New RV System

CRMW
CRMW Registered Users Posts: 7
I have been collecting parts for a new solar system for my fifth wheel trailer for the last couple of months. So far, I have:

3 Sharp 123UJF watt panels
4 6v golf cart batteries
2 12v deep cycle batteries
Sunsaver Duo with temp probe
Magnum MS2012 Inverter
2 trimetric Meters

I'm planning using the sunsaver duo to charge 2 different battery banks, one using the 12v's & the other using the 6v's. I will probally end up getting a Morningstar Sure Sine inverter for the light loads.

I'm thinking 10 gauge from the panels to a roof mounted combiner box, then 4 gauge to the Sunsaver and on to each battery bank.

My question of the day is about fuses & disconnects on the DC system. Where do I need them and what do you recommend for brands and sizes etc. Any other tips would helps as well as I'm planning on starting the install this weekend.

Thanks,

Chris

Comments

  • CRMW
    CRMW Registered Users Posts: 7
    Re: New RV System

    Here is some more info that I picked up from other non-solar boards.

    I am planning on running 10 gauge from the panels to a combiner box (~5') and 4 gauge from the box to the Sunsaver Duo (~20'). I will run 4 gauge from the charge controller to the 12 v bank (6') and 4 gauge to a bus bar for the 6v bank (3'). From the bus bar, I'm thinking about 2/0 from to the Inverter (3') and to the 6v bank (~3'). A 300amp fuse should suffice to the 6v bank and a 30 amp on the leg to the 12v bank.

    Any comments or suggestions will be appreciated.

    Chris
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: New RV System

    Here's a great writeup on how to properly wire your battery bank (diagonally)
    http://www.smartgauge.co.uk/batt_con.html

    I don't know that I understand enough about how you are mixing 6V & 12V batteries to give any advice. Maybe you could make a sketch, scan it, and post it, showing what's what. We have the model #'s from your earlier posts, but If you could include in the sketch the Volt & Amp spec for the components that would save everyone else that has not memorized every PV panel voltage/amp the tedium of looking all that stuff up.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: New RV System

    Chris,

    I think there are a few issues to review before you buy and install the system.

    One issue is to check the manufacturer’s recommended absorption mode charging voltage for the 6 V (“golf cart”; GC2?) batteries. For example, Trojan recommends 7.4 V (at 80 F) for their 6 V GC batteries, or 14.8 V for 12 V applications. US battery recommends 7.75 V for their 6 V GC batteries, or 15.5 V for a 12 V battery.

    See: http://www.trojanbattery.com/Tech-Support/BatteryMaintenance.aspx
    And: http://www.usbattery.com/usb_faqs.html

    The Sunsaver Duo flooded-cell battery charging voltage setting is 14.4 V (at 77 F). This is appropriate for 12 V deep-cycle batteries from Wal-Mart and Interstate, but it’s too low for the big GC2 batteries. The result will be that the GC batteries will slowly loose capacity, and their useful life span will suffer.

    See: http://www.morningstarcorp.com/products/SunSaverDuo/info/SSD_DataSheet.pdf

    A further complication is that the Sunsaver’s EQ voltage setting is just 14.8 V, which is too low for GC2 batteries. 15.5 V is typically required.

    Another issue is the use of #4 wire. The Sunsaver’s terminals are rated and sized for #6 wire.

    I like Morningstar products. However, it’s my view that the voltage settings of some of their smaller controllers are too low for “true” deep-cycle flooded-cell lead-acid batteries like such as the GC2. Their Tristar model is a much more versatile PWM controller, and it offers the appropriate voltage settings via its selector switches or via user programming using a PC.

    See: http://www.morningstarcorp.com/products/TriStar/info/TS_DataSheet.pdf
    And: http://www.morningstarcorp.com/products/TriStar/info/TS_Manual.pdf

    Finally, the #4 wire may be overkill for your application. Large wire reduces voltage drop, but as long as the array can deliver sufficient voltage to push the batteries to their target voltage setting and overcome the voltage drop in the wiring, then the amount of the drop doesn’t really matter.

    The Sharp 123's 17.2 Vmp STC spec should be fine for charging the RV batteries via a PWM controller and #10 and #6 wire. I used to charge camper batteries to 14.4 V from panels rated at 16.8 Vmp, a Morningstar ProStar 30M controller, and a combination of #10 and #8 wire, even while camping in the West in the summer.

    See: http://solar.sharpusa.com/files/sol_dow_123UJF.pdf

    HTH,
    Jim / crewzer
  • CRMW
    CRMW Registered Users Posts: 7
    Re: New RV System

    Wow, thanks for all the info Jim. I saw Mike90045's post yesterday and I was going to start to post the data and links etc. when I saw your post. As Mike90045 mentioned it must be a pain to keep looking the info up whenever a newby comes by. Mike the link you posted was informative, I was aware of the second method but not the third for wiring batteries.

    I made these purchases based on information from various RV forums before I found this forum. I would have done things a little differently if I came here first, but as the saying goes, hind site is 20/20.
    It looks like I will be able to adjust the Sunsaver Duo's set points using a PC MeterBus Adapter.
    http://support.morningstarcorp.com/item.cfm?ItemId=105
    If I can get the charging level up, do you see a problem staying with the Sunsaver Duo? If it will work, and I can find the Meterbus Adapter and it isn't cost prohibitive, I would prefer to stick with the Duo to keep both banks charged and keep the costs down.

    I bought the 6v gc batteries from a local battery supplier, after I found out about the requirement for multistage charging, i went back and talked to them. I got some blank looks and the they agreed with the Trojan spec's as I had a copy with me. I'll try them again and see if I can't get a hold of someone with a little more knowledge.

    I have the #4 wire here, do you see a problem with a little trimming to get it to fit into the Sunsaver Duo? I will replace it if necessary, however I would prefer to spend the money on the Morning SureSine Inverter.

    Thanks again.

    Chris
  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: New RV System

    Chris,

    Thanks for the link to the updated MSview software. My older version did not support the SunSaver Duo. The customization feature should allow the SS Duo to work satisfactorily for your application. :cool:

    I can't recommend clipping off a couple of strands from the #4 to skinny it down, but I have to admit that I've done the same on occasion. :roll:

    Best of luck to you, and I apologize for sending you on a bit of a wild goose chase. :blush:

    Jim / crewzer