Thread: Inverter + wire length = what size wire?

  1. #1
    Join Date
    Mar 2010
    Location
    Dickinson, Texas
    Posts
    10

    Default Inverter + wire length = what size wire?

    I have a 1000 watt inverter I want to install either under the seat or In the center console of my suburban, what size wire should I use? Is there a length/gauge formula?
    Last edited by Jay2mann; 03-12-2010 at 06:16 AM. Reason: had a brainfart while choosing words

  2. #2
    Join Date
    Jan 2008
    Location
    Los Angeles, CA
    Posts
    103
    Quote Originally Posted by Jay2mann View Post
    I have a 1000 watt inverter I want to install either under the seat or In the center console of my suburban, what size wire should I use? Is there a length/gauge formula?
    The manufacturer of your inverter should be able to provide you with specifics for your unit - they probably have a website or customer service number to get that information.

    My experience with higher power inverters (1000-4000 watt) is the power / ground wires should be no longer than 6 feet long, and preferably 3 feet or less. You should use the largest gauge that will fit the connectors on the inverter - likely 4 gauge cable, or 2 gauge if you run a longer cable. Additionally, most inverter manufacturers recommend multiple batteries to support the load required by the inverter - otherwise, you can expect reduced performance from the unit.
    Not all who wander are lost

    W6LPB / WPOK492


  3. #3
    Join Date
    Sep 2009
    Location
    Australia
    Posts
    116
    Quote Originally Posted by Jay2mann View Post
    I have a 1000 watt inverter I want to install either under the seat or In the center console of my suburban, what size wire should I use? Is there a length/gauge formula?
    VOTLAGE DROP =
    [cable length (in metres) X current (in amps) X 0.017] divided by cable cross-section in mm.sq.

    Plan for a voltage drop of less than 0.5V at maximum load.
    You must add the +ve cable length and the -ve length together.

    Cheers,
    Peter
    ......................Enjoy.....................
    OKA196, 4x4, DIY, self-contained motorhome. http://www.oka4wd.com/xt196.htm

  4. #4
    Join Date
    May 2007
    Location
    Hamilton, Ontario Canada
    Posts
    834
    I installed a 1kw inverter in my work truck 3 years ago and regularly use it with loads approaching 800 watts for short periods of time. The manufacturer specified #4 welding cable whose length shouldn't exceed 5 feet and a 150 amp fuse for protection.I had to mount the unit a little farther away so I increased the wire size to 2/0 welding cable.This limited my voltage drop to within spec and the unit works fine.The wire, fuse and holder cost more than the inverter which is a Xantrex unit I purchased on sale.
    Oh, and I only run the inverter when the engine is running because a 100 amp draw out of the battery would kill it in no time flat.
    Last edited by 762X39; 03-12-2010 at 10:04 AM.
    John H.
    1970 Mercedes Unimog
    2004 F150 Heritage Supercab
    1974 Holiday 17' Travel Trailer
    It's not about the truck and it is not about the distance traveled. Get out there with whatever you have, meet people and see things. Push the envelope of your comfort zone and live.

  5. #5
    Join Date
    Mar 2010
    Location
    Dickinson, Texas
    Posts
    10
    I should have signed up years ago, you people know your stuff. I need to go estimate wire length, I at least need to get it inside the cab...Thanks

  6. #6
    Join Date
    Jul 2009
    Location
    Montana
    Posts
    1,354
    Quote Originally Posted by cruiserlarry View Post
    The manufacturer of your inverter should be able to provide you with specifics for your unit - they probably have a website or customer service number to get that information.

    My experience with higher power inverters (1000-4000 watt) is the power / ground wires should be no longer than 6 feet long, and preferably 3 feet or less. You should use the largest gauge that will fit the connectors on the inverter - likely 4 gauge cable, or 2 gauge if you run a longer cable. Additionally, most inverter manufacturers recommend multiple batteries to support the load required by the inverter - otherwise, you can expect reduced performance from the unit.
    The shorter the better, and the bigger the better.

    In particular, page 6 of this: http://www.marinco.com/files/media/g...ech%20data.pdf

  7. #7
    Is it absolutely necessary to have the inverter inside the cab? DC power requires some heavy cable to carry the amperage, but if you mount the inverter in the engine compartment near the battery and use run an extension cord on the output, you can get away with much smaller wires. Going from 12V to 120V cuts your current by 10 fold. Just an idea.

  8. #8
    Join Date
    Feb 2009
    Location
    Austin, Tx
    Posts
    329
    Here is a simple calculator I use for doing VD on site lighting. The red is user entry fields, blue is calculated. VA is your load, the rest is self explanatory. Just put in single run length, the formula already calcs the return run. I forget what percentage I shot for on my truck but I think it was around 1%. There is an online VD calculator too somewhere. If the MFG is saying a certain footage of a certain gauge wire, just reverse engineer what their VD specs are using a 8.3A(1000W @ 120V) load and go from there.
    Attached Files Attached Files
    Last edited by TreeTopFlyer; 03-12-2010 at 05:48 PM.
    KE5ZSJ
    2012 JKUR - The Build Begins -
    2001 7.3 Excursion - Sold -

  9. #9
    Join Date
    Mar 2010
    Location
    Dickinson, Texas
    Posts
    10
    I dont think the high underhood temps are going to do it any good, Its a Aims power pure sin wave inverter 1000watts output, The previous owner had it inside a commercial truck and now that I think about it it wasnt far from the outside battery box. Looking at the web site it says over 10 feet use 1/0 wire that is $10 per foot. its 12" x 16" x 6" tall.

  10. #10
    Join Date
    Mar 2010
    Location
    Dickinson, Texas
    Posts
    10
    reading on... it says 131 max operating temperature, If the ambient temp here is 100, under the hood it not going to do much good.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •