Why do we need an INVERTER? or When??

[bamaboy473]

New to Motorhomes and we are casual users; making visits to family within 1000 miles of us. Just the two of us on board.

What are the tradeoffs of having an Inverter? If we don't have one, what do we miss, or what do we do for the power that an inverter would produce?

We have a diesel genset, so when is an inverter a nicer option to use?

I'm looking at a 2500/5000 PSW Sunforce and trying to justify buying one

[vsheetz]

120vac power can be had from shore power, generator, or inverter (which converts battery power to 120 vac). Using an inverter instead of the generator, or powering the refrigerator from AC power instead of propane while traveling are some common usages.

[SKP Kirk]

You have to define the term "need" in order to answer that question. I know many an RV owner who needs an inverter, yet we lived in a motorhome fulltime for 11+ years and never had an inverter! We got along very well and would not spend extra to get one in the future, but one of the things which determine need is your way of camping.

If you seldom camp where you have no hookups available, the need is much less than for those who love to dry camp in parking lots as they travel or who are serious about boondock camping. We only occasionally stopped for a night in a parking lot and when we did so we just used the on-board generator for power to use our TV, microwave and coffee maker. But an inverter does eliminate the need for that, if you have sufficient battery capacity, which is usually more than just two of them.

It is also useful to have an inverter if your RV has a house type refrigerator in place of the RV type because those must have 120V-ac power to operate on the road, while the RV type can operate on propane or in some models on 12V-dc power supplied by the chassis engine/alternator.

[MCJones]

It is nice to have 120v power when stopped and not have to fire up the generator. IF the weather is cool enough not to need A/C, I use the inverter during the night for my CPAP instead of having to run the gen just for that when boondocking. Stopping at a rest area, I have even used the inverter for the microwave to heat up left over coffee and even watch for the weather on TV. It isn't a "must Have" it is a glad I have it kind of thing. Mine is an older modified sine wave - does anyone know if it hurts the microwave to use it with a MSW?

[Forest Grump]

Basically an inverter is a source of 120v power from a 12v supply when a quiet source of 120v is not available. This occurs at most USFS campgrounds, many non private parks, beaches etc. notice the word quiet, it's a beautiful day in the forest and you want a hot cup of coffee. Turn on the inverter and you have 120v no noise. Turn on the DVD and blue ray and watch a movie no noise. Many inverters can not be hard wired so they are 15 amp plug in circuits. Not 20 or 30 but 15. Notice the increase in power with Hard wired, it is good. You also need to have the correct size of input cables from your 12v source, 2/0 is normally required. If u buy a inverter then an inverter installation kit, oh oh not 2/0. AZ solar supply carries 2/0 welding cable, connectors etc. do it right you will be happy.


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[Dr4Film]

You first have to understand what function an Inverter provides before deciding whether you "need" one or not.

THIS will give you a good idea what Inverters do. I would highly suggest that you read about it first and then you decide.

MCJones,

I do NOT recommend running your microwave using the Inverter. My opinion is that it puts TOO much of a strain on the battery bank plus the microwave groans while using the inverter. To each their own but that's just me. You can each do as you wish.

Dr4Film ----- Richard

[bamaboy473]

Good read, Dr4, and thanks to all for responses. Could a 2500/5000 watt inverter power one A/C unit and the refrigerator's stand-by (already cold, just keeping it cold) systems?

I know that propane is cheap and the refer isn't going to break us, but would like to run the A/C from time to time. A genset running while driving isn't a big deal, but no extra noise coming from under us would be a Plus.

So, could a 2500/5000w inverter power both an A/C and refer?

Also, at $350, is Sunforce an awful brand that doesn't work?? Seems pretty inexpensive.

[vsheetz]

To run air conditioning the limitation is the battery bank capacity, given an inverter with the wattage requirement. So the answer to the question is yes , but only for a few minutes. Air conditioning via inverter is not practical unless one has a very large battery bank. Best to use the generator to run the air conditioning.

[1mainiac]

With a big enough inverter you can run A/C and lots of things however once you do the math you will reconsider many of those things. For example a 1200w microwave will draw 120 amps or more from your battery bank some as high as 160amps. A 13.5 A/C unit draws more than that so if you have the fairly standard 4 6v 220ah battery bank you when fully charged have 440ah let's use a low number and say you only need 120 amps to power the A/C that would give roughly 3hours and 45min of A/C before the batteries were dead or near dead. The problem is not so much about what you can use it for but if you can carry enough batteries to do the job. Much like some of the electric car ideas by the time you have enough batteries to go a long distance there is no room for people or stuff. Some inverters can do power sharing and have gen auto start as well so in that you can sort of call it a hybrid but if you have to follow quiet time restrictions even some times that won't work.

Inverters are great but you need to be realistic in what you can power with them. And if you use auto start for the gen and power sharing you can really get a lot out of your setup.

[bamaboy473]

Originally Posted by vsheetz

To run air conditioning the limitation is the battery bank capacity, given an inverter with the wattage requirement. So the answer to the question is yes , but only for a few minutes. Air conditioning via inverter is not practical unless one has a very large battery bank. Best to use the generator to run the air conditioning.

This answers my needs (I think). We power up the genset when weather demands cool or heat beyond what the dashboard provides.

We use propane for the refer while travelling.

Unless we start boondocking, I guess an inverter doesn't have a necessary place in our system, right? Seems that the 4-bank house batteries do all they need to do when we're staying the night without shore power...and I run the genset for coffee and microwave in the morning.

Did I just save a bit of $$ because I can't justify having one?

Question: our next trip will be in November to NC, so cool nights are expected. Will we be using LP or the genset for heat? If LP, how will the heat get distributed if we don't have an inverter to power the fan?

[Dr4Film]

Your LPG heater is powered by 12 VDC including the fans. No problem or worry.

Dr4Film ----- Richard

[Forest Grump]

I think you are very confused about inverters. A 3,000 watt hard wired inverter can run a microwave well, a hair dryer well, a toaster well, an led TV well if it is properly wired on both sides. It will not run heavy current draw appliances for a long time because you will run out of battery power Ah's and it will get hot very hot which decreases it's efficiency. I have 645Ah ob batteries at 12v. This runs the appliances I have described well for 4-5 days of intermittent use. So figure out the math and do it and you will answer your own questions.


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[bamaboy473]

Originally Posted by Forest Grump

I think you are very confused about inverters. A 3,000 watt hard wired inverter can run a microwave well, a hair dryer well, a toaster well, an led TV well if it is properly wired on both sides.

I'll agree with you if you change the word, "confused", to "un-informed"

The inverters on my boats knew what their jobs were; refer and microwave. A MH has more systems that supply power; hence my confusion...er, lack of information

The point you suggest is that a 2500w inverter is overkill for casual users. My question is whether there is such a thing as overkill? If a 2500w inverter is used at a 25% capacity, does that hurt anything?

If I can get a 2500w inverter for the price of a 1000w inverter, is there a reason to go with the 1000?

P.S. reviews on Sunforce inverters have a lot of negative comments about reliability, so that brand is out....but the questions remain active.

[mojoracing]

We like to use ours while running down the road. If the weather is nice enough and we don't have to run a/c's, we use it to power the TV's and Satellite system. Ive never heard of Sunforce. I would look into magnum inverters.