Why go solar?

[Chowan]

Why go solar if generator/propane is still a must? After looking seriously at fitting rv (when we get it) with solar I am beginning to realize that solar cant keep up with what I want it to do. I want to have a res. refer, tv and sat, computers and cell phone. I want to run AC and heat and cook with electric. Doing all this, I dont see how solar capable to do all of this. maybe with 2000w and many batteries. Am I wrong. I know I can go with propane for refer and cooking and heating and run a gen for ac/tv. SO, If I have to use gen/propane why spend $5k-10k for solar? Is noise the only reason? Cool a reason? Thanks for sharing your point of view.

[Boon_Docker]

Wow,I want one of those chargers.

I think you use a flux capacitor. :B

[BFL13]

GordonThree wrote:

"My Magnum charger will keep pushing high amps right to a 99% state of charge... With a 2000 watt generator it takes about 4.5 hours to recharge my 800ah bank from 50%."

I would like to know how this could be done. I can't get the numbers to work.

I believe a 2000w gen can't run a 100 amp charger that is PF corrected, but it can possibly run a 75 amp non-PF corrected one.

However, to keep it simple, using 100 amps anyway, that is a 12.5% charging rate on an 800AH bank, and you would stay at the 100 till about 85% when tapering starts.(based on Vabs of 14.6) In this case we are staying at Vabs till you get to 100% as was implied for this case.

So the first 35% of SOC (280AH) is done at 100a which takes 2.8 hrs which leaves 1.7 hrs (102 min) to get from 85 to 100%.

My experience with Vabs at 14.6, is that it would take 52 minutes to get from 85 to 90% in that situation, which leaves 50 minutes to get from 90-100%. We all know that can't be done in such a short time.

So, since my calculations don't work out for the 4.5 hours, how do you do actually do it?

Thanks

[elivi8]

Solar allows the entire campground to have a nice camping experience, in the quiet and close to nature. A plug in site also allows this. Generators are noisy and should only be used when necessary. It is, after all, noise pollution.

Only my opinion of course!

[JFNM]

GordonThree wrote:
What do you mean provide enough information?

Are you saying a proper solar system can recharge to 100 percent every day, even in inclement weather?

As I said, not enough information (how "inclement", how many watts of panels, how much power must be harvested, etc...). One can just "guess" at a solar system design or one can actually run the numbers - actually do a design. If one knows how much power you typically consume on a daily basis, what your "environmental" situation is (how much solar energy typically reaches your location on a daily basis), and what your "requirements" are - putting a system together for an RV is usually not that difficult. Solar works without direct sunlight - yes, even with clouds. So, depending on your situation/factors, you plan your storage and collections needs. One does not need the solar system to fully recharge a battery bank everyday if you have designed in storage capacity to accommodate this. Obviously, an RV presents limitations - both storage capacity (size and weight of batteries) and roof space for PV panels. There are limits, like everything.

[JFNM]

Chowan wrote:
Man this is quite a write up. Thanks. You speak of lithium batteries. That is what I want to use. From what I have read, using the ac, 1000watt, with like 1000ah batteries, is marginal.

Thank you! I haven't spent a lot of time figuring out how much AC use is possible with lithium batts as the cost is so far out of my range that it isn't even in the "dreaming of it" realm. :E 😉

[GordonThree]

JFNM wrote:

GordonThree wrote:
Maybe my logic is flawed here.

I would guess that it is but you didn't provide enough information to know for certain.

What method are you using to determine SOC?

What do you mean provide enough information?

Are you saying a proper solar system can recharge to 100% every day, even in inclement weather?

I use coulomb counting to determine SoC. I used to test it with load testing and voltage tables and it has demonstrated more than enough accuracy for my needs.

[JFNM]

bighatnohorse wrote:
Generator is required for ... microwave use.

That may be true for your setup but it is not universally true. I use my microwave a good bit from battery/inverter and my convection oven occasionally from battery/inverter. Also electric coffee pot. I'm only using this as an example of why general statements are so difficult in these discussions - everyone's equipment, location, usage, etc. is different.

[JFNM]

GordonThree wrote:
Maybe my logic is flawed here.

I would guess that it is but you didn't provide enough information to know for certain.

What method are you using to determine SOC?

[bighatnohorse]

Chowan wrote:


200-400watt system will take care of the lights. What else can 200-400wt handle in addition to the lights? Charge phones and
computers? (This is not sarcasm. I am very interested)

You have to remember that everything runs off the "house" batteries. Inverters, lights, fans, USB chargers, etc.
So the only thing we have to charge are the house batteries.

From there we charge: three cell phones, three laptops, two electric toothbrushes, one Fitbit and one iPod - plus the two lead-acid camper batteries.
Cell phones need charging everyday. The other stuff only requires occasional charging.

For off grid:
I've add two small inverters so that we can charge the laptops, toothbrush and (drill motor when needed).
One of the inverters is in the bathroom so I can run the WaterPik AC appliance.

Roof top solar is working all the time - driving down the highway or parked at Walmart.
Many devices are completely charged before reaching a destination.

We wouldn't be without our on-board propane generator though.
Generator is required for AC and microwave use.
Solar is a convenience for us. And we love it.

[GordonThree]

Folks stating they can't recharge over 90% or that it takes forever on generator to achieve a full charge must have something wrong with their charging system.

Granted the common "converter" installed by Elkhart doesn't do a very good job, but they're not the only charging option available.

My Magnum charger will keep pushing high amps right to a 99% state of charge... With a 2000 watt generator it takes about 4.5 hours to recharge my 800ah bank from 50%.

I'll go about two days on battery, then run the generator a little while and fill em up again. Two gas cans last a long time, I'm not constantly running to the gas station for more petrol.

I could spend 5 or 6 grand on solar, maybe I'll get a full charge in a day, maybe not. I'll still need the generator for the maybe not days. In that case, why carry the solar. Maybe my logic is flawed here.

[Chowan]

JFNM wrote:
Howdy Chowan! Do you currently own and use an RV? If so, take a bit of time and measure your actual power consumption. Then you can make decisions with some facts in hand.

I live and work full-time in my RV using solar power - almost exclusively. I sure did not spend the kind of money mentioned. Here is an actual accounting of what I have and what it cost. Here is a post documenting how quickly it paid for itself. Finally, here is my energy audit for my lifestyle.

There is no doubt that solar doesn't work for everyone. I mostly avoid the heat/cold (with elevation and longitude), not everyone can do that. IMO, "needing" air conditioning is a big reason that solar just doesn't work for people (mostly the battery, less so the solar).

There are always a lot of misconceptions/old wives tales mentioned (even in this thread) when the solar topic comes up. It actually works might well for an RV assuming you don't need many Kw/day.

BTW; if I had the kind of money mentioned ($10K), I would have a killer lithium battery bank that would allow me to run my air conditioning! RV'ers are doing it right now - no longer cutting edge.

Man this is quite a write up. Thanks. You speak of lithium batteries. That is what I want to use. From what I have read, using the ac, 1000watt, with like 1000ah batteries, is marginal. Now of course if I head north in the summer and south in the winter the need for heat and ac can be reduced.

[Chowan]

DanNJanice wrote:

SoundGuy wrote:

Chowan wrote:
I want to have a res. refer, tv and sat, computers and cell phone. I want to run AC and heat and cook with electric.

Forget the genset, what you really want are electric sites! :W

Bingo!
Or a house in the suburbs!

That s funny. I live in the country. Suburbs would be like going to the big city. When we drop out of the race we will be seeing our country full time for at least a year. Last night I began making a list of places I want to go. Looks more like at least 2 years. While it might sound like I want the comforts of home (I do) I plan on being outdoors much of the time. At night I find it very relaxing to get on the computer while watching tv. I stay up late and get up early.
I know what camping is. Camping in my life has always been a tent and a campfire. Done many miles on the AT in the last 5 years. And I have tent camped all my life. Seeing the country in an RV is a luxury vacation. (even if its in the woods or in the desert.)

[braindead0]

I use solar to keep battery charged, power the basics in our TT with enough to run the fantastic fan full bore 24x7, radio when we want that.. lights..and still recover if we have decent sun. I'd rather not run a generator (even though ours is pretty quite).

We have a portable generator we bring when it's likely to be really hot so we can run the A/C when wanted.

That being said we can power our TT fine for about 5 days on a single group 24 battery, and that's not really worrying about conserving.. we turn off lights when not in use and the like but don't think about power use at all.

I don't think you can fully plan up front what you'll need until you've actually been out and 'done it'.. then you'll start to get an idea of your specific needs as far as power. Plan on adjusting your plan...

[Chowan]

Thanks to everyone who has shared. Looking forward to hearing more about what you do with your electricity.

bighatnohorse wrote:

Chowan wrote:
Why go solar if generator/propane is still a must?. . .
.
. . .If I have to use gen/propane why spend $5k-10k for solar? Is noise the only reason? Cool a reason? Thanks for sharing your point of view.

1) Because there are times when the only need for a generator is to charge batteries.

2) You would not want to spend $5k or more for solar.
(Exception: you're a hardcore boondocker that never wants to see civilization)

A small 200 or 400 watt solar system will charge batteries quite nicely on sunny days. Cost should be well under $1K and you would enjoy quiet free energy - forever.

Or, always stay at places with hookups.

200-400watt system will take care of the lights. What else can 200-400wt handle in addition to the lights? Charge phones and computers? (This is not sarcasm. I am very interested)

[BFL13]

Off grid you need batteries. You can run the gen to recharge them to about 90% of full but not to get them full, which takes "forever" way to long to run the gen for the 90 to 100 part.

You can't keep doing 50-90s because of progressive capacity loss each cycle from not getting to 100% each cycle. After several 50-90s you must go to 100 to "recover" the batteries. Then you can start over.

Two ways to get to 100%: Shore Power for a day or Solar if enough sunshine before you draw the batteries down again. Or go split bank and get half the batteries to 100 while running on the other half.

So that is what solar is for, so you don't have to get shore power to get to 100 unless there isn't enough sun when you need to get the batteries to 100.

If you have to get full hook ups anyway to do laundry, sani, etc, and that also works out for when the batts need doing up, then you can skip the solar.

Having some solar means you have more flexibility in when you need hook-ups.