Inverter size for microwave or fridge

[DonMcKay]

Originally Posted by Sagecoachdriver

Hey Babock, I think you mentioned it before that doing it the way mentioned here won't work as the inverter drawing off the batteries would power the converter charger and provide 110v to all the coach outlets but would also charge or try to charge the batteries that it's drawing off.

Your converter should have a breaker that powers it, just turn the breaker off to it.

[Sagecoachdriver]

Originally Posted by babock

You just turn the breaker off to the converter.

So doing that will still provide 110v to outlets? Guess I should go for at least 1500 watts if not 2000 watts, right?

BTW, the VA where I was practicing my golf almost daily before the Covid 19 has permanently closed the course. It was free! Now the game will become more expensive!

[notTobyG]

Originally Posted by rockfordroo

Don't know what kind of converter you have, but I just took a look at the WFCO wiring diagram, and it doesn't look like you can actually turn off just the converter by itself. It looks like it's powered by one of the breakers (I would assume the "general purpose branch". Opening this breaker would kill most of your AC outlets and probably defeat the whole purpose. You'd have to install some kind of switch internally between the General Purpose Branch brkr and the converter itself. (It might also be powered from the Main brkr, the wiring diagram is a bit confusing, but that's no better.)

I believe you are correct which is part of the reason why I haven't done it. Since our trailer is in 05' I figured I would wait until the converter crapped out and buy a new one that was switchable. I'm assuming they exist. [emoji16][emoji1696]

[rockfordroo]

Originally Posted by jimmarako

I'm no expert. My previous trailer and current one have WFCO convertors and they were wired to their own breaker. I would think this is the proper way to do it. In the PDF example you posted, if you look really closely at the wiring diagram on the first page the bottom right corner is something like "From 89xxx AC Input" That is a built in receptical. If you follow the three lines coming off of it one goes to ground, one to the neutral bar, and the hot line goes to the tandem handle next to the 30 amp main.

Jim M.

Yeah - If you look at the actual wiring on the left side of the diagram, there's a black wire "pigtail" that it says is "connected to branch circuit," and then in the actual wiring diagram, it shows there are two actual breakers on the "Main" brkr and the convert is wired to the bottom one, with the top one labeled "Main."

But the pic below shows the Main with only a single 30 amp handle, it's not a 2-circuit breaker. So what do you trip to just kill the converter?

If you have one like the pic below, I'm assuming the converter is wired to the "General Purpose Branch" breaker. You could always install a new breaker and wire the converter to it.

[babock]

Originally Posted by rockfordroo

Yeah, but this pic only shows a single 30 amp handle. So what do you trip to just kill the converter?

Mine sure looks different than that. Of course would be simple to just add another breaker and have it just power the converter. Looks like there is plenty of room.

[rockfordroo]

Originally Posted by babock

Mine sure looks different than that. Of course would be simple to just add another breaker and have it just power the converter. Looks like there is plenty of room.

I think I got the pic off the web last year. Not sure what mine looks like with respect to the Main breaker; it's in storage.

BUT clearly some people have just the single circuit Main.

[jimmarako]

Originally Posted by rockfordroo

I think I got the pic off the web last year. Not sure what mine looks like with respect to the Main breaker; it's in storage.

BUT clearly some people have just the single circuit Main.

Well I guess we would need to find the person who posted the picture and ask them. I would have thought the converter always had its own breaker. In your picture I would guess the "general branch circuit" is the converter and the "appliance" circuit is the refrigerator. In both my trailers the circuit for the refrigerator was also the for the GFI string of outlets. I'd imagine that every manufacturer does it different.

Jim M.

[babock]

Originally Posted by rockfordroo

I think I got the pic off the web last year. Not sure what mine looks like with respect to the Main breaker; it's in storage.

BUT clearly some people have just the single circuit Main.

Not only do I have the 120 VAC circuit breaker powering the converter but I have a DC circuit breaker on its output. I long ago got rid of the converter in the power center and put a stand alone unit next to the batteries.


Easy mod no matter what you have to make this work.

[Tom48]

Originally Posted by notTobyG

I run 360 Watt solar panel with a 3000 watt inverter with remote switch. I have approximately 120 Ah of usable battery power. I don't use my microwave that often however, I do like to be able to make coffee in the morning without going outside fire up my generator so I came up with this solution. I installed a waterproof electrical outlet on the outside of my trailer plug into my inverter. Then I plug my trailer into the outlet. When I turn on my inverter I now have power to all my 110 Outlets and can run my Keurig inside the trailer. when I'm done turn off the inverter. This may not be the proper way however for short periods of time, it works.

We ran like that for about 3 years or so in our toy hauler. I put a two hundred amp pure sine wave inverter from a decent brand and an outside outlet.. when we were camping long-term and had plenty of solar going on I plugged the hole coach into that inverter outlet with the appropriate adapter cables

the numbers above are correct or even maybe a little conservative. The microwave can kill your batteries in very few minutes. coffee pot not so much because we normally make coffee in the morning and the solar is going to bring our batteries right back during the morning hours.

the better quality inverter you can afford to buy the better off you will be. I went for a bargain-basement one that I found online years ago and it was rated at 2000 Watts but it cut out at about 1500. and worst of all of it wouldn't handle the surge of my microwave oven which was right in the neighborhood of 1500 watts for just a second or two.

if you're going to invest in something to carry the entire coach even for brief use I would do a lot of studying of inverters. what they call the low-frequency ones are big and heavy and have heavy electronics in them. They're most durable and most expensive. The common ones we see especially on Amazon ae high-frequency ones
They're all digital circuitry they don't hold up as well, they create FCC class radio interference if you are a chronic radio operator . I went with the high frequency unit from a good brand. I really enjoyed doing business with Don Rowe out of Oregon. Their product line is broad their support people are smart and they provide good service.

we only had two big heavy duty golf cart batteries and I always wanted more because 380 watts of solar could have recharged a lot more and I could have engaged in higher usage at night.

[TitanMike]

Originally Posted by Tom48

the better quality inverter you can afford to buy the better off you will be. I went for a bargain-basement one that I found online years ago and it was rated at 2000 Watts but it cut out at about 1500. and worst of all of it wouldn't handle the surge of my microwave oven which was right in the neighborhood of 1500 watts for just a second or two.

Not to say this was your problem but I offer this for the benefit of others.

A lot to times an Inverter will "kick out" under a load approaching it's rated capacity due to voltage drop caused by MARGINAL wire size from batteries.

With any high current DC powered device it's never a bad idea to use the largest wire size you can. Yes, heavy wire like any with an x/0 awg wire size can be expensive, large, stiff, and difficult to work with. However one can use TWO wires on POS and NEG side and in some cases get even MORE current carrying capacity with less voltage drop. For example, two #4 awg wires in parallel have the same current carrying characteristics as a #1 AWG wire and about 3% less voltage drop. On terminals that use a thru-bolt lug just put a connector on each side and run the bolt through all three.

Advantage is more flexible wire that's easier to work with and perhaps a significant saving in wire cost.

Of course wire size won't matter if one's battery bank is low on charge or has developed higher internal resistance due to age. Lots of FLA batteries will provide low current output for many hours to lighting but once a heavy load is added the voltage drop within the battery will cause Inverters to drop offline due to the low voltage. Only fix there is new batteries.


At this point I'll toss in a shameless plug for LiFePo batteries. They deliver plenty of current across a much wider range of SOC. There only wire size is a factor to an inverter.

[nayther]

Originally Posted by DonMcKay

I use a 2000 watt inverter. I also have a transfer switch and that powers the whole RV 110 plugs.

Same here, seamless to use. I just have to remember to turn off the breaker to the inverter so it's not "looping" which is inefficient. Best Converter has an almost plug/play solution; inverter mounted next to batteries with a remote control panel that I mounted next to the electrical dist. panel. Push a button, flip converter breaker and after time delay everything has 110 volt power. The transfer switch is single pole so you have to jump between the two outputs to get both sides of a 50 amp bus hot.

[rockfordroo]

Originally Posted by nayther

Same here, seamless to use. I just have to remember to turn off the breaker to the inverter so it's not "looping" which is inefficient. Best Converter has an almost plug/play solution; inverter mounted next to batteries with a remote control panel that I mounted next to the electrical dist. panel. Push a button, flip converter breaker and after time delay everything has 110 volt power. The transfer switch is single pole so you have to jump between the two outputs to get both sides of a 50 amp bus hot.

I think you swapped your inverter and converter. Don't want to confuse any newbies.

[Sagecoachdriver]

TitanMike, that’s a great idea to use 2 4awg instead do a stiff 1awg. That’s what I will do.

Babcock, what’s the name of the custom cable wire

company again?

[notTobyG]

Originally Posted by Sagecoachdriver

TitanMike, that’s a great idea to use 2 4awg instead do a stiff 1awg. That’s what I will do.



Babcock, what’s the name of the custom cable wire



company again?

I tried using 1awg and couldn't get It to bend the way I needed it to. Didn't stop to think I could have used two 4 awg runs so, I chose to go to a car stereo shop and ask them if they had any scraps of 0/0 awg wire as I only needed 4 feet or so. Normally cable used in stereo installation is expensive but, the pieces were too short to use so they sold them to me cheap. [emoji106]

[Bradmond]

I received custom 10' long 2/0 battery cables from this company today. They will be used to put a 2k inverter in our boat. Might be able to find non marine cables cheaper? The cables are quite flexible for 2/0. They are about 3/4" diameter.

https://www.genuinedealz.com/

[babock]

Same as what previous poster said. I can help you out making cables as well.

Originally Posted by Sagecoachdriver

TitanMike, that’s a great idea to use 2 4awg instead do a stiff 1awg. That’s what I will do.

Babcock, what’s the name of the custom cable wire

company again?

[TitanMike]

Originally Posted by Sagecoachdriver

TitanMike, that’s a great idea to use 2 4awg instead do a stiff 1awg. That’s what I will do.

Babcock, what’s the name of the custom cable wire

company again?

When I upgraded my battery wiring rather than spend a ton on "custom wire" with terminals attached I just bought a crimping tool that could handle the large connectors.

The crimping tool (brand name IWISS) and a large diameter cable cutter was around $35. Bulk terminals were relatively inexpensive too.

I used welding cable as it's extremely flexible and has good weather and chafe resistant insulation. Cut the cost considerably and I was able to tailor wire lengths exactly.

[babock]

Originally Posted by TitanMike

When I upgraded my battery wiring rather than spend a ton on "custom wire" with terminals attached I just bought a crimping tool that could handle the large connectors.

The crimping tool (brand name IWISS) and a large diameter cable cutter was around $35. Bulk terminals were relatively inexpensive too.

I used welding cable as it's extremely flexible and has good weather and chafe resistant insulation. Cut the cost considerably and I was able to tailor wire lengths exactly.

Yep..he lives 15 minutes from me. I have a $300 crimper he can borrow or I can crimp them for him.

[Tom48]

Originally Posted by TitanMike

Not to say this was your problem but I offer this for the benefit of others.

A lot to times an Inverter will "kick out" under a load approaching it's rated capacity due to voltage drop caused by MARGINAL wire size from batteries.

With any high current DC powered device it's never a bad idea to use the largest wire size you can. Yes, heavy wire like any with an x/0 awg wire size can be expensive, large, stiff, and difficult to work with. However one can use TWO wires on POS and NEG side and in some cases get even MORE current carrying capacity with less voltage drop. For example, two #4 awg wires in parallel have the same current carrying characteristics as a #1 AWG wire and about 3% less voltage drop. On terminals that use a thru-bolt lug just put a connector on each side and run the bolt through all three.

Advantage is more flexible wire that's easier to work with and perhaps a significant saving in wire cost.

Of course wire size won't matter if one's battery bank is low on charge or has developed higher internal resistance due to age. Lots of FLA batteries will provide low current output for many hours to lighting but once a heavy load is added the voltage drop within the battery will cause Inverters to drop offline due to the low voltage. Only fix there is new batteries.


At this point I'll toss in a shameless plug for LiFePo batteries. They deliver plenty of current across a much wider range of SOC. There only wire size is a factor to an inverter.

Thanks Mike, but in our case it was just a cheap Chinese inverter. The better brand at same ratings and even weight, but $150 pricier worked great, in the same batteries, location and 3 foot 2 ga cabling.

[rk06382]

Originally Posted by Sagecoachdriver

I want to upgrade my old 400 watt inverter that I use dedicated solely for my Dish receiver and sound bar, nothing else at this time to accommodate running the 12v propane/110v fridge or microwave for 5 minutes. I have 2 Battleborn 100 watt and 300 watts of solar with another 100 watts available with Renogy 100 watt suitcase. I know there will be limitations on how long they can run. My goal is to be able to run microwave in off generator hours to defrost or cook a meal and at other times run the fridge and avoid using propane if supply is limited. Anyone have experience with it?

I started my Inverter project to be able to use my CPAP at night without CG power. I decided on an Inverter/Charger w/built-in transfer switches, large enough to run the all 120v circuits. Solar tax credits help pay for the system.

Because I can recharge the Battle Born batteries as I drive down the road, I run my fridge on the 120v inverter to save propane. I also have no problem using the microwave after the Mr Coffee has brewed while watching a DVD. In the evening my wife uses her Instant Pot & the microwave to cook supper while watching a DVD.

The Inverter is on all the time except while in storage. I can even set the clock on the microwave and not need to reset after switching between shore & battery power. It is like having a UPS for the motorhome.

I used 4/0 awg welding cables cut to custom lengths. I have less than a tenth volt loss between the Batteries & Inverter.

For the long version read the Solar Power & Battle Born batteries link below: