Q's on Calculating Power Consumption Requirements

[Sunking]

FWIW, that sounds exactly like what Sportsmobile does with their RV builds. But like I said, based on what you guys have been telling me on this forum, I need much more than that to handle the daily loads I'm thinking about.

OK Dave I will pull the gloves off and tell you what I think, tough love like a praent..

Quit pussy footing around, there is no system that can do what you want. Well there is but you do not want to pull a trailer around, nor could you afford it. Accept the fact you will need your vehicle alternator or a generator to supplement your needs. You would be a damn fool to keep waisting time and money with this.

Put 2-180 watt panels on the RV, use a good MPPT controller, 2- AGM 150 AH batteries, battery isolator, and get on with it.

SORRY

But wake up and smell the coffee burning.

SK

[dave_in_delaware]

Whoah. We went from this:

Dave sounds like you are doing this right by taking your time and doing the proper homework....

... Lastly just realize you are going to have to use the engine alternator from time to time.

To this:

OK Dave I will pull the gloves off and tell you what I think, tough love like a praent..

Quit pussy footing around, there is no system that can do what you want. Well there is but you do not want to pull a trailer around, nor could you afford it. Accept the fact you will need your vehicle alternator or a generator to supplement your needs. You would be a damn fool to keep waisting time and money with this.

SORRY But wake up and smell the coffee burning.

My apologies SK. I didn't mean to get on your nerves or make you pull your gloves off....

I am trying to learn and absorb all the information and suggestions and calculations everyone has helped me with. I haven't finished reducing my power consumption numbers or trying to find more efficient components. I'm really trying to understand all the info you've given me here so I can use it to properly plan my RV systems. From what has been said so far in this thread, the setups that other van-sized RVs are using sound undersized and the batteries are being drained WELL below the suggested 80%, or 50%, even for AGMs. I'd rather not have that happen, so I want to figure it all out properly.

I haven't put any money into this design process so far, and I don't consider any of this a waste of time, because I find it interesting to learn this sort of detailed process that I can directly apply to one of my future hobbies. I'd rather not need to buy new batteries more often because I discharged them too far. I'd rather not misdesign my electrical system and have to totally redo it in 2 years. I'm a "think about it for a long time before dropping money into it" kind of person, especially when it comes to a project of this magnitude.

I have no problems with using the alternator (along with an isolator) to recharge the batteries while driving around. I had been planning on that. Actually, that makes perfect sense since I'd be driving around anyway. It's easy recharging. If only an alternator will be enough to do the job, then that's cool. If I can safely get away with not having a generator, then that's even cooler.

I sincerely appreciate everyone's effort with helping me understand all these concepts, processes, calculations, etc. This thread has been priceless in my understanding of these RV components. I truly want to see this entire process through to the end, and if it takes me changing my design, re-calculating some things, finding lower power consuming parts, getting larger solar panels, whatever... then it's all worth it to me. It's actually fun to learn about all of this stuff!

I never intended to get anyone upset or frustrated with all my questions.

[Sunking]

My apologies SK.

DO NOT APOLOGIZE to me or anyone else on a forum. You cannot hurt my feelings, nor should I hurt yours.

It's FREE advice OK?

[Sunking]

Dave here is the deal. What you want is infinite Euphoria of power.

It does not exist. You are on the right track of conservation.Keep that up. Reality is you will not be able to generate the amount of power you want with the limited space and restrictions of an RV. The Laws of Physics prohibit it. You have "X" amount of space and weight. You do not have enough of either one.

Best you can do is put two of the largest panels on the roof, a couple of batteries in a cabinet some where, charge controller, and call it done. Does that make sense?

You are going to need a alternate source of power to supplement your needs. That source is either the vehicle engine alternator, or a generator-battery charger. Take your pick....

[dave_in_delaware]

DO NOT APOLOGIZE to me or anyone else on a forum. You cannot hurt my feelings, nor should I hurt yours.

It's FREE advice OK?

No feelings were hurt here I don't think. Things just seemed to take a sharp turn from me trying to figure all this out myself (with everyone's help) and going step-by-step in my calculations, to suddenly being told exactly what to get and just stop trying to design the perfect system for me.

I joined this forum to learn HOW to figure all this out myself. And judging by the numbers I've been seeing from the design process I've learned here, it just boggles my mind how the standard two-panel two-battery system is sufficient enough to power a refrigerator and a forced-air furnace like so many van RV owners use while not killing their batteries every two years. Unless they're running a generator every morning, or driving two hours every day to replenish their batteries....

I greatly value and appreciate your free advice here, SK. Thank you for your patience with my stubborn desire to learn all of this information in detail! LOL.

[dave_in_delaware]

... Reality is you will not be able to generate the amount of power you want with the limited space and restrictions of an RV. The Laws of Physics prohibit it. You have "X" amount of space and weight. You do not have enough of either one.

Best you can do is put two of the largest panels on the roof, a couple of batteries in a cabinet some where, charge controller, and call it done. Does that make sense?

Yes, it does. It's still fun and beneficial to try to conserve more battery power if I can though.... There's nothing wrong with that.

You are going to need a alternate source of power to supplement your needs. That source is either the vehicle engine alternator, or a generator-battery charger. Take your pick....

So you believe that a heavy duty alternator will be enough to help recharge the house batteries? I wouldn't need both for sure? I'd rather not run a noisy generator if I don't have to. Perhaps that would be a good exercise to do: compare the charging power obtained from an alternator and a generator....

[Sunking]

Dave it is like this.

To get the amount of power you want, you need a trailer loaded down with STUFF to tow behind your RV. You will need to find a place where you can pull your chain saw off the trailer of STUFF, and clear cut the forest for all the solar panels you will need to setup camp.

Otherwise you just need to ruff it like the campers before you had to do and turn off electric, and turn on nature.

I suggest your wife, extra clothes, and a dog cuddled up in blankets to keep warm at night when it is cold. Take cold showers, fish, hunt, and drink lot's of beer. Pee on a tree.

[Sunking]

So you believe that a heavy duty alternator will be enough to help recharge the house batteries?

More than enough.

[dave_in_delaware]

Dave it is like this.

To get the amount of power you want, you need a trailer loaded down with STUFF to tow behind your RV. You will need to find a place where you can pull your chain saw off the trailer of STUFF, and clear cut the forest for all the solar panels you will need to setup camp.

Otherwise you just need to ruff it like the campers before you had to do and turn off electric, and turn on nature.

I suggest your wife, extra clothes, and a dog cuddled up in blankets to keep warm at night when it is cold. Take cold showers, fish, hunt, and drink lot's of beer. Pee on a tree.

Understood, Sir!

I'm definitely turning on nature during the daylight hours. I'm planning on using the RV solely as a "basecamp" thing, for after all the nature stuff is finished. Like cooking dinner and some relaxation, then hitting the sack.

More than enough.

That's good to hear. I'd rather avoid the noisy smelly generator if I can.


Thank you for all your help. I have learned a great deal of useful information in this thread alone. I'm sure once I talk with the local suppliers and installers of these system components I'll have a few more specific questions.

[Naptown]

I had to skip a bunch of posts but I remember when I was a kid we had a pop up camper with a furnace that vented through the wall used no power as there was no fan. I can't see a van camper needing much more than this and will reduce the power requirements during the winter dramatically.

[dave_in_delaware]

... a furnace that vented through the wall used no power as there was no fan....

Hmmm. I wonder if this was some sort of catalytic heater but vented to the outside? Do you recall the fuel source? If it's combustion it's still using oxygen from inside the RV...

[Mike90250]

...If it's combustion it's still using oxygen from inside the RV...

BUT, if it's vented, as byproducts go out, fresh comes in. And if you had a completely sealed camper, you would never wake up..... (just sleeping, no furnace, you would burn all the O2 inside)

[Naptown]

here is a link to some furnaces
some draw only 1.8 A @ 12v dc
http://www.ducktec.com./itmidx14.htm
does this lower the amp draw?

[dave_in_delaware]

BUT, if it's vented, as byproducts go out, fresh comes in. And if you had a completely sealed camper, you would never wake up..... (just sleeping, no furnace, you would burn all the O2 inside)

Vented doesn't always mean it has a fresh air intake, nor does it always mean the combustion air source is from 100% outside the RV. It depends on the product specs of course.

I do plan on keeping a window cracked slightly for basic oxygen levels. I just didn't want to worry about oxygen being used up faster just because I want to stay warm.

some draw only 1.8 A @ 12v dc
does this lower the amp draw?

Yeah, that's definitely a lower amp draw. Thanks for the link.


My logic behind wanting to use hydronic heat (over forced-air or catalytic) was that the heat source would be generated inside a water heater, which is already "isolated" from the RV by the way they're installed, with the access panel and vents on the outside of the RV. That way, the hot water being distributed to the heater coil wouldn't have any affect on the oxygen supply or the level of humidity/condenstaion inside the RV.

With that said, I'm still in the design phase for all of this, so I'll do more research and contemplation before making any final decisions.

I'm open to any suggestions or pro/con arguments anyone may have!

[Naptown]

I believe those furnaces use outside combustion air. however even if they didn't and used indoor air for combustion you would have to be sealed up pretty darn tight to have any chance of backdrafting exhaust gas into the RV