Understanding Power

[rodwha]

I've been reading up on power needs and uses, but things aren't quite clear.

For starters I'm looking at the Keystone Passport 2920 BH.

From what I read not all A/Cs run on DC power. How does one figure this out?

To be able to run the A/C during a hot summer I read one would need to have a 3000-4000 watt inverter, but that most trailers have a 1000-2000 watt inverter. I don't see anything on their site or in their brochure that gives specs on this either.

It seems there's some sort of inverter that works off of your propane? Maybe I've just had an overload of info reading from several sites.

I read lithium batteries are the better choice. Again a lack of info. Is this the typical battery on RV's? The Passport seems to be a bit more than a mediocre trailer.

30 amp service seems to be standard unless one has a 2 A/C trailer. I'm guessing there's no issues with upgrading to 50. This would mostly fix issues with running the A/C along with plenty of typical appliances, right?

I'm a bit fuzzy on the load divider. It ensures there's never an issue where the amp draw is too high?

It seems most trailers come with two batteries. This shows two banks of two. No desire to add any?

If 600 watts of solar panel can be set up well enough and the days are partly cloudy how long could this extend a boondock adventure in the summer running the A/C? What of a winter with the lows around 20* F? I'm guessing with neither the A/C or heat working this amount might keep everything else running indefinitely?

Do the trailer batteries do fine when constantly hooked to AC power? I know many batteries don't do well over time like that as batteries are meant to be well used and then charged. I ruined an iPhone keeping it charged.

[tatest]

On a conventional RV like a Keystone Passport you will have a 120V AC system and a 12V DC system. Usually the lighting, ventilation, heating, and controls for fridge and water heater will be on the 12V side, A/C, microwave and convection ovens, and 120V convenience outlets will be on the 120V side, which is externally sourced.

The 120V side includes a AC to DC converter/charger to feed the 12V system and recharge your batteries. Towables will have a pin on the connector to the tow vehicle to provide 12V power while you are towing.

If you have a small inverter, it will be feeding a few specific outlets, usually entertainment systems that could not be sourced as 12V DC appliances.

There exist motorcoaches with large 12V (or 24V) DC systems, massive DC storage and inverter capacity, and autostart generator systems, that can run all electrical appliances, including A/C, but a Passport is not in that category. Typical RVs of the type you are looking at, if they had a 4KW inverter, would have enough battery capacity to run the A/C for 10-20 minutes before the inverter kicks out on a low battery voltage condition.

My experience with 30 amp service, I can run the A/C and the microwave at the same time, but I can't start the A/C compressor if the microwave is running. Any electric heating appliances (water heater, toaster, griddle, coffeemaker, etc) in combination with microwave and A/C are a problem. Vacuum cleaners can be a problem. Blow dryers are a problem. We have a whole lot of household and personal appliances sized to draw the max from a 15 amp circuit, and any two can max out the 30 amp main. My daughter plugs in her curling iron while blow drying her hair, a combo that can pop a 15 amp breaker within a few minutes, or take out the 30 amp main if the A/C starts up.

What works off propane is a generator. If it is a 30 amp service, that would be a 4KW generator. At half load (e.g. A/C running) it will go through 3-4 pounds of propane per hour.

The combination of questions makes me think you are wondering about boondocking but maintaining an on-the-grid lifestyle. It is not easy. I'm configured with a generator to feed my 120V 30 amp system, and can get into a site usually with enough fuel for 60-80 hours operation. But I don't do that. It is either find a place where I plug into the power grid, or I go into a dry camp mode that is not very different from what I do when tent camping. A big part of this choice for me is because I'm not sure that if I go to sleep with a generator pumping CO into the air around my RV, that I'll wake up again.

[allen8106]

2oldman wrote:

rodwha wrote:
eith the proper sized inverter, running an A/C could be done using a generator to recharge during the day. It seems a bank of 4 (unknown output batteries) aren't up to the task for long enough.

No, 4 batteries won't be enough.

I am one of the few on here who runs a/c on batteries - but only occasionally. I have 8- 80a AGMs, a 4kw inverter, 835w solar. It's a 48v system. Why 48v? Because when I tried running air at 12 or even 24v, things started heating up. Cables, connections, batteries. Yes, everything was sized properly, but the high amperage draw eventually made heat. 48v seems to work fine.

I can run my air for about an hour before the batteries start to sag, even at full solar.

You beat me to it. 8 won't be enough.

[valhalla360]

I think a lot of the confusion is while you made a statement about not messing with the battery bank/solar array, you keep asking about a 3000w inverter.

To utilize a 3000w inverter, you need an upgrade to a decent size battery bank and a way to charge it (typically solar), so the presumption is when you kept asking about a 3000w inverter, you were still going down the battery bank/solar array path even though you stated otherwise.

I really suggest reading up on the subject. While there are some RV specific books, you might try a boating one as the cruising world has a longer and larger history off grid power generation. It's really not that hard but there are a few concepts of how voltage/watts/AC/DC/Amps work that would make this discussion much easier because you are mixing and matching without understanding.

As stated in a prior comment, if you don't understand and don't want to understand, hire an electrician to set it up for you. If you want to understand there are some good books out there or you might check with your local community college as they might have something.

[Sam_Spade]

rodwha wrote:
But it still goes back to my misunderstanding of the need for an inverter.

AND maybe even more importantly, you seem to think that you are obligated to answer, reply, rebut or otherwise clarify every answer that you get. Often that just confuses matters more.

Accept and acknowledge those replies that are helpful.....even if "negative"....and ignore those that aren't helpful. ALL replies are offered with good intentions, even if misplaced a bit sometimes.

And keep the discussion in ONE thread. Once it's "out there" you can't really start over.

[pianotuna]

Rod,

If there are only two batteries then about 1000 watts is the upper limit for an inverter. I suggest you try the prowatt as it is a throw away after the warranty period.

I used mine as a back up recently and it sure did save my bacon.

[EsoxLucius]

Thank you for trying to understand the situation. Sometimes it is apparent that these forums have limitations for communication and accommodating personality styles. Good luck with your project! Please be aware that it does no good to try to get direct responses with multiple inquiries in different threads asking the same things.

[rodwha]

Sam Spade wrote:

rodwha wrote:
I'm sorry if my ignorance riled people up and caused confusion.

You are being too sensitive......about the wrong things.Maybe so. I felt the response was uncalled for, especially in light of how I was pretty clear that I was not trying to run an A/C off of batteries. However my misunderstanding of an inverter and the need (or not) of one for running a generator as my misunderstanding was I'd need one certainly didn't help, and I can't expect others to see my statement and know it's not my intention yet talk of the need for a device to do just that.

Some folks read your questions for the first time many days after the discussion got started. Some of them commented while looking at ONLY your first post. That's just the way these things work.Most certainly. I've seen it on plenty of other forums. This person certainly kept up though.

BUT THEN.....you saw fit to continue to discuss related matters by starting up NEW THREADS which just serves to confuse everybody. Some likely didn't see your first discussion.....or some of the subsequent ones. That just confuses everybody.It was because I was continually told I couldn't do what my OP was looking to do despite there saying I got it, that it wasn't reasonable.

Keeping ALL OF THE RELATED DISCUSSION going in the same thread would have helped a LOT (but some people still jump into the middle).Accept that it didn't work, which is why I started over.

And then moderators seem to be as scarce as hens teeth here.....again.....still. I don't know why one of them isn't trying to help clean up the mess that you made. And yes YOU made most of it.

I certainly didn't help the situation with my ignorance whatsoever. But I had no other way to make it more clear than to say I understood I couldn't do it reasonably and that I had abandoned it altogether. I'm at a loss for anything else that could have made it more clear without bold red letters. But it still goes back to my misunderstanding of the need for an inverter.

[Devocamper]

I am out !!

[2oldman]

Sam Spade wrote:
Some of them commented while looking at ONLY your first post. That's just the way these things work.

Another way things work is that only the Subject is read and commented on.

I understand the OP's frustration. My advice is to simply ignore the repetitive and inattentive answers. Happens all the time.

[Sam_Spade]

rodwha wrote:
I'm sorry if my ignorance riled people up and caused confusion.

You are being too sensitive......about the wrong things.

Some folks read your questions for the first time many days after the discussion got started. Some of them commented while looking at ONLY your first post. That's just the way these things work.

BUT THEN.....you saw fit to continue to discuss related matters by starting up NEW THREADS which just serves to confuse everybody. Some likely didn't see your first discussion.....or some of the subsequent ones. That just confuses everybody.

Keeping ALL OF THE RELATED DISCUSSION going in the same thread would have helped a LOT (but some people still jump into the middle).

And then moderators seem to be as scarce as hens teeth here.....again.....still. I don't know why one of them isn't trying to help clean up the mess that you made. And yes YOU made most of it.

[rodwha]

I'm not that concerned with that. Quite frankly even persnickety people have experiences and view points that can be helpful. Though it may be annoying as has happened in this case it's not reason enough to hide.

[Bumpyroad]

rodwha wrote:
I see. So it's my fault then if others don't read the rest of the thread and continue to believe it's still stuck at the beginning before things became understood? Got it....

Hopefully at some point we can all move beyond this. I'd certainly like to gain understanding from those who know.

*EDIT*

Looking back over this thread you can see that I understood batteries and solar weren't going to cut it on my second post. My third post made it very clear I wasn't looking at this as an option. And yet here we are on the fourth page with people still thinking for some reason that I'm trying to run an A/C with batteries and/or solar... I don't see how I could have made it any more plain and straight forward.

As I said I had wondered if it was my misunderstanding in why and how an inverter worked or my using inverter and converter in the wrong ways in these various threads. I'm sorry if my ignorance riled people up and caused confusion.

If you don't like the way you are being treated here, you can always block a member. As a matter of fact, I am doing that right now.
bumpy

[rodwha]

I see. So it's my fault then if others don't read the rest of the thread and continue to believe it's still stuck at the beginning before things became understood? Got it....

Hopefully at some point we can all move beyond this. I'd certainly like to gain understanding from those who know.

*EDIT*

Looking back over this thread you can see that I understood batteries and solar weren't going to cut it on my second post. My third post made it very clear I wasn't looking at this as an option. And yet here we are on the fourth page with people still thinking for some reason that I'm trying to run an A/C with batteries and/or solar... I don't see how I could have made it any more plain and straight forward.

As I said I had wondered if it was my misunderstanding in why and how an inverter worked or my using inverter and converter in the wrong ways in these various threads. I'm sorry if my ignorance riled people up and caused confusion.

[Sam_Spade]

Bumpyroad wrote:

hey, it's not OUR fault.

Indeed.