how to install inverter in r v

[honda1]

how do manufacturers install inverters , how its wired up for residential fridg , is it hard wired , or do u have to turn inverter on every time u get off shore power ? ...

 

[Mudbug]

how do manufacturers install inverters , how its wired up for residential fridg , is it hard wired , or do u have to turn inverter on every time u get off shore power ? ...

That is a lot of questions in a short amount of space but I will try to answer them if I can.

Mine came from the factory, prewired. The electrical outlet for the fridge is wired directly to the output of the inverter. I then have a wire from the breaker panel to the inlet of the inverter. The inverter is automatic. If I plug into shore power the inverter see this and switches to shore power. If I unplug the TT it switches back to battery power.

As for turning the inverter off that depends on what I am doing. If I store the TT and I can plug into 110 then I leave the inverter on but turn off the fridge. If I am storing and don’t have power to keep the batteries topped off then I shut off the inverter and leave the fridge on. I could shut off the inverter when I shut off the fridge on shore power but I haven’t. No reason really just one less thing for me to forget before I drive off.

 

[honda1]

that is what i was wondering about , do u know what brand & size iverter u have , most i have seen 1000 w psw . tks .

 

[Mudbug]

that is what i was wondering about , do u know what brand & size iverter u have , most i have seen 1000 w psw . tks .

Well as much research as I did When I first bought it you would think I remembered but I didn’t. I went out and took a picture for you. Ignore the little in line fuse,that is from me adding cargo lights and tieing into the 12 volt side of the inverter for power. The 110 inlet and outlet or wired into the right side with the plastic cover hiding the wires. This is a pure sine wave as well. Better for sensitive electrical items.

 

[honda1]

thank you .

 

[jimla]

It all depends on how you want the inverter to work. The one that is installed in ours is a pass through style. In other woods when you have shore power, the 110 passes through while turned on. The inverter is only to power the refrigerator. The refrigerator is also powered through a breaker in the breaker panel. If you turn the breaker off to power refrigerator down, you also loose power to other 110 outlets. In case you are wondering, the residential refrigerator we have has no capabilities to turn it off, other than unplugging it or turning breaker off.

 

[jimmoore13]

1. For a purpose of running a residential fridge, choose one that has a built in transfer switch. When there is AC shore power available, it will choose that. When you unplug, it will draw from the battery. No muss, no fuss. This is an illustration, not a recommendation: https://smile.amazon.com/APT1200-12...fix=inverter+with+trans,automotive,175&sr=1-5
2. When installing the inverter, locate it as close as possible to the battery, and use HUGE cable to connect directly to the battery. Add a fuse or DC breaker in the line unless the inverter has its own input protection circuitry.
3. For the transfer switch function to work, you'll have to supply the inverter with a 120 volt feed...best option is straight from an open breaker on the panel, but you could pick-off power from a nearby outlet...assuming the chosen circuit has the capacity to support the intended load. Another way to approach this is to snag the wire feeding a nearby outlet, use it to feed the inverter, then plug the RV outlet into one of the outlets on the inverter. But be aware that all circuits in an RV are likely to be fed through a GFCI, so tripping the GFCI would shut off 120 volt power to the inverter and transfer the load to the battery. You might not notice this, but with those loads, if you're connected to shore power, the cooling fan on the RV converter/charger would run continuously as the battery is pulling a 50 amp charge through the converter. Details.

The most important thing to remember is that the inverter supplies 120 volt power from a 12 volt source, so ALL calculations relating to load must be based on 12 volts. Let's say you install a 1000 watt inverter. That inverter will draw 100 amps (that's right, one hundred) when supplying 1000 watts of 120 volt power to your load. Your fridge may be more like 500 watts, so the load from 12 volts will draw 50 amps of current from your battery bank.

Also add about 5% to 10% for inefficiencies in the inverter...and the power it consumes.

There's a chart on wire size at 12 volts for any given distance here: 12 Volt Wiring: Wire Gauge to Amps | Offroaders.com
But most installers would use 2/0 AWG wire to connect the inverter to the battery bank. This "welding cable" minimizes losses at any load and preserves your battery bank. Smaller wire will waste power in resistance that becomes heat.

Note that I said battery bank. A typical single group 24 battery installed in a small camper can only supply 35 to 40 amp-hours before needing to be charged. The "gold standard" of 4 x 6 volt golf cart batteries wired in series/parallel can deliver about 225 or so amp hours. If you're fancy and rich, Battleborn and other LiFePO4 batteries can do even better, but at a kilobuck/battery, emphasis on rich. Anyway, to run your fridge and the inevitable other 120 volt loads you will be tempted to add, you'll need a big battery bank.

For argument's sake, let's say your fridge draws 600 watts to start, and uses 300 watts to run. Again, for argument's sake, lets assume you're camping in TX in the summer, and the fridge is running on a 50% duty cycle....this makes the math easy. 300 watts at 12 volts is 30 amps. 50% duty cycle means running for 12 hours. 30 amps/hours x 12 hours = 360 amp/hours. Ooops!

Your real numbers will differ and probably be quite a bit less, but here's the calculator to help you figure things out: https://www.rapidtables.com/calc/electric/watt-volt-amp-calculator.html
Remember, EVERYTHING through an inverter is 12 volts, even if the item is a 120 volt appliance. The ultimate source of power is your nominally 12-volts battery bank.

Unless you like the drone of a generator, you'd best investigate solar if you plan to boondock with a residential fridge. That's another whole big topic.

 

[TitanMike]

2. When installing the inverter, locate it as close as possible to the battery, and use HUGE cable to connect directly to the battery.

If able to mount the inverter close to batteries my suggestion is to use the largest wire that the lugs will accept if it has lugs that wire is inserted into then clamped in place with a set screw.

If the terminals on the Inverter don't have the above type of socket/set screw design it's possible to run double wires to both positive and negative terminals with the connectors placed on each side of the terminal and secured with a bolt.

Some Inverters are supplied with wiring kits that use this method. Benefit? More flex in two smaller wires than one huge wire.

Amp capacity of wires centers around the "Circular Mils" of the wire which simply put the area of a cross section of the copper wire. A "huge" 2/0 wire has over 130,000 Circular Mil's and two #2 Awg wires have over 66,000 Circular Mils. When connected in parallel they carry pretty much the same amperage.

A 2/0 wire is around 3/8" in diameter (Wire part) and a #2 wire is 1/4" (again wire part). This can make for more flexibility if having to make sharp turns and also easier to find a Crimping Tool to crimp connectors on #2 awg wire than for the "huge" 2/0 wire and connectors.

For some reason Inverters always draw more current than you think they will so it's best to go with the largest wire that's practical. If a chart suggests one size, if you can use one or two sizes larger. Avoid as much voltage drop as possible.