HELP understanding inverters or electricals.

[doit2010]

Background:
I do not understand inverters or electricals. I have a new Minnie Winnie 22R with a generator and no transfer box. When I use the shore power I unplug it from the receptacle in the cubby hole that holds the cord and plug into the outside electrical source. When not on shore power I plug the cord back into the receptacle to get the power from the generator. This part I follow. I also have two 12 volt house batteries.

I am not a boondocker, but I do foresee a need for some type of inverter set up to operate a coffee maker, toaster, and TV, all at the same time, And maybe even a hair-dryer, when generators use is restricted. Will also need to charge cell phones, and run laptop computer.

My frig and water heater are gas or electric only, not 3-ways. These items I do not plan to use an inverter for. Same for my heating source, its LP gas but uses to much battery power to run the fan at night, I think.

Now for the questions:

·What size inverter is needed?
·What brand recommend?
·Do I wire it directly? Or just plug these appliances into an inverter?
·How long will a TV run through an inverter with fully charged batteries and not kill them?

Thanks for any and all help

ESW

[KIX]

Originally Posted by doit

.................................................. ....inverter set up to operate a coffee maker, toaster, and TV, all at the same time, And maybe even a hair-dryer, when generators use is restricted. Will also need to charge cell phones, and run laptop computer.[/FONT][/SIZE]

Coffee maker, toaster and hair dryers use a LOT of wattage. Running all that at the same time will not only take a large inverter but a much larger battery bank than your 2 twelve volts. Sounds like you'll need to make some compromises. I.e. using one of those appliances at a time. Even then you'll likely need to be frugal with the useage.

Now for the questions:

·What size inverter is needed?
You'll need to do some research and determine the wattage or amps needed to power each appliance you would like to run via inverter. Your two 12v batteries may only store 120 amps at 12v = 1440 watts x 2 (batts) or 2880 watts. (Remember that I'm guessing here). You only want to discharge batts to a max. of 50%. So, that means you'll only have about 1440 watts to use. After you add the wattage required by all you want to run then you'll have a guesstimate of how large the inverter will need to be. You can then determine the size of the battery bank needed. After all that you can figure out the battery charger to recharge the batteries in a reasonable time. When all that is figured out the other questions will then be important to answer for you.
·What brand recommend?
·Do I wire it directly? Or just plug these appliances into an inverter?
·How long will a TV run through an inverter with fully charged batteries and not kill them?

Thanks for any and all help

ESW

Good luck in getting it all just like you want it.

[1bigmess]

You need to get the wattage of the various devices you want to use in order to start figuring this out for you.

Start learning here: The 12volt Side of Life (Part 1)

[SkiSmuggs]

We just use a Coleman coffee maker and use a propane flame for toast. The larger and cheaper the inverter, typically the more power they use while idle. But for TV and DVD player, a 300w PSW inverter is all you need. You are looking at 1500-2000 watts for the rest of it.
There is a thread in the mod section from a guy who went to a bigger inverter for his residential refrig and cut his battery life in half. Turns out the new inverter used 4 amps instead of .5 amps like his old one.

[Waiter21]

Years ago, I installed a 1500 watt inverter in my Ole Toyhouse. I did not have a generator and we used the inverter for coffee and microwave.

You may consider two inverters, a high power one for the coffee and toaster, and a small, low power one for the TV, laptop, etc.

Remember, most inverters draw a small amount of power, even when they are turned off.

Pay attention to how the high power unit is installed.

1500 watt Inverter Install - Improvement and Do-It-Yourself Projects you have done to Share! - Toyota Motorhome Discussion Board


And here is a low power unit I installed in my Mirada fr small 110 volt loads while we are traveling and don't want to run the generator.

Installing small 400 watt inverter | 2001 Coachmen Mirada 300QB

..

[frankdamp]

The basic equation is Volts x Amps = Watts. If a 120V appliance uses 1200 watts, that's 10 Amps on the 120V side. It's 100 amps on the battery side. A toaster, hair drier, curling iron, coffee maker are all big power users.

A stove-top coffee maker would be one power-saving move, using propane instead of battery power. Dry hair with a towel or outside in the sun, or don't wash it until restricted hours end.

There's no chance that two 12V batteries can run all that stuff at once. You should plan on using only one appliance at a time. The TV in a MH is usually fairly low power and charging the lap-top and cell phones shouldn't be a big deal.

KIX has confused things a tad. Watts is the measure of electrical flow rate, just like gallons per minute for water. The amount of electricity stored in batteries is in "watt-hours", quite literally how many hours can you draw a certain number of watts. Even the "small" inverter Waiter21 mentions will pull 40 amps from the batteries.

[HHIDan]

I'm in a 43 foot DP and have 4 batteries. I run the coffee maker in the morning, I run the microwave an average of 5-10 minutes per day, I run the TV for about 2 hours, run lights, run battery chargers for 2 phones and 2 laptops, water pump. With very typical lifestyle I can go about 24 hours before I recharge with Generator or Engine while driving or Shore Power where and when I stop.

I do not run a LP furnace, the fans on them draws quite a bit...

I would recommend a Magnum MS2012 for about $1215 and a ME-RC remote (about $150). 2000 watts which is more than enough and 100 amps to charge your batteries fairly quickly. 3 stage charging which means long battery life as you never overcharge.

Look up the installation manual and see if you want to tackle a full installation and fire away if you have questions!

[ChasA]

Well Frankdamp, I hate to do this, but your electrical education is really screwed up. You have confused watts with amps. Battery capacity is stated in amp hours. Watts is a measure of power (ie. Work).

[powercat_ras]

Some coffee pots come very close to maxing out a 120 volt outlet, drawing 1,400 watts. I know this is the case with Keurig single cup brewers that I own. You can find some small Mr. Coffee, etc. that use less. Toasters are also high draw, like 800 watts. So you may want to re-consider your desire to run both Toaster and Coffee Pot at exactly the same time. The other factor is the bigger the inverter the more 12 volt amps it will draw at full load meaning bigger wiring from the batteries to the inverter. For example, a 1000 watt AC output will draw almost 100 Amps from the batteries, which would require 2 AWG wires.

A 2000 watt AC output would draw almost 200 Amps from the batteries, which would require 00 AWG wires.

Also each 12 volt deep cycle battery generally stores about 100 Amp-Hours, and you can only use 50% of that stored energy and still get long life from them. Personally when I put an 1500 watt inverter in my former Travel Trailer to mainly use with a coffee pot, but also computer and 120 V TV, i also put in a second deep cycle battery.

You may also want to get a better inverter that puts out at least a "modified Sine Wave" output or perhaps even a "full Sine Wave" output. The modified sine wave is much cheaper but you may have problems with some loads you plug in like a TV not liking the output waveform.

Just to help you understand how you use up your battery storage with a loaded inverter:

100 Amp-hour 12V deep cycle battery -- 50 amp hours usable to maximize battery life

1000 Watt Coffee Maker for 10 Minutes - 18 amp-hour used
700 Watt Toaster for 10 Minutes - 13 amp-hour used
50 Watt LED TV for 4 hours - 20 amp-hour used

[JFNM]

Originally Posted by doit

What size inverter is needed?

How long will a TV run through an inverter with fully charged batteries and not kill them?

Hi ESW,

I really hate to say it as it generally just annoys people but.... These questions cannot be answered without some data.

Either the exact make and model of equipment (so someone can go research it, I doubt anyone is going to do that) or (better) some actual measured data. If unable to measure the power consumed by your devices, at least the power consumption listed on their labels (usually not very precise but better than nothing). The problem is that there are many different types and sizes of everything you listed and they are not the same - a big LED TV will consume far less power than a small "old" (tube type) TV (for example). Same with your batteries "two 12 volt house batteries" doesn't tell us much - we can guess but that won't give you a very accurate answer.

Here is a link to one 'how to do an energy audit' article. There are many of them out there.

[mel s]

Originally Posted by doit

Background:
I do not understand inverters or electricals. I have a new Minnie Winnie 22R with a generator and no transfer box. When I use the shore power I unplug it from the receptacle in the cubby hole that holds the cord and plug into the outside electrical source. When not on shore power I plug the cord back into the receptacle to get the power from the generator. This part I follow. I also have two 12 volt house batteries.

I am not a boondocker, but I do foresee a need for some type of inverter set up to operate a coffee maker, toaster, and TV, all at the same time, And maybe even a hair-dryer, when generators use is restricted. Will also need to charge cell phones, and run laptop computer.

My frig and water heater are gas or electric only, not 3-ways. These items I do not plan to use an inverter for. Same for my heating source, its LP gas but uses to much battery power to run the fan at night, I think.

Now for the questions:

·What size inverter is needed?
·What brand recommend?
·Do I wire it directly? Or just plug these appliances into an inverter?
·How long will a TV run through an inverter with fully charged batteries and not kill them?

Thanks for any and all help

ESW

doit
See: RV Power Inverter Basics
And: RV Electricity Explained
Mel
'96 Safari