Community Forums

Hillbilly2 · 04-15-2008, 04:42 PM

I thought 6/0 was kinda strange, because in the electrical business, wire size only goes up to 4/0, then it starts with 250 kcmil and goes up from there.

Gary RVRoamer · 04-15-2008, 05:48 PM

It may be the motor/compressor in the little fridge doesn't like modified sine wave power.

Max Hubrich · 04-16-2008, 03:06 PM

Update,

The box the inverter came in shows a color picture of a freezer similiar to mine that can be used with this piece of equipment. The freezer is not working properly now.

I'm goin to plan "B". Two new units are in the UPS system to me now.

I'll post updates---

Gary RVRoamer · 04-16-2008, 04:10 PM

Remember, the picture on the box was put there by Marketing rather than Engineering!

sparetire · 04-16-2008, 06:38 PM

"Remember, the picture on the box was put there by Marketing rather than Engineering!"

I got a chuckle out of that, but ain't it the truth!! Sometimes a picture isn't worth popcorn gas!

Take care,
Sparetire

Max Hubrich · 04-17-2008, 04:26 AM

While I'm waiting for new units, I did a little research-- still don't know much and can't figure out the copper diameter of 1/0 and 3/0 cable. I can use a micrometer if I can figure this mess out in thousands--

By definition, No. 36 AWG is 0.005 inches diameter, and No. 0000 is 0.46 inches diameter. The ratio of these sizes is 92, and between them are 38 sizes, with equal ratios between each adjacent pair of sizes. (The 40 different sizes result in 39 size changes.) (Sizes with multiple zeros are successively larger than No. 0 and can be denoted using "number of zeros/0", for example 4/0 for 0000.) Therefore, the diameter of a No. n AWG wire is

and its cross-section area is

.
For an m/0 AWG wire, use n = âˆ’(mâˆ’1) in the above formulas. For instance, for No. 0000 or 4/0, use n = âˆ’3.

The ratio between successive sizes is the 39th root of 92, or approximately 1.1229322.[2]

The sixth power of this ratio is very close to 2, which means for an increase in six gauge numbers, the wire diameter is changed by a ratio of 2 (No. 10 is about one-half the diameter of No. 4 AWG). A decrease of three gauge numbers doubles the area of a wire. A decrease of ten gauge numbers, for example from No. 10 to 1/0, multiplies the area and weight by approximately 10 and reduces the resistance by approximately 10.

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zeddy · 04-20-2008, 07:23 PM

I just put an xantrex pro 2.0 inverter/charger in my coach this weekend. 4 guage will not support 300amps dc, I was told to use 1/0, which I did. my 2000watt inverter had no problem running my microwave and my ac at the same time, although not for long as it will kill any battery bank, I have six trojan t135.

I read in the mannual that some motors and compressors have a really high start up current, maybe your freezer does not like the modified sine wave, or your power wire is too small?

Forest Grump · 04-21-2008, 08:17 AM

A 2000 watt inverter with a 4000 surge capacity should have 2/0 gauge wire or better dependent upon wire length. On my Xantrex 1850 I used 2/0 for a 5 foot run and have had no problems. You are 6 - 8 sizes too small. The positive and ground wires should be the same gauge, both are limiting. You are lucky you didn't have a fire.

I make up my own cable. On a Xantrex too small a size 12V cable like you have will show as a fault.

Your inverter should be fine but you fried your Frig.

Get 2/0 it's very thick, about the same diameter as your pinky finger. Use 2/0 or better for both the positive and negative 12v. wiring. If close to 5' or slightly over go to 3/0. Don't go over 8'. Take the negative off the negative battery post not from coach ground. Both leads need to come from the battery.

Max Hubrich · 04-21-2008, 09:08 AM

Thanks Forest,

I'll do it!!!

Forest Grump · 04-22-2008, 11:32 AM

Don't forget to get a 400 amp fuse. If you want the type and brand let me know and I'll send you info on it. It should be mounted on the positive line inches from the battery.

Max Hubrich · 04-22-2008, 03:41 PM

Forest,
I installed a 500 amp current limiter.

Forest Grump · 04-22-2008, 05:44 PM

High Amperage JLLN (class T) Fuses are recommended for this application. I am not sure if a current limiter will protect you.

MarkS · 05-04-2008, 04:57 PM

Max, I'm not sure if you ever got the answer to your question regarding the AWG guage number versus the size of the wire. There is a formula. I recommend you read:

http://en.wikipedia.org/wiki/American_wire_gauge

-Mark

Max Hubrich · 05-18-2008, 09:46 AM

Good news update-

I re-did the whole operation.

I installed a 1000 watt pure sine wave inverter("Cotek" brand). I used 2/0 ga cable, the longest run is about 42" (neg). The chassis ground wire is 6 ga. I overkilled the whole wire gauge situtation. My "Good Governor" no longer "ground faults". The new Freezer/refrigator is running fine (-22F).

We're happy campers in Maine right now.

Thank you all for your inputs-- Here are some pics,

Inverter install

2/0 cables

New Freezer/Refridge