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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: christopher on April 04, 2010, 01:31:16 PM

Title: welding wire for an invertor
Post by: christopher on April 04, 2010, 01:31:16 PM
is it ok to use #4 welding wire for an 800-1000 watt invertor? the battery will be 8' away
grainger has it for $40.00 for 25'
thanks
chris
mci5c
Title: Re: welding wire for an invertor
Post by: bevans6 on April 04, 2010, 01:56:33 PM
I would personally use it, I've been using it to wire my race cars for many years, so I will be interested to see what the experts say.

Brian
Title: Re: welding wire for an invertor
Post by: Lin on April 04, 2010, 02:01:09 PM
Here is a chart that should help.  In short, if the inverter is 12vdc and its surge capacity is no more than 1000, #4 seems to be okay.  If the surge is between 1100 and 1500, you will need #2 wire.  Size according to the highest possible output.  What size fuse does the manufacturer recommend?  This is not an expert opinion. 

http://www.solar-electric.com/solar_inverters/inverters_for_solar_electric.htm (http://www.solar-electric.com/solar_inverters/inverters_for_solar_electric.htm)
Title: Re: welding wire for an invertor
Post by: christopher on April 04, 2010, 03:08:42 PM
good question,
what size fuse should i use?
the tv is 700 watts and the dvd player is 140 watts.
do i even nedd a fuse as is there not one built into the invertor?
Thanks
Chris
mci5c
Title: Re: welding wire for an invertor
Post by: Stormcloud on April 04, 2010, 05:53:01 PM
Its a real good idea to fuse the 12 volt circuit side of your inverter. It will protect the battery and YOU if you happen to be in the vicinity.

A blown fuse is an inconvenience; a blown battery can be deadly.

JMHO

Mark
Title: Re: welding wire for an invertor
Post by: Sean on April 04, 2010, 08:55:25 PM
Quote from: christopher on April 04, 2010, 01:31:16 PM
is it ok to use #4 welding wire for an 800-1000 watt invertor? the battery will be 8' away

Not really.

1,000 watts is 83.3 amps at 12 volts, and #4 is just under that capacity at most rating temperatures.  A bigger issue, though, is that an 8' cable run of #4 carrying that amount of current will have a voltage drop of 3.1%, considered unacceptable by most standards.

Use a minimum of #2 for this capacity.

Quote from: christopher on April 04, 2010, 03:08:42 PM
what size fuse should i use?
the tv is 700 watts and the dvd player is 140 watts.
do i even nedd a fuse as is there not one built into the invertor?

Yes, you need a fuse.  A fuse (if any) built into the inverter is to protect only the inverter.  You need a fuse at the battery end of the cable to protect everything else -- a wrench or screwdriver being used to tighten the lugs on the inverter could easily weld itself to the bus if inadvertently touched to ground with these size cables, in an impressive shower of sparks.

If your TV really draws 700 watts and the DVD really draws 140 watts, then a 1,000-watt inverter is the minimum size you can get away with, and for that you will need a minimum 80-amp fuse (which will carry 960 watts at the nominal 12 volts, but over 1,000 watts at the actual operating voltages).

At this amperage, I favor ANL fuses, which are widely available.  ANL fuses and holders are widely used by the eardrum-shattering audio crowd, and thus found cheaply on eBay and other similar venues.  Easy to install and easy to change.

-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Title: Re: welding wire for an invertor
Post by: bevans6 on April 05, 2010, 04:02:16 AM
My real curiosity was about the welding wire - is the thin stranded welding wire OK to use, or is a thicker stranded and stiffer wire better?

Brian
Title: Re: welding wire for an invertor
Post by: gumpy on April 05, 2010, 06:07:31 AM
Quote from: bevans6 on April 05, 2010, 04:02:16 AM
My real curiosity was about the welding wire - is the thin stranded welding wire OK to use, or is a thicker stranded and stiffer wire better?

Brian

I used 4/0 welding cable on my 4000 watt Trace. No problems with it.

Follow Sean's advice on size and fuse.

craig