QUESTION: I'm stuck on an Install in Sprinter based, class c motorhome

outwestbound
outwestbound Registered Users Posts: 38 ✭✭
edited May 2018 in Caravan, Recreational Vehicle, and Marine Power Systems #1
Hi folks. 

I have a MAJOR space constraint on an install of my inverter into a 23' class c motorhome. My 2,000 watt Samlex SSW 2000 watt inverter is 9.5 feet from a 260 amp hour battery bank. It's very tight and space constrained at the battery bank, which is in the "stair well" of the motorhome. I'm looking at connecting the inverter with 4/0 cable. 

To minimize cable length, etc., can I attach the T class fuse directly to the positive battery bank terminal? This would reduce cuts in the cable and reduce the cable's length. Cost isn't a factor, just space. The battery compartment is very well contained/ secured in the motorhome's stairwell. 

Edit: Samlex sells this. Will this be ok to use? https://www.amazon.com/Samlex-Solar-DC-FA-300-Fuse-Assembly/dp/B005ELATP6

My experience is limited, but I've only seen the larger 2" X 7" type T class fuse holders. 

Thoughts? 

Thanks so much!
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Comments

  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #2
    If it's a Samlex product it most likely is of reasonable quality, better something than nothing, a disconnect would be nice but understandable, space constraints limit options.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #3
    That fuse holder and the "Buss" brand fuses are good quality and a good product to use in tight locations.

    You still want (if you can find the space somewhere to install) a DC disconnect to make it easier to shut off the inverter when RV is in storage and when servicing the inverter. Here are some typical marine switches.

    https://www.solar-electric.com/catalogsearch/result/?q=battery+switch

    Mini Blue Sea Battery Switch 1-2-OFF 300 Amp

    Blue Sea Systems On-Off Battery Switch 9003e Rated 350 Amps

    And some other options:

    https://www.amazon.com/Volt-Battery-Disconnect-Kill-Switch/dp/B007O0BBFM
    https://www.amazon.com/battery-power-switch/s?ie=UTF8&page=1&rh=i:aps,k:battery power switch
    https://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias=aps&field-keywords=battery+post+power+switch&rh=i:aps,k:battery+post+power+switch

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #4
    FWIW, the Bluesea version is apparently AYBC kosher for main DC fusing on boats, presumably the Samlex version is as well.
    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
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #5
    It looks like both (Bluesea and Samlex) use the same fuse from Bussman (class/mfg).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • outwestbound
    outwestbound Registered Users Posts: 38 ✭✭
    #6
    Thanks guys. I'm happy with the one I linked to that may be installed onto the battery threaded terminal. Bill, I have a disconnect as you suggested, and will try to fit it into the battery box, but if I can't, I may have to forego this and just pull the terminals off to kill power to the inverter. My big concern is being so far from the batter bank with the inverter (about 9.5 feet one way), so less may be more. 
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #7
    You have fused protection in the battery box.

    You can put the disconnect anywhere else in the wire run.

    What awg cable are you using (voltage drop)?

    Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #8
    I think it was 4/0 in an earlier post. Presumably really is 4/0 (thumb sized), not 4ga (much smaller). Hopefully the 9' run doesn't include sharp bends.

    When I installed my cabin system, I ordered and was charged for 4ga, but was drop shipped 4/0! I'll find a use for it.
    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
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  • outwestbound
    outwestbound Registered Users Posts: 38 ✭✭
    #9
    BB. said:
    You have fused protection in the battery box.

    You can put the disconnect anywhere else in the wire run.

    What awg cable are you using (voltage drop)?

    Bill
    Thanks Bill. I'll put the blue sea disconnect by the inverter where I have room. 

    I'm thinking I'll use 4/0. On a tape measure, the two locations are 7' apart, so I figure 3 feet of turns, drop into the batt compartment, etc., so 10-11 feet. I don't like this distance, but have to accept the constraint. Is 4/0 enough, or should I consider doubling up something smaller? I'd like no greater than 2%, but typically look for 1%. MIght have to live with some inefficiency on this system. 

    I have one LG 300 watt mono panel (about 32 volts, 9. 5 amps or so) with just a 6' run to a BlueSky 3000i MPPT controller using #8 wire. #8 just 4 more feet to the batt bank - 2 crown 6CRV260 6v AGM in series, for 130 AH useable. Tri metric 2030 meter. Wanted a magnum inverter, but the samlex's form factor fit, so I got it, plus a display. Got an average quality converter/charger in the class c vehicle, plus 150amp Bosch alternator with a feed to the batt bank. I also carry a NOCO G15000 15amp charger to use when AC power sources are questionable, rather than running AC through my coach's power service. Using the NOCO portable charger and then living off the inverter is much safer, given the poor quality of AC down there. I also have a 110-120/220-240 transformer. 

    This is a little system, but flexible in charging methods, on a campervan going to South America for a year long trip. 

     
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #10
    Per calculator.net, voltage drop at 12v 166a for 4/0 over 10' is ~1.5%
    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
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #11
    What is the reason you are looking at class T fuse ?  Check the terminal mount   MRBF fuse blocks

    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
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  • outwestbound
    outwestbound Registered Users Posts: 38 ✭✭
    #12
    Thanks for all your help guys. I'm good. 

    Estragon, that drop is ok; between 1-2 works. 

    Mike95490, yes, I'm going with the fuse screwed right onto the battery terminal. Thanks
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