RV/Trailer wiring, AC and DC

[TheEquineFencer]

I've about finished ripping the interior out of Linda's horse trailers living area. The roof vent leaked and rotted the underlying attachment wood and such out, then the interior roof fell in. It has a 120V 20A male plug inside a weatherproof cover outside feeding into a two breaker disconnect box. They had a single 120V 20A breaker fed from the outside male plug into the disconnect and out feeding the single 120V receptacle. They jumpered the other pole for later adding another 20A breaker to feed the wiring for the A/C unit that she never installed. Previously it just had (1) 120V receptacle over the hand pump sink, (1) 120V wire run to the roof vent for an A/C unit for a future A/C unit, the rest of the switches are for 12V interior lights.

Now here's what I want to do as far as the AC Voltage. I want to power the trailer with a 4000W Onan KY generator or from shore power. For now it will be used as a mobile/portable generator, later I plan to mount it to the trailer. I want to run a 30A "service" to a junction box/disconnect, then have two 20A circuits, one for the rooftop A/C unit I'm going to add and the other for that single receptacle and probably a few more I'll add.

I need some ideas for the interior lighting, I'm thinking LEDs. It already has one 12V light switch mounted on the wall. I'd like to add a few more lights. One has to be mounted under the cabinets I've got to reinstall after they are repaired. We've done away with the hand pump sink.

Now here's the 12V dilemma. We stopped at a place that does RV/Living quarter conversions, they were planning to install some kind of converter box that will switch from the 120VAC to charge the (2) 12V batteries I've got to add. She wants the trailer lighting to be self powered on 12V when it either unhooked or powered from 120VAC and also can be run from the trailer light cord when it's plugged into the truck or running on generator power. I guess this is where the convertor box comes in.

If it's running on shore power or generator power is where that convertor box comes into play I guess. The box is not going to be used to power the A/C unit when all that's available is battery power.

Something that bugs me a bit is the guy at the trailer conversion place said that you do not wire the trailer the same as far as the grounding for the AC power like you would a house. Is this true?? The way it looks now, it was wired the about same. It has a GFCI receptacles inside wired back to the disconnect and is grounded with all the grounds at a common inside the disconnect. Then is wired to the power plug coming in.

I'm open to suggestions and ideas for the wiring. Links to more info and wiring and "convertor boxes" would be helpful.

 

[motofool33]

you wire the 12volt lighting direct to battery if you want to use them without the house power hooked up. might help to wire in a disconnect also for these so they dont drain the batteries.

the converter box is powered by a/c power and charges the batteries and also converts power to the 12volt stuff by use of the ac power instead of battery power.

then when the ac power is not there the converter takes battery power and converts to ac and will **** them batteries dry fast.

IMO its better to use a power inverter that has a charging function built in.

best setup would be like in my RV and class A had.

4 golf cart Trojan T-105 6volt batteries wired in series and parallel. then the inverter plugged in to the house wiring and charging function hookedup to the batteries

with 4 golf cart batteries and the 2000 watt inverter i could go 4-5 hours of watching TV and charging things before the batteries dropped below 10.5volts and the inverter switched off.

when you have the generator on the inverter will sense power and auto charge the batteries back up and keep them at float voltage.

Magnum is the best american made inverter company. I marine usa has the best prices on them. second best inverters are the xantrex inverters. GO for a Pure sinewave if you want to use Computers/laptops/ newer fridgerators, HD tv's or satelite receivers in the trailer.

 

[theoldwizard1]

IMO its better to use a power inverter that has a charging function built in.

I have to agree, but you want one that automatically switches from battery to "shore power". Basically, you wire your shore power/generator inlet directly to the the input side of the inverter. If there is outside power, it charges the batteries. If not, it converts the battery DC to AC.

This type of inverter is not cheap, but it gives you the simplest solution.

Simply wire the DC lighting directly to the batteries. 2 - 6V golf cart should be adequate. Don't waste your time on AC lighting.


One down side to this. The air conditioner(s) MUST be wired directly to the AC inlet (not to the output of the inverter). If you had a large enough inverter (>2000 watts ?) you could wire your air conditioner to the outlet of the inverter, but you would probably need a 24V battery bank.

 

[Falcon67]

What they said. On our race trailer, I just wired in a relay that switches between the little 16AH host battery and the truck feed. Our F150 only powers the trailer connectors when the engine is running. I do not have the small interior LEDs hooked to the 120V power. I just use a solar charger at the track, throw it up on the roof. I have a couple of 24" emergency power flo light fixtures - thinking about putting one in the trailer and hooking that battery to the two LED lights.

 

[rockwithjason]

http://www.adventurerv.net/parallax...rtsfeed_ppc&utm_medium=cpc&utm_source=Froogle

this is the kind of load center that rv manufacterers use. read the manual on it and i would bet that this will solve most if not all of your problems.

as far as the grounding goes, the most important thing is to bond the frame to ground as well as all outlets

 

[Falcon67]

Here is a full discussion on generators and trailer grounding:

http://www.garagejournal.com/forum/showthread.php?t=252428

 

[TheEquineFencer]

Good stuff so far. Thanks.

 

[theoldwizard1]

Outback Power makes some very nice inverter/chargerss that would work well !

Their VFX2812M (23A @ 120V continuous) would probably run most RV air conditioners, but not for very long before the batteries shut down (around 10.5V). Their VFX3524M (29A @ 120v continuous) costs about the same but uses a 24V battery bank, like what motofool33 has.

 

[theoldwizard1]

On our race trailer, I just wired in a relay that switches between the little 16AH host battery and the truck feed. Our F150 only powers the trailer connectors when the engine is running.

Good, but not the best way to recharge your trailer "house" battery.

Most (all?) 7 pin trailer connectors have a wire coming from the vehicle battery/alternator (possible controlled by the ignition switch like Falcon67 did) for battery charging. Not the best because the voltage drop in the wire from the vehicle battery to your house battery will always limit the charging voltage. It will be difficult/impossible to get a full charge on those batteries regardless of how many hours of driving you do.

As stupid as it sounds, you would be better off with a small 100W sinewave inverter in your vehicle, connected to a standard extension cord running to the trailer. There, plug in a battery charger/tender (like a Battery Tender 5A Power Tender) mounted close to your battery bank. If you want to completely recharge your battery on your days drive after depleting them the night before, you will need a bigger charger and a bigger in-vehicle inverter.

 

[TheEquineFencer]

Outback Power makes some very nice inverter/chargerss that would work well !

Their VFX2812M (23A @ 120V continuous) would probably run most RV air conditioners, but not for very long before the batteries shut down (around 10.5V). Their VFX3524M (29A @ 120v continuous) costs about the same but uses a 24V battery bank, like what motofool33 has.

Thanks for the idea, but she doesn't plan to run the AC unit from the batteries. She just needs to power the 12V lights as far as I know. She might decide later on she wants to power some 120V stuff, I'll cross that bridge I guess when I start actually getting ready to order the parts in the next day or two. Right now I'm having a heck of a time getting the roof vent out.

 

[Falcon67]

Good, but not the best way to recharge your trailer "house" battery.

Yes, but our "house battery" is a cast off wind turbine 16AH backup bank battery - little thin thing, not good for much of nothing. It was free. If we had a REAL deep cycle 12V in the box, then yea - it's be running off a charger or inverter. With us, it's be a charger since the 3500 runs all day at the track. We only need a little light to load the car. I haven't found a reason yet to put a full deep cycle in the trailer.

BTW - our 13,500 BTU roof mount pulls 17A measured in 100F weather. It's an old Coleman Mach, paid $250 for it.

BTW #2 - if that roof vent in like the one I pulled to put in the AC unit, yea. I did it in summer and put some OSB on the roof so I could work up there. Scraping off the goo to get at the screws is the worst part. All our trailer screws require a #2 square bit.

 

[sberry]

I wouldn't bother with anything 12V, you could but may not even do that, recharge with shore power when possible and run a small inverter. Back to shore when you could. We got an old airstream, its got all that junk as an inverter wasn't a ********* when they made it, pia, always was.

 

[sberry]

Don't waste your time on AC lighting.

Not that a guy couldn't have a 12 v light but this is backwards, I wan the light to run AC when it can come from a line.

 

[TheEquineFencer]

The vent screws were covered in roof sealer. The guy helping me thought they were rivets, so he took the sander to them after the drill bit wouldn't cut through easy enough, then we found out they were SS screws screwed into the aluminum frame. I had to drive them through after I ground them flush. If the new AC units hits the same holes I guess I'll break out the spool gun and try filling and re-drilling.

I think what would be nice for the power situation is an inverter/converter that I could feed 12V into and 120V. Then have it put out 120V to the 120V stuff and also charge the batteries if I'm on the generator or shore power and when it's on Battery power put out 120V and just not run the AC unit.

The truck, a 2006 Cummins powered Dodge 3500 4x4 also feeds 12V to the trailer as it is now configured. I'd like to have it so it can charge the batteries when running but not be able to kill the truck batteries if she cuts the truck off and is running the inverter/converter.

I think in the morning I'm going to go to a couple of RV places and look around.

 

[mdbeck1]

I've got a 18 foot bumper pull Travel trailer. The lights, water pump, refer, and blower motor for the heater are all 12 VDC. The AC, microwave, and electric plugs are all 120 VAC. When you plug into shore power you can run the AC, microwave, and electric plugs. Otherwise you're out of luck. Not the ideal situation but it works.

 

[theoldwizard1]

Not that a guy couldn't have a 12 v light but this is backwards, I want the light to run AC when it can come from a line.

Why ? That means you need 2 fixtures and 2 bulbs (unless there is such a thing as a fixture that has both sockets for both). LEDs are so bright now a days, this seems redundant.

 

[theoldwizard1]

I think what would be nice for the power situation is an inverter/converter that I could feed 12V into and 120V. Then have it put out 120V to the 120V stuff and also charge the batteries if I'm on the generator or shore power and when it's on Battery power put out 120V ...

A good inverter/charger, with built in transfer switch, will do just this. All 12V loads are wired directly to the house battery (with appropriate fusing). When on generator/shore power the batteries will be continuously recharged.

The inverter/charger inlet is wired to the generator/shore power inlet. It will "feed-thru" 120V AC if it is present. Wire all of your 120V loads to the output of inverter/charger. If 120V AC is not present, it will invert (convert DC to AC) and run you 120V loads.

...just not run the AC unit (when on inverter).

Simple. Wire the air conditioner to the same connection as the input to the inverter/charger.

The truck, a 2006 Cummins powered Dodge 3500 4x4 also feeds 12V to the trailer as it is now configured. I'd like to have it so it can charge the batteries when running but not be able to kill the truck batteries if she cuts the truck off and is running the inverter/converter.

Those feed are typically "hot at all times". Buy a heavy duty (40+ A) automotive relay and wire it into this feed so that it is controlled by "hot when key ON" feed. This is very easy, once you locate the wires.

I think in the morning I'm going to go to a couple of RV places and look around.

They will charge you an arm and a leg.

The real question is what kinds of 120V loads are you going to run ? If you are talking about a TV, stereo, DVD player, computer, box fan, etc. you only need a couple hundred watts. Coffee pot, microwave is "a whole 'nother thing !"

What ever you do, do NOT buy a pseudo-sine wave inverter. They don't work well with electronics.

 

[theoldwizard1]

A good inverter/charger, with built in transfer switch, will do just this.

A good quality computer sine wave Uninteruptable Power Supply will do just this !

This APC SUA1000XL Smart-UPS is designed for continuous use when connected to a large battery (most computer UPS do not have adequate cooling).

You can frequently find these cheap on CL (SUA1000), without the internal batteries and without the extra cooling. A good computer fan is all you really need.

 

[Falcon67]

I use AC lights - T8 4' fixture - in the race trailer. 99% of what we use is 120V. Phone chargers, fans, laptop, etc. I wired up the little battery for misc loading equipment at night. I took out the 1156 bulbs in the trailer overheads and replaced with haywired dual 48 LED squares bought from Joe Jujitsu in Hong Kong. 4 squares draw .1 A at 12V.


On your AC unit - you do know to get a big foam seal from an RV house to seal that to the deck. If this is a new unit, then it should come with a seal. If it's a real RV unit, it does NOT use any of the old screw holes. You will want to seal those holes with RTV. Our Coleman uses 5 long bolts to secure the lower unit of the AC to the roof unit. Word of advice there - put a dab of Loctite Blue on the bolts AND check them for tightness periodically. The gasket will relax and let them loose, and you will get a leak. I know - I just discovered this on ours after half a season. Now I'm going to pull the lower cover every couple of months and check the bolts. When I pulled the lower cover, one of the bolts fell to the floor and the others were coming out. Not good!

 

[TheEquineFencer]

A good quality computer sine wave Uninteruptable Power Supply will do just this !

This APC SUA1000XL Smart-UPS is designed for continuous use when connected to a large battery (most computer UPS do not have adequate cooling).

You can frequently find these cheap on CL (SUA1000), without the internal batteries and without the extra cooling. A good computer fan is all you really need.

Yes, it does sound like what she needs/wants is something that functions like a UPS. 120V in and if it's not there it uses the 12V supply.

 

[motofool33]

Yes, it does sound like what she needs/wants is something that functions like a UPS. 120V in and if it's not there it uses the 12V supply.

with a computer and 2 monitors those last barely 30mins. we have them at work

a inverter with golf cart batteries will go 4-5 hours or longer depending on the amp load

 

[TheEquineFencer]

with a computer and 2 monitors those last barely 30mins. we have them at work

a inverter with golf cart batteries will go 4-5 hours or longer depending on the amp load

I understand. What I was talking about was something that did the switching like the UPS does. A UPS waste a lot when it's sitting there "doing nothing."

The reason I'm going to the RV places is to see what they have/use to get some ideas of what OEM uses and to look at lighting ideas.

I've looked at some video on YouTube about installing rooftop AC units and see what Falcon67 was talking about with the bolts and install. Right now I figure I've got to get on the ball with the wiring. I've figured out all the rest for the most part. I just need to figure out what invertor/ATS/whatever I'm going to use and get it coming and figure out what LED lighting I'm going to use and get it coming too.

LED interior lighting ideas would be good. How small of a wire is required for the LEDs? I know that's a big advantage with the semi-trucks, you can run much smaller wire. I know she wants a light under the cabinet. I'm thinking some kind of LED strip light. I have yet to try pulling out the OEM 12V light switches, they look riveted in place.

When I get time later today, I may post some pictures of the trailer/wiring and such.

 

[theoldwizard1]

with a computer and 2 monitors those last barely 30mins. we have them at work

a inverter with golf cart batteries will go 4-5 hours or longer depending on the amp load

I said that an external battery bank would be required as well as additional cooling. How long your battery bank lasts, depends on the load and capacity of the battery bank.

I understand. What I was talking about was something that did the switching like the UPS does. A UPS waste a lot when it's sitting there "doing nothing."

Not true. Yes, there is some loss. A good one will have losses in the range of 2-9% when it is just monitoring the AC input (not inverting). I would recommend turning the inverter off if you have no need for 120V (traveling, overnight). UPS inverters are about 80-90% efficient when in use (making AC from DC) while a top of the line inverter would be about 92-97%. This difference is significant if you are trying to live off grid with all of your power generated by solar or wind.

The reason I'm going to the RV places is to see what they have/use to get some ideas of what OEM uses and to look at lighting ideas.

I will be surprised if they have anything better !

LED interior lighting ideas would be good. How small of a wire is required for the LEDs?

I would use 18AWG for interior LED lighting. Exterior I would pay the extra for marine grade wire.

 

[TheEquineFencer]

I'm looking at USED UPSs on CL now. Thanks for the idea.

 

[theoldwizard1]

The reason I'm going to the RV places is to see what they have/use

This is the latest model APC Smart-UPS 750 (500 watts) - Amazon $260. 91-97% efficient. I can not find and specs on "no load" usage current, either on AC or on DC.

 

[TheEquineFencer]

This is the latest model APC Smart-UPS 750 (500 watts) - Amazon $260. 91-97% efficient. I can not find and specs on "no load" usage current, either on AC or on DC.

So far I've found a used UPS 3500W output for $450 kinda local, but it's untested.

 

[ishiboo]

Now here's the 12V dilemma. We stopped at a place that does RV/Living quarter conversions, they were planning to install some kind of converter box that will switch from the 120VAC to charge the (2) 12V batteries I've got to add.

That's simply called a battery charger.

She wants the trailer lighting to be self powered on 12V when it either unhooked or powered from 120VAC and also can be run from the trailer light cord when it's plugged into the truck or running on generator power. I guess this is where the convertor box comes in.

Yes. For this reason, typically RVs use 12v for tasks like lighting/plumbing, and 120v where appropriate - AC, stove if electric, microwave.

Something that bugs me a bit is the guy at the trailer conversion place said that you do not wire the trailer the same as far as the grounding for the AC power like you would a house. Is this true?? The way it looks now, it was wired the about same. It has a GFCI receptacles inside wired back to the disconnect and is grounded with all the grounds at a common inside the disconnect. Then is wired to the power plug coming in.

It's more or less the same. Neutral-ground not bonded at the trailer panel. If installed with a generator, the generator will have the bond and the neutral and ground will be switched.

The biggest question is whether or not you need 120VAC power when the generator is not attached, and what you want to run. Realize 120vac stuff ***** up large battery banks quickly.

If you need 120VAC capability, an inverter/charger like the Xantrex HF1000 or HF1800 would be a good option. They provide 40A of charging/12v output and have a transfer switch. Transfer switching alone is not a big deal, you can do it with a relay.

If you only need 12V when the generator is not attached/running, then all you need is a 12V charger. Again, we need to know your loads before we recommend specific sizes of a charger, inverter, and battery bank.

 

[TheEquineFencer]

That's simply called a battery charger.



Yes. For this reason, typically RVs use 12v for tasks like lighting/plumbing, and 120v where appropriate - AC, stove if electric, microwave.



It's more or less the same. Neutral-ground not bonded at the trailer panel. If installed with a generator, the generator will have the bond and the neutral and ground will be switched.

The biggest question is whether or not you need 120VAC power when the generator is not attached, and what you want to run. Realize 120vac stuff ***** up large battery banks quickly.

If you need 120VAC capability, an inverter/charger like the Xantrex HF1000 or HF1800 would be a good option. They provide 40A of charging/12v output and have a transfer switch. Transfer switching alone is not a big deal, you can do it with a relay.

If you only need 12V when the generator is not attached/running, then all you need is a 12V charger. Again, we need to know your loads before we recommend specific sizes of a charger, inverter, and battery bank.

I just spoke with the "Boss" a little while ago, she does want 120V available when the generators not attached/in use. The load is another issue. I'm guessing she wants to run a TV and such, probably not the A/C, I'm guessing possibly a small 900-1000W microwave for short term use.

Just out of curiosity, if she has a 4000W inverter,how many 12V amps DC input would it take to run it at full load or at a 17A load? How long would a set of let's say 2-3 850 CCA batteries run it before it shutdown for low voltage?

 

[motofool33]

I just spoke with the "Boss" a little while ago, she does want 120V available when the generators not attached/in use. The load is another issue. I'm guessing she wants to run a TV and such, probably not the A/C, I'm guessing possibly a small 900-1000W microwave for short term use.

Just out of curiosity, if she has a 4000W inverter,how many 12V amps DC input would it take to run it at full load or at a 17A load? How long would a set of let's say 2-3 850 CCA batteries run it before it shutdown for low voltage?

with a bank of 4 Trojan t105 6volt golf cart batteries and a 2800 watt magnum inverter pure sine wave i could get 4 hours of use running stuff inside, a 4000watt inverter at full tilt could pull upto 200amp from the battery bank and drain them very quickly.

a 2000watt inverter is standard in a 40ft class A motorhome, a 2800watt is considered high end. and above that they recommend going to 24volt battery bank.

the microwave will drain the battery bank in about 20mins with other stuff running.

plan on the inverter running everything except the microwave and A/c's.
most RV's run the Microwave through the inverter so it gets clean power but its meant for the generator to be running.


the problem i see with the UPS method is the charging function takes along time to get the batteries back up to full. many hours.

with a 2000 watt inverter they generally have a 100amp charger and with house power can charge the batteries to full in less then an hour.

 

[theoldwizard1]

So far I've found a used UPS 3500W output for $450 kinda local, but it's untested.

Besides being heavy and HUGE, it will likely require 48V battery bank !

The "sweet spot" is 1000VA-1500VA (largest quantity sold), but some of those require a 24V battery bank.

Many of these UPS will not "power up" if they do NOT have charged batteries.

 

[theoldwizard1]

Just out of curiosity, if she has a 4000W inverter,how many 12V amps DC input would it take to run it at full load or at a 17A load? How long would a set of let's say 2-3 850 CCA batteries run it before it shutdown for low voltage?

Very rough rule of thumb ...
Watts out = watts in times the efficiency. Watts = volts x amp

If you are using 2000 watts @ 120v, you are using 16A@120V, which is actually more than most individual circuits in your home. For 2000 watts output, with a 95% efficient inverter, would be pulling 175A@ 12V !!!

So 1000 watts output would need about 87A@12V. Most counter top microwaves (smaller than 1.0 cubic foot) use less than 1000 watts. Make sure your inverter is rated at a "peak" load of >1200 watts.

Cold Cranking Amps (CCA) is not the proper way to measure capacity of deep cycle battery used for an inverter. You want to know discharge time at a fixed rate. 2 - Trojan T105 6V golf cart batteries (top of the line ) can be discharged at 75A for about 115 minutes.

 

[motofool33]

Very rough rule of thumb ...
Watts out = watts in times the efficiency. Watts = volts x amp

If you are using 2000 watts @ 120v, you are using 16A@120V, which is actually more than most individual circuits in your home. For 2000 watts output, with a 95% efficient inverter, would be pulling 175A@ 12V !!!

So 1000 watts output would need about 87A@12V. Most counter top microwaves (smaller than 1.0 cubic foot) use less than 1000 watts. Make sure your inverter is rated at a "peak" load of >1200 watts.

Cold Cranking Amps (CCA) is not the proper way to measure capacity of deep cycle battery used for an inverter. You want to know discharge time at a fixed rate. 2 - Trojan T105 6V golf cart batteries (top of the line ) can be discharged at 75A for about 115 minutes.

and when you get 4 and wire series and parallel you get even a little better performance and they take a high amp recharge like a champ.

the t-105's to get optimum performance they need to be charged at 40amps or better.

 

[TheEquineFencer]

I'm wiring my VFDs for the mill and lathe in the shop tonight. I did some checking today, I think what I need for the most part is about a 2000W inverter/charger with a "pass through" for the 120V. I talked with Zantrax today while I was driving and need to get back to looking at their website and see what the Tech guy was talking about. It sounds like i can use what he was talking about to charge and run the 12V stuff when on shore power and do a little "creative" wiring to get the whole trailer switched to a 30A circuit, bypassing the 120V output from the inverter/charger, but still have the inverter/charger active to run the 12V charging for batteries and lights. I'll add a 30A transfer switch to do this. This will switch the load from the inverter to the shore power or generator depending on what is proving incoming 120V power.

 

[theoldwizard1]

I'm wiring my VFDs for the mill and lathe in the shop tonight. I did some checking today, I think what I need for the most part is about a 2000W inverter/charger with a "pass through" for the 120V. I talked with Zantrax today while I was driving and need to get back to looking at their website and see what the Tech guy was talking about.

Zantrax is spelled Xantrex. The parent company of Xantrex owns several inverter companies and APC power. Most equipment in the RV inverter world is based on designs that are over 10 years old. UPS equipment has gone through 1 or 2 generations of improvement in that time,

It sounds like i can use what he was talking about to charge and run the 12V stuff when on shore power and do a little "creative" wiring to get the whole trailer switched to a 30A circuit, bypassing the 120V output from the inverter/charger, but still have the inverter/charger active to run the 12V charging for batteries and lights. I'll add a 30A transfer switch to do this. This will switch the load from the inverter to the shore power or generator depending on what is proving incoming 120V power.

30A circuit ? Are you going to wire the trailer 10/2 ?

All the outlets in the trailer can be on 1 - 15A circuit, except for the A/C. The A/C should be on it own 15A circuit.

There are a lot of ways to wire things. It is even possible to have an "automatic transfer switch" with a simple DPDT relay. My suggestion for the UPS is probably the simplest.

The important things are

• Buy a sine wave inverter. Most electronics (including micro waves) do not work well with a pseudo-sine wave inverter.
• Understand exactly what your 120V AC loads are. Until you have this nailed down you are just wandering in the dark. A good salesperson will sell you something you don't need or worse, won't work. (Hint, you don't need a 2000 watt inverter. 1000 watts with an "honest" 1500 surge capacity.)
• The only real way to compare inverters (besides rated output and surge capacity) is inefficiency (which varies under load) and idle current. If they won't show you these numbers, walk away.
• If you are buying new, make sure the you know what the stores return policy is. Many "specs" are out and out lies and the equipment can not do what is stated on the box.
• Buy good batteries. Flooded cell (the old fashion kind that you need to check the water level on. FREQUENTLY !) Trojan are some of the best.

And you don't need a pass-thru if you are going to wire in your own "transfer switch".

 

[theoldwizard1]

Here is how I would wire it.

• 30A female RV pigtail feeds into the trailer
• Inside the trailer, the pigtail goes into a fused A/C disconnect box (cheap) with 2 - 15A fuses. Because you only have 1 hot, wire it to both fuses.
• From 1 fuse run 14/2 Romex to you air conditioner.
• If your inverter has a built in pass-thru (another word for automatic transfer switch), wire it to the directly to the second fuse. Wire all AC loads to the inverter.
• If you are going to use a "manual" transfer switch you can use a Leviton 1282 DPDT
  • Inside the disconnect box splice together 3 - #14 wires. The first one will go to the terminal of the second fuse.
  • One of the other #14 will go to the input of the inverter/charger.
  • The third #14 will go to one of the inputs of the DPDT
  • The other input of the DPDT will be from the outlet of the inverter/charger.
  • The common from the DPDT will go to all 120V AC loads in the trailer.

Wire all 12V loads fused directly to the batteries.

If there is power at the plug, the inverter charge will charge the batteries, all the 120V load will run and the A/C will work.

If there is no power at the plug, 120V AC will be provided by the inverter. If you don't have a pass-thru you will have to flip the switch.

 

[TheEquineFencer]

Here's what I'm looking at, Freedom SW 2012 (815-2012). http://www.xantrex.com/power-products/inverter-chargers/freedom-sw-12v_newgen.aspx

2000W version.

I just did some measuring, this thing is HUGE. It'll do a 4000W surge for 5 seconds and do everything she needs but would be a pain to fit where it'd need to go. I'm starting to think I'd be better off with a 30A simple ATS, bring Utility power in one side of the ATS and just have a 120V plug from the inverter powered from the batteries into the other side of the ATS and have the ATS feed a simple two breaker panel. One breaker for everything but the A/C unit. Put the A/C unit on it's own breaker. Then add a charger to charge the batteries when plugged into utility power.

 

[TheEquineFencer]

I figured I'd use a 30A RV plug to go from shore power to the inside of the trailer. The generator she will be getting shortly will be an Onan 4000W KY. I figured going into the panel from the RV plug on 10/2, coming out of the panel I'd wire everything on 12/2 with 20A breakers.

 

[motofool33]

Here's what I'm looking at, Freedom SW 2012 (815-2012). http://www.xantrex.com/power-products/inverter-chargers/freedom-sw-12v_newgen.aspx

2000W version.

I just did some measuring, this thing is HUGE. It'll do a 4000W surge for 5 seconds and do everything she needs but would be a pain to fit where it'd need to go. I'm starting to think I'd be better off with a 30A simple ATS, bring Utility power in one side of the ATS and just have a 120V plug from the inverter powered from the batteries into the other side of the ATS and have the ATS feed a simple two breaker panel. One breaker for everything but the A/C unit. Put the A/C unit on it's own breaker. Then add a charger to charge the batteries when plugged into utility power.

i have an older version of that unit i just took out of my Class A before putting in a new Magnum inverter.

if your in no rush for the unit we could work something out but right now i cant get to the unit as im 3hours from home working

 

[TheEquineFencer]

i have an older version of that unit i just took out of my Class A before putting in a new Magnum inverter.

if your in no rush for the unit we could work something out but right now i cant get to the unit as im 3hours from home working

The one you have, how big is it, physical size? PM me about price and when you can get it please.

I think I just figured out a simpler way to get around the A/C problem. If I bring in 120V from shore power, wire the A/C unit in BEFORE going through the inverter, if she has shore power available, she can use the A/C unit. If she doesn't then she just runs on the batteries and the inverter.

 

[motofool33]

The one you have, how big is it, physical size? PM me about price and when you can get it please.

I think I just figured out a simpler way to get around the A/C problem. If I bring in 120V from shore power, wire the A/C unit in BEFORE going through the inverter, if she has shore power available, she can use the A/C unit. If she doesn't then she just runs on the batteries and the inverter.

these inverters have an auto pass thru function when generator/house power is detected