Standard vs Residential Refrigerator

That's impressive.

CA Traveler wrote:
John,

Impressive numbers but I'm not sure we're speaking the same language. Firgidare lists a 22.6 cu ft side by side refer as 8.5A/120V. A cool down in 40 minutes with 35 minutes of running seems impossible to me unless the refer is already cold. The freezer drops from say 70F (typical temp) to 0F in 40 minutes at startup? I'm confused.

I'm guessing the 8.5 amps would be startup current. My meter is able to capture instantaneous as well and I get around 9 amps plus or minus on start up. The Samlex and my meter concurs with around 95 to 110 watts or around 1 amp. The other couple of residentials I have helped install were around the same. The defrost cycle pulls more but I haven't been able to nail down how long it runs for as the couple times I have caught it I got distracted and wasn't able to follow it through. We are in year three with ours and are happy with it. Dry camping hasn't changed much for us but we have always run our genny during meal prep times so figure in a total of 1 hour to 90 minutes per day of run time. We did this before we got the residential to so life hasn't changed much for us. There have been a couple times where we couldn't run the genny in the morning but the supper time session seemed to take care of things. We had a robust solar system before we got the residential so that helps. I have always advocated a 400 watt solar array if installing a residential. Our friends have 4 x 6 volt and 2 x 160 watt panels and they seem to fine for 3 or 4 days....if it's sunny. :). I think he is adding another 160 watt this year. Solar is cheap and big rigs have lots of roof. :).

Bob, this is just cooling the empty box starting out with the unit at a normal home ambient of about 75 degF. If the box is in a 100 degF RV, it will take longer.

Ken

John,

Impressive numbers but I'm not sure we're speaking the same language. Firgidare lists a 22.6 cu ft side by side refer as 8.5A/120V. A cool down in 40 minutes with 35 minutes of running seems impossible to me unless the refer is already cold. The freezer drops from say 70F (typical temp) to 0F in 40 minutes at startup? I'm confused.

CA Traveler wrote:

John & Angela wrote:

CA Traveler wrote:

rsbabson wrote:
Im looking to buy a Columbus 320rs with the residental fridge also. So you cant load the fridge up and roll down the road with your groceries?

Never is that a good idea. The contents will warm up before they cool down in the warm refer and that is asking for bacteria problems.

Using a 300W refer draw for example you would need to supply 300W/12V = 25A so use 30A to allow for losses including the inverter. Your alternator may/may not have that extra capacity. Typically a truck and trailer wiring will not have the capacity to carry that amperage without significant voltage loss. One option is to have an inverter in the truck and run a 120V line back to the refer.

Almost any option includes a precooled refer. This also allows the refer to cycle on/off which reduces the overall power over a period of time. Plus once cooled you may be able to turn it off for a period of time while driving.

Your power usage estimate is off. Typically they draw about 1 amp at 120 volts. They will run for about 5 to 7 minutes and then cycle off for 10 to 12 minutes. No problem for an alternator in a truck. I agree with earlier comment insuring that the charge line to the trailer be of sufficient gauge. The running lights on the trailer will draw as much or more than the fridge.

It depends upon the actual model which the poster did not specify. One model of the previously mentioned Samsung RF197 indicated it draws 15A at 120V which may well include the worse case scenario. But I gave the poster the formulas he can use for his application.

Refers do cycle on and off which certainly helps reduce power. But this poster wanted to start with a warm refer which won't cycle until it cools. However I certainly hope no one does that as bacteria develop quickly with warm food.

You make a good point re the cool down. Ours seems to do it in an initial 15 to 20 minute cycle followed by a little 5 minute break and then on for 10 to 15 more and it's cool. I would imagine that 15 amp thing that you saw referred to start up current for the first 1/2 second which is irrelevant to the overall power budget. Most draw 1 to 1.3 amps when cycled on. This translates to around 10 amps DC. Our Samlex inverter actually reports in watts and it is usually between 95 and 110 watts of power. Not even a grunt for an alternator. Ours is a 22 cubic foot frigidaire. We have an older flat screen TV in the rig. It uses about the same....except its duty cycle is 100 percent...when its on of course.

pcm1959 wrote:
Chris, ORDER THE RESIDENTIAL refrig! You won't regret it. We are pretty much the same type of campers as you.
I ordered a 2014 Lifestyle LS36fw with an optional Norcold 1210 side/side refrig which was a $2800 option. I took delivery of the rig in early March. The Norcold has been nothing but trouble. I should have saved my money! But that is all another story. I pulled-out the Norcold and sold it on CList for $1750. That paid for a 1000 pure sine wave inverter, transfer switch, cables, a Samsung RF197 French door refridge and anything else I needed to do the mod. I already had 2 deep cycle 6 volt batteries. So I just added an inverter with a dedicated line to the refrige with the transfer switch.
I don't know what model refrig you will be getting but the Samsung draws 3 amps upon compressor start-up and about 1 amp while running otherwise. The inverter has a 1.4 amp no load draw.
We live in FL and it will take about 3.5 hours to cool down from the mid 90's to -2/37 degrees!!! Starting out with full batteries they are drawn down to about 2/3 to 1/2 in that time. Once hitched up the truck prevents any further draw. If you keep the doors closed, it will stay at safe temp for hours during travel IF you don't want to run the inverter. We leave the inverter on without issue. you could always add 2 more batteries or a solar panel if your reserve battery power concerned you. If is not a problem for us.
Ours has the ice maker but no filtered water. That is fine as we don't use a lot of ice and filter all the water coming into our rig. We are not big ice users either but make ice in the old-fashioned ice trays. We have five of them and we just dump the ice from them in freezer ice bin and use a scoop when ice is needed. Like you, we are not full timers and didn't want the stale water setting in the lines between trips nor the worry of winterizing.
We LOVE the latest mod and feel such freedom from the NO-Cold. I can't imagine you'd regret going the residential route. Good luck. Phillip

Residential should be an easy decision! (as in "no-brainer")..:W

*SAFE*,, reliable - and easy options for power.

Try a search on residential refrigerators in the Motor Home forums.

There are still some AC/Propane lovers - but they are getting to be few and far-between.

The quality -and longevity- of AC/propane is *NOT* what it used to be - a guess would be due to inferior Chinese components.

The proof of that is the replacement of the above with the Amish cooling units - which (IMO) is still throwing money at something that should be scrapped ASAP when it fails. (and it will)..:(

BTW - in re: "Safe".
Anyone with a new or old AC/Propane refrigerator should have a fusible link activated extinguisher in the rear of the freezer compartment.
The life (and RV) you save - may be your own..;)

~

missourijan wrote:
Just my 2 cents, this has been discussed a lot over on another rv forum, IRV2.com..

It's been discussed a lot here too.

In addition to the links I posted, it's easy to search 'residential' in Tech forum (or this one, or Class A) and find hundreds of posts. If you want weight, Search within results= "weight". Yes, it might take a few minutes, but it might beat waiting for an answer - and add to one's skill set. :)

Just my 2 cents, this has been discussed a lot over on another rv forum, IRV2.com. Hate to burst bubbles but the Samsung rf197, which fit perfectly in the box where the Dometic is(and maybe the Norcold), is being discontinued. There is a model that is replacing it but it sticks out 2 inches more, which won't work for those of us that have a center island close to the frig. If you do a search on IRV2.com just put in "Samsung rf 197" and those discussions will show up.

Interesting subject.

My wife and I are frequent dry campers mostly on weekends and 2-3 weeks in the summer. Right now we have your typical Nor-Cold n(I think.?) and it is not big.

However I have seen in a number of Citations and some Travelaires, a 10 Cu ft fridge that I must say have a ton of room...Still the idea of an ice maker and cold filtered water on demand..is VERY appealing.

My only concern is that our fridge is located in one of the slides opposite the entry door.

For those that have done this mod...what was the weight difference between a 12V/Propane powered unit and a residential..??

Thanx,

Stk

lynndiwagon wrote:
Sorry John, your calculations are incorrect..

Which post are you referring to?