I just completed an upgrade to my little coach, where I added four group 31 AGM 12v batteries and a Magnum Energy MS2812 inverter. I'll type up a little photo essay about that later. Right now, I have a few operational questions.Any electrical engineers out there, I have some tech questions!Firstly, the manual states the inverter will cause TV and radio interference and to not locate it near either. So I have interference on my raido, on every channel, even the strong local ones. There are no OTA channels in my area for me to test tv reception. My inverter is located about 10-12 feet diagonally from my radio antenna, which is on the other side of the aluminum roof. The side walls of the rig are also aluminum. I'm not not sure how the interference is getting into the radio, but I suspect it's actually from the DC wiring and not the RF input.Secondly, when the inverter is on and inverting (ac disconnected), I can hear a high pitched buzzing / whine coming from the DC light bulbs. It is not super loud, but in a quiet coach, I can easily hear it. The DC lights are sharing the battery with the inverter, and I tried to provide a low impedance path for the small DC loads separate from the inverter, but I fear it is flooding the entire DC bus with some nasty switching noise / ripple and the batteries aren't providing enough capacitance to absorb it.I will get my scope out and take a look at the DC bus this weekend, to confirm my suspicions.As far as mitigating the noise, what options do I have. Should I put a choke on the supply lines feeding my small load fuse box. Should I get a big capacitor and put it across the DC bus at the fuse box (with a fuse of course)... or should I explore something else?

Look with scope first, then either cap or choke.

Good luck - this is normal for any high powered INVERTER setup. The Pure Sine Wave Inverters do better than the Modified sine wave inverters...Even if you install the Inverters down in the bottom compartment just next to the batteries the RFI interference follows the 120VAC connections to provide AC power to the rest of the trailer.Will take some real big efforts to eliminate all of it.I got hit with two RFI issues.. First was the INVERTER setup then it was the LED lights I installed that had built-in regulators. Solved the LED problem by using the cheap $4.99 ebay/China non regulated LED SMD boards... Still fighting the RFI issues with the INVERTER installs...I use a smaller Pure Sine Wave Inverter just for the Home entertainment items which helps alot with the RFI signals from the bigger 1500WATT Inverter setup I have. Make sure you GROUND the INVERTER direct to the frame ground using the solid copper ground wiring. This also helped me alot cutting down on the RFI signals.This is my floorplan layout showing where all of my units area located.I even experimented in temporarily mounting the heavy INVERTER in the truck and routed 120VAC cables from there but still got roughly the same level of RFI signals..I think I would have good luck using an isolation transformer on the 120VAC side with good short length grounds on the INVERTER chassis to frame ground. Finding a right size isolation transformer to fit the RV mounting schemes is a problem... You would think 1500WATTS in my case shouldn't that big of a transformer required to handle the loads. Maybe its time for toroids and filter chokes...Of course messing with TOROIDS then you may have to deal with the outer space folks living among us... This messes with their lifestyle I am told...Just my thoughtsRoy Ken

Wow, I would consider that kind of rf leakage to be unacceptable for such an expensive inverter. No problems like that with my Prosine 2.0.Sort of sorry to hear they warned you in the manual.I'd call up Magnum tech support and ask them for the fix or a return authorization!

Nah, I don't think there is anything defective. It's the nature of the beast. This unit is built to handle almost 400 amps DC continuously, so there is some beefy switching silicon in there, and parts like that are going to make some noise. Filter caps and chokes drive up the costs and introduce other problems, like Roy pointed out ... TORRIDS are a black art

Unacceptable. I've heard of MSW causing problems running some devices, but nothing like you've described.For that kind of money I'd return it and get a PSW. No noise anywhere. Isn't it toroids?

MagnaSine Inverter Questions | Good Sam Community

tenbear
Explorer
Jul 01, 2013
I bought an el-cheap-o 300w PSW inverter on eBay that produced some electrical noise.

Here is a link to the post with a lot of suggestions. The last post is my solution.
aeejbe
Explorer II
Jul 01, 2013
GordonThree:

I’m now subscribed to this thread because I have the same MagnaSine MS2812 that works in tandem with four 6V AGM batteries. I also get RFI - but only on my AM radio stations. My setup was professionally installed, & later was checked over by a second professional.

Do follow up with your results. I’d be very interested in learning if you have any improvement after you ... "take everything apart again and investigate, as well as upgrading the chassis ground wire."
What is your coach?
time2roll
Nomad
Jun 28, 2013
MagnaSine says 5% distortion
Samlex 5%
Wagen 5%
GoPower 3%
Voltec 3%
KISAE 3%
My Prosine 1800 1%
GordonThree
Explorer
Jun 28, 2013
Every electronic inverter is a modified sinewave inverter, regardless of the marketing about "pure" or "true" sinewave. I accept this. The difference is the number of steps.

A good inverter's wave will have a lot of steps, so it looks "smooth" compared to the el-cheapo inverters you can find on ebay that claim 1000's of watts for only a few 100 dollars. The Magnum runs its stepped wave through a heck of an inductor (its heavy), to smooth those steps as best they can. Other inverters use digital trickery to shave those steps, but they are still there, especially when it comes time to drive heavy inductive loads and those with poor power factors.

I've had a chance to spend more time in my rig, and it appears the ringing in the bulbs only happens when the CHARGER is operating and not the inverter. The radio interference is present all the time. I will put my scope on the AC and DC sides out of curiosity and post the pictures here.

I suspect the radio interference may be due to an insufficient chassis ground of the inverter. I admit I got impatient and used a smaller chassis ground wire than was recommended, rather than put off finishing the project another day. Time and weather permitting this weekend, I'll take everything apart again and investigate, as well as upgrading the chassis ground wire.
Gdetrailer
Explorer III
Jun 28, 2013
RoyB wrote:
Good luck - this is normal for any high powered INVERTER setup. The Pure Sine Wave Inverters do better than the Modified sine wave inverters...

Even if you install the Inverters down in the bottom compartment just next to the batteries the RFI interference follows the 120VAC connections to provide AC power to the rest of the trailer.

Will take some real big efforts to eliminate all of it.

I got hit with two RFI issues.. First was the INVERTER setup then it was the LED lights I installed that had built-in regulators. Solved the LED problem by using the cheap $4.99 ebay/China non regulated LED SMD boards... Still fighting the RFI issues with the INVERTER installs...

I use a smaller Pure Sine Wave Inverter just for the Home entertainment items which helps alot with the RFI signals from the bigger 1500WATT Inverter setup I have. Make sure you GROUND the INVERTER direct to the frame ground using the solid copper ground wiring. This also helped me alot cutting down on the RFI signals.

This is my floorplan layout showing where all of my units area located.

I even experimented in temporarily mounting the heavy INVERTER in the truck and routed 120VAC cables from there but still got roughly the same level of RFI signals..

I think I would have good luck using an isolation transformer on the 120VAC side with good short length grounds on the INVERTER chassis to frame ground. Finding a right size isolation transformer to fit the RV mounting schemes is a problem... You would think 1500WATTS in my case shouldn't that big of a transformer required to handle the loads.
Maybe its time for toroids and filter chokes...

Of course messing with TOROIDS then you may have to deal with the outer space folks living among us... This messes with their lifestyle I am told...

Just my thoughts
Roy Ken

B.S.

I suspect the OP got BURNT by marketing hype.

I found a couple of things in the manual that tips me off.

Manual CAN BE FOUND HERE

Page 26 of the manual..

"Use a true RMS multimeter to verify 120 VAC at the coach?s AC outlets."

Page 33 Trouble shooting..

"AC output voltage seems Wrong type of voltmeter used Use a ?true? RMS voltmeter.
too low when using a meter. (displays 80 VAC to 100 VAC)."

BOTH of those statements are what is needed for MEASURING MSW inverter outputs.

To measure using any multi meter capable of AC voltages will read sinewaves correctly whether it is true RMS or a $5 one.

MSW DOESN'T read correctly unless the meter is RMS type.

I would bet that if the OP scopes the AC output instead of the DC (battery) I think they will find some very bad squarish waveforms with a lot of harmonics.

A GOOD quality MSW inverter gives off VERY LITTLE RFI.

I have no problem with ANY of my MSW inverters with RFI for AM, FM, TV, in fact I have used MSW to run stereos, TVs, along with computers.

One of my favorite MSW inverters is made by Tripplite.

If I was the OP I would get my money back and go buy a BETTER inverter.
2oldman
Explorer II
Jun 27, 2013
GordonThree wrote:
To clarify, this is a pure sinewave inverter, however the trouble I'm having is with DC loads.
Thanks.. but, this (in my book) is totally unacceptable. I wouldn't even be trying to remedy it.

I've had a Prosine, a Prowatt and a Samlex (all 2kw inverter) and no problems like you're having.
time2roll
Nomad
Jun 27, 2013
Can you isolate the 12v DC supply with a second source for testing?
GordonThree
Explorer
Jun 27, 2013
To clarify, this is a pure sinewave inverter, however the trouble I'm having is with DC loads. The AC loads all operate without flaw.

I even tested fluorescent lights (my coach doesn't have any) and AC fan motors. They look and sound the same on battery power as they do on shore power, other than a -CLICK- noise the inverter's transfer switch makes. You can't even tell when switching between the two power sources.

I don't consider either issue serious, I just get obsessive over details, picking nits so to speak.
RoyB
Explorer II
Jun 27, 2013
YUP thats it - Ferrite Toroidal Cores - sorry for the fat fingers on this end...

Roy Ken
2oldman
Explorer II
Jun 27, 2013
Unacceptable. I've heard of MSW causing problems running some devices, but nothing like you've described.

For that kind of money I'd return it and get a PSW. No noise anywhere.

Isn't it toroids?

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