Pure Sine Wave vs Modified Sine & Refrigerators

[sundancev]

Many thanks for all the input guys.  One of the big reasons I like FMCA so much.  Paul

[rlbarkleyii]

My never cold N8xx recently required a lower door from hanging gallon jugs on it, all plastic!   It's now 15 years old so I am making replacement plans. I will replace it with a residential and power it via ice maker plug. At the breaker box which is at the end of the bed frame, I will isolate the wire from the refrigerator and reroute it direct to the outside electric bay approximatly 8 feet away. The electrical bay as I call it houses the shoreline, transfer switch, surge protector, and has a lot of available space. I plan to install a PSW inverter on the side wall and run the refrigerator line with a breaker to the PSW. The PSW will get DC power from cables connected to the house batteries less than a foot away. The inverter must be a ATS featured type that will sence when AC power is available and act as a transfer switch. I will also install a separate DC line to the interior of the coach so I can shut off the inverter completely when I am concerned about battery drain. The DC shut off-on would be handled by a continuous duty  Solinoid. 

Has anyone identified the best replacement for the NORCOLD 800 series reefer?

I would appreciate opinions and/or comments in regard to my plans.

[five]

On 9/18/2017 at 5:54 AM, jleamont said:

....I have heard of a few installing a 2nd inverter by itself dedicated the refrigerator, that a different game all together that would require some wiring...

I don't know if they are still doing it, but American Coach used to put in two 2800 watt inverter/chargers and each had four AGM 6v batteries to power it...with one dedicated to the refer.  A second inverter is not necessary.  My Whirlpool uses 3 amps when the compressor is running.  I think Carl has this set up.

[BillAdams]

Be careful when placing an inverter too near your batteries.  This could be a fire hazard if the batteries are able to out gas such as wet cell and some "no maintenance batteries.  The Samsung is often mentioned as a nearly exact replacement for some Norcold models.  You might want to do a search on the Tiffin RV Fourm as a number of folks have done the replacement and at least a couple did full photo documentation.

[manholt]

FIVE is correct, I have 2 of the 2,800 PSW inverter/converter.  1 is dedicated to a Whirlpool Gold 23 cu. side by side with ice, water in door dispenser.  Each 2,800 takes 4 AGM 6V batteries.

I don't know the space available that you have in your coach, but mine is probably overkill....suggest you PM to Joe or Herman, since they both had no cold and put in their own residential.

[elkhartjim]

In my 2008 Bounder Diesel, I replaced the Norcold with the Samsung RF18. I used the ice maker plug for power, 2000W pure sign wave inverter, 4 - 6Volt wet cell batteries. Never had any power issues but always had hard ice cream. 

Lowes drivers unloaded the Norcold and set the Samsung in the Norcold opening for me all through the passage door. I gave them 20 bucks each. 

BTW...its currently on sale for $999 at Lowes.

[abyrd]

I also have the Samsung RF 18, I also have it plugged in the original ice maker receptacle, I have a modified sine wave inverter and it works fine.

Jim

[huffypuff]

50 minutes ago, elkhartjim said:

In my 2008 Bounder Diesel, I replaced the Norcold with the Samsung RF18. I used the ice maker plug for power, 2000W pure sign wave inverter, 4 - 6Volt wet cell batteries. Never had any power issues but always had hard ice cream. 

Lowes drivers unloaded the Norcold and set the Samsung in the Norcold opening for me all through the passage door. I gave them 20 bucks each. 

BTW...its currently on sale for $999 at Lowes.

$998 at Home Depot will save you one dollar.  Don't spend the savings in one place.  

[hermanmullins]

I put in a RF-18 Samsung 2 years ago and it has run on my 2000 watt Modified Sine Wave Inverter for the entire time. Never a problem.

Herman

[thezafts]

One of the early questions was "can I use a Small, (say 500w) PSW inverter to power the residential refrigerator only"?

if yes can I wire it to the current inverter?

[wolfe10]

2 hours ago, thezafts said:

One of the early questions was "can I use a Small, (say 500w) PSW inverter to power the residential refrigerator only"?

if yes can I wire it to the current inverter?

You could, but much better to wire it directly to the battery (close but not in same compartment.  The battery will both act as a "filter" and provide less electrical loss when operating off the battery (larger gauge cables AND shorter run).

[kaypsmith]

6 hours ago, thezafts said:

One of the early questions was "can I use a Small, (say 500w) PSW inverter to power the residential refrigerator only"?

if yes can I wire it to the current inverter?

If you are speaking in terms of the DC to the inverter, as Brett suggested is best. If you are speaking in terms of AC away from the inverters, ABSOLUTELY NOT. Never try to mix any two AC sources without the proper routers to do so, and never try to mix MSW with PSW, there are no routers available to do this. Also, if the refrigerator is rated at 4 amps maximum draw, that's 500 watts, I would not recommend only 500 watts, I would recommend 750 to 800 watts for a longer life expectancy of the inverter, when you near the maximum output of an inverter, you shorten the life of that appliance due to excessive heat for the rating of the inverter.

[wildebill308]

7 hours ago, thezafts said:

One of the early questions was "can I use a Small, (say 500w) PSW inverter to power the residential refrigerator only"?

if yes can I wire it to the current inverter?

I can't think of any situation where it would be good to piggy back one off the other.

Bill

[thezafts]

I was just looking for a close DC source for the small inverter, batteries are 6' away vs 2'. No mixing of psw and msw.

The refer I am looking at is rated 338 KWh so around 80Ah or 500watts.

Does it make any sense to install a 800 watt inverter that is on 24/7 instead of running the 1500 watt inverter 24/7?

We do have 250 watts of solar which is on the low side for this but then we boondock only occasionally, and we still have the generator for a needed boost.

What would you do? The Norcold is 13 years old, 7.5cf,  leaking door seals, repaired hinge. New is $2300, small residential 10.7cf is $450.

thank you

[blakeloke]

It wouldn't make a lot of difference if you find a refrigerator that fits and will run on MSW.  If you have to use an PSW inverter I would look into upgrading to the larger inverter if your house wiring is sized correctly.

With a larger inverter you should be able to use smaller appliances and TV in conjunction with your new refrigerator.

For example: we went from a Norcold 1200 to a Fisher & Paykel residential.  Fisher & Paykel was the only French door residential refrigerator that would fit into our space.  The manufacturer had no experience with running the unit on MSW so we opted to change the inverter and control system to PSW.  At the same time we went from 2,000w to 3,000w.

Blake

[jleamont]

If a dedicated Inverter is all that Powers the refrigerator that seems to me as more of a roadblock vs a benefit. When on generator or shore power that Inverter is still working and so is the charger portion of the main unit keeping up. Seems like it would stress more items than it's worth. Am I missing something here?

[wolfe10]

39 minutes ago, jleamont said:

If a dedicated Inverter is all that Powers the refrigerator that seems to me as more of a roadblock vs a benefit. When on generator or shore power that Inverter is still working and so is the charger portion of the main unit keeping up. Seems like it would stress more items than it's worth. Am I missing something here?

Again, we need SPECIFICS to know how to advise.

If your converter or inverter/charger is of limited capacity, this is a very valid commend and would warrant looking for a unit with a built in ATS or wiring through a separate ATS.

But, if a high-amp converter or inverter/charger, may be a non-issue.

[jleamont]

Agreed, but wouldn't it be more beneficial to upgrade the main Inverter in that situation? I realize there is more of a cost associated to upgrade the main Inverter/charger but the long term benefits seem to outweigh.

[thezafts]

I will leave it simple for now, just use the existing 1500 watt msw inverter/charger and leave it on all the time.

i do know of coupe of other rv'rs that have installed the small Whirpool refer and it does work on the msw inverter, but they are not hard core boondockers either.

Thank you for the help,

Harry

[manholt]

Harry.  You posted yesterday that you only boondock occasionally...I'm confused!

[thezafts]

"Not a hard core boondocker either"

harry

[bm02tj]

Modified sine works on most things but does cause more heat in motors and small chargers 

where the pure sine cost more and is easier on your stuff your call 

[manholt]

Harry.  Sorry, I miss read it, my bad.   Samsung runs on MSW.  At 1,500W your only restriction is size, I would check on the unit that Joe has....definitely get rid of No Cold, we don't like our ice cream runny!  

[kaypsmith]

1500 is plenty sufficient with a Samsung, it is very low amp draw, just need to watch other appliances to make sure that you don't call on too many at the same time. I'm not trying to sell Samsung, there are many others, LG makes a great fridge, but will not run on MSW. If it were me actually going to make replacements, I would replace the 1500 MSW with a 2000 (or larger) PSW, only real rewiring that will need is to enlarge the wire from batteries to the inverter.

[thezafts]

Have small RV, need small refer.  The Whirpool 10.7 cf fits with minor trim, I know it runs on msw inverter, she likes it better then other brands, don't need any vents, and yes hard ice cream again!!!!  Also 40% more room than No Cold, which means more salmon & crab to bring home from the NW !

harry