Inverter hook up

[Jamie414]

I need to hook up a 2000 watt pure sine inverter to power my residential refer in my coach. The wires that run from the battery bank to where the inverter goes are #8 awg & the cables that came with the inverter are #6 awg. Is it ok & safe to eliminate the #6 awg wires & hook the # 8 awg wires directly to the inverter?

[twinboat]

8 gauge wires are much to light for a 2000 watt inverter.

Minimum should be 2-0 gauge cables for any distance.

Are you sure your inverter doesn't come with 6 MM cable ? That is 2 gauge, the minimum needed for 2000 watts.

[Clomok]

Install the inverter as close to the battery as possible, 14/2 Rolex and a inline transfer switch is ALOT cheaper then a running 2/0 cabling

[John Hilley]

Originally Posted by Clomok

Install the inverter as close to the battery as possible, 14/2 Rolex and a inline transfer switch is ALOT cheaper then a running 2/0 cabling

You mean 14-2 Romex or 14-2 NM you should use 14-2 with Ground NM

[Jamie414]

Thanks. What is the biggest inverter I could hook up with 8 awg wire? pulling new wire may not be an option!

[John Hilley]

Depending on distance from batteries 600 watts

[HarryStone]

I don't know about your inverter, but my Xantrex 2k inverter instructions said the battery(s) and the inverter should not be more than 5 feet apart.

[Jamie414]

Originally Posted by John Hilley

Depending on distance from batteries 600 watts

Thanks John! It's about 13 feet from where the inverter will be located to the battery bank (which is 6 6v US 2200 232 AMP Hour deep cycle batteries being charged from 2 solar panels) Do you think a good 600W pure sine inverter would run my residential refer that is 96w 1.1 amp (running) & LRA 6.2 amp start up in that location & length of #8 awg wires?

[Persistent]

The actual voltage delivered to the inverter 12 volt input is what matters. The more current the inverter draws, the lower the voltage due to line loss.

The battery state of charge also matters. The lower the state of charge the quicker the inverter terminals drop below minimum input voltage.

A long 8 gauge wire will work until the inverter tries to draw too much current. The input voltage will drop and then the inverter will trip off. The lower the battery state of charge the quicker it will trip off. Of course that means the refrig will stop working until you restart the inverter.

As pointed out in posts above, the reliable way is to put the inverter near the battery and use short large wire. Do what is ever necessary to relocate the inverter. Use 120 volt AC cable from the inverter to the refer. Do this for reliable operation.

It is possible terminals and connectors could over heat and cause smoke and/or fire. The 8 gauge wire could also get hot. Hot insulation deteriorates fast. Bad things can happen.

A 2000 watt inverter working at near full capacity draws about 170 amps. An 8 gauge wire will get HOT or the inverter will trip out. 8 gauge wire is OK for 50 amps. (50 amps X 12 volts = 600 watts.) The inverter will still trip off sooner or later when battery state of charge drops.

Specifications for the refrigerator will tell how much power it needs. Different refrig have different needs. It will have a starting current, a running current, and a locked rotor current. Current times voltage is equal to watts. (So 10 amps X 120 volts = 1200 watts. 3 amps X 120 volts = 360 watts.) Watts are watts, what ever the voltage. Current and distance determine the size of the wire.

There will be conversion losses so you may wish to plan an inverter that only works at 80% of capacity. Look at the specs for the refer.

I wish you good luck and happy trails ahead!

[John Hilley]

With your battery bank a 600 watt inverter would not be a problem. As mentioned above the problem comes in when the battery voltage drops. With your battery bank that shouldn't be too much of a problem. A 1000 watt inverter will probably be usable.

[Jamie414]

Originally Posted by John Hilley

With your battery bank a 600 watt inverter would not be a problem. As mentioned above the problem comes in when the battery voltage drops. With your battery bank that shouldn't be too much of a problem. A 1000 watt inverter will probably be usable.

So your saying with all the dynamics I have (13 feet from where the inverter will be located to the battery bank (which is 6 6v US 2200 232 AMP Hour deep cycle batteries being charged from 2 solar panels) I would do better to hook up a 1000 watt inverter with the #8 awg wires? That battery bank is charging all day with the solar panels & usually hangs around 13.4 & I have never seen it drop below 12.2 even at 5 am even with the refer plugged in with an extension cord in a 2500 mod sine inverter on the other side of the coach (which I could do every night when I stop driving even though it's a hassle!) I need this new inverter there to run the refer during the day when I'm driving.

[whybother]

I doubt a 600w inverter would reliably handle the startup current for your fridge, and even then, the max run for 8AWG @ ~60A would be ~3.5 ft., (maybe ~6 ft. if frame was used for negative) so not even close with your current wiring.

My batteries were about 15ft. from my transfer switch and breaker panel. I mounted my inverter as close to the battery as possible, (Ended up being under the dash.) and used 2/0 wire to the battery, then ran 12/2 NM from the inverter to my custom transfer switch that only enables the air conditioner when on shore/generator power. (Out of habit, I don't use 14/2 for anything any longer. In this case, I wish I ran 10/2 in case I ever up size my inverter.)

Also, double check the continuous and peek output of your inverter. Some cheap inverters advertise the peek wattage as the inverter's wattage. If it's a high frequency inverter (most are), surge/peek/whatever-they-want-to-call-it numbers should be ignored. Continuous is all that matters in high frequency inverters, and even those, depending on how reputable the manufacturer, should be taken with an appropriately sized block of salt. For motors, like on fridges, you'll want to aggressively oversize your inverter (at least x4 your expected continuous load) if it's a high frequency one -- and make sure the runs to the battery bank, including things like battery disconnect relays, are up to the task. (Low frequency inverters can usually be identified by their size, price and relatively large peek ratings, like over twice the wattage for 20 seconds or so, instead of the milliseconds high frequency inverters can provide.)

Assuming ~170 amp DC peek, and you're running both a new positive (+) and negative (-) wire from inverter to the battery (not using a short negative jumper to frame), you can run (per run):

~5 ft. of 2 AWG Copper Welding Cable (~10 ft. total for both + and -)
~6.5 ft. of 1 AWG Copper Welding Cable (~13 ft. total for both + and -)
~8 ft. of 1/0 AWG Copper Welding Cable (~16 ft. total for both + and -)
~10 ft. of 2/0 AWG Copper Welding Cable (~20 ft. total for both + and -)

You can stretch those a bit, (and even a bit more if the RV frame is used for negative path) but I wouldn't push it too far. It's always better to oversize the cable. And make sure it's copper cable -- not aluminum or copper clad.

If you can get the inverter close enough to the battery, these are a relatively cheap and available option:
https://www.harborfreight.com/3-ft-i...awg-63748.html

[Jamie414]

Originally Posted by Persistent

The actual voltage delivered to the inverter 12 volt input is what matters. The more current the inverter draws, the lower the voltage due to line loss.

The battery state of charge also matters. The lower the state of charge the quicker the inverter terminals drop below minimum input voltage.

A long 8 gauge wire will work until the inverter tries to draw too much current. The input voltage will drop and then the inverter will trip off. The lower the battery state of charge the quicker it will trip off. Of course that means the refrig will stop working until you restart the inverter.

As pointed out in posts above, the reliable way is to put the inverter near the battery and use short large wire. Do what is ever necessary to relocate the inverter. Use 120 volt AC cable from the inverter to the refer. Do this for reliable operation.

It is possible terminals and connectors could over heat and cause smoke and/or fire. The 8 gauge wire could also get hot. Hot insulation deteriorates fast. Bad things can happen.

A 2000 watt inverter working at near full capacity draws about 170 amps. An 8 gauge wire will get HOT or the inverter will trip out. 8 gauge wire is OK for 50 amps. (50 amps X 12 volts = 600 watts.) The inverter will still trip off sooner or later when battery state of charge drops.

Specifications for the refrigerator will tell how much power it needs. Different refrig have different needs. It will have a starting current, a running current, and a locked rotor current. Current times voltage is equal to watts. (So 10 amps X 120 volts = 1200 watts. 3 amps X 120 volts = 360 watts.) Watts are watts, what ever the voltage. Current and distance determine the size of the wire.

There will be conversion losses so you may wish to plan an inverter that only works at 80% of capacity. Look at the specs for the refer.

I wish you good luck and happy trails ahead!

Thanks Persistent! The problem is where the refer is located & the #8awg wires that are already pulled through the coach to that location. I can't locate where the #8awg wires land at the battery bank or I would just pull new (bigger) wire through the coach from where they land at the battery bank. I had a 1500 watt mod sine inverter hooked up there originally (which should be more than enough to power the refer but it was shutting down at night!) I thought the inverter was not big enough that's why I bought the 2000 watt pure sine inverter & hooked it up the same way the 1500 one was which had the 6mm wire tied to the #8awg wire but that didn't work longer than 15 minutes till the inverter started beeping & then shut down! (electric is not my specialty!)

I have since found out that the refer is only 96w 1.1 amp (running) & LRA 6.2 amp start up so I figured it was the way I had it wired (the 6mm tied to the #8awg) That's why I was asking about the #8awg going directly to the inverter.
I thought it might be a problem with the 2000w inverter but I hooked it up to my Toyota Tacoma truck battery with the truck running & a good set of jumper cables & it ran a 1200w 9A vacuum for about 15 minutes before the inverter started beeping so I'm still not sure there's not a problem with the inverter!

[whybother]

Originally Posted by Jamie414

I have since found out that the refer is only 96w 1.1 amp (running) & LRA 6.2 amp start up so I figured it was the way I had it wired (the 6mm tied to the #8awg) That's why I was asking about the #8awg going directly to the inverter.

6.2AMP 120V AC is around 750 watts, and will need about 70 AMPS @ 12v DC to run an appropriately sized inverter.

Your 13 or so feet of 8 AWG wire will drop your voltage at least 5%. So at full charge you're probably only getting around 11.6 volts to the inverter @ 70 AMPS. After the sun sets and you lose solar power, you'll quickly drop below what the inverter needs to power the fridge.

Edit: Yes, removing the 6AWG and wiring directly to the 8AWG would help, since the extra 6AWG wire is only adding to line loss, but it won't help enough to make a real difference.