Routing wire for simple inverter install

[garyb1st]

Picked up a 1000 watt inverter and 6 ft long #2 cables.  Plan on ordering a fuse block and 150 amp fuse.  I only plan on using the inverter to power my computer, the TV and maybe the coffee maker from time to time.  I'd like to mount the inverter on the wall close to the stair well where the batteries are located.  My question is what is the best way to run the wires to the inverter.  There are two vent holes in the metal box that holds the batteries so I can run the wires through the holes.  But I'm at a loss about how to run them back through the floor or walls to the inverter. 

 

[garyb1st]

Update.  Routing solved.  I just drilled a hole through the floor.  Received Aims 1000 watt pure sine wave inverter, in line fuse holder with 150 amp fuses and 9" cable.  The longer 5 foot cables should be here tomorrow.  As mentioned, it's a simple install and I think I've got what I need.  Still, I have two questions.  First, is my 150 amp fuse too big for the set up?  I'm using #2 awg wire.  Second, I plan on running the ground wire through the floor and attaching it to the frame.  It will  be about a foot from the propane tank.  Is this adequate separation? 

Thanks for your thoughts. 

 

[Lou Schneider]

My question is what is the best way to run the wires to the inverter.  There are two vent holes in the metal box that holds the batteries so I can run the wires through the holes.  But I'm at a loss about how to run them back through the floor or walls to the inverter.

Hi Gary ...

Is this a steel or an aluminum box?  If it's steel, don't run the wires through separate holes with metal between them.  When you draw a lot of current, you'll set up a magnetic field around the wires and this will send magnetic flux through the steel in between them, heating it up.  Running both wires through a single hole cancels out the magnetic field.

This is a worry with AC generators where the wires can heat up intervening metal like a pan on an induction cooktop.  I'm not sure if the effect is as pronounced with DC wires, but better to run them both through a single hole in the box to be safe.  You also don't want to completely block the battery vents.

First, is my 150 amp fuse too big for the set up?  I'm using #2 awg wire.  Second, I plan on running the ground wire through the floor and attaching it to the frame.  It will  be about a foot from the propane tank.  Is this adequate separation? 

Thanks for your thoughts. 

#2 AWG is rated for 90-130 amps continuous,, depending on the temperature rating of it's insulation, so a 150 amp fuse is fine for a catastrophic fuse.  Generally these are 1.5 - 2 times the maximum current the circuit will draw in normal use so they'll only blow if there's a hard short on the wires.  A 1000 watt inverter will draw about 100 amps at full load and has internal protection to shut itself down on a routine overload.

The routing of your ground wire is fine.

 

[garyb1st]

Lou, thanks for the reply.  Can't find one of my many magnets so can't tell for sure, but think it's aluminum.  However, unless I'm misunderstanding, it's always OK to run both wires through the same hole which is what I'll do.  The only concern I have with the fuse rating is the possibility it's too large.  From what I read, the fuse is there to protect the wiring.  If it's too big, the wires can burn before the fuse blows.  Again, thanks for your help.

Gary

 

[Lou Schneider]

I think the key point is the fuse at the battery is designed to open only in the case of a severe overload, i.e. a direct short in the wiring.  A direct short will send hundreds of amps through the wires, more than enough to guarantee the fuse will blow.  By the same token, you want it to be large enough so it won't blow under normal use, but will if there's a catastrophic short.

#2 wire is sufficient to carry the inverter's maximum normal load and it will protect itself against overloads and even direct shorts on the AC side by shutting down.  You don't need the battery fuse to blow under those conditions, only on in case of a severe current surge.

 

[BT5210]

I have a situation to over come... I bought a new pace arrow, 2018...with it came the resident fridge..at first, I was total against the idea... but that's the only way they come now...but, after owning the coach... I wouldn't have it any other way...but what they did was put every plug in the coach through the inverter..the only thing that's on shore power is the micro, and the ac's..thought I hated that idea also... but again I love it now...after a couple trips out to the dunes and desert..I'm convinced that taking the path needed to get to our camp spot is just gonna destroy our new coach...so bought a desert rig.. 2002 sightseer on the work horse chassis..I would like to hook up the power to the plugs in the same manner... so probley get a 2000 watt inverter...so the question? would I have to pull all the home runs to the inverter that is there and by pass it?... the shore power now charges the battery's... the system is the type that you have to plug the  shore power in to the gen plug.. so it doesn't have the relay..the only down fall I see is that the inverter runs constant or no power...sure is nice on the new coach to watch tv, run coffee maker with out the gen running..and un less the micro or roof ac is needed not having to run the gen going down the road..

 

[TranceX2]

Consider conduit flex tubing around each wire that is next to each other.  Vibrations when travelling can cause the insulation to wear (happened to me) and eventually can cause a bad short and possibly fire.

 

[garyb1st]

Lou, it's done.  I can now watch TV without turning on the genny.  Thanks so much for your help. 

Now I'm wondering if I need to add a battery monitor or if I can just check the one that's already in the motorhome.  The motorhome panel give me the current voltage of the batteries.  I've checked it with my multimeter and it's pretty accurate.  Not sure what else I need to monitor.  The inverter has an on/off button and green light when powered.  Hopefully it will not consume any power when turned off.  I thought about adding a battery switch but decided against that for now. 

 

[garyb1st]

Update.  It works.  Have watched tv and computed for 4 hours with about 12.3 v left in batteries.  At least, that's what the motorhome meter shows.  After charging and sitting for an hour, the meter shows that both the house and starter batteries are at about 12.6 - 12.7 v.  House batteries about 3 years old.  Now I need a better way to charge and check the SOC.

Have read through HandyBob's material on solar, charge controllers and monitors.  Was very impressed and thinking I'll just do what he suggests.  Then I read a thread and at least one member suggested HandyBob may not be the guy to listen to. 

In any event, I've got the solar bug, know I need a better way to charge the batteries and need a battery monitor. 

I'll probably start a new thread after rethinking solar but would appreciate any thought at this time.

 

[kdbgoat]

Have read through HandyBob's material on solar, charge controllers and monitors.  Was very impressed and thinking I'll just do what he suggests.  Then I read a thread and at least one member suggested HandyBob may not be the guy to listen to.

One thread and one member doesn't like Bob. How many threads has been Bob been recommended in? How many other members have followed Bob's suggestions or used Bob's services? Put simply, his systems work.

 

[garyb1st]

One thread and one member doesn't like Bob. How many threads has been Bob been recommended in? How many other members have followed Bob's suggestions or used Bob's services? Put simply, his systems work.

Well he does suggest that pros don't always agree with him.       

 

[Kevin Means]

Hi Gary. Glad to hear you got your inverter working. Good job! I think you'll be very happy with a good battery monitor. Our Trimetric, which was recommended by Bob and many others, has been one of the best mods I've done to our RV. Those who don't boondock very often, would probably feel that they're a waste of money, but for those who do frequently boondock, they really take the guess work out of knowing your battery's SOC. A lot of people like the Victron battery monitor too. They can communicate with a phone or tablet, so you can check the SOC from your bed, campsite or...

FWIW, Bob Shearer (HandyBob) was very helpful when I was installing our solar setup - not so much for the basics, but for some expansion issues I knew wanted to address down the road. He was very giving of his time and experience, with no strings attached. He never asked for a dime, but I paid him for the extra help he provided nonetheless.  Opinionated... yes he is, no doubt, but it comes from many years of real life RV solar and boondocking experience, so I think he's earned it.

Say hi to Maria. We hope you guys can make it to KOFA again.

Kev

 

[garyb1st]

Thanks Kev.  Pretty stoked about the install.  It's got me thinking Solar, more batteries, a charge controller and battery monitor.  Hope to pick your brain at KOFA if we're able to make it.  Won't know until early January.  Looks like the party is shaping up  nicely.  Hopefully you'll get the same location or at least something as nice close by. 

Hope you and Cyndi are enjoying your travels and that you have left your health issues in the dust. 

Gary

 

[kdbgoat]

Well he does suggest that pros don't always agree with him.       

Yep. Like Kevin says, He's opinionated, but earned it.

 

[garyb1st]

Consider conduit flex tubing around each wire that is next to each other.  Vibrations when travelling can cause the insulation to wear (happened to me) and eventually can cause a bad short and possibly fire.

This is the one thing I didn't really think through.  The access point to the inverter is through a hole in the floor.  While I managed to get the two AWG 2 wires and smaller ground through the hole, it was such a tight fit, I wasn't able to add any insulating material.  However, the wire  barely move so I'm hope there's minimal rubbing.  The wires routed from the battery box are through a predrilled hole which is maybe an inch in diameter.  That's the area more likely to be a problem with rubbing.  My intent was to add a grommet before the install.    Now I'd be happy with anything that will keep the wires from rubbing.