frecku
Idaho
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I recently installed a pure sine wave Magnum Energy MS2812 inverter in my Winnie 31C. Everything works fine except I get interference on the TV when the microwave is on; the picture wobbles on both sides of the TV scream.
Of course I could refrain from using the microwave while watching TV but the kids always want that corndog at the most annoying times!!!
The microwave-Samsung is in a built in cabinet right next to the TV-RCA, the inverter is on the floor at least 8’ away and the cables are also on the floor nowhere near the TV or microwave.
This setup works just fine on shoreline power or generator power. Since I purchased a true sine wave I thought I WOULD BE ABLE TO AVOID SUCH PROBLES.
I called customer service but they claim they have not come across such a scenario.
Any way to insulate the microwave from the TV, aluminum foil between them perhaps. As a last resort I would be willing to replace the TV if there is a model out there less susceptible to this interference. The problem is the built in cabinetry, there is no other place to place the TV.
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MNtundraRet
Bloomington, MN
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You do not state how many batteries are in your battery-bank. I suspect you mean you are running both the television and the microwave, using the inverter and battery-bank only. It would not make sense to run the television through the inverter if you had 120v AC to run the microwave.
Your problem may not be interference, and customer service never saw your interference problem. The microwave is drawing a heavy amp load from the battery-bank, and I think your battery voltage is dropping and there is not enough power to run the television properly.
Mark
Mark & Jan "Old age & treachery win over youth & enthusiasm"
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frecku
Idaho
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I have a huge battery bank 6 x U2200 batteries for a total of 690AH. It is in 3 sepatate banks, very well balanced, drawing just over 50 Amps per line with microwave running, I did not skimp on cable either and used 4/0 with a calculated maximum voltage drop on the DC side of 1.8%, my battery voltage at this running load is still 12.8V , the AC voltage at the outlet is 109-110V.
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ron.dittmer
We Danced & Won, Check Out My Website
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frecku,
99.99% of us here are not able to run the microwave off the inverter as we don't have 6 batteries to make that work. You have a very unique problem the rest of us cannot comment informatively.
I work at a company that runs into "noisey power" troubles. I am not an electrical engineer here, but I design the circuit boards that package engineering circuity, typically using a 12v power source. The general methodology is "filtering" the power input. This sometimes is done using a ferrite noise filter. The answer might be as simple as wrapping your 110v power cord numerous times around what looks like a huge donut made of carbon. They might be sold at Radio Shack or on-line electronics supplier. Something that looks like this.
To give you a better idea of what I am describing, another common home video item that have them are low voltage power cords that supply power to a video camcorder. In that case the donut looks more like a cylinder, having the thin low voltage power cord winding through it a number of times. They look like this.
In the case of 110V that donut or cylinder will likely be quite huge by comparison.
I am no expert on this, but this is worth the research. If it works, it would be very simple to implement. Here is an on-line source for those ferrite filters. It may be worth a call for advise. Click Here
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frecku
Idaho
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OK, I went back and took some precise measurements, kudos to MNtundraRet, he nailed it on the head :
MNtundraRet wrote:Your problem may not be interference, and customer service never saw your interference problem. The microwave is drawing a heavy amp load from the battery-bank, and I think your battery voltage is dropping and there is not enough power to run the television properly.
I started taking measurements and adding appliances at the same time looking to see if I get the interference.
Voltages per bank at :
Rest 12.93V
TV/VCR 12.49V NO Interference
TV/VCR and 1000W toaster 12.04V Interference
TV/VCR and 1500W microwave 11.74V Interference
The AC voltage at outlet fluctuates as I add and remove appliances 114-128 but always returns and stabilizes at 118 Volts in less than a second.
Here is what I do not get, if the TV runs on AC power supplied by the inverter which is relatively stable why does the evident drop in my DC Voltage matter ?
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MNtundraRet
Bloomington, MN
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The voltage drop did not matter to the microwave but does to the television. Even though you have a large battery-bank, you created your own "brownout" condition for your 120v AC circuit. Do not forget that deep-cycle batteries are somewhat limited in how many amperes they can give out over a short time frame. In Minnesota, in January at 25F below zero, our car's starter may draw 200 amperes to start the car. No way for a deep-cycle battery. If the equipment draw needs are high, the voltage has to drop.
Digital televisions are not forgiving for short voltage loss below normal minimum operating voltages.
Mark
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frecku
Idaho
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But, but, even if I create a temporary brownout on the 12V line the inverter sill maintains a constant 118V on the AC line so what gives ?
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MNtundraRet
Bloomington, MN
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The inverter is not fast enough to give the constant voltage the television needs. For small fractions of a second the voltage drops below the televisions operating voltage. Your monitors sampling rate is too slow to pick up on it.
Mark
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frecku
Idaho
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So even if the microwave runs for several minutes and my voltmeter shows a stable and constant 118V you are saying that it does not pick up minute fluctuations that affect the operations of the TV ???
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MNtundraRet
Bloomington, MN
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After reading your latest replies again, I noticed you had the batteries isolated into 3 separate battery-banks. I would suggest you disconnect the isolators and parallel the battery-sets. It won't cost you any money, and they may cause the momentary voltage drops. You can always hook them back up if nothing changes.
Mark
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