Yes GipC agree if all batteries are connected to the 12V house side.

I was more talking about how the output of the inverter is connected to the 120V systems. I am not sure if it is connected only to the fridge side out will power the entire coach. From what I've heard from people it only powers the residential fridge no other 120V devices.

Yes GipC agree if all batteries are connected to the 12V house side.

I was more talking about how the output of the inverter is connected to the 120V systems. I am not sure if it is connected only to the fridge side out will power the entire coach. From what I've heard from people it only powers the residential fridge no other 120V devices.

Probably the best way to determine that would be by the size of the inverter. A residential refrigerator is probably around 10 amps or so. 10 amps x 120 volts would equal 1200 watts. If the inverter is 1500 watts, I would propose that it is connected only to the refrigerator. However, if it were my unit, I might connect 1 TV to it since the fridge does not run continuously...A slight risk of overload depending on the fridge model and TV model. It would also depend on the inverter model. Some low value inverters might not last too long...

The couple next to us have a class C motor home & yesterday lost power to the residential frig & both tvs, after some testing/investigation found a reset on their inverter tripped. So others may also power frig & a couple other outlets.

On our '16 MB there is a direct line from the inverter to the Fridge outlet. Now we could plug something else into the outlet if we wanted.
As to power, these new Residential Fridges are very energy efficient. When running on the Inverter it only draws 11 amps from the batteries, so with four 12V batteries we can go a few days before needed a recharge, since the Fridge has a very low Duty Cycle.

Here are a couple of quick math formulas:

Total Watts (there are other factors such as line loss, power factor corrections, etc), but this is the basic formula that you can use and be extremely close):

V x A = Watts

For Amps (sometimes you know watts and volts but may not know what the total amps are):

W / V = Amps

If you go by NEC Codes (which RV manufacturers are not required to do), then figure a max breaker or fuse load to be 80%.

You won't want to necessarily install an inverter at 100%. Sure, there are duty cycles and you can run closer to the limits for short periods but I like to think of it in relationship to your tow vehicle. You might be good driving with the RV at 100% load but do this long enough or over mountainous territory and you will find yourself out of service real quick. And repairs don't come cheap.

Just do your math and don't overload your system or run greater than 80% if you want your equipment to last (or in the case of electrical equipment, catch fire. You generally only have 20-30 seconds by the time you discover it to get out of an RV when there is a fire)

And this assumes the system was installed correctly to begin with....You might want to check wire sizes and the way the installer made their connections.

Loose connections (as typically found with these cheap RV receptacles) are a cause of voltage drop and heat build up.

The RV manufacturers love using the wire "stab in" models as it is much faster than striping the wire and wrapping the wires around the terminals.

Speed means more money...less quality...

Gypsy,

Can you tell me how much voltage drop would occur when drawing 16 amps at 12 v D.C. thru 25 feet of 16 gauge copper wire? That is how my electric brakes were wired from the pin box to the wheels and I have now changed to 10 gauge wires down each side.

Gypsy,

Can you tell me how much voltage drop would occur when drawing 16 amps at 12 v D.C. thru 25 feet of 16 gauge copper wire? That is how my electric brakes were wired from the pin box to the wheels and I have now changed to 10 gauge wires down each side.

This will be for straight up results based on 12V, 16A. There are other variables such as the type of controller used, the condition of your battery and alternator, and the connections of the wires. If they get water in them, resistance goes up:

#16 AWG
Volt Drop 3.21
Percent Loss 26.75%
Volts at end 8.79

#12 AWG
Volt Drop 1.27
Percent Loss 10.58%
Volts at end 10.73

#10 AWG
Volt Drop 0.8
Percent Loss 6.67%
Volt at end 11.2

#8 AWG
Volt Drop 0.5
Percent Loss 4.17%
Volt at end 11.5

Resistance of Copper Wire at 68 degrees F per 1000':

#16 4.016
#12 1.588
#10 0.9989
# 8 0.6282

Generally , you want to stay at 5% loss or less. But for your electric brakes, 0.3 Volts is not that much since your less than 25'.

If you want a real performance increase, consider disc brakes in the future. It's night and day, summer and winter, male versus female.....

Gypsy,

Can you tell me how much voltage drop would occur when drawing 16 amps at 12 v D.C. thru 25 feet of 16 gauge copper wire? That is how my electric brakes were wired from the pin box to the wheels and I have now changed to 10 gauge wires down each side.

This will be for straight up results based on 12V, 16A. There are other variables such as the type of controller used, the condition of your battery and alternator, and the connections of the wires. If they get water in them, resistance goes up:

#16 AWG
Volt Drop 3.21
Percent Loss 26.75%
Volts at end 8.79

#12 AWG
Volt Drop 1.27
Percent Loss 10.58%
Volts at end 10.73

#10 AWG
Volt Drop 0.8
Percent Loss 6.67%
Volt at end 11.2

#8 AWG
Volt Drop 0.5
Percent Loss 4.17%
Volt at end 11.5

Resistance of Copper Wire at 68 degrees F per 1000':

#16 4.016
#12 1.588
#10 0.9989
# 8 0.6282

Generally , you want to stay at 5% loss or less. But for your electric brakes, 0.3 Volts is not that much since your less than 25'.

If you want a real performance increase, consider disc brakes in the future. It's night and day, summer and winter, male versus female.....

Thanks. No wonder the factory brakes are so poor with over 3 volts drop! Yikes!

Yes that is huge loss @ 16 AWG.

Gypsy,

Can you tell me how much voltage drop would occur when drawing 16 amps at 12 v D.C. thru 25 feet of 16 gauge copper wire? That is how my electric brakes were wired from the pin box to the wheels and I have now changed to 10 gauge wires down each side.

This will be for straight up results based on 12V, 16A at exactly 25'. There are other variables such as the type of controller used, the condition of your battery and alternator, and the connections of the wires. If they get water in them, resistance goes up:

#16 AWG
Volt Drop 3.21
Percent Loss 26.75%
Volts at end 8.79

#12 AWG
Volt Drop 1.27
Percent Loss 10.58%
Volts at end 10.73

#10 AWG
Volt Drop 0.8
Percent Loss 6.67%
Volt at end 11.2

#8 AWG
Volt Drop 0.5
Percent Loss 4.17%
Volt at end 11.5

Resistance of Copper Wire at 68 degrees F per 1000':

#16 4.016
#12 1.588
#10 0.9989
# 8 0.6282

Generally , you want to stay at 5% loss or less. But for your electric brakes, 0.3 Volts is not that much since your less than 25'.

If you want a real performance increase, consider disc brakes in the future. It's night and day, summer and winter, male versus female.....