Plugging shore power into inverter

JRRNeiklot wrote:
Just looking for the simplest way to do it, as I am not up to speed on everything electrical.

But you're getting there by asking on here.

As for the MW, you have enough battery, but you'll likely need a more robust inverter. There are two outlets, meaning one may not handle the mw, and, in a lot of cases wattage ratings are highly optimistic on lower-priced inverters. It may be possible to wire those two outlets in parallel.. not sure on that model.

Thanks everyone for the advice.

I've got a battery bank of 4 trojan T-105s, so 450 amp hours, which will give me 225 to work with. As I said, I'll be running a tv, computer,a fan or two, and a microwave. I really want to be able to use the microwave a few minutes a day, it's just so convenient. The trailer is parked at a location where I will have no shore power access. I'll charge the batteries with a generator for now, but ultimately, I have two 250 watt solar panels I want to install, but that's a project for another day. Right now I just want access to the interior outlets. The trailer has no 12 volt plugs installed, so I'm wanting to keep everything ac. Just looking for the simplest way to do it, as I am not up to speed on everything electrical.

I recommend skipping the microwave and getting a quality 300 watt sine wave inverter such as Go Power. I also recommend wiring it in with a transfer switch and remote power. Push a button and your small stuff comes to life.

If you really want the microwave you are looking at 2000 watts and four plus batteries to drive it.

By the time you allow for inverter losses (they are at best about a 12% loss), dividing the watts by ten gives you the draw at 12 volts. So the Microwave may draw 90 amps, not 9.

If the microwave says 900 cooking power, it may draw as much as 1300 watts. Now the draw may be 130 amps.

To size an inverter take the largest load and multiply by 125%.

JRRNeiklot wrote:
At 900 watts, the microwave will draw 7.5 amps if used for 6 minutes(by my math). That's probably more than I will use it in a day. But yeah, it will require a larger inverter.

RoyB wrote:
I use my heavy wattage items like making coffee etc when I am re-charging my battery bank each morning for three hours starting with breakfast using my on-board smart mode charging powered by my 2K Honda Generator.

I too have an EU2000i and can do the same BUT whether we're intentionally dry camping or camping without shore power because it's failed I wanted the ability to instead power my coffee machine and toaster with the inverter rather than the genset as I'm an early riser. Running a genset mid morning is one thing, running it at 6 am quite another. :E

JRRNeiklot wrote:
I'm about to buy an inverter for my travel trailer. It has no 12 volt outlets, so I think ac is the easiest way to go.

Why would you expect an inverter which converts 12 vdc to 120 vac to have any 12 vdc output? ... and why would you want it to when your trailer is already wired with 12 vdc? :h Also, without knowing what you intend to use as battery source supply to power this inverter it would be really difficult to say what you could realistically power with this inverter and for how long.

Can I plug the shore power plug (with an adapter) directly into the inverter and power the outlets in the trailer?

Yes, with some consideration. What you're wanting to do is wire the inverter's output to feed the trailer "whole house", just what I did (7 pics) earlier this year ... works fine with some inverters but you sure wouldn't want to do this with any inverter wired with a 60/60 centre bonded neutral output. :E If you don't understand what this means then you'd be best to pass on the idea, keep the inverter's output wiring entirely separate from the trailer's, and simply use your inverter to feed individual devices directly. ;)

Unfortunately you haven't said anything about why you want to do this. :h If it's because you regularly intend to dry camp then I'd say a "whole house" wiring scheme makes sense because you can plug in as part of your setup and leave it that way for the duration of your stay. However, if it's only going to be used intermittently for back up those times campsite shore power may fail then I'd say "whole house" is more trouble than it's worth. A case in point ...

Last month during what should have been a pleasant fall camping weekend on a 30 amp electric site we were hit with a foot of snow, tree limbs falling all around us, and as it turned out power lost to the campground for 36 hrs from 4 am Sat to mid afternoon Sun ...



... and I can tell you it was no fun climbing out of bed in the middle of the night and getting dressed to go outside, trudge through the snow to unplug the trailer's main service cable from the (now dead) campsite post and move it over to the inverter output receptacle. Back inside I also had to turn off the converter, force the fridge to gas, and switch the water heater element off, none of which I initially remembered to do that early in the morning. :M So ... since my use for this inverter is as emergency back up and not because we do any amount of planned dry camping I'll be removing this "whole house" wiring scheme in the spring and instead wiring the inverter's output to three additional duplex receptacles I'll install for the purpose - two on each side of the bed and one near the kitchen galley. To use I won't have to go outside or remember to do anything special at all - just turn the inverter on with the remote control which I have mounted inside the camper and plug whatever device we want to use into any one of those 3 receptacles. Having learned this lesson the hard way I'd suggest that in your case you first need to define just what it is you really expect to use this inverter for, then design your installation based on those requirements ... and that you can't do until you determine just which battery supply you intend to use as source power.

In my case, because my inverter is intended only as back up for those times we may lose shore power, I use my existing G27 battery and with that can power a couple of 120 vac fans, a 550 watt coffee machine, a 650 watt toaster, or even my wife's hairdryer on it's low setting of 350 watts. I could care less about the microwave oven, which is a good thing since there isn't a chance on the planet this 1000 watt inverter nor the single G27 battery feeding it could meet the load. Next year, I might replace the G27 with a pair of G31s which will enable the inverter to handle these loads more easily and for longer periods of time before a recharge is necessary. However, in your case because you're also talking solar, you really should be planning your inverter installation not as a separate project but as one that's part of a integrated battery, solar, and inverter system designed to meet your specific requirements.

I have what I call my workhorse INVERTER. It is a 600WATT PURE SINE WAVE AIMS model from AMAZON ($259). Have had it installed since 2009. This is used all the time (always ON) for my small wattage daily use items.

I kept it simple and just ran a couple of multi-head receptacle type extension cord from the Inverter two 120VAC ports. One goes to the Home Entertaiment Center area and the other goes to the bed nite table area... This is used mostly for the must have ON low wattage items for use all the time like the CELL PHONE chargers-WXRADIO-Computer chargers-small 120VAC Fan-etc...

I use my heavy wattage items like making coffee etc when I am re-charging my battery bank each morning for three hours starting with breakfast using my on-board smart mode charging powered by my 2K Honda Generator.

I also have a 1500WATT PSW Inverter that output is routed to a OUTSIDE weather type 120VAC receptacle right next to the SHore Power Connection where I can use a short 3A-15A SHore Power long adapter Adapter to connect the SHore Power to my 1500 WATT Inverter receptacle. This works pretty good but I have to turn OF a bunch of things. 1500WATTS is not much power... I had to install a BONDING plug on this setup to grounds the GROUND and NEUTRAL connection together for the Inverter to keep working (Had GFCI trips in the trailer also).

The 1500WATT Inverter also really rulled down on my batteries. My 255AHs battery capacity is really maxed out. The 600WATT INVERTER is much better running the 255AH battery capacity I have. Actually I found out I really very seldom use the 1500WATT Inverter setup for this reason I guess... The 600WATT Inverter is ON all the time and I control what is being turned on using it. Without anything turned on it does not draw much power from the Battery bank.

Here is floorplan of my OFF-ROAD POPUP Trailer setup - Note my battery connections are right at 5-feet away from my 255AH battery source.




How big is your battery bank going to be....
My current battery ban here consists of three ea GP24 85AH 12VDC batteries connected in parallel depending on my main DC Switch positions. I am planning on getting two new 150AH 12VDC Batteries...

Keep in mind INVERTERS are really DC POWER HUNGARY and when your batteries drop down to the 12.0VDC level (Appr 50% Charge State) you should stop using them until you re-charge back to the 90% charge state right away otherwise you will be doing harm to the batteries and replacing them soon.

Just some of my thoughts
Roy Ken

JRRNeiklot wrote:
Why set the fridge and water heater to propane? Do they draw too many amps?

Thanks.

Fridge draws 2.5 to 3.5 amps at 120 volts,, For 12 volt due to assorted loss factors multiply that by 10

Water heater is 12 amps at 120 volts. or 120 amps at 12 volts.

Group 24 battery holds 73 amp hours, you can use about 25-30 of them over a 20 hour period. (less if you use it faster)

A GC-2 pair (Two six volt golf car batteries) 210-230 and you can use half of those over 12 hours.

in short,, Big Ticket items burn a lot of amps.


Better plan if you can is to run a 2nd power line to the TV's and Radios. Put in a new outlet (Make it red or orange, indicating that it is live during a power fail) and feed it with the inverter.

Inverter goes in the compartment NEXT to where the batteries live (Short heavy 12 volt cables but not where it breaths battery vapors).

And enjoy.

If the plan is JUST to run the electronics. Go with a True Sine Wave and don't even bother plugging the stuff into the regular outlet.

Option 2.. If the electroincs are on a single circuit breaker (*mine are) just re-route it to the inverter (the lead connected to it)

Most convewrters can ewasily keep up with the inverter on this kind of load and.. If you use a True Sine Wave inverter you will have "invented" a "Power line conditioner" I once saw in an electronics store for well over 1,000 dollars.. It had 3 modules


Converter---Battery--True sine wave inverter.

It was kind of impressive as to what it could clean up.

JRRNeiklot wrote:
At 900 watts, the microwave will draw 7.5 amps if used for 6 minutes(by my math). That's probably more than I will use it in a day. But yeah, it will require a larger inverter.

It will draw 7.5amps if it's on for 1minute or 1year (assuming it doesn't fail or something odd happens).

A big issue you need to look at is how many amp-hrs you draw and how that impacts:
- Battery Bank Size
- Charging System

Take your microwave running at 900watts, it draws 7.5amps for 6min. That translates as 7.5amp-hrs (7.5*6/60*120/12: Divide by 60 to change minutes to hours and 120/12 to convert 120v to 12v)

By itself that's not too bad but you need to run the same calcs for every item you expect to use (both 120vAC and 12vDC) and add them up.

Every device should have wattage or amps on the UL lable. Divide watts by the rated voltage to get amps. You will have to guess on the time duration.

Add those up and that is how many amp-hrs you need to supply.

Then you need to determine how many days you want to go between charging (even with solar, it's good to assume 2-3 days as you will get minimal charging during cloudy days).

Your battery bank amp-hr rating should total 3-4times the total amp-hrs you come up with. The reason being is if you drag battery bank much below 50% charge it significantly shortens the life of the batteries.

Charging can come from many sources.
- If you will plug in, the trailers charger is probably fine.
- If you run a generator, you need to figure out how much time is worth the effort. After 80-90% full, batteries absorb charge much more slowely, so completely filling them takes an exceedingly long time (another reason to get a bank that is rated at 3-4 times the size you calculated)
- If you go to solar or wind, you need to factor in when the weather does not cooperate, so they should be able to put out more than you need in a day in case the first day had negligible output and the second day is trying to catch up.

Reality there are some efficency losses when you convert back and forth and store in the batteries but if you size for 3-4times your need for 2-3days worth of use, you typically have enough fluff that it isn't important.

Oops, that's right. The Sunforce has two 500s and you can't run all 1000 from one of the receptacles.

With a Xantrex and many others you can. Several forum members have this one.(made by Xantrex) On sale for the next few days only (till Thursday ISTR)

http://www.canadiantire.ca/en/pdp/motomaster-1000w-pure-sine-wave-inverter-w-remote-control-0111892p.html#.VkAyNnmFNjo