Inverter for Mini Fridge

[Greengas]

Good Evening Heartland Family

I've put a 110v 4.5cu mini fridge in the front closet of our landmark San Antonio. We use it as a beverage fridge and it works great. That is, it works great while we are plugged into shore power. What I want to do is put in an inverter that I can attach to the back wall of the battery compartment and connect directly to the batteries and run a cord from that to my mini fridge. Then, while I'm on the road I can plug the fridge into the inverter outlet and it will keep things nice and cold. When we plug into shore power I will plug the fridge back into the regular outlet, turn off the inverter, and be good to go. We don't boondock much at all and when we do it is at the most, one night.

Now, reviewing the specs of the fridge, according to the label it uses 226 KWH annually. (can't get to the fridge right now so that number will have to do) Doing the math I found on line on how to convert that to watts it uses just about 26. Of course, I will be getting an inverter larger because I understand about loads, and the fact that I don't truly believe the gov sticker. My thought was at a minimum a 750 watt. I've seen lots of them on line, some with an auto on/off switch and others that I guess you put in line and they can run your rig (if you have the battery power) and then auto transfer when you plug into shore power.

Right now, I don't really have any use for 110 power when not plugged in other than the fridge (might be nice to be able to watch TV when boondocking, but...)

For batteries I will have 2 new 12 volt Group 31 AGMs each with 105 amp hr ratings.

So, I'm looking for recommendations on how to set this up. Should a 750 watt be sufficient? What about pure sine wave or not? Should I look at auto transfer set up and then not have to worry about plugging and unplugging or is that overkill for my use? What about installing a second battery cutoff between the inverter and the batteries or put it after the cut off that is already there so when I shut down the batteries it shuts down the inverter as well (no parasitic draw)?

So many questions, but I'm confident that my Heartland Family will come up with some great recommendations.

 

[Oregon_Camper]

Before I did the MAJOR overhaul to our Bighorns electrical system, I added a small inverter to run our Theater Chairs. We boondock most of the time and without 110v we couldn't even open them.

If you are just using this for the refrigerator...you will not need a pure sine wave inverter. Now...if you plan to power stuff like computers, TV, etc...then you would want pure sine wave.

I used an the 1100w inverter from Energizer and added the remote start switch. This was a bigger job for me, as I had to run Romex and phone cable from front of our RV to the rear.

For your needs, this will do great. You can then turn the inverter on with the remote (in closet?) or at the inverter itself. We added a dedicated 110v outlet for this, that only gets power from inverter.

Here is the inverter from Home Depot (wasn't available on Amazon)

Link to Remote on Home Depot

 

[carl.swoyer]

Good Evening Heartland Family

I've put a 110v 4.5cu mini fridge in the front closet of our landmark San Antonio. We use it as a beverage fridge and it works great. That is, it works great while we are plugged into shore power. What I want to do is put in an inverter that I can attach to the back wall of the battery compartment and connect directly to the batteries and run a cord from that to my mini fridge. Then, while I'm on the road I can plug the fridge into the inverter outlet and it will keep things nice and cold. When we plug into shore power I will plug the fridge back into the regular outlet, turn off the inverter, and be good to go. We don't boondock much at all and when we do it is at the most, one night.

Now, reviewing the specs of the fridge, according to the label it uses 226 KWH annually. (can't get to the fridge right now so that number will have to do) Doing the math I found on line on how to convert that to watts it uses just about 26. Of course, I will be getting an inverter larger because I understand about loads, and the fact that I don't truly believe the gov sticker. My thought was at a minimum a 750 watt. I've seen lots of them on line, some with an auto on/off switch and others that I guess you put in line and they can run your rig (if you have the battery power) and then auto transfer when you plug into shore power.

Right now, I don't really have any use for 110 power when not plugged in other than the fridge (might be nice to be able to watch TV when boondocking, but...)

For batteries I will have 2 new 12 volt Group 31 AGMs each with 105 amp hr ratings.

So, I'm looking for recommendations on how to set this up. Should a 750 watt be sufficient? What about pure sine wave or not? Should I look at auto transfer set up and then not have to worry about plugging and unplugging or is that overkill for my use? What about installing a second battery cutoff between the inverter and the batteries or put it after the cut off that is already there so when I shut down the batteries it shuts down the inverter as well (no parasitic draw)?

So many questions, but I'm confident that my Heartland Family will come up with some great recommendations.

If you could find an inverter with a built in automatic transfer switch it's going to be a great application. You I'd the circuit involved with the fridge outlet and run the wires thru the inverter. The transfer switch will toggle between shore power and lack of, but ac to that circuit would be constant.

Sent from my XT1254 using Tapatalk

 

[Greengas]

Before I did the MAJOR overhaul to our Bighorns electrical system, I added a small inverter to run our Theater Chairs. We boondock most of the time and without 110v we couldn't even open them.

If you are just using this for the refrigerator...you will not need a pure sine wave inverter. Now...if you plan to power stuff like computers, TV, etc...then you would want pure sine wave.

I used an the 1100w inverter from Energizer and added the remote start switch. This was a bigger job for me, as I had to run Romex and phone cable from front of our RV to the rear.

For your needs, this will do great. You can then turn the inverter on with the remote (in closet?) or at the inverter itself. We added a dedicated 110v outlet for this, that only gets power from inverter.

Here is the inverter from Home Depot (wasn't available on Amazon)

Link to Remote on Home Depot

On running the Romex, I noticed the inverter has what look like standard plug receptacles. Did you build you own cord by using Romex from the dedicated outlet box and then wiring a plug on the other end? Also, did adding the shut off switch completely shut down the inverter? I've heard that some continue to have a draw unless you formally disconnect it from the batteries.

- - - Updated - - -

If you could find an inverter with a built in automatic transfer switch it's going to be a great application. You I'd the circuit involved with the fridge outlet and run the wires thru the inverter. The transfer switch will toggle between shore power and lack of, but ac to that circuit would be constant.

Sent from my XT1254 using Tapatalk

if I'm following you correctly, I find the Romex going to the outlet I will be using, then cut it before it hits the fuze box and run it instead to the inverter that has auto transfer capability thereby making it a dedicated circuit (since I would be taking it away from the fuze panel would I need to put in an in-line fuze our would the fuze on the inverter take care of that?)

I think I understand how the auto transfer would work and I think I have one in my rig because I got the generator prep which I believe would have an auto transfer. Anyway, how would I hook up the inverter so it would know what power is coming in? I'm sure there would be instructions in the box but I sure would like to have an idea before deciding if I should jump into the deep end. If I do, I will also include the outlet that the bedroom TV is running so if we are Boondocking we can watch some over the air channels, or a movie.

 

[Oregon_Camper]

On running the Romex, I noticed the inverter has what look like standard plug receptacles. Did you build you own cord by using Romex from the dedicated outlet box and then wiring a plug on the other end?

Ok...I had to go back to my plans. I was wrong...i did not use Romex for this job, I purchased a 75' 10 gauge (10/3) cord for this. I then ran that and the telephone cable to the back of the RV. Then wired the new outlet in an approved junction box.

You will only need (at most) 20 feet as both will be in front of RV.

...did adding the shut off switch completely shut down the inverter? I've heard that some continue to have a draw unless you formally disconnect it from the batteries.

Regarding the shut-off switch. From what I can tell, the inverter is OFF. Is there some parasitic drain? I have no idea. When I put my RV in storage, I always turn the built in cut-off switch to off, so nothing ever drains our batteries.

 

[porthole]

Find yourself a 1000 watt inverter with an auto transfer switch.
Most lower end inverters average about 80-85% efficiency, so a 1000 watt inverter is closer to 800-850 watts.
As temps go up, efficiency goes down.

And you don’t want to be running your inverter near it’s max output all the time.
Keep in mind that although your ‘run’ power draw may be low, it is the startup compressor draw that you need the reserve for.

If you move up to a pure sine wave model, the quality tends to go up as well as efficiency, sometimes 90% or better.
All inverters have an idle current draw, so you should consider having a battery cut off switch in line.
Even models with remote switches may have a minor draw when off.

The auto transfer switch in the inverter operates in milli-seconds, your fridge won’t see the power switch.
The auto transfer switch for you gen prep has a bit of a delay and the switch is wired to give the genset priority.