RV Solar Power Set-up Advice Needed

2

Comments

  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    Hi Jim,

    Yep we live off of Springdale Ave that Skylab Street exits onto.

    These discussion threads, both active and archived, are very helpful for getting a feel for this stuff. The MK's sound like a very reputable option to the pricey Concordes. Plus, I was born in PA so there's some built-in loyalty!  I already have an Anaheim MK contact who is going to call me back with a quote for the 8A8D's.

    I don't think I'll make it a practice to run both A/C and Solar Controller charging at the same time. But it's good to know it is probably harmless if, by mistake, I leave both on at the same time.  That being said, I can imagine the two oscillating playing tag trying to compensate for each other's alternating voltages, LED's blinking furiously, emitting all manner of electromagnetic disturbances.

    BTW I broke the news about the two additional KC130 modules to the little lady today and, as you can see, I am still alive. But I'd better sleep with one eye open tonight to be safe. If it were up to her we'd just go to bed at sundown to save 2 cents! Just kidding but she is a very practical minded person.  The examples of those guys in New England using solar to make it through the winters there impressed her and me as well.  If anything, I'll have a decent start on a good alternate energy system that I can transplant to our home once we get tired of rv'ing.

    How did you like your system Jim. We'll be using about 100 to 150 Ah/day. Do you think that 6 each KC130 modules should be enough solar power to get the batteries up to "float" each day in average California weather - say 4-5 hours of sun each day?

    Phil
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: RV Solar Power Set-up Advice Needed

    Phil,

    You should be on the "fat side" of close--even up to 150 amp*hours... A lot of it depends on your local weather, angle of panels, and shading...

    From April through September, I averaged better than 15 kWhrs per day on a 3.5 kW (STC) grid tied array... (San Mateo, CA--with some shading outside of 9-3pm, ~30 degree pitched roof, pointing about 155 degrees (SE))...

    Based on my numbers (not an optimal array orientation):

    15,000 Whr/day * 6*130watt/3,500 watt = 3,343 watthours per day or 3,343/14 volts = 239 amp*hours per day...

    I am in a OK sunny area of the SF Bay Area (don't get coastal fog very often. not too windy or too hot)... Your area/weather pattern/temperature may be different from mine.

    Remember, that you only have so much storage... Once the batteries are full, there is no more power saved. With Grid Tie, I can store, essentially, all of the power I can generate (no 6 days of clouds for example). But the long term average looks good.

    You can compare various regions in the US on the following link.

    http://rredc.nrel.gov/solar/pubs/redbook/

    I would suggest downloading the PDF file first. It is very easy to read and compare locations, panel orientations, and tracking options across months and the year. They also show a scatter plot of solar energy gathered over the years (min-max).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    Bill,

    We do the lion's share of our Fall/Winter camping in your area, Big Sur, Big Basin, Santa Cruz, Half Moon Bay Bodega Bay. I've seen many days on-end where the coastal marine layer just hangs along the W side of the Santa Cruz Mountains where we camp at Half Moon Bay.  We've been deluged many times spending the Holidays camped at Big Basin and Big Sur. This year was cold but clear and beautiful by comparison.  The year before that we almost had to evacuate from Bodega Bay bec uase of the Russian River flooding in that area. 

    Or, to make a long story short, we need lots of AmpHours battery reserve for the foul winter weather camping that we do. I'm from Back East and like to get a nice "Christmassy," chilly/rainy change of weather from sunny S California. Nice area up there, specially in the Redwoods, Berry Creek Falls, Condors, Ketch Joanne/Princeton Harbor, Phil's Seafood Market/Moss Landing, etc.

    Summertime we camp in the Sierras with only occasional mid afternoon storms passing through.

    Man it sounds like you are collecting a lot of power per day up there! 15KW/Day! I hope they are paying you back for a lot of that.

    Thanks again!

    Phil
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: RV Solar Power Set-up Advice Needed

    Phil,

    Grew up in Pacifica and had a light plane at HMB airport for many years... On the coast, it was pretty much 4 days of fog and 2 day of sun... (I had to watch the weather for days to fly). That coastal range sure makes a difference in the weather.

    I am only 10 miles from the coast--but it is a huge change in weather.

    I drove by HMB Airport a few weeks ago and noticed a two story house just north of the airport (east side of rt 1) that has three sides of its pitched roof (E, S, & W) completely covered by solar panels--I really wonder how much solar they collect. I would be hard pressed to recommend solar to anyone on the coast--I would guess that they would get half of the sun that I do (at best).

    I had about a $286 credit last year (first year of solar--E-7 TOU rate plan, 1 year net metering--so the credit zero's out at the end of the year--or I pay if I owe)... I over sized my array to allow for that pluggable hybrid car sometime in the near future (I hope)--or for a little AC if "global warming" continues.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    Bill,

    That is cool to have credits like that. I guess you'd be right over the 92 from HMB.

    We stayed at the RV Park at Pacifica a few times. That is, until one winter about 8 years ago when the storms got so bad that the houses next to the Pacifica rv resort slid off the cliff into the Pacific!

    I like the Pacifica Hardware store there off of PCH/Rt 1. HMB has a real nice one too. We always go to the Orchid greenhouse (Shelldance) up on the hill there in Pacifica too.

    Those Santa Cruz mountains really lock-in the moisture. Up on Skyline Drive we always see the marine layer just hanging to the West side with bright sunlight to the East. Bacjk in Big Basin Redwoods they get about 10" of rain in Dec and January. The rangers have warned us about "widow makers" or falling timber from the Redwoods in high winds.

    HMB's a great place to spot an rv: easy acces to SF and also points south, hiking, biking, eating galore - but it can be dreary! Here in HB we have the "June Gloom" marine layer that usually burns off in the early afternoon. Lately it seems it has been thicker lasting into late July - global warming too?

    I guess the HMB airport runway is now moslty used for law enforcement driving training.

    Once again, thank you for your analysis. It's good to know we've got a viable solar system for extended off grid camping - or whatever!

    Phil
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: RV Solar Power Set-up Advice Needed

    Phil,

    You’re still alive! Springdale and Skylab: I know it!

    In general, I wouldn’t worry about any bad interactions between the chargers. Both are so-called “smart” chargers. They’ll individually track the battery bank’s voltage and adjust their operation according to the voltage measurement and the batteries temperature. For example, once the batteries reach their absorb voltage setting (~14.35 V at 77 F), the chargers will only supply enough current to maintain that voltage for the length of time you’ve selected. If the voltage starts to rise -- even just briefly -- one or both the chargers will reduce current to compensate.

    My system stated on my small camping trailer. It started at ~180 W and grew to 300 W. With the latter configuration, we were able to generate >100 Ah per day when camping in the Rockies in the summer (6-7 hours of full Sun per day), and it worked very well. We really enjoyed the peace of being able to set up in a no-generator loop at Colter Bay campground in Grand Teton National Park.
    We'll be using about 100 to 150 Ah/day. Do you think that 6 each KC130 modules should be enough solar power to get the batteries up to "float" each day in average California weather - say 4-5 hours of sun each day?

    The answer to your question is complicated. Correctly aligned, your 780 W STC array should be able to generate ~48 A from full summer Sun. Assuming 98% coulombic efficiency, the system will easily replace 150 Ah in four “hours” of full Sun, although the actual amount of recharge time will be longer – perhaps six or seven hours, including ~three hours for the absorb stage.

    There are several key parts to successful battery charging strategy. One is timing, another is load shifting, and a third is day-skipping. In general, I like getting the batteries to their absorb voltage by ~local solar noon. This will usually allow enough time to complete the absorb charge stage before the Sun sets too far, and it somewhat synchronizes the absorb stage’s falling current requirement with the gradually decreasing array current available from the setting afternoon Sun.

    The absorb stage limits charge current to the battery bank. Accordingly, there’s often power available that not being used to charge the batteries. Load shifting takes advantage of this phenomenon by shifting loads from the morning bulk stage to the afternoon absorb stage, but you have to be careful to might divert current away from charging the batteries.

    The day-skipping approach is to only worry about achieving a float state every other day. It’s a variation of load-shifting, and entails concentrating loads on day one (say, 150 Ah), lightening up loads on day two (say, 100 Ah), and allowing the system to complete a full absorb cycle on the second day. To me, this is better than leveling loads and never quite getting to float on any day.

    As you and Bill have discussed, local weather patterns will greatly influence your system’s operation. I lived in Marina del Rey when I first moved to SoCal, but I moved to the SFV after three cycles of June gloom – I was literally and figuratively in a fog and just could not function. IOW, don’t expect miracles when there’s little- or no direct sunlight striking the PV array.

    Another issue will be PV alignment. Flat mounted PV modules do well enough in the summer when the Sun is high and the cosine error is low. However, the combination of “short” days and low Sun will greatly reduce winter energy generation.

    The insolation link Bill provided is a good one. The same data is available from here: http://rredc.nrel.gov/solar/old_data/nsrdb/redbook/sum2/state.html My link isn’t better, but the downloads are shorter, and, being a creature of habit (both good and bad), I’m stuck with where I got started.

    Finally, your 1,000 Ah battery bank will give you some flexibility. It should be able to meet your energy needs for ~three days without too deep a discharge, and, if the Sun is still hiding, you’ll need to crank up the generator for a while.

    HTH,
    Jim / crewzer
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    Jim,

    At the risk of sounding Polly-Annish - solar power camping and utilizing my array and gear will put me even more in-tune with nature, in addition to better preserving her. I'm very excited about taking the solar power plunge.  I mean why stop at just camping and why not get a big Grid-tie set-up like Bill?  We'll be moving back East in a few years and will have the opportunity (read: cash from closing) to install/apply some AE while re-settling. Since we will already be living "off-grid" on our vacations, it will certainly be forefront in our minds.   

    Back to your advice about my rv set-up: Without some prudent power conservation I can see how there would not be enough hours of sunlight to float the batteries daily.  Actually we are already conservative so we should be able to adopt the staggered full charge cycle every other day that you outlined.  Maybe even every 2-3 days to get to 25% DoD.  However, I foresee that keeping my growing boy amused in this High Tech Age will be a growing power consumption item - loud music, video games, etc.  We try to keep him as grounded and close to nature as possible, (thus all the camping), but inevitably he will get bored with camping/roasting marshmellows. I built him a beautiful holiday Lionel Train set but already it can't compete with the more interactive/stimulating/challenging computer games and mostly just gathers dust.

    Some of his buddies already have the latest First Person Shooter games, Call to Duty2, etc.  Hell, even I like to get in a little trigger time once in awhile. Once he hits adolescence I imagine he won't want to trade off the HB surf and beach scene (read: Hot Bikinis) for a nature walk with Mom and Dad. We foresee him taking a buddy along camping, and further increasing power use. So I figure the system we have just designed will have enough depth to handle these future needs until our boy reaches 18 in 10 years. Then he's gotta get his own power, (and hopefully will be imbued with good conservation practices). Man is this getting OT or what?

    I would love to be able to tilt my panels. I keep imagining a rack with central pivots that would allow tilting the panels to either side of the rv. That would be cool. Even a shallow angle to keep them low wind profile for safe travel, would probably provide a significant increase. I am contacting a pro installer, a friend of a friend, to make sure this part is done correctly - but maybe we can improvise something more flexible than just pasting them onto the roof.

    Finally, one last question. This is the very last of the last questions! This one will really reveal my electrical theory ignorance. Since the Magnum MS 2012 is rated for 100Amp charging, and my generator is only rated at 29 Amps,110V AC, will it only charge at 29Amp 12VDC?  Can the Magnum make 100Amp 12VDC out of 29Amp 110VAC?

    As I mentioned to Bill the June gloom is lasting longer and longer into July down here in S California. And it is thicker too, sometimes never burning off along the coast. I used to live in Arlington and Falls Church and loved it there. Having lived in S California for almost 20 years, and SE Asia (Thailand) for about 12 years prior to that, I miss the woods, green trees, autumn colors Back East.  It won't be long until we will be moving back to my roots around Bucks County, PA. Just a few more years to go...

    Thanks again guys,

    Phil
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: RV Solar Power Set-up Advice Needed

    Shelldance Nursery over looks the valley to the south were I grew up for almost 30 years (first traffic light off of the freeway). It was a great place to grow up (hiking, riding motor cycles, fishing, etc.)... I used to help take care of the pasture/horses across the highway and repair fences on the ridge line (guy rented the property from the Daily City Ice company for horses and raised a few odds and ends of cattle). Used to be a Nike missile radar site at the top of the hills.

    HMB Airport taxiways are used for driver training for the local police/sheriffs deputies. They also used to run one of the fastest drag strips there on the west coast (again, on the taxiways).

    Now held there is the "Pacific Coast Dream Machines" show (canceled in 2006 due to rain turning the already unpaved areas of somewhat marshy land into near soup):

    http://www.miramarevents.com/dreammachines/

    To be honest, I have never gone because the traffic is terrible during that time (and the rest of my family is not really that interested in mechanical stuff--oh well).

    They have painted displaced thresholds (for noise abatement and to allow more development on the edges of the airport) on the runway (built in WWII at 5,000 ft with huge concrete pads at each end of the runway for carrier plane landing practice--not used much during the war except to launch tow planes with targets to train anti-aircraft crews up the coast. HMB used to be a weather alternate for SFO airport.

    Its a small world.

    Regarding the inverter/charger... Basically (ignoring efficiencies for the moment)... Power = Voltage * Current.... So 100 amps at 14 VDC charging would require 100a*14=1,400 watts = 120vac*xxA => xxA=11.67 amps of 120vac current.

    There are some other issues (Power Factor, typically 80% efficiency of power conversion => 11.67a/80%=14.6amps required for charging, how clean the generator wave form is, if the Inverter/Charger has a 120VAC pass through--UPS like function--how it manages sharing a limited amount of AC input power between the downstream AC load + Battery Charger load, etc.)... but without reading the manual, you certainly are in the ball park (might have issues running generator + 100amp charger + microwaving breakfast all at the same time--ideally the inverter/charger should back down on the charge current during heavy AC usage).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: RV Solar Power Set-up Advice Needed

    Phil,

    We sort-of cross paths again: I currently line in Vienna, VA, just a bit west and outside the 495 Beltway from Arlington and Falls Church.

    We had pretty good luck with keeping our sons occupied while camping. We took their bikes, canoes and kayaks, and they watched DVD’s on a laptop computer. There was indeed a period when they felt they were bored, but they developed their camping skills and are now in high demand by their camping-challenged friends. My younger son, who is legally blind but actually has “low vision”, earned his BSA Eagle rank and now helps lead young scouts on summer camping trips in Virginia (Goshen), New Mexico (Philmont), and Wyoming (Wind River Range).

    As Bill indicated, the Magnum’s charger will supply ~14.4 V x ~100 A = ~1,440 W. But, because the charger’s efficiency is ~85%, it’ll draw ~1,700 W from the generator. However, the generator is rated for 29 A x 110 VAC = ~3,200 W, so it should be able to handle the charger with no problem. Powering the charger and, say, the microwave from the generator at the same time might be an issue, though.

    Note that you’ll need a DC breaker (not an AC breaker) rated at 125 A 250 A continuous to put between the Magnum charger and the battery bank. Let us know if you’ve got that covered or if you need some assistance.

    Finally, there are several folks here who can help you plan your residential RE system, especially Bill. I’m designing an off-grid system for my next home, but it’ll be anywhere from eight months to a couple of years before I actually build it. Beyond the technical stuff, you’ll also want to look into local, state and federal incentives for such a project. Here’s a good place to start: http://www.dsireusa.org/

    I hear you’ve got a great weather forecast for this weekend – 77 F – enjoy! It’s supposed the be 8 F here tomorrow AM… Brrrrr!

    Regards,
    Jim / crewzer
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    Bill,

    I know exactly where you mean in Pacifica. I have photos of my wife and son on the gravel ridge road behind the uppermost Shelldance greenhouse with that valley and the hills beyond, behind them in the background to the South. I usually spend an hour or two there shooting photo macro shots of the orchids and enjoying the peace/tranquility of the place in general. We also make it a point to go down to Duartes in Pescadero Creek. This year we rode our bikes from the 1 entrance to Big Basin, up the Waddle Creek Canyon to Berry Falls. Very interesting shipwreck stories at Pigeon Point too. It must be a wonderfull place for a boy to explore and grow up.

    Jim, Scouting is great for boys. We parents here, including those rocket and satellite scientists, are nurturing a little core group of our boys to grow up together and hopefully provide positive peer support against some of the bad peer pressure influences in adolescence. We do the Scouting activities and camping, plus, we do our own group weekend camping, hiking boating, etc. Your son's achievement of Eagle Scout rank, particularly with his limited eyesight, is a high honor.  And it also reflects very favorably on you, Jim. You spent a lot of time over the years helping him get all of those merits badges! He has a huge responsibility guiding younger boys in the backcountry. You really have to know your stuff.  I backpack a couple of times a year n the Sierras and %$it happens out there all the time! (Did Mt. Whitney last summer).

    I have an older son (previous marriage) who is working his way through college. Coincidentally, to make some spending money he was tearing off a large shed roof yesterday in a very well-to-do area of Santa Barbara.  I've been advising him to talk to the owner about  installing a couple of PV modules on the finished roof, lowering her "Carbon" useage rate, maybe get my son some experience and sidework doing solar installations.

    With that recent U.N. report of 90% of scientists agreeing that man's activity has contributed to Global Warming, I'll bet AE issues and personal spending are about to see significant increase in interest. But you guys have been at this for much longer than me and I'm not saying anything new here!

    Time to go burn some calories isntead of writing about burning power!

    Thanks again you guys. If you ever need anything down this way give me a holler. I'll be monitoring this page too.

    Phil

  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: RV Solar Power Set-up Advice Needed

    Phil, niel;

    I deeply appreciate your compliments on my son's scouting accomplishments. You're right: It was a lot of work. However, he did most of the work, and he genuinely enjoyed the learning, the camaraderie and the mentoring. Kudos also go to his troop, as they had no hesitation about taking on a visually impaired child and help turn him into a young man who's now a sophomore at the University of Wyoming.

    Thanks, Gents!
    Jim / crewzer
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    Jim,

    I love hearing success stories like this. He must fill your heart with pride. Mine younger one is a Wolf Cub Scout. My older one is on the honor roll in his last year at UC Santa Barbara gong for an accounting degree, and has paid for it completely on his own, with the help of the Mongomery GI Bill.

    Well I have everything on order except for the batteries. We have a Honda 3500 contractor type generator. It's a reliable unit but a real screamer. I'll be replacing it with the Yamaha 2400is - unless my wife lets me get the Yamaha and keep the Honda around for home emergency use.

    The trailer should be built by April. A good look a the roof field, the compartments and the OEM wiring will give me an idea of the best installation layout - can't wait!

    Phil
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: RV Solar Power Set-up Advice Needed

    jim,
    others are probably wondering why you are thanking me too. i have to tell them i made my comments via a pm to you about it. you are very welcome.
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    Hello Again,

    I was just browsing John Wiles articles on PV installation safety, inspection and codes:

    http://www.nmsu.edu/~tdi/Photovoltaics/Codes-Stds/Codes-Stds.html

    So much more to absorb to ensure a safe and weather tight installation. I guess all of my grounding will be to the main ground stud on the trailer chassis.

    Does anyone know where I can get MC crimping tools? I viewed the instructional video at the Multi-Contact website but now can't find a retail source for these tools. The pre-made cables are pricey.

    Besides, I just wired my house with CAT5e and coax for a gigabit home media network doing all the crimping/connections myself, so I see a big chance here to expand my crimping tool collection!

    Phil
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: RV Solar Power Set-up Advice Needed

    Phil,

    John Wiles is a wealth of information… I think he’s generally referred to as theNEC Guru” of the PV industry.

    Just to make sure there’s no confusion, I’m not sure that I would consider the camper’s chassis to be “ground” unless it’s actually connected to a true ground, i.e., via the docking cable and power post or via a ground wire to a cold water pipe. In other words, unless the chassis itself is grounded, then it’s really just “common”. You’ll also need to look into if/how/where the camper’s 110 VAC neutrals are bonded to ground. A few things to consider when boondocking…

    See page 6 of the MS inverter’s user manual: http://www.magnumenergy.com/Literature/Manuals/Inverters/MS Manual (64-0007 12-04).pdf

    I’m afraid I can’t help you with the crimper…

    You’re right: Battery and inverter cables are expensive! I found the following on-line store offers fair prices on high-quality cables made from Cobra “X-Flex” wire. It really is very flexible heavy wire, which makes it fairly easy to work with during installation.

    See: http://www.solarpanelstore.com/solar-power.wire.html

    HTH,
    Jim / crewzer
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed


    Don't know if this will help, but I go to my local welding supply and
    buy welding lead (braided wire) available in different sizes and crimp
    type ends fairly reasonably priced.

    brad
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: RV Solar Power Set-up Advice Needed

    Doh! You can also make your own cables from the right kind/size wire and Blackburn mechanical connector lugs available at Home Depot. See page #66 of the following document: http://www-public.tnb.com/util/docs/CG_MC_Full.pdf

    HTH,
    Jim / crewzer
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    Those weld leads and the Blackburn connectors look very robust for battery and inverter cable connections. I'll be needing those and some buss bars, circuit breakers, GFCI breakers, A/C distribution box for the inverter, etc.

    My solar modules have the Multi-Contact (MC) connectors and I thought I'd get a neater and less expensive result if I could custom fit the wiring leads between the series rather getting pre-made leads and wiring. The MC connectore looks like the best, most weather-tight connection. Just got to find the parts and UL listed crimp tools to make them.

    It'll be a couple of months before I take delivery of the trailer so I've got plenty of time to gather this stuff in preparation - may be get some more ideas of the best way to install the PV modules on the trailer roof to withstand high winds and w/o causing the roof to leak like a sieve!
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: RV Solar Power Set-up Advice Needed

    I think that this is the web site for getting the MC tooling (and parts?)... It appears that they want you to take an online course before they will sell you the product:

    http://www.multi-contact-usa.com/certification/

    Others have suggested to just purchase male/female cables already made up and just cut them to length to terminate in your J-Box or where ever you need them:

    http://store.solar-electric.com/incaforsoelp.html

    I am sure that Wind-Sun can help you with your installation needs directly too.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    Bill,

    I would be able to use pre-made cables lengths if my array was all lined up side-by-side and I could plug them into one another and then cut the last couple that terminate in the J-box.  But, due to existing rv roof-top fixtures to work around,  I will probably have 3 pairs of modules, each at a different spot on my rv roof.  So I figured I'd need custom Lengths of cable to to get the pairs wired in parallel before terminating at the j-box. I guess it would be prudent to just wait to see exactly how I am going to lay things out.  One or two custom cables would probably be less than a set of the crimping tools.

    Phil
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: RV Solar Power Set-up Advice Needed

    Phil,

    Pre-made cables are typically not required to connect the PV modules to the combiner and controller. Assuming the KC-130 modules you ordered are each equipped with a “J-box”, there are several types of wires you can use.

    One type is "600 V UL-listed type MTW or THWN-2 or THHN or Gasoline and Oil Resistant II or AWM" (all of this mumbo-jumbo is printed on the wire insulation). It’s readily available from Home depot (and probably Lowes), where they likely refer to it as "THHN"

    Another solution is “tray-cable”. See: http://store.solar-electric.com/10-2-tc.html and http://store.solar-electric.com/8-2-tc.html

    Here’s a link to Kyocera’s installation manual: http://www.kyocerasolar.com/pdf/specsheets/Kyocerainstall.pdf

    A common wiring route from the roof to the interior of the camper is via the roof vent for the fridge. The Kirkby’s “RVer’s Guide to Solar Battery Charging" is a bit dated technically, but it might be useful for planning your installation. See: http://www.rvsolarelectric.com/books.htm

    You’ll need a way to electrically combine the two- or three sets of sub-arrays before connecting to the controller. A suggested solution is the Midnite Solar MNPV-3 with three 10 A DC breakers. See: http://www.midnitesolar.com/

    You’re also going to need a way to safely integrate the wiring and breakers for the controller, the inverter, the batteries, and the main AC inputs and outputs. Again, Midnite Solar offers several “all-in-one” solutions. See: http://www.midnitesolar.com/MidNite-Products.html

    The AC breaker panel may be pretty easy and cheap. Take a look a small Square-D breaker panels and their QO breakers at Home Depot.

    Designing a solution to mounting the PV modules to the roof of your camper might take some work. In my case, I had Yakima cross-bars installed on the roof of my camper, and then I used aluminum angle as intermediate carriers between the modules and the cross-bars. I really liked this approach because it allowed for cooling air to circulate under the modules.

    HTH,
    Jim / crewzer
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    Hi Jim,

    I agree the frame style modular mounts seems to be the most solid. My KC130 modules do not have j-boxes and are pre-wired with the MC connectors with leads long enought to inter-wire them if they were installed side-by-side. The more I think about the 3 DC breaker box for the PV series interrconnect, the more I like it. The E-boxes sure are nice too... In the end the E-box may be the way to go to save space an dmoney buying individual components, specially the DC breakers. Gott run.

    Phil
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    A little update...

    I have a Midnite Solar Mini DC breaker box with 3 each 15A DC breakers to combine my PV input (3 pairs of 2 KC130's), another 175A DC Breaker for between the inverter and battery bank and a 63A breaker for the MX60. I'm also getting a lightning arrestor for the DC side of things. There's a lot of afternoon lightning up in the Sierras in the summer. I don't think an arrestor would help with a direct hit on the PV's but hopefully it will help limit surges when things get close and charged up with all that exposed wire and panels on the rv roof. Anyone have any ideas about lightning arrestors on an rv?

    Phil

    P.S. Yamaha 2400 is on it's way too! I am a mad gear junkie.
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: RV Solar Power Set-up Advice Needed

    Phil,

    I like the Midnite Solar breaker boxes. The 15 A breakers for the PV subarrays sound good (assuming two modules in series per breaker), and the 63 A breaker sounds OK for your application of the MX60.

    Magnum’s input spec for the 2012 inverter is 190 ADC (full output power from a “low” battery voltage), so, assuming a 100% continuous duty rating, the typical breaker spec would be 190 ADC x 125% = 238 A. The closest size is 250 A – a tad larger than the 175 A breaker you’ve spec’d. You may want to reconsider... However, if you're using "small" cable from the batteries to the inverter, a 175 A breaker may be appropriate, but this configuration will likely limit full power operation.

    See: http://www.magnumenergy.com/Literature/Data%20Sheets/Inverters/MS_series_mobile_data_sheet_revc.pdf
    and: http://www.magnumenergy.com/Literature/Manuals/Inverters/MS Manual (64-0007 12-04).pdf   (page 17)

    Surge/lightning arrestors need a good ground in order to be effective. If you decide to add one, you’ll also need to address the grounding issue we discussed earlier.

    Sounds like your making progress!

    Regards,
    Jim / crewzer
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    Hi Jim,

    Thanks for that! I'll make sure a 250ADC breaker goes in. I guess the only ground in the rv that we'll have the chassis ground. Hopefully, if anything, the arrestor will impede surges to a certain degree.

    Can't wait to install everything and put it through it's paces.

    Phil
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    I wonder if I can bother you all with one last question...

    Now that I have an inverter/charger, what should I do with the existing rv AC converter/charger and it's attached DC load in my trailer?

    Do I just disconnect the converter and re-connect the DC load after the 12 volt battery 250 ADC breaker, (where the inverter DC input is connected)?  I figure the Magnum charger, rated at 100Amps, can supply plenty of DC power. 

    However, I'm not sure if that is the optimum set-up. For example, can the converter be set up when AC is present to "strand alone" to handle all the DC loads w/o tapping the batteries and w/o interrupting the Magnum's charging output/battery charging?

    I know this question exposes my complete lack of understanding. I have an idea but I can't be sure.

    Phil

    I think I found the answer please allow me to think out loud and correct me if I am wrong:  Converter/chargers are designed to work best handling DC loads in tandem with a battery. The Magnum DC Inverter/Charger will supply the DC loads the same way that the AC Converter/Charger would. Since the Magnum is far more programmable/safer, plus, delivers more amperage... The AC converter/charger is redundant and would only rob the Magnum of a certain degree of AC power and reduce it's ability to operate at full output. Plus the AC converter/charger "boost" charges at a higher voltage (14.4) than is recommended for AGM's and, unlike the Magnum, does not have any temp sensor/comepensation.

    Eventually I'll probably remove all of the this solar power and inverter componenets to restore the rv electrical system to it's stock/OEM state before selling the trailer. Otherwise I'd ebay the converter/charger, (Progressive 9280 with built-in Charge Wizard).
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: RV Solar Power Set-up Advice Needed

    Phil...

    I think you got it!

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    I thought I had it all figured out...but... Can I ask just one more last question?

    I will be getting 4 ea, 4D size AGM's (MK's) for "house" use and am considering two Group 27 size AGM's for chassis use. The Group 27's will be about 8 feet away from the bank of 4D's. Combined, I would have 1,000 Amp Hours.

    But, can I parallel the Group 27's in with the 4D's when charging them and using them? Or, will the Group 27's drag the 4D's down or cause premature failure, etc?

    Alternatively, should I use one of those boat battery selector/isolator switches?

    What is the best way to configure this that optimizes and protects both banks?
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: RV Solar Power Set-up Advice Needed
    "...considering two Group 27 size AGM's for chassis use."

    I'm not sure I understand what you mean by "chassis use" in an RV trailer... Typically, all of the trailer batteries are connected together and considered the "house bank". Some RV's (i.e., class A's) have separate battery banks for "house" and "chassis" applications. The "chassis" batteries are use for engine starting and the usual automotive loads.

    More later,
    Jim / crewzer
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    Hi Jim,

    I'm stuck for space and can only fit the 4 ea. 4D's (800Amp Hours) in one compartment, but still have room for two more group 27's (200 Amp Hours) in the normal battery compartment.

    It'd be great if I could just combine their use and charging but I am not sure that is possible. Alternatively, I was thinking about isolating them and using them for the trailer emergency brake and for powering my hydraulic leveling and slide-out system.

    Therefore, in case something happens to the main bank, I'd still have the "emergency power" to pull-up stakes and move out.

    Phil

Sign In or Register to comment.