I am thinking about changing my fridge out to a residential unit but I would need to be able to run it from my inverter for up to 8 hours at a time. (I have 4 new Trojan T105 batteries) I have read where the residential refrigerators do not work on Modified Sine Wave. In my manual it says my inverter (Xantrex Freedom 458) is a Filtered Modified Sine Wave. What is the difference between Modified Sine Wave and Filtered Modified Sine Wave? Does anyone have any experience running the residential fridge on this inverter? I do not want to change out the inverter to a Pure Sine Wave.

Some of the HIGH DOLLAR HIGH END Modified Sine Wave units will work... I wouldn't do it myself but mayby you should try out something with a motor like maybe a 20-inch portable fan. If the motor speeds up normal and DOES NOT START GETTING HOT OR MAKING LOUD HUMMING NOISE then you should be OK I guess...We have found anything with motors-transformers-solid stat electronics really need the PURE SINVE type Power Inverters. These duplicate the SINWAVE much like is being produced from the shore power and generator connections...Again I would not do that here as I have always purchased PURE SINE WAVE Power Inverters which works well with all things RV Camping...I did have a HIGH END 2000WATT House UPS Setup that had internal Batteries to swith to when loss of power. It was a MSW type Power Inverter circuit and looked good with an oscilloscope hooked up to the unit and worked with everything I had conencted to it. This was a high dollar item however...I kinda put the Xantrex Freedom 458 in the high end catagory just because of the cost of the unit... What you are reading about on-line is these cheap built and low cost chinese items that you find in the auto parts stores and Walmart-Lowes... Hopefully some one on here that has the Xantrex unit will dime in here... but a local test using a 20-inch portable electric fan might give you an good feeling as well... You can tell right away if it is not liking your Modified Sine Wave. It will HUM real loud and try to run at a normal high speed when you plug it. If you leave it plugged in very doing this thene you will soon see the so called 'BLUE SMOKE' coming out of the motor for a few seconnds then it is toast... Your fridge uses an electric motor so it will do the same thing if it doesnt like your MSW Power Inverter. Just my two cents from experience..Roy Ken

RoyB wrote:Some of the HIGH DOLLAR HIGH END Modified Sine Wave units will work... I wouldn't do it myself but mayby you should try out something with a motor like maybe a 20-inch portable fan. If the motor speeds up normal and DOES NOT START GETTING HOT OR MAKING LOUD HUMMING NOISE then you should be OK I guess...We have found anything with motors-transformers-solid stat electronics really need the PURE SINVE type Power Inverters. These duplicate the SINWAVE much like is being produced from the shore power and generator connections...Again I would not do that here as I have always purchased PURE SINE WAVE Power Inverters which works well with all things RV Camping...I did have a HIGH END 2000WATT House UPS Setup that had internal Batteries to swith to when loss of power. It was a MSW type Power Inverter circuit and looked good with an oscilloscope hooked up to the unit and worked with everything I had conencted to it. This was a high dollar item however...I kinda put the Xantrex Freedom 458 in the high end catagory just because of the cost of the unit... What you are reading about on-line is these cheap built and low cost chinese items that you find in the auto parts stores and Walmart-Lowes... Hopefully some one on here that has the Xantrex unit will dime in here... but a local test using a 20-inch portable electric fan might give you an good feeling as well... You can tell right away if it is not liking your Modified Sine Wave. It will HUM real loud and try to run at a normal high speed when you plug it. If you leave it plugged in very doing this thene you will soon see the so called 'BLUE SMOKE' coming out of the motor for a few seconnds then it is toast... Your fridge uses an electric motor so it will do the same thing if it doesnt like your MSW Power Inverter. Just my two cents from experience..Roy KenThat is my fear. I do not want to spend $1200 on a fridge and the time and trouble to install it then toast it the first time I run it on the inverter.

Hi,This might help you decide:Hi all,This protocol was suggested by mexicowanderer whom I have the greatest respect for:TEST: Shore power versus alternative power. Put glass of water in microwave and start, if voltage drops to 109 vac or less at same outlet as microwave is plugged into, end of test. Energy source is inadequate.Stage 2 Same glass of water, start at room temperature with oven thermometer. Set timer for one minute high. Remove glass measure temperature on shore powerStage 3 Do the same with alternative power source and compare temperature difference to test above.If there is a large temperature difference, then your microwave is going to unlove you trying to suffer through inadequate voltage or waveform.

You might consider adding an inverter dedicated to the refrigerator.

Pure Sine Wave vs Modified Sine Wave for fridge

MEXICOWANDERER
Explorer
Jun 29, 2016
My Trace 4024 MSW inverter runs my Viking. But at a cost. More more noise, more heat and more wasted battery amperage. You don't even want to begin to know what these inverters cost around the year 1991. 203 watts extracted from batteries versus 182. 24/7 usage it really adds up. The Trace "may" have an extra "step" in it's pseudo sine wave. Be aware that inverters revert to pure SQUARE WAVE if their capacity limit is approached.
MrWizard
Moderator
Jun 29, 2016
my PV1250 has been running my fridge for Almost 6yrs
will be six yrs in oct/Nov

Filtered
usually means a heavy transformer and a Pi network inductance filter on the output A/C too smooth out the wave form

i can tell you this
my 80w florescent kitchen fixture behaves better on my tripp-lite 1250 than my it does on my go power 300 PSW

how ever my electric mattress pad will not turn on with the PV1250 and runs soley off my go power 300
time2roll
Nomad
Jun 29, 2016
JnJnKatiebug wrote:
I was hoping someone could tell me what filtered modified sine wave means and how that is different from regular modified sine wave.
It is a non-scientific definition. Sine wave is measure in THD or Total Harmonic Distortion. Most sine wave are rated 3% to 5% THD.

Regardless most non sine wave inverters have a lower peak voltage than what equipment like microwaves and motors are looking for. Motors may run hotter, microwaves run at a lower power level. Apple products are also known to give trouble.

If you want all to run as designed then you need sine wave even if some might muddle along fine with modified.

I have and recommend GoPower sine wave inverters but they do not make an all in one like the 458. And on that note I prefer separate components anyway for when something fails that is all you replace.
phillyg
Explorer II
Jun 29, 2016
I know nothing about inverters other than Montana installed a pure sine wave to power my residential fridge.
hugemoth
Explorer
Jun 30, 2016
The 15+ year old refrigerator in my house has never run on anything but a modified sine wave inverter. Never a problem.
BoonHauler
Explorer
Jun 30, 2016
FWIW, I'd have to think your bigger problem is going to be running the inverter (loads) off of 4 batteries.

That would be an absolute minimum in my eyes.

Just my 2 cents, good luck.
MrWizard
Moderator
Jun 30, 2016
the $900 freedom 458
Filtered Modified Sine Wave Means exactly that

is NOT a cheap 'chopper' square wave inverter
its not a $49 'car parts store' inverter

my $300? PV1250 weighs 22#, and has NOT let the 'Magic blue Smoke' out of anything in this RV in 6yrs of everyday use

there are So called PSW inverters out there that can't hold an LEd candle to the quality of my Tripp-lite or the Freedom 458, it may not be the best inverter ever built, but its far better than most of the stuff you people are trying to compare it to

MSW does not mean BAD, and PSW does not always mean Great

Options, always have options, and the journey goes much smoother
....
JnJnKatiebug
Explorer
Jun 30, 2016
BoonHauler wrote:
FWIW, I'd have to think your bigger problem is going to be running the inverter (loads) off of 4 batteries.

That would be an absolute minimum in my eyes.

Just my 2 cents, good luck.

I am looking for 8 hours of run time for the fridge only. When we need other power we will be connected to shore power or running the generator.
MEXICOWANDERER
Explorer
Jun 30, 2016
The TRACE pure and genuine, was the finest transformer MSW inverter ever built. Look at the FET part numbers and count 'em. 1991 to 2016 is not a spring chicken either. The lightweight inverters are like a wad of chew. Roll down the window.
JiminDenver
Explorer II
Jun 30, 2016
I bought the same PV1250 Mr Wizard has at his recommendation. It doesn't make the chargers or satellite box hot like my PowerBright MSW inverter does. It doesn't add lines to the flat screen TV either. It has a BIG fan, not some screaming mimi and it starts that little air conditioner so smooth that I have to check the Kill a watt just to make sure the compressor is on. $200 on ebay delivered.

I wish I had talked to him before buying a cheap PSW unit. It would have been fine just running the microwave, coffee pot, cooktop, hair dryer and more. That little A/C starting was just too much and poof...there goes $200. Still, for the rest of the stuff it was fine.

Lots of options to fill your needs. I'm glad it didn't cost me a arm and a leg to fire up the A/C once in a while.