Inverter wiring

[exportman]

I am planning to install a larger inverter in my RV. Currently have a small 400w unit but want to put in a 2,000 watt unit. Can I assume that I need to upgrade the wiring to the batteries? What size red and black wires are needed? Thanks.

[exportman]

OK. Got it. Thanks everyone for the info and the lesson. 16 years of being on this forum and it never disappoints as to how many fellow RVers come to the assistance of others.

For those helping me out (and for what it's worth) I am going to delay installing the bigger inverter until next winter. I will travel through Quartzite, AZ when all of the merchants and installers are there in January and have them install an extra 2 Trojan 6 volt batteries, the inverter and the heavy duty wiring. Heading to Alaska in Spring/summer 2017 and the upgraded inverter/ battery system will likely be needed.

Thanks so much

[tenbear]

On the 12v side you will be drawing more than 1800 watts, probably about 2000 watts, or 167 Amps. The wire size depends on the length of the wire and your tolerance for voltage drop. 4/0 would be playing it safe, see SoundGuy's chart.

Of course, your battery bank has to supply at least 12v at that current.

[time2roll]

#12 120v wire should be fine.

[Byrogie]

exportman wrote:
Lots of good info .
To Sound Guy:
As I read your chart tell me please if I am reading it right. If I buy a 2,000 watt inverter and never use more than 1800 watts, I think I would be using 14 or even better 12 g wire. I got to this by dividing 110 volts into 1800 watts getting 17 amps. At <6 feet, the gauge wire is 14. Am I doing it right?

You need 1800 watts @ 12 volts which is 150 amps from the batteries to produce 1800 watts @ 110 volts which is 17 amps.
Big wire needed from the batteries to the inverter.

smkettner has it right

[exportman]

Lots of good info .
To Sound Guy:
As I read your chart tell me please if I am reading it right. If I buy a 2,000 watt inverter and never use more than 1800 watts, I think I would be using 14 or even better 12 g wire. I got to this by dividing 110 volts into 1800 watts getting 17 amps. At <6 feet, the gauge wire is 14. Am I doing it right?

[time2roll]

^^^^ I would go 4/0 with 300a fuse. See my link above. Unless the manual calls for larger.

[Slownsy]

Not to hijack tread but has same question.want to install a 2700W PSV Magnum cable length 5' from batteries to run a hairdryer, laser printer, and a small amount of microwave 1000W and including light and fan 1500W rated of 4 6V 280A batteries. ? cable size and fuse. Thank you.
Frank.

[SoundGuy]

exportman wrote:
What size red and black wires are needed?

Who knows? ... you haven't told us how long the runs are. :R I used this Blue Sea chart to decide that 6' long 4 gauge cables were suitable for my own inverter installation, considering it's rated capacity and how I expected to use it.

[brulaz]

exportman wrote:
I am planning to install a larger inverter in my RV. Currently have a small 400w unit but want to put in a 2,000 watt unit. Can I assume that I need to upgrade the wiring to the batteries? What size red and black wires are needed? Thanks.

You haven't mentioned the wire length.

The size of the wires you choose depends upon the current passing through them, their length, and how much voltage drop your inverter can handle at your max loads (bigger wire, less voltage drop).

Bigger is always better.

[tenbear]

exportman wrote:
I inadvertently posted this in the wrong forum as I have a motor home but you guys have given me good info that works for whatever vehicle.

AFAIK there is nothing to say that Class A technical problems have to be posted in the Class A forum. In fact, I think any technical problem would reach a wider range of technical experts in this forum than in any other.

We have nothing against Class A owners. 🙂

[SoundGuy]

exportman wrote:
Maybe I don't need to get the bigger inverter.

Yes, you do. I installed a 1000 watt PSW inverter in our trailer and use it to power a couple of fans, a 2-slice toaster, 4-cup Cuisinart coffee machine, and even my wife's hairdryer (on LOW). It's powered by a single 8 yr old G27 Interstate battery, 'though when it eventually does die I'll replace it with a couple of batts for greater reserve capacity and much improved ability to power the inverter without excessive draw down. A 1000 watt inverter is the minimum I'd consider for this task.

[Boon_Docker]

If the batteries are fully charged you will use up approx 15 percent of the usable capacity of the batteries in 5 mins.

[MrWizard]

run the engine to power the 1500w inverter
and maybe you won't kill your (2) 6v GC batteries

is the suggestion

this is only so you can delay buying more NEW batteries

[Mike008]

The only way the your 400 watt inverter is going to work is if you find a hair dryer and coffee pot that use less then 400 watts. I don't think you will find them.