Taking the solar plunge

[stamar]

http://www.solarblvd...oduct_info.html

throwing a polycrystaline panel on the rv isnt a bad idea, a lot of power per square foot.

Where to throw this panel? IMO, from my experiences its actually going to be over the window in the overhang and pointing the truck at the sun over the course of the day around 60 degrees.

yes I have seen them on rvs exactly like that, if youre willing to give up the window thats the best spot.

I could see myself doing this

IMO throwing this panel horizontal on the roof isnt going to do much.

this is another top pick per dollar

[zero]

well i chose amorphous panels first because they happen to be the cheapest in the world, whereas normally they are the most expensive, more a luxury item.

I think 4 batteries would run a window ac well. I havent personally rved in the desert yet so Ill jump that cliff when I get there. My rv doesnt have the roof ac right now.

I feel like 2 batteries is the right amount but i could see 4 with 2 under the couch and 2 near the converter box.

I haven't had the same experience with amorphous panel prices. Where I buy (Sun Electric in Miami) they have always been much cheaper then polycrystaline panels and overall - much less efficient. Amorphous panels are often only 1/2 the efficiency of a polycrystaline panels. That being said, when Evergreen of Massachusetts went bankrupt the market was flooded with there government-boondoggle poly string panels for 30 cents per watt. I bought a pallet of them. In regard to partial shading, all panels can suffer from it. If you use polycrystaline panels with ample blocking diodes - and wiring separate strings and NOT in series, the partial shade loss is greatly minimized.

In regard to batteries running a window AC? A 5000 BTU unit will draw near 15 amps when it first starts and then run on 5-6 amps. That 15 amp surge every time it comes on is the big problem with batteries and an inverter. Two fairly big deep-cycle 6 volt batteries like Trojan T-105s cannot keep DC input voltage above 11 volts under a surge of 13-15 amps. When that DC input voltage spikes low even for a second - the inverter shuts down. It takes four such batteries to do it - or -use two batteries and have the truck engine running so the alternator can send charge current to help. Four batteries e.g. Trojan T-105 or Deka-NAPA 8144s can probably run a 5000 BTU window AC unit for 3 1/2 hours of steady use before they are dangerously discharged. So much depends on how often it comes on. If half the time, the run time is 7 hours with four 225 AH 6 volt batteries.

[Totem]

bleh I could do it with a couple trojans, a huge inverter and a Supco SP6 in the AC i think.. that and like 2000 watts of roof power

[zero]

bleh I could do it with a couple trojans, a huge inverter and a Supco SP6 in the AC i think.. that and like 2000 watts of roof power

Maybe. Can't say I've tried. A "hard start" cap kit like Supco sells that can drop the AC-side surge from 15 amps down to something like 8 amps. Two Trojan T-105 batteries when hooked to an inverter and hit with a 8 amp AC surge on the inverter results with a DC voltage drop to 11 volts at the input. Due to some losses there will be an 80-85 amp draw on the batteries. Some inverters will trip at 11 volts and some won't until it drops to 10.5 volts. It has nothing to do with the size of the inverter. Just the make and particular design. Some of the newer inverters with the common-trip module are more problematic than the older models that had circuit breakers, separate heat sensor, and a beeping low-voltage alarm. I've got a new "pure sine wave" Ramsond 3000 watt inverter that trips at exactly 11 volts at the input and an 8 amp AC surge will trip it on two T-105s unless the truck engine is running. My newer AIMs mod-wave 2000 watt inverter hooked the same works fine and does not trip. I have a new AIMs "pure sine wave" inverter sitting here in the box that I'll be testing soon.

[stamar]

The concept of air conditioning which is wasteful of electricity and fossil fuel and solar power ( on the road no less) were possibly not meant to ever meet quite correctly,

I believe the true engineering in this project is not to make solar any better but to invent a low powered ac compressor

[Totem]

Agreed, I was thinking of something on the lines of being powered by solar cells and TEC modules. Direct convert ion of electricity to cold, m

No compressor... I would use a small bucket of water and freeze it with the TECs then blow air through it. Maybe have two freeze blocks even so while one is making a block one is blowing air across and melting another. Air across ice was the original AC back in the day.. I have in my possession now 10 high temperature TEG modules to build my own thermal stove battery charger. TEC modules are cheaper and larger and with a bit of ingenuity I think my block chiller

Idea could work. I know they have them for semi trucks already, just ones that freeze using compressors. TECs can chill much faster freezing water in a few seconds...

[Totem]

I don't think the world has even begun to explore the power of bismuth telluride yet...

[zero]

The concept of air conditioning which is wasteful of electricity and fossil fuel and solar power ( on the road no less) were possibly not meant to ever meet quite correctly,

I believe the true engineering in this project is not to make solar any better but to invent a low powered ac compressor

The simplest cooling is how they did it 70-100 years ago. Cut ice out of pond in the winter, cover it with saw dust and it lasts all summer. When you want some cooling - stick an ice block next to a fan or at an open window with a breeze. Might not be convenient in a Toyota motorhome though. Ice stores the winter cold to cool things in the summer, and trees store solar heat for us to get warm - when we burn them.

On a smaller scale, we've used ice many times for our dog when left in a parked RV for awhile. Small fan and a chunk of ice.

[Totem]

TECs are also used in instant ice machines... Wow why hasn't anyone made an AC out of this tech yet I wonder...

[stamar]

well i ordered my first one

http://www.ebay.com/...d=110966605139

there is actually a 136 watt panel for sale on ebay for 1$ less but it doesnt have the cables or the mc3 connectors which is at least a 20$ value.

also its 18 foot and this is 16 foot. my measurements show me theres only one spot on the whole roof that can deal with 16 feet and 18 feet has to go over the edge. it so happens that that spot makes the panel cover a window in the front or the back ( or just roll it up and leave it unused for 2 feet)

one last thing is that 136 watts actually exceeds a 10a solar controller by 6 watts. so I needed a 15amp controller or larger to start wheres I can get a 10 amp controller just for this panel.

so this is it it will be here next week.

Ill do as many experiments as I can with it before I stick it. This is meant to be horizontal on the roof but im going to do an experiment putting it vertical on the side. the reason this is, is theres only one more spot for a panel this big on the whole motorhome its on the drivers side vertical. the next one on the roof has to be 10 feet or smaller so like this one

so like this for the roof

http://www.ebay.com/...=item337e2df739

or like this for the side ( it will be a couple inces over the side window on the overhang)

http://www.ebay.com/...d=110966605139

so I have a calculation to make before I buy the next one, which makes more power a 68 watt panel on the roof or a 116 watt panel on the side? because they cost the same. any guestimates are welcome

many thanks to the guy who showed us the picture of his 9 foot panel and then disapeared.

I might be the first person to put a full 16 foot panel on a toyhome or an rv and my sole reason for going with the bigger ones is this.... they cost about the same.

theres no doubt that the 9 foot panels fit the roof way more conveniently you can fit 4 on the roof.

edit one more spot for 2 more panels this big is to wrap them around the back under the window. so youd point the back end towards the sun if you could. overall an extremely difficult thing to figure out because the vertical placements can sometimes generate no power at all depending on the way the vehicle is parked.

again using a solar panel under your awning is sort of a bad idea you want one or the other usually.... so one of those is a mostly bad idea

[stamar]

i ordered 2 more parts for my set up

I got the branch connectors for 7.50 and the solar charger for 35$ shipped by lowball bidding on ebay.

I needed the branch connectors for my next panel.Im not actually positive i need them honestly depending on where my next panel goes but I do believe my next panel goes on the roof and ill wire it to the first one.

I got the regulator for a few bucks off. what they normally go for.

I cant review it without using it obviously. You can get a 10 amp one from ebay for 7-10$ that probably works just as well but I actually want the voltage read out and the amps etc.

http://www.ebay.com/...=item25784dc9a6

Theres a certain amount of saved power used by trying to make the panels power the same wire and go through one connector overcoming the resistance.

but then again there could be a loss by forcing a panel thats closer to the battery to back track....

so I can see getting 100 watt panels and 10 amp controllers one at a time. its too late i didnt do that.

all thats left is to buy some 8 gw wire

I started these purchases with the two 116 watt stick em panels in mind, for a 232 watt solar panel set up, and thats it.

The charger regulator can handle a third one but I have no plans for it im off to other things.

[stamar]

http://www.wind-sun....y-small-systems

dang i just got this info at the last second so what i want is an mppt controller, 10-30% more power. cant live without it cancelled the controller order.

http://www.ebay.com/...=item2a26916dd1

this is what i really want.

normally for 400 watts or below you do want a pwm one

but for me in my case ive got 24 volt panels with 12 volt battery so i need a mppt

this is the cheapest one

http://www.ebay.com/...=item1c2cf768b6

I think i need a day to decide but overall this looks like the best one for me.

If I expand the system ill get 12 volt panels and also those cheap 7$ 10 amp regulators. I think I have a logical system progression figured out.

[Totem]

http://www.ebay.com/itm/MPPT-10A-Solar-Regulator-Charge-Controller-12V-24V-Autoswitch-Solar-Panel-/121013495990?pt=LH_DefaultDomain_0&hash=item1c2cf768b6

mine is mppt. works great. Mppt has been around a while... only crap like the harbor freight charge controller is not mppt...

[stamar]

ya i think thats the one to get too

unfortunately it only covers my one panel. but ya i am going for the mppt.

some people in this rv situation can get away with a pwm controller but its not me. those are going to be for 12 volt panels in a 200 watt or less array.

http://www.ebay.com/...=item3cb7108c3d

here we go this will controll both panels

oh crap lol 82$ shipping. Dumb yankee

both panels will use the same wire to overcome resistance.

Im almost sure this is the right one for me.

If I expand solar I can get a 125 watt poly 12 volt panel, and get a 7$ pwm 10a controller for it and its own wire.

[stamar]

ya this is some crap because i know im getting another solar panel for christmas I know already i need 20 amps of mppt now.

just 10% power lost is gonna pay for itself really fast too.

and using two wires and two controllers is gonna be another 10% im sure. cant do it I need a 20 amp mppt controller.

ill have to get back to this on monday.

[Totem]

ya i think thats the one to get too

unfortunately it only covers my one panel. but ya i am going for the mppt.

some people in this rv situation can get away with a pwm controller but its not me. those are going to be for 12 volt panels in a 200 watt or less array.

http://www.ebay.com/...=item3cb7108c3d

here we go this will controll both panels

oh crap lol 82$ shipping. Dumb yankee

both panels will use the same wire to overcome resistance.

Im almost sure this is the right one for me.

If I expand solar I can get a 125 watt poly 12 volt panel, and get a 7$ pwm 10a controller for it and its own wire.

I like that they show whats inside and that it has cooling fins... VERY nice... maybe i will get this one also.

[stamar]

that one is expensive its got a high shipping cost.

I cant find one thats cheap with 20 amp and mppt.

[Maineah]

Got really deep pockets? http://www.outbackpower.com/docman/2205125050340900-0134-01-00RevA.pdf this one will control what ever you can throw at it.

[stamar]

this is just a comparison using the actual cheap chinese solar controllers im trying to buy. It works mppt is for real.

edit duh its 130 watts in 12 volt panels or 260 volts in 24 volt systems.

so a 10 amp mppt will cover my whole system

[stamar]

Got really deep pockets? http://www.outbackpo...4-01-00RevA.pdf this one will control what ever you can throw at it.

oh no man were like 350$ into this project as it is. not that it isnt 350 well spent really it will pay for itself when i have the internet and laptop set up...

but im more of the mindset to get the cheapest controller possible and then maybe upgrade it all sometime after christmas when i have a better grasp of what all is going to be the best for me.

but i like gadgets, thats obviously more for a whole house.

I wonder how you could get 5000watts of solar panels on a toyhome....

[MontanaChinook]

Talk about overwhelming! I could definitely recommend this thread to anyone wanted to get talked out of getting a solar system set up : )

I'm sure there are some basics which once you understand, makes this all less confusing, but this stuff seems complicated! I'm not in the market, but I would like to add some panels to my chinook eventually. Looks like I'll need to do a LOT of learning and a lot of research before I do anything.

[Derek up North]

My eyes glazed over days ago. However I'm guessing that if you buy a 'kit' from one source you'll probably be fine. Maybe at the expense of a % or 2 in efficiency, but ...

[MontanaChinook]

Yeah, I guess there's a big difference between going with a tried and true kit that is known to work for general purposes, and really understanding this stuff and piecing something together to fit my exact purposes...

[zero]

Got really deep pockets? http://www.outbackpo...4-01-00RevA.pdf this one will control what ever you can throw at it.

I've got twin Outback inverters running my house and barn. Outback GTFX 3048-2 Power panel with 2 inverters cost me $5200 five years ago.

Also have twin Outback controllers for my battery bank. 2 MX-60 Charge Controllers, breakers and disconnects were $2300.

My eight Rolls-Surette S-460 batteries from Canada were $2000.

[zero]

My eyes glazed over days ago. However I'm guessing that if you buy a 'kit' from one source you'll probably be fine. Maybe at the expense of a % or 2 in efficiency, but ...

Some of the efficiency claims are nonsense when it comes to practical purposes. Much depends on what part of the country you live in and what specific type of use. That goes for the various types of panels, MPPT, pulse-width-modultion controls, panel-sun-trackers, etc. Kits can be fine to save leg work and guess work but most I've seen are prices kind of high - as compared to what the individual components cost if you shop around.

One other problem is finding track records for reliability on anything that is solar electronic (except the panels). Devices change so often in design and in brand name - it's very hard to find anything that's been around for awhile and has a history to be checked. Solar panels themselves can't go bad. They can have individual cells go bad or get weak, or diodes blow, but they can be repaired. With controllers and inverters - many low priced ones are throw-away items. Bigger ones made by well established companies e.g. Trace, Outback, Beacon, Fronius, etc. have had pretty good parts support.

I had two thyristors go bad this year in my twin Outback inverters. 5 years old . They sent me out free replacements along with full instructions. I had them fixed in two hours..

[zero]

Talk about overwhelming! I could definitely recommend this thread to anyone wanted to get talked out of getting a solar system set up : )

I'm sure there are some basics which once you understand, makes this all less confusing, but this stuff seems complicated! I'm not in the market, but I would like to add some panels to my chinook eventually. Looks like I'll need to do a LOT of learning and a lot of research before I do anything.

Solar electric, if anything - is simpler then many other electronic systems. There isn't a big learning curve if you already know basic electronics. A solar panel sold as "12 volts" makes up to around 18 volts when no load is on it. If the total wattage is 15 watts or less you can hook it directly to a truck battery with no controller. If over 15 watts - you need a controller which is basically just a voltage/current regulator. It keeps the battery from getting overcharged. A 120 watt panel in the northeast might make 5 amps of charge current for a 12 volt battery in the best sun. A 15 watt panel in best sun might briefly squeeze out 1 amp. The rest is just basics. You figure how much charge capability you' d like and work from there.

When it comes to solar and RVs . . . having portable panels are nice to have. When you park and camp you can stand them up outside and point towards the best sun. Some people mount panels on the roof pointing straight up. That works when they are pointing towards the sun but obviously - that is not always easy to accomplish. Expect maybe 1/2 rated capacity in the best noon sun here in the northeast. Southwest is different and so is winter and summer as the sun angle changes.

If you were running 40 solar panels on the roof of building wired series-parallel with 200-400 volts DC -then some of newer controllers (and trackers in the southwest) can make a substantial difference in gain. Not sure if the extra cost ever justifies it though. In a low voltage 12 or 24 volt RV system, simple is usually gives the most volts for the buck over time.

[zero]

Yeah, I guess there's a big difference between going with a tried and true kit that is known to work for general purposes, and really understanding this stuff and piecing something together to fit my exact purposes...

If you want to get a good understanding of solar at an RV 12-volt level - I suggest you read some info from companies that specialize in off-grid low-voltage solar. Unlike grid-tie companies that like to sell kits (they did not design), off-grid people deal with the issues you're probably wondering about. They also stay up to date on what components are working well and which ones do not.

Back Woods Solar has a free catalog that is pretty much an intro solar manual that is great reading for someone new to solar. New England Solar also has one just as good. Great people at both places who will spend a lot of time helping even non-customers - free. I'm cheap but even so - have bought equipment from both simply because of the great service they give. The guys in New England ar electrical engineers that dropped out of the corporate world (to a degree) and established their own off-grid company quite a few years ago.

http://www.backwoodssolar.com/ http://www.newenglandsolar.com/

Note that neither place the cheapest prices across the board. Just great service and a lot of free info. I mention that so somebody doesn't start ranting about the prices. I bought my solar refrigerator setup from Backwoods and have bought several Outback controllers from New England.

By the way - about longevity of some stuff that is still around. 10 years ago I bought a batch of used solar controllers that had been in service in California. I bought a dozen of them for $20 each. Since then not one single failure. I gave two to a friend in Florida that uses them in his RV and backyard when home. Little seemingly indestructable ASC Specialty Concepts Inc. 12 volt controllers. I've got the ASC 12 models - 12 amp max and for a 12 volt system. Amazingly bullet-proof. The new ones now come with a 10 year warranty. One controller and up to around a 170 watt panel is a "system." If I ever see any more for sale uses at a reasonable price I will buy for sure.

http://www.specialtyconcepts.com/special_home.html

Some of their info: THE AUTOMATIC SEQUENCING CHARGER™ (ASC™)

The ASC™ is a solid-state charge controller for use in PV systems with currents up to 16 amps. It is available in 12 and 24 volt models (6-, 36-, and 48-volt on special order only). Options include low-voltage load-disconnect, battery temperature compensation, and user adjustable setpoints. General Specifications:

• Completely encapsulated and waterproof
  
• Optional INTERNAL or EXTERNAL temperature compensation
  
• Optional 10A Load Disconnect (12, 24 volt only)
  
• Available in 4, 8, 12, and 16 amp versions
  
• Available in 12 volt and 24 volt (6 volt, 36 volt, and 48 volt on special order)
  
• Guaranteed to FULLY CHARGE a COMPLETELY DEAD battery
  

[MontanaChinook]

Thanks!

[stamar]

My actual set up is actually pretty simple I'm just getting ahead of myself.

ended up getting a 10 amp ebay china pwm controller for 7$

I will get aan mppt charger when I actually have the panels for it early next year.

At that point I can move the smmall pwm controller to a different 12 volt array or ppanel.

I have onyl the 116 watt panel paid for and the controller

That's actually perfect for the beginner. That's 140 iin a panel and 7 in a controller, and nothing else is needed.

I am in the process of learning but ill have a direct link of what I use in my signature here. The led light bulbs the solar panel the deep cycles and eventually the alternatpr

[Eve "n" Stephen]

Backwoods Solar is a great outfit. I used to live fairly near them and got to know them pretty well. I bought my batteries for my off-grid home from them back in the early 90's. These were used "calcium" cells, 6V and about 160 pounds each, 200 AH. They were 10 years old, used in float service as backup power at a phone company. We used them for another 12 years, then cracked the case on one when moving it. I patched it and sold them to another person (for what I paid for them) and he got another 5 years of use from them.

Steve

[zero]

. . . really understanding this stuff and piecing something together to fit my exact purposes...

One thing that makes solar power quite different from battery power or wind power. You can take a solar panel while in full sun and short it out with NO ill effects. You take the NEG and POS power wires and tie them together and no harm is done. You cannot do that with two wires hooked to a battery - unless you want some melted wire and maybe a fire. The older controllers worked by doing just that. When the sun was shining and your batteries were fully charged - the controller just shorted the panel out.

[Maineah]

If any of you all are in the Northern New England area or a up for a trip (yes there is camping on the grounds) a really great event is Solar Fest in VT. http://www.solarfest.org/ they do classes have vendors great nightly entertainment that I might add is totally solar powered I watched their system supply over 6,000 watts all during the 4 hour nightly entertainment. If you bring kids there are programs for them also. This is an event for believers every one is there to answer all of your questions.

[stamar]

I have all this stuff now actually except the wires and controller but I work 12 hour graveyard shifts and its haard to get the energy. Allthough I'm excited about it.

My wiring diagram is exactly like the guy who posted his unisolar panel picture here, and there's another person who did it the same way in the toyhome email string. That being to drill a hole next to the exhaust pipe. For the furnace and follow it down to my battery box. I will put the charger in thhe closet that the pipe travels down so I can look at it.

Literally one hole to drill as the wiring will connect to a junction right outside the battery box.

All that I'm doing different is adding a 2nd panel on the roof that will send a wire across the roof to the connectors on that panel.

That's the best set up I've seen.

The very last thing to stop me is to test the power coming from this unisolar panel when its horizontal vs if it were vertical. I may or may not test it first I might just feel like sticking it where I want it and living with it.

[Maineah]

Another method of getting wires into your camper is down the tank vents generally they run inside of closets no holes in the roof and easy to seal up.

[zero]

Another method of getting wires into your camper is down the tank vents generally they run inside of closets no holes in the roof and easy to seal up.

Voltage drop is the BIG issue with wiring low voltage solar. If you had three 120 watt panels on the roof (7 amps max each at 12 volts) - hooked in parallel and used just one pair of wires for 15 feet - a copper wire would be thicker then your battery cables that go to the starter motor.

21 amps at 12 volts run 15 feet needs copper wire 7 mm in diameter (#1 gauge battery cable). That's why on houses - panels are usually run at high voltages sometimes up to 600 volts.

If you take the same three 120 watt panels and hook in series to make 36 volts - and run the two wires for 15 feet - you can use 14 gauge wire instead of massive #1 battery cable. But then you'd need a 36 volt controller and things get complicated.

This is why if using a low 12 volt setup - you are better off with each panel with its own set of wires going to the controller. This also eliminates "total loss" if one panel gets shaded while another has sun. In a series hookup if any one of the panels in the "string" gets shade - they all stop working.

Just one 100 watt panel with a 20 foot pair or wires needs 12 gauge wire (copper 2 mm diameter). One 120 watt panel with a pair of wires running 10 feet needs a 14 gauge wire (1.5 mm diameter copper).

Having portable panels that you stick on the ground when camping keeps the wire runs nice and short.