also added a switch panel that will feed off of the + bar.
I’m still trying to figure out if the 10g Red wire on the 7 way connector for the truck will charge the batteries at idle or only while driving.
I don’t have the DC to AC inverter.

If you intend to charge your battery off your tow vehicle you should add a DC to DC charger. The Tow vehicle charge wires connect to the DC to DC charger input. This offers the tow vehicle a very low resistance dump for the current produced by the tow vehicle. It may only be 10 volts but the current may be 20 amps depending on your tow vehicle. Without the DC to DC charger the battery has high resistance so the charge will be a trickle at best. The problem is the voltage drop from your alternator to the trailer battery. The DC to DC charger takes what ever it can get from the tow vehicle and boosts the voltage to a usable charge voltage for your battery. I usually locate the DC to DC charger at the front where the seven pin cord enters the trailer. If you want to pursue this I can help.

[Serf27]

This is the crimp connector I used.
https://www.homedepot.com/p/Gardner-...310C/202526312

It slides over both grounds and crimps them together. 1 ground then goes to the metal box and the other ground to the receptacle.

I think I’ll leave the 2 boxes I did with the crimps, as it should work…?
I will try wrapping the ground around the receptacle and then using the green nut to see if it is easier.

When I start traveling, I’ll be plugging into campgrounds. When parked at home, the batteries will be unplugged or maybe on a battery tender.
I am assuming I will connect the inverter to the house electric to charge battlers to 100% before traveling.
The EMS you linked Richard, it’s more than I thought I’d spend. I see some for $40, but if the $40 won’t do much and the $240 is the one to go, I’ll just get one later.

I’m not sure how much dry. camping I will do. I tried to set it up to the point where I could use the trailer if there are no hook ups. Lights are 12v led, if I use the minimum lights needed, it should save charge.
Cooking/heat will be on propane.
Fridge is the only thing that will be 120v so I may need an inverter.

A DC to DC charger sounds good.
Can it charge the batteries at idle? I think that’s when I’d need it the most, to charge the battlers when there’s no hook ups.
From what I understand, the + wire on the 7 pin charges the barriers a little while driving, but not much. I was told I could use 6gauge wire and run it directly from truck battery to trailer battery while driving for extra charging?
Looking at DC to DC units, the truck battery is hooked up to the trailer battery with the DC to DC unit in between?

I think I am going to want to add a DC to AC inverter as well.
I’ve just started looking at inverter info.
Looks like the 12v - and + go to the inverter and the inverter is grounded to the frame and that’s it?

Thank you both for the help.

[Jcondon]

Originally Posted by Serf27

This is the crimp connector I used.
https://www.homedepot.com/p/Gardner-...310C/202526312

It slides over both grounds and crimps them together. 1 ground then goes to the metal box and the other ground to the receptacle.

I think I’ll leave the 2 boxes I did with the crimps, as it should work…?
I will try wrapping the ground around the receptacle and then using the green nut to see if it is easier.

When I start traveling, I’ll be plugging into campgrounds. When parked at home, the batteries will be unplugged or maybe on a battery tender.
I am assuming I will connect the inverter to the house electric to charge battlers to 100% before traveling.
The EMS you linked Richard, it’s more than I thought I’d spend. I see some for $40, but if the $40 won’t do much and the $240 is the one to go, I’ll just get one later.

I’m not sure how much dry. camping I will do. I tried to set it up to the point where I could use the trailer if there are no hook ups. Lights are 12v led, if I use the minimum lights needed, it should save charge.
Cooking/heat will be on propane.
Fridge is the only thing that will be 120v so I may need an inverter.

A DC to DC charger sounds good.
Can it charge the batteries at idle? I think that’s when I’d need it the most, to charge the battlers when there’s no hook ups.
From what I understand, the + wire on the 7 pin charges the barriers a little while driving, but not much. I was told I could use 6gauge wire and run it directly from truck battery to trailer battery while driving for extra charging?
Looking at DC to DC units, the truck battery is hooked up to the trailer battery with the DC to DC unit in between?

I think I am going to want to add a DC to AC inverter as well.
I’ve just started looking at inverter info.
Looks like the 12v - and + go to the inverter and the inverter is grounded to the frame and that’s it?

Thank you both for the help.

You are confusing the conveter and inverter but you are pretty close. The converter uses 120 volt AC and converts it to 12 volt DC, The inverter uses 12 volt DC and inverts it to AC. The rest is pretty good.

[richard5933]

Just a couple of quick definitions to make sure we all mean the same thing...

Inverter - pulls 12vdc power from your batteries and spits out 120vac power to run household appliances

Converter - uses 120vac power from shore power to supply 12vdc power for your 12v devices and to charge your batteries.

If your fridge is 120vac, you will definitely need an inverter to use it when not plugged into shore power or on a generator. If all you're running is the fridge, it doesn't need to be too big.

The EMS I linked to is a popular one, but there are less expensive ones out there which will do more than just surge protection. You can also keep an eye on the classified ads - there is a used one there for $155 right now.

https://www.airstreamclassifieds.com...olorado-366797

Most of the units in the $40 price range I've seen were just surge protectors. Better than nothing but don't offer all that a true EMS does.

Charging from your tow vehicle while it idles can be hit and miss. Some vehicles have very low output at idle and won't do much charging. You'll definitely get better charging if you are driving and the engine RPMs are up. Another option to keep your batteries topped off while dry camping is a portable solar panel with a built-in controller. Simple to connect and will likely charge more than your stock engine alternator at idle. These are often found on the classified ads as well.

[Serf27]

Yes, the converter changes AC to DC and inverter does the opposite.

I have not gotten a converter yet. It is a question I always think to ask but forget.
Would a 35 amp converter be good for 2 batteries?
I am not sure what batteries I will get yet.

What size inverter do you both recommend?
When dry camping, I will rely on the batteries for 12v lights and water pump. The inverter will only power the 120Vac fridge.
Currently, at idle, I can power the lights and vent fans with some alligator clips on the truck battery.

The idle charging I ask about is mainly for dry camping when juice is running low.
I really have no idea how much camping I’ll do and in what areas.
I may drive go from dry camp site to a second dry campsite and charge the batteries while driving fhere, but again, not sure.
I’d just like to be prepared for each situation, or avoid said situations.
What are your thoughts on having some thicker cables on the truck battery going to the trailer while driving, for increased charge?

I will look into some type of solar panel charger that doesn’t break the bank.

Thanks.

[richard5933]

Check out the max watt draw from the fridge and make sure that the inverter you get has enough capacity to handle it. I'd suggest getting one with more though - once you have an inverter it's nice to have at least one outlet available to make use of it for other things.

Without doing the math, I'd guess that an inverter1,000 watt range should give you ample ability to run the fridge and another small appliance like a television, computer charger, etc. These smaller inverters are relatively inexpensive.

You do want to get an inverter which has a pure sine wave output, as some appliances will not function properly on a modified sine wave.

If your two batteries are not lithium, a 35-amp converter/charger would likely work. I think the one I used for my two lead-acid batteries was 45 amps.

Charging from the tow vehicle's factory wiring will likely allow charging at up to 4-5 amps, less at idle. Some tow vehicles do better, some worse. Running larger sized wires will allow better charging, but at idle it might still be limited.

[Serf27]

The fridge I am looking at is 110W and 1.4 running amps.
That’s about all the info I could find on it.
https://www.homedepot.com/p/Magic-Ch...10SE/205429696

I see this inverter.
1000W pure sine wave.

ROARBATT Power Inverters Pure Sine Wave 1000 Watt 12V DC to 110V/120V AC Converter 2 AC Outlets Car Inverter with 3.4A USB Port Cooling Fans and LCD Display https://a.co/d/akKIh9s
Some reviews mentioned it was fine for a small fridge and a fan.

Anything with 1500W is either a modified sine wave or $250+.

To hook up the inverter to 12v, they have the + and - terminals.
Do I run wire to those terminals directly from the batteries? Fuse box and ground bar? Or 12+ bar and ground bar?
I see they have 110v outlets.
Do I use an adapter and plug the breaker box to the converter?

This is the converter I’ve had my eyes on.
It says lithium compatible and the 45 amp isn’t much more than the 35 amp, so I may get the 45 amp.
Powermax 110 Volt AC to 12 Volt DC Power Supply Converter Charger for Rv Pm3-45 (45 Amp) https://a.co/d/gptsL0b

The batteries are going to be the most expensive piece of this.any recommendations?

[richard5933]

Originally Posted by Serf27

The fridge I am looking at is 110W and 1.4 running amps.
That’s about all the info I could find on it.
https://www.homedepot.com/p/Magic-Ch...10SE/205429696

I see this inverter.
1000W pure sine wave.

ROARBATT Power Inverters Pure Sine Wave 1000 Watt 12V DC to 110V/120V AC Converter 2 AC Outlets Car Inverter with 3.4A USB Port Cooling Fans and LCD Display https://a.co/d/akKIh9s
Some reviews mentioned it was fine for a small fridge and a fan.

Anything with 1500W is either a modified sine wave or $250+.

To hook up the inverter to 12v, they have the + and - terminals.
Do I run wire to those terminals directly from the batteries? Fuse box and ground bar? Or 12+ bar and ground bar?
I see they have 110v outlets.

First, that fridge draws 1.4 amps at 120vac. The inverter will have to make that power by pulling from the batteries. It will pull 14 amps from the batteries when the fridge is running. It's 10x the amps from the batteries as the fridge draws on 120vac (12 x 10 = 120).

This is an important thing to keep in mind - your battery bank has to be large enough to be able to sustain the draw by the inverter to power the fridge. If you assume that the fridge will run on a 50% duty cycle, that means it will deplete your batteries about 7 amps/hour. For a 12-hr stay somewhere that means your batteries will be down 84 Ah. Add this to whatever else you might be running from the batteries, do the math, and see if your batteries are going to be big enough.

The inverter will have its input lines connected to the 12vdc pos & neg bus bars. The output side you will use to plug in your fridge and maybe a small power strip to use to plug in whatever else you will run from the inverter.

Originally Posted by Serf27

Do I use an adapter and plug the breaker box to the converter?

This is the converter I’ve had my eyes on.
It says lithium compatible and the 45 amp isn’t much more than the 35 amp, so I may get the 45 amp.
Powermax 110 Volt AC to 12 Volt DC Power Supply Converter Charger for Rv Pm3-45 (45 Amp) https://a.co/d/gptsL0b

The batteries are going to be the most expensive piece of this.any recommendations?

The converter CAN NOT plug into the inverter. Ever. That would send things in a loop and run down your batteries in a heart beat.

The converter must be plugged into a 120vac outlet that you wire to be powered from your shore power connection. I think you know this, but I'm seeing some confusion in the way you wrote it.

What caught my eye is your question about an adapter to plug the breaker box to the converter...The converter plugs into an outlet powered by shore power. The output of the converter goes to your 12vdc pos & neg bus bars so it can charge the batteries.

When you start seeing all the things that go to the bus bars, it's easy to see how they are an advantage over making all those connections directly to the batteries.

[Serf27]

Ah, I mistakenly called the inverter the converter, sorry.

Yes I have a 120v outlet that the converter will plug into to charge the battlers from the breaker box/shore power.

I was asking about how the inverter sends power out.
I thought the 120v outlets on the inverter were somehow connected to the breaker box and this sent power to all 120v outlets in the trailer.

You’re saying that the fridge or anything else I decide to use is to be plugged directly into the inverter?

[richard5933]

Originally Posted by Serf27

Ah, I mistakenly called the inverter the converter, sorry.

Yes I have a 120v outlet that the converter will plug into to charge the battlers from the breaker box/shore power.

I was asking about how the inverter sends power out.
I thought the 120v outlets on the inverter were somehow connected to the breaker box and this sent power to all 120v outlets in the trailer.

You’re saying that the fridge or anything else I decide to use is to be plugged directly into the inverter?

How you get the power out of an inverter depends on the inverter.

Most of the ones in the 1,000 watt and smaller size range will have a pair of outlets on the end of them, and you simply plug in whatever you want to power. Simple and effective.

Larger inverters will usually have a way to hardwire directly to the output side of them, as do some nicer smaller inverters.

But, you absolutely cannot just hardwire the output of the inverter directly to the breaker panel. This would allow a situation where you can be plugged into shore power and powered from the inverter at the same time. In order to connect the inverter to the breaker panel you must use a transfer switch - this allows you to choose either shore power or the inverter to power the breaker panel, but never both.

To make things more complicated, you have to consider the bonding between your neutral and ground conductors on the 120v system. When you are plugged into shore power you do NOT want to have your neutral and ground bonded (connected). They will be isolated because they are bonded back at the main panel back in the building supplying your shore power, and it's not permitted to have the neutral & ground bonded in more than one place.

It is always supposed to be bonded at the source. When you're plugged into shore power the shore power is the source, and that's where the bonding takes place. When you are running from the inverter, the inverter becomes your source and so now you need to bond your neutral & ground.

Transfer switches designed to switch between shore power and inverter power will automatically handle bonding the neutral & ground when necessary, and disconnecting them when it's not necessary. Some nicer inverters have the transfer switch built in.

Okay - what's the best/easiest way to handle this?

Simplest is to install a couple of dedicated inverter outlets - one for your fridge and another to use with a power strip. Whenever you need to run the fridge the inverter has to be on, so you can just leave it plugged into the inverter all the time.

If you're on shore power, then the converter will be turned on and it will be charging the batteries. The inverter can draw from the batteries to power the fridge and things are good. When you unplug from shore power, your batteries stop charging and the inverter will continue to draw from the batteries until they run down. Most inverters will turn off if the batteries get too low.

[Wazbro]

There is another option you can look into, an inverter/converter/charger. some of these are designed to be installed between the shore power coming in and the breaker box with a builtin transfer switch. When plugged in A/C power goes through and it charges the batteries. When not plugged in the inverter portion powers all outlets from the batteries. Makes it more convenient and some have a boost function that can let you run your AC from a 15 amp circuit or small generator without making sure everything else is off.

There are 2 downsides though,
1 If your air conditioner is running and power goes out it will try to run it from batteries if to small to run AC it will blow fuses or cycle on and off, if large enough to run AC it will run batteries dead quickly.
2 If your batteries run down too low for the inverter/converter/charger it will shut down ALL power going in or out of it. You may need to charge the battery some other way before it will let A/C through or charge your batteries.

[Serf27]

When I set up for camping, I will either have the inverter turned on and converter disconnected from the 120v outlet or the inverter off/nothing connected to it and the converter plugged in.

I wasn’t thinking of hard wiring the inverter into the breaker box.
This is what I was thinking. It sounds similar to the transfer switch.

The inverter has the 110v outlets on the side of it.
If I take a a small extension with a 110v plug on one end and plug that cord into the 30amp connector on the side of the trailer, it would send power through the breaker box to all outlets, wouldn’t it?
That would only be plugged in when dry camping.
Does that make sense?
It would be a cord with a 110v male to plug into the inverter and a 30amp female to plug into the side of the trailer. Here’s a photo.
This is a scenario where I am dry camping and the converter is not plugged in.

If that will not work, I will just mount the inverter near the fridge and run the +/- wire to the 12dcv bus bars and I’ll just leave the inverter isolated from the system when I am connected to shore power.
Avoids any ground issues and extra switches.

I do not have any current plans on an AC unit yet.
I see some cheap 12v evaporative coolers that I may try out in the future.

[richard5933]

Basically what you're describing is using the inverter as you would a generator - plugging it into the shore power inlet when needed. This works, and it eliminates the need for a transfer switch.

Couple of thoughts on this as a plan though...

1) Since you'll want to be able to run the fridge while you're driving from place to place, you'll have to have a way to connect the inverter which allows for the trailer to be rolling down the road. Not so handy to drive down the road with a cord hanging outside the trailer.

2) The inverter should ideally be mounted close to the batteries. The voltage loss is much greater on the 12vdc side than on the 120vac side, so it's better to keep your 12vdc feed to the inverter as short as reasonably possible. If you have to make it longer than a few feet, going up one size in wire gauge can help offset the voltage drop.