How to route wire from battery to inverter?

[efnord]

What's the best way to get a pair of wires from the stock battery to the inside of my 1995 Astro? I'm looking to add a 1000W inverter to power a freezer with a 1/3 HP compressor- it'll be a 250W load except for right when the compressor kicks on. I've run this on a 1000W Honda generator before (EU1000I). I figure the stock alternator can put out an extra 20-25A and the battery can supply 75A for a split second.

Any suggestions about how many feet of wire to buy or how to route it? Do I need to spring for a 100A fuse or 1000W amp install kit? I really don't care where the inverter is in the van; that's what extension cords are for. It's a RWD 1/2 passenger van.

[webcat]

For one thing you dont need a pair of wires you only need a positive thick guage wire to run to the invertor and then run a ground wire from the invertor through the floor and connect the ground wire to your frame.

[Big_kid]

Keep the run as short as possible, and use the largest cable you can get. Yes, you should put a fuse inline, put it on the positive cable as close to the battery as possible. If the insulation rubs through where it passes through the firewall (or near an AC line, transmission line, etc) you don't want the fuse to be downline form the short. When I put the inverter in my work van I connected the fuse to the battery itself and used shrink wrap over both ends of it. No fuse holder necessary that way. I also ran a negative cable to the battery too. What Webcat says will work, but during times of heavy current demand you stand a chance of overheating the negative battery cable (engine running, lights & wipers on, stereo on, fridge running, etc... it adds up.

[TheRealDaddy]

For one thing you dont need a pair of wires you only need a positive thick guage wire to run to the invertor and then run a ground wire from the invertor through the floor and connect the ground wire to your frame.

There isn't much point in running the wire through the floor and then to the frame since these are uni-body vehicles and the only frame is the engine cradle whoch doesn't have it's own ground straps and is virtually separated from the rest of the system by rubber bushings. By going out through the body all you'd achieve is creating a new hole in your van.

The main ground cable bolts to the core support and then to the engine creating a very good body ground so as long as you get a good connection to the body somewhere you should be set. I would recommend using an actual bolt and nut with a star washer if you want to get the best ground but I understand that a bolt and nut may not be very easy to install. Whatever you use and where ever you ground make sure it's a good connection or you will have problems later.

As far as a way of getting the wires inside the vehicle, it really all depends on what size wire you use. I would say you would be safe with a #10 wire which holds 30a easily. A 1000 watt 115v inverter should be drawing just over 8.7 amps. A quick way to get the wire inside is to poke it through the emergency brake grommet although not exactly up against the cable. (wear could eventually cause a short if you place the wire right up against the metal cable) If you have an awl you can easily make a small hole in the grommet to push your wire through. This trick is only good for one or two wires at the most. If you want to a larger wire, in the anticipation of more load bearing accessories at a later date you should think about drilling a hole in the firewall and installing your own grommet that you can purchase at an auto parts store or your local radio shack. Always make sure there is some rubber or at the least tape between the wire's sheath and metal. The sheath isn't made for constant friction and you will eventually have a big problem. I would also recommend buying the grommet before you drill the hole, you never know what you will be limited to.

Always use fuses!!

[tedanderson]

I'd suggest running the hot wire through the floor under the van and enclosing it in a length of wire loom material so that you have that added protection against the jacket hitting anything metal. For a 1000 watt inverter, I think that I'd go with #4 or #2 gauge wiring assuming that your freezer is going to be somewhere behind the back seats. Being that your wire run is going to be at least 6 to 10 feet (with all of the twists, turns, and routes from point A to point B) you don't want to starve your inverter for power, even if the full load is only going to be for a split second as it peaks. Also, having a thicker gauge wire also prevents those electrical gremlins from popping up like buzzing in the radio and so forth.

[Big_kid]

X2 Ted

[webcat]

For one thing you dont need a pair of wires you only need a positive thick guage wire to run to the invertor and then run a ground wire from the invertor through the floor and connect the ground wire to your frame.

There isn't much point in running the wire through the floor and then to the frame since these are uni-body vehicles and the only frame is the engine cradle whoch doesn't have it's own ground straps and is virtually separated from the rest of the system by rubber bushings. By going out through the body all you'd achieve is creating a new hole in your van.

The main ground cable bolts to the core support and then to the engine creating a very good body ground so as long as you get a good connection to the body somewhere you should be set. I would recommend using an actual bolt and nut with a star washer if you want to get the best ground but I understand that a bolt and nut may not be very easy to install. Whatever you use and where ever you ground make sure it's a good connection or you will have problems later.

Good point , i forgot that the Astros dont have a frame.

[TheRealDaddy]

Good point , i forgot that thae Astros dont have a frame.

Yeah it's getting pretty sad, the only things that have frames any more are trucks. My G20 Full size Chevrolet van had less frame than the astro's and safari's did.

[webcat]

Good point , i forgot that thae Astros dont have a frame.

Yeah it's getting pretty sad, the only things that have frames any more are trucks. My G20 Full size Chevrolet van had less frame than the astro's and safari's did.

Thats strange , my 1996 G10 van has a frame , what year is your G20 ?

[tedanderson]

Come to think of it, my G20 didn't have much of a frame either. I had a 1990 and when I would work under it, I would find it interesting that the shocks, the fuel tank and many of the other under-the-car stuff is mounted to the body.

But Then I remembered something that was equally as interesting that I read in a car forum back in the early 90's. When the mini-trucks were gaining popularity (e.g. mini-vans, small pick ups, small SUV's) it was commonly thought that they were scaled down versions of the big trucks. Instead it was the exact opposite. The smaller trucks were actually built from the ground up using the newer technology of that era (e.g. unibody construction) and then then they started applying some of those things to the newer trucks.

Hence, a G-Series is very similar to an Astro minus the body shape.

[TheRealDaddy]

My G20 was a 92 and it was uni body except for the engine cradle. (And believe me the engine cradle was minimal) It's odd to think that the manufacturer would switch to uni body construction and then change their design back to a framed model. (Talk about reverse engineering) I had noticed that the vans of the generation previous to my van seemed to be in better overall shape while the vans of my van's generation all seemed to rust out at the rocker panlels. It's possible that this prompted them to rethink the design and take a step backward, so to speak. I have only owned the one full sized van and haven't inspected others with great purpose so I'm not entirely sure what years had frames and what years didn't. I just know that my 92 was definitely uni body.

[d0nk3y]

As far as a way of getting the wires inside the vehicle, it really all depends on what size wire you use. I would say you would be safe with a #10 wire which holds 30a easily. A 1000 watt 115v inverter should be drawing just over 8.7 amps.

P = i V

For 120V, 1000W = 120i, or 8.3A
HOWEVER

For 12V. 1000W = 12i, or 83 AMPS

If the OP's fridge draws 250W running, and say, 750W peak to start the compressor, that represents a steady 23A load and nearly a 70A load during start up (assuming 90% inverter efficiency). He's going to need a little more than #10 gauge wire.
If going with a 1000W inverter, size the wire for the maximum draw of the inverter, not the fridge; IMHO, I'd use 100A as a figure to compute wire gauge vs. distance.

I would suggest this information when sizing inverter wiring: http://www.zetatalk3.com/energy/tengy10s.pdf Good info there, would hate to see you get hurt using the wrong wiring.

I have a 700W inverter in my camper that I used universal - style battery cables (#4 gauge) to connect to my battery bank 2o inches away.

[astroturf]

Great Ref Donkey

Thanks

Jim

[TheRealDaddy]

As far as a way of getting the wires inside the vehicle, it really all depends on what size wire you use. I would say you would be safe with a #10 wire which holds 30a easily. A 1000 watt 115v inverter should be drawing just over 8.7 amps.

P = i V

For 120V, 1000W = 120i, or 8.3A
HOWEVER

For 12V. 1000W = 12i, or 83 AMPS

If the OP's fridge draws 250W running, and say, 750W peak to start the compressor, that represents a steady 23A load and nearly a 70A load during start up (assuming 90% inverter efficiency). He's going to need a little more than #10 gauge wire.
If going with a 1000W inverter, size the wire for the maximum draw of the inverter, not the fridge; IMHO, I'd use 100A as a figure to compute wire gauge vs. distance.

I would suggest this information when sizing inverter wiring: http://www.zetatalk3.com/energy/tengy10s.pdf Good info there, would hate to see you get hurt using the wrong wiring.

I have a 700W inverter in my camper that I used universal - style battery cables (#4 gauge) to connect to my battery bank 2o inches away.

Yeah I was doing my math based on 115v not 120v or 12v. And I was figuring on the output being the 1000 watts not the input. Shows what I know, Glad there's more than one of us here to help get these problems solved, if you had listened to me you'd all have meltdowns.

[Jasen]

Heres how I routed the 4 ga. to my amps.

This enters the van just in front of the rear wheel well on the drivers side.

[d0nk3y]

Yeah I was doing my math based on 115v not 120v or 12v. And I was figuring on the output being the 1000 watts not the input. Shows what I know, Glad there's more than one of us here to help get these problems solved, if you had listened to me you'd all have meltdowns.

Oh - I still have meltdowns, only they're mental ones, and not your fault Carter.

[Lumpy]

Heres how I routed the 4 ga. to my amps.

This enters the van just in front of the rear wheel well on the drivers side.

Jason -

I think you go through panels and firewalls the same way I do...

Instead of using a traditional rubber grommet, I use a length of rubber fuel hose.
Find a hose that has an ID that's about the same as the OD as your cable.
Cut a length of that hose about the thickness of the panel plus about an inch.
ie if your panel is 1/4" thick, cut a length of hose about 1 1/4" long. It can
be longer if you like.

Drill your hole through the panel the same size or just a gnat gnut larger
than the OD of the hose.

Slip the hose over the wire. If you already have the wire in place or there's
connectors that won't allow the hose to slip over, then slit the hose and
wrap it around the wire.

Place a worm clamp on one side of the hose and wire, thread the thing
through the firewall or panel into your predrilled hose. De burr
the hole, squirt in some RTV, place a worm clamp on the "other side"
of the hose.

Now you've got a wire protector that's a lot tougher than the typical
rubber washer thingies that they sell as grommets. The hose clamps
on either side of the hole hold it in place. The RTV cuts down on
vibration and if appropriate, seals exhaust gasses or engine/outside heat
out of the interior.

Hope my verbal description makes sense.


Lump

[94 Van Guy]

Instead of using a traditional rubber grommet, I use a length of rubber fuel hose.
Find a hose that has an ID that's about the same as the OD as your cable.
Cut a length of that hose about the thickness of the panel plus about an inch.
ie if your panel is 1/4" thick, cut a length of hose about 1 1/4" long. It can
be longer if you like.

Drill your hole through the panel the same size or just a gnat gnut larger
than the OD of the hose.

Slip the hose over the wire. If you already have the wire in place or there's
connectors that won't allow the hose to slip over, then slit the hose and
wrap it around the wire.

Place a worm clamp on one side of the hose and wire, thread the thing
through the firewall or panel into your predrilled hose. De burr
the hole, squirt in some RTV, place a worm clamp on the "other side"
of the hose.

Now you've got a wire protector that's a lot tougher than the typical
rubber washer thingies that they sell as grommets. The hose clamps
on either side of the hole hold it in place. The RTV cuts down on
vibration and if appropriate, seals exhaust gasses or engine/outside heat
out of the interior.

Hope my verbal description makes sense.


Lump

Explained well Lumpy...

[tedanderson]

X2! Brilliant!