Norcold replacement/inverter

[robert5158@att.net]

It seems to me, back when members first started replacing Norcolds, there was a lot of talk about having to add/replace our 2000-6 square or modified wave factory installed inverters with a pure sine wave inverter when converting to a residential refer. I think the supposed problem wasn't so much running the refer, but with automated/timed functions such as defrosting, etc. Anyway, lately I haven't seen that mentioned, and have seen several report their residential refer conversions running just fine with their older/original inverters. I'm considering going residential, and would appreciate any thoughts or comments about using my old Xantrex 1500 w inverter/charger.......which has been rebuilt, and working fine.

 

Robert Barton

2003 HR Endeavor

[David White]

Robert, I added a separate 1200 pure sine inverter dedicated to the fridge.  It has capacity for another circuit too.  It has a built in switch to auto change back and forth between shore power and batteries and the cost is less than a new house inverter.  About a year ago, it was about $250. A 1000 with transfer would work well, and they are readily available.

it appears you present 1500 is small if you add the fridge.

Edited June 24, 2020 by David White

[Just Jim]

I don't know about compressors, etc in a fridge, but computers and other electronics like pure sine wave energy.  In my mind I would think you would need a inverter larger than 1500 watts and you also usually see people add batteries to the bank as well. 

[CTerry]

                I replace d a not so cold with a Samsung about 6 years ago in my 2003 Beaver. Plugged in to receptable that is hot all the time if plugged in or on inverter. Original inverter and still only the 4 batteries. No problems at all. Will run all night on the batteries with very small voltage loss.  

[Steve Hepfer]

I have a 200 watt Modified Sine Wave inverter running a new Samsung RF18 residential refrigerator. I leave the inverter on full time so if I change or loose power the unit will automatically stay on. Works fine so far with no complaints.

[Tom Cherry]

Best memory on this topic is the following....

Just to CLARIFY....you have a 2000 Watt Square Wave Inverter....that is the factory.  You have a 1500 Watt SPARE inverter and want to use it exclusively for the Samsung.  If that is the question, then here is my response....

THAT DEPENDS....  You need to check with the vendor as to the Square Wave compatibility.  Samsung, I think, does not care....as long as it is 115 VAC.  

Assuming that the brand of ResRefer that you choose is compatible with the Square (MW?) 2000 Watt inverter, then there might not be any reason to add the second inverter....unless you just "want too".  I had some doubts many years ago.  IF you do not routinely have HIGH capacity appliances working all the time, you will NOT have any capacity (wattage) issues.  We have the 2000 watt RF18.  We run a coffee maker in the morning.  We do NOT microwave when using the coffee maker.  We do NOT run fry pans or other appliance, including hair dryers) when we microwave or are making coffee....or if the wife is doing some cooking in the fry pan, she does NOT use any other high current or demand items.  The Samsung works just fine.

There will be additional costs for installing a supplemental Inverter.  You will have to "Cable it" to the existing inverter to to the House Bank.  You will have to run an AC line from the Refrigerator bay to the Inverter.  MOST folks have an Inverter Outlet (typically for the icemaker) in the Refer compartment and just plug in there.  The DC cables are not cheap.  Running them or the AC might not be convenient.  

When folks install a supplemental inverter, they seem to be as polarized as FORD vs CHEVY.  SOME will install it with NO ATS, so that you are always "inverting" and running the ResRefer OFF the batteries.  Some put in an ATS so that when you are on Shore (or Genny), the ResRefer runs off the pass through 115 VAC AC.....and not continually being ON or in use.

As I said....I was a "NEED the additional Capacity FREAK or Zealot" and opined about it and wanted the ATS.  Some objected and were equally adamant about NOT needing a supplemental and then we had the FRINGE.....Use the supplemental....but no need for extra mess like the ATS..

I have done fine for several seasons with just my 4 bank set and my OEM 2000 Watt Inverter and see NO need to do such.  I did boon dock for a while and never needed to run the genny but ONCE per day.

 

[Guest Tim503]

If you hear a buzz coming from your TV then plan on a pure sine. The days of modified are over. Do not rebuild a 20 year old unit but it is nice they still operate. I have gone more solar and use a 4000 watt pure sine. You need at least a 2000 watt to run the micro, the start up surge on the fridge and a vacuum etc.along with your electronics. My fridge was a Home Depot $288 apartment fridge. Once I got it home it said do not install in a RV and do not run it on an inverter. The starting surge is 10 times so I bought a Harbor Freight modified sine 2000 watt for $129. It worked. It is still working. I just converted to pure sine and hope to power my AC.

[Guest Cruzbill]

Getting off topic here a bit: for solar AC see 

https://www.gonewiththewynns.com/off-grid-solar-rv-air-conditioning

Its the size of your battery bank that is important for large loads such as AC. Try a $7,000 investment in lithium batteries to start.  

 

[Tom Cherry]

WHOA and Company HALT....

Back to Basics.  The Samsung RF series works on Square Wave or MSW units.  Again....check with the manufacturer.

Second, unless you do a LOT of dry camping or boondocking and don't like the sound of your genny, then Solar is the only answer.  NOT CHEAP....but an alternative.  

A Genny, run once per day....with a FOUR Battery Bank (2 6VDC in series and the pair in parallel) will provide 450 Amp Hours of capacity.  As long as your run the Genny around 2 - 3 hours per day when dry camping, you have no issues with that size bank.  This is from my own experience as well as countless folks here and at the Gatherings.

As to the need for more than 2000 Watts.  YES, if you purchase a "Surge Hog" refrigerator, it will definitely cut into your capacity.  BUT, if you have a Samsung or similar, then you rarely, if ever, notice the surge.  I was, as I said, a proponent of a separate inverter for the Refer....WITH a small 15A ATS.  I looked at the costs and trouble of hooking that up.  I said...."We'll see" and we have not had any issue.  

I probably WOULD put in a NEW 1000 Watt PSW Auxillary Inverter IF I needed MORE capacity.  But, if you use the Energy setting on the Samsung when dry camping and such, you don't need one.  

Magnum upgraded their line to include a 2800 (may be 3000 now) so that you had 2000 watts of power and also 800 watts for the Refer.  They provided THREE circuits.  House, Microwave and Refer.   You can purchase a very nice Xantrex PS-1000 (memory) and their 15 A ATS for less than $400 if you need it for the Refer.  The cabling will probably run upwards ro $200 or so.  The EASIEST way is to put the NEW Inverter next to the OLD one and Parallel the cables to the Inverter.  Monaco use 4/0 Cables.  that has MORE than enough ampacity to support 3000 watts.  That will reduce the cost.  THEN, you run the AC line from the back of the Refer Area to the Inverter...  If you do it the other way and try to get the Inverter close to the Refer.....you spend a fortune.

As to Lithiums.  Well, as long as you have a state of the art NEW inverter and a BMK and know what you are doing and constantly monitor the and don't abuse them.....great.  Many folks here have swapped from flooded to AGM's and had issues as they were not being properly monitored and charged and such.  IF you abuse an AGM, it is toast.  I would worry abut such with the Lithiums....  SO plan on a very expense Inverter to support the Lithiums....or you may end up with a very expensive mess.  Unless I was an expert or had a really GOOD Solar and Lithium dealer, I would totally gut my MH and start out with a NEW Inverter designed for Lithium and then put in Lithiums and if I wanted a LOT of capacity....add a big solar farm to the top.  Would NOT be cheap....  Batteries....$8K.  Inverter (installed) $5K, Solar....$5k???.  BUT, you would be set....

[Chuck B 2004 Windsor]

The issue would be if the manufacturer's warranty would cover their frig if there was a problem while running on a modified sine wave inverter.  

[Guest Cruzbill]

At 50% discharge, flooded lead acid battery bank capacity is 225 amp hours, not 450 amp hours. For 4x GC2 6v batteries in series-parallel.  

 

https://www.powertechsystems.eu/home/tech-corner/lead-acid-battery-downsides/

[Tom Cherry]

48 minutes ago, Cruzbill said:

At 50% discharge, flooded lead acid battery bank capacity is 225 amp hours, not 450 amp hours. For 4x GC2 6v batteries in series-parallel.  

 

https://www.powertechsystems.eu/home/tech-corner/lead-acid-battery-downsides/

Yes, the "usable" or recommended capacity is 50% of the total ampacity to prevent damage to the batteries.  I know NOT what AGM's will stand or Lithiums.

However, as i stated previously, if you have 450 Amp Hours of battery capacity, then if you run your genny for about 2 - 3  hours every 24 hours or once daily, you will, ASSUMING the batteries are capable of achieving for receiving a FULL charge, NOT GO BELOW 50% SOC.  That is based on personal experience....as well as others.  

The RF18 uses, per Samsung and Govt testing, around 562 KWH or 1.54 KWH/day.  Bill Groves, Richard and several others, including myself measured the energy consumption.  I think were were all in that range....but for purposes of estimating, use 1.75 KWH or 1,750 Watts over a 24 hour period.  Use a nominal voltage of 12.25 VDC.  That equates to 143 Amps or Amp Hours if you want to look at it that way.

EDITED.....Correction.  The 143 Amp Hours is actually for a 24 hour period.  If you run the Genny for 3, then you only will consume 125 amp hours.    The Magnum PSW inverter along with the other parasitic loads will average around 2 Amp or 42 (21 hours inverting).  That is a total of 167  Amp hours.  OK, you will have some pump run times and other such items.  You can also make ice during the 3 hours of RUN TIME.    Therefore, you are using 75% of the available 225 Amp Hours for OTHER purposes.  

BUT, if you use the "Energy" setting, that greatly reduces the load.  MOST folks when the boon dock will turn OFF or pull the plugs to the HEC.  I have power strips for that.  Most folks have also upgraded to LED lights....so the lighting load is reduced.  Most folks will NOT make ice during this period.

With a little common sense and energy conservation,  you will STILL easily get the 24 hours of consumption, without putting the batteries at risk.  We have proven that by use.  We have calculated that many times.

Adding in a single bank does NO get you to 48 hours....so if you want 48 hours, then you need to have a bank of 8....which many Dynasties and upper ends have.  But, a single bank of 4 works fine....  In fact, if you actually exercise or drain the batteries periodically.....as in parking at a stop or such, you will get longer life from flooded cells in a MH with a Res Refer than one without.  Trojan says that always having the MH connected to power and never draining the batteries to around 50% or so hurts them.

One final point....since we have gone down this path.  If you have a Res Refer and use the AGS and have GOOD flooded cells and no excessive drain....then you can safely set the AGS to around 11.8 or 11.9 VDC.  WHY.....the actual battery voltage will be around 0.1 - 0.2 VDC higher.  If you do the load test.....read the Magnum remote and then the actually bank.  The battery voltage is always higher on the bank.  Trojan says that they do not "advertise" this as they want to make sure that you have adequate Amp Hours to crank the Genny, but YES....if you want to go to a 50% SOC, use the lower voltage and not the charts...

Edited June 30, 2020 by Tom Cherry
changed parameters for calculations to reality

[Guest Cruzbill]

Just replaced our Norcold (worked just fine) with a new Fisher Paykel 18cuft french door fridge. Upgraded our inverter to  pure sine wave (per F&P). I took some readings using  a Kill A Watt meter and found AC consumption was about 30-40 watts / hr with .33 amp AC draw. Runs all the time as its an inverter type fridge.  So that's a hair shy of 1 kw/day. 

[veraken]

The best/easiest thing to do is to add a separate pure sine wave inverter with a built in transfer switch for the fridge. I would suggest you look at a KISAE SWXFR1210 1000W Pure Sine Inverter w/ Transfer or KISAE SWXFR1220 2000W Pure Sine Inverter w/ Transfer. I haven't personally used this, but I know of others that have and are very happy.

The 1000 watt Kisae Pure Sine Wave inverter specs list a idle amp draw of 1.2 amps. That means it will be drawing that much even with the fridge off. Another option is the Xantrex ProWatt 1000 Pure SineWave draws <.6 amps at idle . The Xantrex ProWatt doesn't come with an internal transfer switch but Kisae makes a nice external one.

[Guest Cruzbill]

Your original question; can you use your existing MSW inverter, its OK with me. If you opt for a F&P refrig, then no, as they say PSW (pure sine wave only). As for a dedicated inverter, I considered that, then wound up just moving the 120 fridge circuit from the main panel to the inverter panel and replaced our MSW inverter w/ PSW. Simple, no issues or worry about heating up the motor in the fridge using MSW or warranty. You pays your money and you take your chances.  I doubt if they would cover a warranty repair on any residential refrig in an RV anyway. 

[Rich Cutler]

Last year I converted to a RF18 Samsung French door and we love it.  The Nocold was still working but not worth the risk and not that cold.  Kept the 2000 w modified inverter.   I was concerned on my first boondock at Perry GA but there were no issues at all with battery life.  Generated one hour per day and battery bank was never below 12v.  We have 4 wet cell , 4 yr old in a 2006 Windsor.

remember the RF18 is an inverter compressor and modified sine will not work with all brands.  It is a good drop in for the 4 door Norcold replacement.

[Chuck B 2004 Windsor]

3 hours ago, Cruzbill said:

Your original question; can you use your existing MSW inverter, its OK with me. If you opt for a F&P refrig, then no, as they say PSW (pure sine wave only). As for a dedicated inverter, I considered that, then wound up just moving the 120 fridge circuit from the main panel to the inverter panel and replaced our MSW inverter w/ PSW. Simple, no issues or worry about heating up the motor in the fridge using MSW or warranty. You pays your money and you take your chances.  I doubt if they would cover a warranty repair on any residential refrig in an RV anyway. 

What about the RV that has a factory installed residential frig?

[Guest Cruzbill]

Chuck, are you referring to a warranty claim on a factory residental refrig? well like every thing else on a RV, the component warranty prevails, not any warranty from the RV mfg. Would Newmar fix a brand new fridge on a new coach? I don't know but we're talking retrofit here, not a new install. If I read you correctly, that is. 

[Tom Cherry]

8 hours ago, veraken said:

The best/easiest thing to do is to add a separate pure sine wave inverter with a built in transfer switch for the fridge. I would suggest you look at a KISAE SWXFR1210 1000W Pure Sine Inverter w/ Transfer or KISAE SWXFR1220 2000W Pure Sine Inverter w/ Transfer. I haven't personally used this, but I know of others that have and are very happy.

The 1000 watt Kisae Pure Sine Wave inverter specs list a idle amp draw of 1.2 amps. That means it will be drawing that much even with the fridge off. Another option is the Xantrex ProWatt 1000 Pure SineWave draws <.6 amps at idle . The Xantrex ProWatt doesn't come with an internal transfer switch but Kisae makes a nice external one.

Xantrex almost makes (around $65) a 15 Amp ATS that is designed to work well with the ProWatt.  The only thing I do not like about the ProWatt is the GFCI receptacle.  NO Res Refer needs GFCI.  That is a disaster waiting to happen.  The NEC does not require a GFCI for a dedicated Refer circuit.

Look at the specs....it has been a while.  Watch out for ANY inverter that just "Cuts OFF".  You want one that cuts off at say 11.0 VDC and will NOT start inverting until maybe 11.6 VDC.  Otherwise, the inverter will shut off.  the load is gone.  The batteries slightly recover....then in a few minutes....it shuts down.  Many do NOT have the "cycling prevention" circuitry

[Chuck B 2004 Windsor]

1 hour ago, Cruzbill said:

Chuck, are you referring to a warranty claim on a factory residental refrig? well like every thing else on a RV, the component warranty prevails, not any warranty from the RV mfg. Would Newmar fix a brand new fridge on a new coach? I don't know but we're talking retrofit here, not a new install. If I read you correctly, that is. 

Since Monaco is no longer in existence, you can forget about them.

[jacwjames]

When I was investigating putting a Samsung someone on the forum recommended this is the 1000 watt pure sine wave inverter.  Benefit is that it does have a built in transfer switch and also has the capability to charge batteries.  Aims 1000 Watt Pure Sine Inverter Charger Hardwire Only.   If wired into the engine heat circuit it could be turned off an on via the dash switch.  These cost ~$350. 

Edited July 2, 2020 by jacwjames

[Tom Cherry]

22 hours ago, jacwjames said:

When I was investigating putting a Samsung someone on the forum recommended this is the 1000 watt pure sine wave inverter.  Benefit is that it does have a built in transfer switch and also has the capability to charge batteries.  Aims 1000 Watt Pure Sine Inverter Charger Hardwire Only.   If wired into the engine heat circuit it could be turned off an on via the dash switch.  These cost ~$350. 

I pulled the manual on the Xantrex and the Aims.  Originally, the Xantrex had instructions or troubleshooting notes that said that the batteries had to be restored or recharged by almost a volt (or maybe 3/4) DC.  That prevented the cycling on and off of the inverter every few minutes due to a depleted battery.  That language is missing now.  The Aim does not address it either.

If there is a risk of running down the batteries, then I would purchase one that had an adjustable Low Battery Cut Off (like our Magnums) and also make sure that the inverter, with a low battery bank, will not just cycle.  Not good for any electronic device.