Everything Solar - All member topic

Started by MSN Member, March 16, 2009, 08:35 AM

Previous topic - Next topic

0 Members and 3 Guests are viewing this topic.


Its literally 'cool' too how the panels keep the heat off the roof and out of our Rv's,yet another benefit of solar panels.

I tell you the rig I enjoy most here is DanD2Soons solar setup.The professional installation quality and top quality products/size is a whitepaper on how to do it right.Just an absolute thing of Beauty.

Very nice job you've done Dan if Ive neglected to say so before,and I think I have.

Hail the Solar,my kind of Nuclear power!

LOL,am I a solar advocate or what,LOL!  >>!!

BooBoo<------"Must get a Life!"  :laugh:


 :-[ aw shucks BooBoo - thanks.


Heres another Solar Outfit that will send ya a free catalog with a lot of info on Solar                                                      (incl  prices)                                                                            RV Solar Electric PO Box 25313 Scottsdale AZ 85255  480 443 8520  rvsolarelectric.com      Frank  P.S. same outfit reccomended by Jim
"The Journey is the REWARD !"
Member of 15 years. We will always remember you, Frank.


2 dollar/watt solar panels,refer and freezer costs

Soooo....just got another 800 watts approx. of panels at 2 dollars/watt off of Craigslist.Let me just say this,used panel prices are outrageously cheap right now,just spend some time looking and reap huge savings!

So now its time to crunch some usage/cost numbers in putting them to use.

OK,solar refer and freezers.Look at this,the standard voltage mains/grid powered whirlpool(made by Woods in Canada) is almost twice as large as sundanzer but costs 500 bucks(todays price) and only uses 345 kw/hrs vrs 140 for sundanzer.So would need about 200 watts panels for almost twice the size vrs 75 for sundanzer.Panels would be 250 dollars more(extra 125 watts),including inverter losses, pretty close at 2 dollar/watt panels.

So 750 for whirlpool vrs 1200 for sundanzer and almost twice the size.

These cheap panels really are skewing the numbers for costs of appliances.The newest energy star freezers/refers are INCREDIBLY efficient,our 1999 freezer,same size as sundanzer 8.1 cf uses 297 kwhrs.Its a whirlpool too(Woods in Canada)

These conclusions sound about right?

..............  :)
Whirlpool Chest Freezers
Whirlpools makes a very energy efficient chest freezer, model number EH151FXR (similar models are EH151FXQ or EH150FXQ). This 14.8-cubic-foot freezer is rated at 354 kWhrs per year. The average cost to run this freezer for year is $29, according to Energy Star.

Though it requires manual defrosting, it sport a number of other features including an interior light and a temperature alarm. Its key-eject lock means that the freezer can only be opened when the key is pushed in and turned â€" a safety feature helpful in homes with small children. Four baskets (two upper, two lower) make it easier to organize the contents â€" especially on the lower level.

It’s available from Amazon for $405.

Sundanzer Freezers
The most efficient DC-powered chest freezer is the SunDanzer. This eight-cubic-foot capacity freezer has an exceptionally low energy consumption â€" it uses around 140 kWhr / year. It incorporates the highly efficient Danforst compressor. It also has a super-insulated cabinet that is wrapped in four inches of polyurethane. Because it runs on either 12 or 24 volts DC, the SunDanzer freezer is mostly used in off-grid homes or in remote locations, because a 75 watts solar panel and and two six-volt golf cart batteries can power the freezer.


A Reply to another members questions...

A)How many watts to run a roof ac  1500?

It depends on the size and age of your AC Unit.   The old rule of thumb was 1500watts for a 15k BTU AC unit (12.5amps).   I also would take a gamble that a 10K BTU Ac Unit would only use 1000watts (8.3amps).

B)how many watts to run a small refrig( 2.5 cf)  750?

That is a hard one to answer too.   It really depends on how well the manufacturer has designed the fridge and what components they have used.  I would imagine you could expect 150 to 300 watts on a mini fridge.    A good tool to have is a "Kill-A-Watt" Meter.   You can find them at Harbor Freight as well.


You plug this meter into an outlet, then plug your device into it and it will tell you how many amps/watts the device is currently pulling. 

C) how long will two or three trolling motor batteries last, running a 2500 watt inverter, for the above.  1) alone
             2) with 45 watt harbor freight solar panel.

Math can get tricky with this question.  Most Trolling batteries will have an Amp/Hour rating on them.  And some people say you really shouldn't deplete the battery past 50%, however I run mine down to 20%.  There is also another issue that complicates things, Peukerts Law.  A bit hard to explain, but to put it simply the more amps you pull, the less capacity your batteries will hold.   http://en.wikipedia.org/wiki/Peukert%27s_law

For example, I found out last summer that I could run my AC on high with 4 golf cart batteries (500ah) for about 1 hour before the inverter shut down when the batteries depleted.   With 8 golf cart batteries (1000ah), I was able to run it full blast for a little over three hours.  As you can see doubling the batteries gave me 3 times as much run time on the AC because of Peukerts Rule.   

With 8 batteries, I can run the AC through the night if I'm easy on the thermostat.   The next issue is getting the batteries charged back up the next day. 

The HF Panels are rated at 45 Watt, about 2.5amps in a perfect world.  2.5amps is normally considered a trickle charge.  If your battery is 100ah and is completely dead, it will take 40 hours of sunshine to recharge not including any loss due to poor efficiencies.  (100ah/2.5a=40hr)

D) can you supplement the above from the chassis alternator?

Alternators have one minor flaw that isn't talked about much, their continuous rating.   A 250amp alternator might only be able to handle 250 amps for 10 to 15mins, after that it will most likely overheat and fail.   In a regular vehicle situation, this isn't an issue as after 10 to 15 mins your battery is almost charged and the regulator will start to taper back.    But if your charging a large amount of batteries that can take the full 250amps for large amounts of time, you will kill your alternator.   I read last year that there are a few companies making sort of an amp regulator for alternators, this spring I will look into this for my configuration.

Also an appliance such as a 15k BTU AC unit that requires 12.5amps at 120volts AC will require 125amps at 12v, not including the loss in your inverter.  It will require very large wires going from your alternator, inverter and batteries.  I used 1/0 welding cable on mine and even they get warm when running the AC. 

A few more things to consider, Motors and compressors require 3 times their rated wattage for startup.   My 1500/3000 watt inverter would not start my 15k BTU AC, but my 3000/6000 watt inverter does the job.  Inverters now days are sold as Modified Sine Wave inverters and Pure Sine wave inverters.   Pure Sine Wave inverters cost more, but give out a much cleaner power output.   Some devices such as battery chargers, motors and even some microwaves will not run with a Modified Sign Wave.

When trying to figure out Watts, amps and voltage, just remember PIE.



Helpful Links:

The 12volt Side of Life (http://www.ccis.com/home/mnemeth/12volt/12volt.htm)
Battery Information (http://www.batterystuff.com/tutorial_battery.html)
Inverter Information (http://www.windsun.com/Inverters/Inverter_selection.htm)

Some Solar information:

Solar panels are usually one of the three.

Multicrystalline (Polycrystalline)
Amorphous (Thin Film)

In general regarding efficiency and price is directly related, Monocrystalline is the best, multicrystalline is second best, and amorphous is on the bottom.    Most of the cheaper panels you see on the market today are amorphous, thin film usually painted on glass.    They will get the job done, but usually require more space per watts than any other panel.  The majority of panels imported from China are also thin film.

Monocrystalline cells are cut directly from a sylicon nugget, Multicrystalline cells are peices of the nugget, up close the cells look like glass partical board.

Space might not seem like an issue at first, but get on the roof with your tape measure and make sure nothing is in the way.   I picked up two US Solar panels for my RV, and they are rather large in size, I might be able to fit three more on my roof but that would be pushing it.   They are 64 watts a panel, and a total of 5 would be 320 watts.   However I've found monocrystalline panels that are much smaller and 96.2 watts.   Due to their small size I can easily fit 9 on my RV, 865.8 watts.   Depending on your needs, you can see size can be important depending on your available roof space.
Constipated People Don't Give a crap!


Great Post Dilbert.

I got my last used monocrystalline panels for 1 dollar a watt,and nephew got a bunch of Unisolar 64's for 60 cents/watt!!!!

Craigslist folks,thats where the bargains are.

Regarding appliances....Energy Star appliances are almost as efficient as the very expensive sunfrost style freezers/refers that use the Danfoss compressors.With the prices plummeting on panels its now reasonable now to use much cheaper Energy Star appliances.

New panels can be found right now for less than 2 dollars a watt!!

This is a solar opportunity right now as prices have never been anywhere near this low for top name panels,so if you are thinking of going solar,DO IT NOW,may never have this chance again.


Another thought......

You want to go solar but dont think you can hook it up?

Buy those panels NOW and just store em.Then when you go to a jam ya'll can get together and cobble the system up.All you do is mount the panels,run wires from them thru a fuse to the charge controller and from there to a fuse to the batteries and the 12 volt side is done. If you want 120 volt you get an inverter and run the wires from the battery to a fuse then to it,POOF,120 watt power.Its very simple.

Cool thing about panels is storage is like putting food in the deep freeze,they dont age one bit,they only age out in the sun.


Btw,my next project is to solarize my pickup.It has a metal shell that I want to mount a couple Unisolar 64's on.Then put a charge controller in the side drawers and wire to 4 AGM 12 volt batteries I have,then wire a cheapo 1500 watt inverter.

POOF! Plenty of 12 volt storage on board,enough power to jump start the Cummins Diesel with em,plus 120 volt power anywhere.

Gotta LOVE it!

Going with the unisolars because of their strength from damage,you can shoot a bullet thru em and they still work,and no glass on em that can shatter.


Anyone have the solar article Dave posted for me once...which I can't find...written by this fulltimer RV solar guru that seems a bit of a know it all, but makes a lot of sense?

Also, is there a difference between an "On Grid" panel, and an "Off Grid" panel?

Also, what is a darn good charge controller that can handle a 27 volt output, stepping it down to the required voltage for a 12 volt system, and also handle 470 watts of panels?

Thanks guys!

Kev and Patti, the furry kids, our 1981 Ford F-100 Custom tow vehicle, and our 1995 Itasca Suncruiser Diesel Pusher.


Morningstar  makes some great controllers, The best one for an rv is their dual bank controller but its rated at 30 amps max, They will handle 25% more amps for short periods. 470 watts will exceed that. You need a 40 amp controller for that wattage. Over 30 amps and you are pretty much in the mppt controller market which are way much higher in price.

I split my system and used 2 of the dual contollers, 135.00 each with the inside remote panels, kinda nice because if something happens I still have a working system at half the wattage.

Mppt controllers do a better job of maxing out your panel watts just because of how they work. You can mix panel voltages and it handles that. But....... it is best to use panels of the same voltage so one lower voltage panel dosent drop the voltage of the other panels. Also buy the highest voltage panels for 12v that you can, usually 17.xx to 18.xx but if you are using a mppt controller you will be using higher voltage panels, thats what mppt controllers are all about.

On grid , off grid  no real differance except the voltage output. most so called on grid panels and the high voltage ones.


Might want to look into the TriStar-MPPT-45 by Morningstar.

They also make a non MPPT (PWM) in 45 and higer as well, but personally, I would try to fit a MPPT into the budget. 


Keep your roof capacity and the weight of the panels in mind!
Constipated People Don't Give a crap!


perfect, I was just fixing to post the same info :)


Thanks guys...that is what we wanted to know.  Looks like the one that will work with the panels we are buying is the MPPT Tristar 45...and yep, its the expensive one...although I found one place that has them for 366.00.  Too bad Best Converters doesn't carry Morningstar products!  I like doing business with them, and they usually have the best prices.

Also, the MPPT Tristar 45 can handle 3 of these panels, at over 700 watts of solar, according to their string calculator...its a thought, although it might be overkill, and a third panel wouldn't fit where I plan on putting the frame I designed that can be tilted 4 directions when parked.  I'd have to put a third panel up front with its own frame, so not sure if I'll go that route.  It would be nice though...with that much solar it can be crappy weather or slightly shaded and we'd still have so much charging power we'd hardly ever have to run the genny.

I found the solar link that Dave sent me once...its http://handybobsolar.wordpress.com/the-rv-battery-charging-puzzle-2/

This is one damn good informative link about solar I tell ya.

So we decided to wait to pick up the panels until after next weekend since then we'll be able to afford the charge controller as well, and the wiring of course, and the 2 more golf cart batteries for a total of 6. 

This week I'm buying Patti her Splendide washer/dryer at a Camping World.

So what do you guys think?  Should I pick up the 2 panels at 470 watts max output, or should I take the plunge and spend the extra 300 bucks and have 705 watts of max output?  Its just over 1 dollar a watt for brand new panels, and I doubt I'll find a deal on them like this again.

Lastly, has anyone ever heard of Canadian Solar, and do they make a decent panel?

Thanks guys!

Kev and Patti, the furry kids, our 1981 Ford F-100 Custom tow vehicle, and our 1995 Itasca Suncruiser Diesel Pusher.


Dont know about canadian solar, I would put as much solar up as you can afford since you have 6 "wow" batteries. They say you want a max of 13% charge rate of your battery bank.

Not sure on your amp hours but I assume its about 330 ah so thats about 43 amps. Your 705 watts will give you about 50 amps at 14v and 705 watts will work well on cloudy days. You really dont need to tilt the panels. They work fine flat, even more so with all the sqft you will have in panels. Mine are flat and do great and put out max watts just fine. Granted tilting will give you a little more but with 700 watts you wont have to tilt them :)


BTW thanks for the link. That is a great article and pretty much covers it all. Smart guy. I read a lot before I put my solar on and pretty much did it they way he states but , It took a lot of time and many many articles and info searching. That gives it all in one spot !!  :)clap :)ThmbUp :)ThmbUp :)ThmbUp


So the verdict is in...only 3 panels will fit on the roof, instead of 4.  And I'm going to flat mount them using 4 inch aluminum angle stock as both the frame and mount...it will allow 3 inches of air and wiring space under the panels, distribute the weight of the panels across a greater area of the roof, and give me a very secure mounting to the roof.

Also definitely going with the Morningstar MPPT 45 controller, since it will handle 3 panels perfectly.

Now, to find the time to go get the panels!  Busy 3 day weekend coming right up!

Kev and Patti, the furry kids, our 1981 Ford F-100 Custom tow vehicle, and our 1995 Itasca Suncruiser Diesel Pusher.


Another mounting choice is the flat track that electricians use in buildings that has sliding bolt plates you pop in, it comes in 1.5 in and 3/4 in. It limits the holes in the roof you have to drill and makes a nice spot to bolt future stuff on the roof without more holes. Its heavier than the aluminum but sure makes a nice bolting surface for stuff.

Also pay very close attention to anything that will shadow even a small section of a panel before mounting.


Thanks Gadgetman.  I have to go to Home Depot this morning for a few more sticks of wood...my employee accidently cut up some that was set aside for the bigger catapults I have to build today, so I have to make the early morning trip so I can get everything done.  While I'm there I'll walk up and down the rows and try to get some alternative ideas for the mounts...maybe be able so save some money on something like the electricians track you are talking about.

So I'm assuming that just brackets attached to all the bolt holes on the frame that is already on the solar panel won't be strong enough?  Am I right in assuming that the frame has to be supported by another frame, or is the frame strong enough that is already on the panel to mount it to brackets I can attach to the roof?

Kev and Patti, the furry kids, our 1981 Ford F-100 Custom tow vehicle, and our 1995 Itasca Suncruiser Diesel Pusher.


The entire solar panel project is finished!  705 watts of Canadian Solar panels on the roof with a Van Tech air foil in front of the first panel, a Morningstar Tristar MPPT 60 amp charge controller, all the wiring, 2 80 amp DC breakers and a fuse block that doubles as a wiring block (both courtesy of Blue Sea, which you can get at any West Marine store), and a remote meter.

Storage is 6 Interstate deep cycle golf cart batteries wired to 12 volts.

Because I had to install the charge controller horizontally instead of the recommended vertical wall mount, I installed a 48 volts muffin fan that blows cool air across the heat sink of the controller.  Its wired directly through the solar panels after a 1 amp fuse, so it runs during the day and shuts down at night when its not needed.  Even in the shade where we are right now the fan runs just fine.

The remote monitor says I had a maximum voltage yesterday of 32.5 volts coming from the panels, and that is under the trees and in the shade where we are parked right now.

Pictures coming soon!

Kev and Patti, the furry kids, our 1981 Ford F-100 Custom tow vehicle, and our 1995 Itasca Suncruiser Diesel Pusher.


amps amps amps amps    :D  volts really dosen't say much :)  But add the amperage to it and tell the voltage. Now there is a story ! :)


Logged data on the monitor says she put out 3.2 amps max yesterday...not very much, but we are under heavy tree cover with hardly any direct sunlight on the panels at all.  I'll let you know how she does when we're in full sun later this week.

Kev and Patti, the furry kids, our 1981 Ford F-100 Custom tow vehicle, and our 1995 Itasca Suncruiser Diesel Pusher.


You have a huge battery bank, if you want to see what the solar can really do, wait till about 11 am to 2 am and crank up the draws. Turn on everything you can to load the batteries. This will cause the controller to crank out the available amps for the sun at the time.

Batteries charged up and little load, the system will just idle at almost no amperage. Your system should easily give you 250ah - 350ah a day. That's a lot.   :)clap


We've got an almost 800 mile trip coming up starting this Friday, so I should be able to see what this system is capable of pretty quickly.  We'll be making the trip in 2 days, using the inverter at night, and the last day we'll roll into the parking lot of the Renfaire while its still daylight and park for the night...then make camp on Sunday.  Should see what she can do in the full sunlight of the rest area and the parking lot.

Kev and Patti, the furry kids, our 1981 Ford F-100 Custom tow vehicle, and our 1995 Itasca Suncruiser Diesel Pusher.