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Topic: Modified Sine vs Pure Sine Inverter (Read 1417 times) previous topic - next topic

Modified Sine vs Pure Sine Inverter

We just put a Keurig coffee maker in the coach and it won't turn on connected to the old original 1500 W inverter - and Tammy wants to make coffee in the morning without starting the genny...

So, does anyone out there know if a Keurig will run on a Xantrex Freedom 458 2500 with modified sine - which is what I am considering...
Peter and Tammy Fleming
1991 U300 GV 40 - Sold, owned for 4 years
Downsized to Roadtrek Popular 210 class B

Re: Modified Sine vs Pure Sine Inverter

Reply #1 –
Pure sine wave is only for laser printers and will run microwaves at designed speeds rather than about half as fast on the OEM inverter. Don't understand why the Keurig won't run on the OEM inverter. Are you sure you have juice to that outlet on the inverter? Electronic controls need some kind of AC but the heating element should like even DC. We use our Mr. Coffee latte maker on the OEM inverter. It has only a mechanical control but should not make a difference.

Wonder if the inverter is getting full house battery voltage? Might check the outlet voltage with a toaster running on the duplex outlet next to the test probe. What kind of battery voltage do you have with the inverter on?

Pierce

Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Modified Sine vs Pure Sine Inverter

Reply #2 –
Some devices other than laser printers also have finicky switching power supplies that require good clean sinusoidal ac power.
Tom Lang K6PG (originally  KC6UEC)
and Diane Lang
2003 38 U295 build 6209
2016 Jeep Grand Cherokee Summit Ecodiesel
still have tow-ready 2006 Acura MDX 
Temple City, California
Motorcade 16681 California Chapter President
SKP 16663 member of SKP Park of the Sierra, Coarsegold California
FMCA F071251
Retired electrical and electronic engineer

Re: Modified Sine vs Pure Sine Inverter

Reply #3 –
Mine runs on the 2500 Watt so maybe it is drawing more then the 1500 can put out.  I can run it on a 2000 too in the Born Free.
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: Modified Sine vs Pure Sine Inverter

Reply #4 –
We had a small device that burned up twice on modified sine wave.  Then we found it was not the device, it was our modified sine wave inverter.  One could say that there are no devices designed for modified as all shore power is sine wave.
Modified sine wave was popular years ago when true sine wave inverters were much more expensive.
In my opinion, no one should install a modified sine wave inverter these days.  Everything runs better on true sine wave.  Had a friend with TV problems that was probably resolved with a change to true sine wave.
We changed to sine wave after we had a fire in an electronic device that may have been triggered by our old modified sine wave inverter, which then also failed.
If cost is an issue, buy a standalone true sine wave inverter, as they are much less expensive than the combined inverter/charger.  Then continue to use the charger function in the old unit, but not the inverter.

Re: Modified Sine vs Pure Sine Inverter

Reply #5 –
Peter,
  My old Kureig pulls 15 amps at 120 volts = 1800 watts.  Chances are the 1500 W inverter is being overloaded. I have heard all of the hype about mod sine wave inverters burning out all kinds of devices like electric toothbrushes, computers, TV's etc, but over 7 years with my 2K mod sine inverter, I have had no problem. However, as others have stated the cost of the pure sine wave units have come down in price to the point where if I have to replace mine it will be with a Magnum pure sine unit. Not quite sure what model I would get but here is a start for your research with one of our Foreforum commercial members;

Chargers, inverters, and refrigerators
Good luck,
Rick

Re: Modified Sine vs Pure Sine Inverter

Reply #6 –
Quote from: prfleming –
We just put a Keurig coffee maker in the coach and it won't turn on connected to the old original 1500 W inverter - and Tammy wants to make coffee in the morning without starting the genny...

So, does anyone out there know if a Keurig will run on a Xantrex Freedom 458 2500 with modified sine - which is what I am considering...

Some discussion about Keurig's not playing nicely with inverters is contained in this topic (thanks to Search) Xantrex 3012 Freedom Converter/Inverter Problem
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Modified Sine vs Pure Sine Inverter

Reply #7 –
I was hoping Dick would chime in as he had to have the computer part reprogramed and give an update on the exact repair and how it has helped. I don't know all the details as he has went round and round with his but it is some better as of last time we chatted.

Pamela
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Modified Sine vs Pure Sine Inverter

Reply #8 –
To Pierce's point, we also have a toaster plugged into the same outlet, works fine - not used at the same time of course.

Rick, I think you might have it, the Keurig just draws too much power for the OEM inverter.

I considered getting a sine inverter just for the coffee machine, but I also want to upgrade the charger.

Those Magnum inverter/chargers look like something to check out.

Michelle, I could search - but I know how much you enjoy it!  8) Interesting so many other people have had Keurig issues.

Peter and Tammy Fleming
1991 U300 GV 40 - Sold, owned for 4 years
Downsized to Roadtrek Popular 210 class B

Re: Modified Sine vs Pure Sine Inverter

Reply #9 –
Don't forget you can get a discount on Magnum and Sterling products at Bay Marine Supply.  Ask gor Alan, tell him you are a Forum Member.

Roger
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Modified Sine vs Pure Sine Inverter

Reply #10 –
I can't imagine upgrading an inverter today to anything other than a pure sine wave inverter! Even if all the doodads you have now run just fine on MSW, what about the doodad you buy next year?

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."

Re: Modified Sine vs Pure Sine Inverter

Reply #11 –

Ok, so I have been doing some research and am amazed how far pure sine inverters have dropped in price. Here are some examples for under $450. Has anyone tried one of these or something similar? My plan now is to retain the Progressive Dynamics 80 amp battery charger put in by the PO, and also use the external OEM inverter transfer switch and just replace the OEM inverter. On one of these I should be able to remove the cover, drill a hole and hard wire the 120V wire connections to bypass the plug in.

MicroSolar

Voltec

SunForce

Power Bright

Samlex

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Peter and Tammy Fleming
1991 U300 GV 40 - Sold, owned for 4 years
Downsized to Roadtrek Popular 210 class B

Re: Modified Sine vs Pure Sine Inverter

Reply #12 –
Amazon.com: Xantrex PROWatt 2000 Inverter, Model# 806-1220: Automotive

Moved up to this one from modified sine wave, running a chest freezer at the house from batteries and
solar panel only, noticed big difference in battery state. With modified sine wave, voltage had dropped to
12.3 by the morning, with new sine wave, never getting below 12.5. Appears compressor in freezer is
much happier with psw inverter.

Jim
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Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: Modified Sine vs Pure Sine Inverter

Reply #13 –
Excellent suggestion. I ran across this full load test on youtube:

Xantrex Prowatt SW2000 full load test

Pretty impressive little unit, I went ahead and ordered one. I will increase my OEM fuse from 175 amps to 250 amps, and will try using the OEM 3/0 inverter 12V supply cables and see if I can get full power without hitting the low voltage limit.
Peter and Tammy Fleming
1991 U300 GV 40 - Sold, owned for 4 years
Downsized to Roadtrek Popular 210 class B

Re: Modified Sine vs Pure Sine Inverter

Reply #14 –
Thinking about the 1000w prowatt sine wave unit as dedicated inverter on dedicated battery for residential refrig when I take out my propane tank
Tim Fiedler    2025 LTV Unity MBL on Order
2000 Chevy Tracker 2 Door Convertible 4WD Now lifted 4.5"
1985 Citroen 2CV6 Charleston
Murphy Rebel on wheels with 175HP Titan
Cessna P337
1980 48' Westport MY (!/4 Share)

Re: Modified Sine vs Pure Sine Inverter

Reply #15 –
Hi Tom,

I bought a 1000 W Prowatt and it failed within four months. Hope you have better luck, sorry.
Jim

2002 U320
Jim Frerichs
2002 U320 42'

Re: Modified Sine vs Pure Sine Inverter

Reply #16 –
Thinking about the 1000w prowatt sine wave unit as dedicated inverter on dedicated battery for residential refrig when I take out my propane tank.

Tim, might go for a 1500 or 2000 watt psw inverter. I tried the 1000 watt prowatt  xantrex first on my freezer and it tripped on overload. At that time I was running 6 gauge from the batteries, so that may have been the problem, but the difference in no load draw between the 1000 and 2000 watt units in very small, so I might go overkill in this situation. By the way, have been running the 1000 watt xantrex on my small norcold frig/freezer for a year with no problems.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.
 

Re: Modified Sine vs Pure Sine Inverter

Reply #17 –

Just finished my Xantrex ProwattSW 2000 inverter install. After studying the existing PACS OEM inverter setup I decided the transfer relay was an integral part of the system and could not be used alone as I originally planned. So, I left the OEM inverter as-is, and added a dedicated outlet in the kitchen just for the Xantrex. Been testing and it runs the Keurig coffee maker, and our 4 slice 1800 watt toaster (could only run one side before), and runs the micro-wave much better than the old inverter.

Fyi, 4/0 extra flexible cable is available from Amazon:

4/0 awg extra flexible cable

I got mine at a local Menards for 25 ft - $125.

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Peter and Tammy Fleming
1991 U300 GV 40 - Sold, owned for 4 years
Downsized to Roadtrek Popular 210 class B