Battery to house, fuse size?

Discussion in 'Wiring' started by Vance, Aug 8, 2017.

  1. Vance

    Vance New Member

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    Jul 2, 2016
    League City Tx.
    I want to replace some of the old cracked and corroded wires. Looking at my battery set up I have a 10ga. red wire on Positive side, that leads to house inverter. It has an inline fuse holder on it that needs replaced. What size should this fuse be? I am currently using a 25 amp fuse but not sure if its correct. I would like to change it out to a resettable breaker. How do i find the amp rating for this location?
    Camper is an 2007 fleetwood popup, dual 12v batt.
     
    Last edited: Aug 12, 2017
  2. tfischer

    tfischer Well-Known Member

    By "house inverter" do you mean your camper's converter?

    Mine has a 30A fuse, which 10 gauge wire supports. Not sure it's worth putting in a breaker here, you should rarely, if ever, be blowing that fuse, and throwing in a few spares will be a lot easier and cheaper.
     
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  3. Vance

    Vance New Member

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    Jul 2, 2016
    League City Tx.
    Yes converter. Then I shall rewire in a new fuse holder with a 30A fuse.
    Thank you.
     
  4. f5moab

    f5moab Retired from the Federal Government

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    What's the converter rated for?
     
  5. Customer

    Customer Well-Known Member

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    Jun 5, 2014
    Tell us brand and model of converter together with the wire gauge and we can tell you the fuse size.
     
  6. Vance

    Vance New Member

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    Jul 2, 2016
    League City Tx.
    World friendship co.
    WF-8945AN W-plastic
    Wire is 10ga.
     
  7. f5moab

    f5moab Retired from the Federal Government

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    45A converter with that wire size you could do a 40 AMP fuse. That's a powerful converter for a popup trailer.
     
  8. mstrbill

    mstrbill Active Member

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    Mar 17, 2013
    Austin , Texas
  9. Customer

    Customer Well-Known Member

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    Ten gauge would be 30 amp but that converter has a maximum of 45 amps output which will burn a 30 amp fuse. I'm guessing someone replaced the original converter without upgrading the wire as they should.
     
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  10. Boatnman

    Boatnman Active Member

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    Jan 19, 2017
    western Colorado
    The Parts Books for most of the 2005 series indicate a 25 amp converter as standard - the Highlander series and the Scorpion model had a 35 amp converter as standard. So, as Customer said, the converter was probably upgraded.
     
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  11. Vance

    Vance New Member

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    Jul 2, 2016
    League City Tx.
    Thanks friends. On a side note, what's the advice leaving shore power connected to this converter to float charge the batts while in storage?
     
  12. Snow

    Snow Well-Known Member

    8,369
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    Jul 19, 2007
    Ontario
    According to the specs for the converter it has a 3 stage charger, so shouldn't be an issue with maintaining the battery charge.. Only issue I see is that with the pup closed up, there might be an excessive amount of heat build up inside due to the converter being powered.. But as long as you don't pile things up in front of it and it has some airflow, it too should be alright..
     
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  13. f5moab

    f5moab Retired from the Federal Government

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    Eastern Idaho
    Should be no problem, but nice to check it to make sure it is functioning in the 3-stages as required. For this converter, it does have a 13.2 V float mode. After plugging in, it will take about 48 hours to drop down from the normal 13.6 V range. If the batteries are quite low it will go up to a 14.4V charge mode.

    I leave mine plugged in during the camping season (spring to summer) and have had no problems. However, I do on occasion check to make sure after a few days of initial plug in, with no drains, the converter does drop down to the 13.2 V float mode.

    During the winter months, the batteries are in the garage on a battery minder.

    It should be in the manual, if you don't have one, here is a link to the series 8900 converters...
    http://wfcoelectronics.com/wp-content/uploads/2017/01/8900-Operators-Manual.pdf
     
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  14. rabird

    rabird Howdy!

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    How often does the 25A fuse burn out? if ever :wink:

    10g wire 30A or smaller fuse.
     
  15. Vance

    Vance New Member

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    Jul 2, 2016
    League City Tx.
    Fantastic, thanks for the manual.
     
  16. f5moab

    f5moab Retired from the Federal Government

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    May 7, 2013
    Eastern Idaho
  17. rabird

    rabird Howdy!

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    does OK consider voltage drop?
     
  18. Vance

    Vance New Member

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    Jul 2, 2016
    League City Tx.
    I haven't had a fuse blow out since I bought it, however changing the plastic battery boxes to a power armor box, I noticed a few 10a fuses in the bottom of the box. That's what prompted me to investigate the fuse rating of the converter. Other than the lights their is only a few electric things- radio, microwave, water pump, fridge is tri power, co2 detector and not sure if the heater uses power at the t stat.
     
    Last edited: Aug 12, 2017
  19. rabird

    rabird Howdy!

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    Mar 3, 2006
    TX
    The fuse works both ways, converter amps charge when ya got utility power and loads draw on the battery without utility power.
    Typical fuse at source or change (smaller) in wire size but as above it goes both ways since both 'charger' and batt can be the source!

    Ideally you would upgrade the converter to battery wire to 8g or larger for your 45A 'charger' (50A fuse) but as you've witnessed, you likely won't ever see that much battery charge and your 25A fuse has been enough. That doesn't mean that someday your battery is deeply discharged and the converter will want to to put out its rated voltage/current or you add more battery capacity that can accept more current.

    micro is a 120v item, the rest if all turned on (not the fridge) won't exceed 15A or so. Furnace fan 4A or so.
     

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