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Old 08-25-2017, 01:12 AM   #1
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Default TRUTH or fiction

Can you run your AC off your batteries with a Roadtrek Solar system and for how long before the engine generator comes on.

How reliable is the under hood engine generator with that long belt and unit hung under the frame? Thanks for your answers.
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Old 08-25-2017, 01:19 AM   #2
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Can you run your AC off your batteries with a Roadtrek Solar system and for how long before the engine generator comes on.

....


How much solar do you have? How many watts?

Do you know the wattage of the AC?


I guess you got my drift.
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Old 08-25-2017, 01:22 AM   #3
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have not bought a van yet hence I ask the question here. Any input is much appreciated.
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Old 08-25-2017, 01:52 AM   #4
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have not bought a van yet hence I ask the question here. Any input is much appreciated.

You can check the spec to see how much solar they have.
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Old 08-25-2017, 01:56 AM   #5
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.

Nothing really runs off the solar...

You use the solar to charge the batteries,
which in turn provides power to the appliances.

A typical AC is 1,200~1,800 watts.

If you want to run the AC off-line,
you will need a large battery bank.
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Old 08-25-2017, 02:06 AM   #6
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From what we have heard from other users, you can't get enough solar on the roof of a B to have a significant effect on AC run time.

What we have heard is that 800ah of batteries will run 4-5 hours before the engine generator is needed, but then there can be an issue with being able for the engine generator to keep up with running the AC and charge the batteries at the same time, especially at idle speeds. It is commonly called the "death spiral", and you wind up out of battery capacity and engine generator cycles, so no AC.

There are lots of discussions on this forum about this issue, and if you are looking to be able to reliably run AC off of the batteries and engine generator, it would be good for you to look at all of them. It is not a cut and dried conclusion, by any stretch of the imagination.
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Old 08-25-2017, 05:50 AM   #7
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Quote:
Originally Posted by BBQ View Post
.
Nothing really runs off the solar...
You use the solar to charge the batteries,
which in turn provides power to the appliances.
/squinting

I don't think that is a supportable position.

Experiments:
  1. attach loads direct to panels; see if loads run off solar
  2. Assume battery at 100% SoC. Run CC output, battery, and loads to the same bus. Does power come from the CC, hit the bus, run down to the battery pos terminal, back up the same wire back to the bus and out to the load? If so, why?
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Old 08-25-2017, 11:52 AM   #8
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/squinting

I don't think that is a supportable position.

Experiments:
  1. attach loads direct to panels; see if loads run off solar
  2. Assume battery at 100% SoC. Run CC output, battery, and loads to the same bus. Does power come from the CC, hit the bus, run down to the battery pos terminal, back up the same wire back to the bus and out to the load? If so, why?

You write well,
but you should work on your comprehension.

I did not say you CANNOT run off solar.
You can attach a LED light to to the panel. It would work, during the day.

I asked how much solar...
If you have enough panels (not likely in a ClassB) you can run your AC directly during midday sun.
But is it practical? Can you run your AC this way on a hot humid night?

Oh yea you can attach directly to solar,
but nothing really runs off solar,
You use the solar to charge the batteries,
which in turn provides power to the appliances.

A typical AC is 1,200~1,800 watts.

If you want to run the AC off-line,
you will need a large battery bank.
Whether the electron is coming from the wire or the post
is academic. And I don't think you have a PhD on the subject.
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Old 08-25-2017, 02:01 PM   #9
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Best just to say the solar maybe can generate enough power to run whatever it is, some of the time. The rest is academic at that point.

Most people just look at power harvesting during the day by checking the solar controller, if it has that data. Power generated by the solar at the same time as power is being used is substantially more efficient as it doesn't have the charge and discharge efficiency losses.

Nearly every solar controller needs to have a battery in the circuit so that the controller can regulate the voltage properly. How big to make the battery is totally open as long as it is big enough to accept the full solar output continuously or the controller is temperature compensated.
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Old 08-25-2017, 02:16 PM   #10
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you could look at underfloor AC. it is run on DC and uses less power.
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Old 08-25-2017, 02:44 PM   #11
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Note: my intent here is to keep newbs and interested onlookers at the beginning of their journey from being misled by incorrect (or ambiguous) information. Not to pick a fight. Not to see who is alpha.


Quote:
Originally Posted by BBQ View Post
...you should work on your comprehension.
There is no need for personal attack, brother.



Quote:
Originally Posted by BBQ View Post
You can attach a LED light to to the panel. It would work, during the day.
...
If you have enough panels (not likely in a ClassB) you can run your AC directly during midday sun.
I agree. Those are reasonable statements and I take no issue with them. I encourage you to compare them to your initial claim.

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Whether the electron is coming from the wire or the post
is academic. And I don't think you have a PhD on the subject.
It is a test of your claim that "Nothing really runs off the solar... You use the solar to charge the batteries, which in turn provides power to the appliances."

You are correct that my doctoral work is not in E.E. I hope that won't be a source of friction between us going forward.
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Old 08-25-2017, 03:06 PM   #12
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Quote:
Originally Posted by fratermus View Post
Note: my intent here is to keep newbs and interested onlookers at the beginning of their journey from being misled by incorrect (or ambiguous) information. Not to pick a fight. Not to see who is alpha.

...

It is a test of your claim that "Nothing really runs off the solar... You use the solar to charge the batteries, which in turn provides power to the appliances."

You are correct that my doctoral work is not in E.E. I hope that won't be a source of friction between us going forward.

Let's see how much you understand about electrons.

Which electron comes out the other end?

A?
1?
2?
3?
4?
Others?
Attached Images
File Type: jpg electrons.jpg (19.1 KB, 9 views)
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Old 08-25-2017, 03:21 PM   #13
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Which one is wearing Nikes?
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Old 08-25-2017, 03:44 PM   #14
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Moderation note:

Hey gang,
Please keep it substantive and on-topic.
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Old 08-25-2017, 03:47 PM   #15
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Whats an electron? Doesn't it happen every 2 and 4 years.
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Old 08-25-2017, 04:36 PM   #16
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Quote:
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Whats an electron? Doesn't it happen every 2 and 4 years.
Not sure, the Russians would know.

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Old 08-25-2017, 04:38 PM   #17
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Quote:
Originally Posted by BBQ View Post
.
Nothing really runs off the solar...
I have some difficulties understanding why this statement has being questioned. I have never seen RV or marine installation with solar panels directly connected to loads, PV panels are not voltage regulated so at least a charge controller is needed to regulate the voltage. Batteries are used as energy buffer to provide stable energy source. Perhaps someone can provide a concise point what is the issue with the above statement.
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Old 08-25-2017, 05:06 PM   #18
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Just ordered a 2018 Roadtrek Zion with an Outback pkg. This stuff has gone way over my head, so I will just avoid extreme temps as I don't like hot climes anyway. I am so excited! Regrettably production is behind demand so must wait until December. On the positive side that lets me get more financial ducks in order. Not good at using these chats so perhaps I will be booted! I'll try out the AC at dealership, then if something doesn't go correctly, I will have help. Just don't want to ruin those expensive batteries.
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Old 08-25-2017, 05:23 PM   #19
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Quote:
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Let's see how much you understand about electrons.
Which electron comes out the other end?
I already said I wasn't trying to pick a fight.

My understanding, and I am willing to be corrected:
  • given the slow drift of electrons along the conductor no single electron will enter and exit the wire for a long while.
  • since electrons do not move in a straight path there is no way to predict which one will come out the end first
  • the overall direction of flow of electrons is, by +/- notation, backwards by longstanding convention

I do not think you are acting in good faith, so it wouldn't be productive to continue interacting with you on this forum.
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Old 08-25-2017, 05:25 PM   #20
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For pity sakes, it's like the 3rd grade came and asked a question that's been discussed about 1000 times on this forum.

Here's another twist on it:

Your air conditioner will need 1200-1500 watts to run. It may need 2000-2500 watts to start up.

The max I've seen installed on a Sprinter van from Roadtrek is 600 watts. Before Davydd chimes in, yes ARV's Solar Womp had much more, but that's an abberation IMNSHO.

So you tell me, how much AC can run off solar. Answer: NONE. It runs off the inverter fed off the batteries.

Ya'll can head out to recess now...
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