boondocking musicians want to go solar in RV

GypsyStewGypsyStew Registered Users Posts: 2
We are traveling musicians living full-time in our '94 Monaco 38' diesel pusher. We rarely utilize shore power for extended periods of time.  That means a lot of generator usage (about 3 hrs/day).  We want to install solar charging capabilities but are new to the whole field and don't know what we don't know.  Looking for some guidance about who to ask, where to source, how much we need, etc.   We have a 315 amp-hr (3) 12v battery array but hope to eventually move to (4) T105 6v golf cart batteries which would give us 440 ah.  I am installing a Samlex EVO 2212 inverter since my 22 yr old Freedom 20 died. I will also install a Trimetric TM 2030RV battery monitor.  Now it gets murky (for me anyway).  How big should the system be?  One source suggested 600w of panels would be appropriate. Should they be PWM 12v (in which case should I choose Trimetric's sc-2030 solar charger?) or MPPT technology? Cost is a factor but long term value will trump lowest initial cost.  Other factors are - we are based around Los Angeles during the winter months then travel throughout the country during the summer so no cold weather operations and we don't need to support microwave usage or other hi power consumers (we have an LED tv, Playstation 3 for dvds/games and a Mifi for internet data, we keep 2 smartphones and 2 laptops charged).  Comments in not-to-technical detail are greatly appreciated. Any ideas on brands and/or sourcing that could save some $$'s?

Comments

  • littleharbor2littleharbor2 Solar Expert Posts: 1,436 ✭✭✭✭
    Couple things, Depending on how much available space you have on the roof and what your power usage is you can absolutely SUPPLIMENT your needs with solar. It's not easy to completely run a class A RV on solar without knowing what your loads are, conserving whenever possible and having a well designed system. Definitely MPPT and larger grid tie type panels, they are much cheaper than 12 volt panels. Check Craigslist there's some pretty good deals on solar panels in your area lately.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • EstragonEstragon Registered Users Posts: 4,177 ✭✭✭✭✭
    Generally speaking folks around here consider around 600w of panel to be the point where it might make sense to go Mppt. You'd want to check local panel prices to see if savings on panel offset higher cost contoller. The more expensive controllers also offer a number of extra features which may or may not be useful.

    600w sounds ok for 4xGC, although if you have space you might want also consider L16 size 6v for ~370ah. That would avoid having parallel strings, which although common and can work fine, can cause problems.

    You may find the output of the panels is considerably less than 600w in your mobile application as it's hard to get panels oriented and tilted properly and unshaded most of the day. A good approach mught be to run the genny for an hour or so in the morning if the bank needs charged and solar output may not be able to charge to acceptable levels. This saves genny fuel and noise while still keeping your batteries happy.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • westbranchwestbranch Solar Expert Posts: 5,163 ✭✭✭✭
    first  off: LOADS, go to flea bay or amazon and get a Kill-a-Watt meter for all the AC items.
    Just put it in the outlet and then the regular plug into it, great little starter tool...
    I am having a tough time coming up with a good low cost battery monitoring device that could give you some of the tool set you would get if you had a Classic MPPT CC...    I had (have) a Xantrex Batt\Mon that looks very much like a Victron monitor.. a bit pricy for a small system.
    Consider a Clamp meter for any DC loads that have a positive and neg line that is not joined together as you measure only one of the lines, 2 cancel each out each other...  Bill posts about A Sears model frequently..

    Read some of the recent threads that are on busses and trailers, lots of ideas and issue to look into.

    hth
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • BB.BB. Super Moderators, Administrators Posts: 29,698 admin
    This DC Current clamp meter (really AC/DC clamp+DMM) is not expensive and "good enough" for our needs:

    http://www.sears.com/craftsman-digital-clamp-on-ammeter/p-03482369000P

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PhotowhitPhotowhit Solar Expert Posts: 5,022 ✭✭✭✭
    I would agree with most of what has been said here, MPPT primarily due to your limited space, it will allow for slightly higher production, but suspect you may decide to increase the wattage at some point and have limited roof space.

    Do you also charge your battery bank while the RV is running?
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • GypsyStewGypsyStew Registered Users Posts: 2
    Thanks for the comments.  i'm getting a much clearer picture of what I need to do next.  No, coach batteries do not charge during driving unless the generator is on, which is our usual practice.  That also enables A/C for the hot drives. 
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