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Open Roads Forum  >  Class C Motorhomes  >  Class C

 > Inverter 'Power" Interference

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frecku

Idaho

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Posted: 11/10/09 10:17pm Link  |  Quote  |  Print  |  Notify Moderator

MNtundraRet wrote:

When you tested the batteries, you stated almost 12.9 volts. That is a surface charge. When you tested the batteries with the heavy load you stated around 12.0 volts and 11.7 volts. That is an extreme voltage drop. I think the current problem may actually be a battery, or two, with a bad cell. Try to isolate the problem by checking voltage, with a multimeter, at the terminals of each individual battery-pair, while under load. The fact that the reading of 12.49 volts (85% charged battery) for television setup alone suggests some bad batteries.


Well I got back from the rv with some data on the batteries. I will list only one bank as all 3 are identical and well balanced.

Resting 12.90V

TV @ battery,,,,,12.55V,,,,,TV @ Bussbar,,,,,12.53V

Microwave @ battery,,,,,11.84V,,,,,Microwave @ Bussbar,,,,,11.76V

So even at my highest Amp draw the voltage drop from the battery to the bussbar is only 0.08V , good thing I went with the 4/0 cable LOL.

Once the draw is switched off the battery returns to 12.55V then slowly creeps up to 12.76V and stabilizes. it could have been higher but I did not want to stick around, ambient temp is only 38F.

I would like to also point out that through the elimination process I know that the microwave is not the culprit of the interference. If I plug in a toaster or kettle on the other side of the RV the symptoms are the same.

Great idea on the extension cord "klhutch" from shoreline to the TV, I can't wait to try it out in the morning. I am more curius on the cause than the cure right now.

pianotuna

Regina, SK, Canada

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Posted: 11/10/09 10:52pm Link  |  Quote  |  Print  |  Notify Moderator

Hi frecku,

If it isn't the microwave then it must be the inverter. Toasters don't produce a lot in the way of electronic "noise".


Regards, Don
Kustom Koach Class C 28'5" 256 watts solar, 875 amp hours in two battery banks 12 volt batteries 2500 watt inverter.

MNtundraRet

Bloomington, MN

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Posted: 11/11/09 05:47am Link  |  Quote  |  Print  |  Notify Moderator

The problem may be the inverter. However; I am having problems with your voltage readings. Since a fully charged battery is about 12.65 volts, you cannot possibly have reading such as: 12.90v at start (Did you just finish charging? Surface charge.), and 12.76 volts after the test. Your meter must be giving incorrect readings (reads higher than actual voltage). Did you take individual voltage readings at each battery after the test? For 6-volt batteries multiply voltage reading times two for comparison to a 12-volt battery percent charge versus voltage chart. Example: 6.32 volt reading times two is 12.64 volts or 100% charged battery. Your batteries may be okay but you have lost me with the high readings. Other members with who run inverters to power a microwave off batteries may be able to comment if your voltage drop, under load, was normal.

Mark


Mark & Jan "Old age & treachery win over youth & enthusiasm"
2003 Fleetwood Jamboree 29


frecku

Idaho

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Posted: 11/11/09 05:59am Link  |  Quote  |  Print  |  Notify Moderator

I garantee you the readings are correct, I used 2 separate meters after your initial posting. I did have those lower readings before i upgraded to the PD9270 converter/charger.

The batteries are 6V so parallel connected to get 12V, but I could go back and test each one, i remember before hooking things up that they were in the 6.44V to 6.52V range A DAY after charge.

frecku

Idaho

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Posted: 11/11/09 06:17am Link  |  Quote  |  Print  |  Notify Moderator

I will post my findings on the "extension cord" tests tonight, In the meantime I would like to stop beating up on the poor microwave, just in case we get fixated on its inner workings, the TV interference appears with ANY HIGH AMP APPLIANCE draw :

Kettle 1000W
Lg. kettle 1500w
Toaster 1200W

klhutch

Sububan Chicago

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Posted: 11/11/09 07:52pm Link  |  Quote  |  Print  |  Notify Moderator

frecku wrote:

the TV interference appears with ANY HIGH AMP APPLIANCE draw :



It is good that you eliminated the microwave oven. If the problem occurs with any high current load then it is likely to be the inverter. That maybe normal since as the load current increases the strength of any interference the inverter generates would increase as well. At some current it become great enough to bother the TV.

Ken

frecku

Idaho

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Posted: 11/11/09 10:14pm Link  |  Quote  |  Print  |  Notify Moderator

EUREKA !!! I finally found the culprit for my TV interference, I performed the “extension cord” test and this is what I found out.

I forgot to mention that I have a DVD/VCR combo machine; yes I know that VCRs are obsolete but all the kids Disney movies are still on VCR.

So I isolated the TV and plugged it into shoreline power, the rest was in the inverter, and finally the first break. I had the TV interference when the inverter was under load and playing the VCR but NO interference playing the DVD.

Next I plugged in the TV AND the DVD/VCR box to the shoreline power and put the inverter under load by plugging in a toaster. Once again I had TV interference playing the VCR and none when playing the DVD.

So in short the VCR component does not like to be in the same room with the inverter when under load, I attempted to correct the VCR distortion by using the tracking button with no effect.

Can the Ferrite noise filters help in this scenario?

pianotuna

Regina, SK, Canada

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Posted: 11/11/09 10:21pm Link  |  Quote  |  Print  |  Notify Moderator

Hi frecku,

That was good sleuthing. I wish I knew a solution--but congratulations on finding the problem.

frecku wrote:


I forgot to mention that I have a DVD/VCR combo machine; yes I know that VCRs are obsolete but all the kids Disney movies are still on VCR.

So I isolated the TV and plugged it into shoreline power, the rest was in the inverter, and finally the first break. I had the TV interference when the inverter was under load and playing the VCR but NO interference playing the DVD.

Next I plugged in the TV AND the DVD/VCR box to the shoreline power and put the inverter under load by plugging in a toaster. Once again I had TV interference playing the VCR and none when playing the DVD.

So in short the VCR component does not like to be in the same room with the inverter when under load, I attempted to correct the VCR distortion by using the tracking button with no effect.

Can the Ferrite noise filters help in this scenario?


frecku

Idaho

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Posted: 11/11/09 10:24pm Link  |  Quote  |  Print  |  Notify Moderator

I failed to mention that The TV works perfectly by itself even when plugged into the inverter power under even the highest loads.

frecku

Idaho

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Posted: 11/11/09 10:33pm Link  |  Quote  |  Print  |  Notify Moderator

Having done this test and got these results I went back to work (I am a nurse at a hospital)and got some X-ray jackets.

Wrapped the inverter and the DC cables but showed absolutely no difference. I guess this form of shielding does nothing to the RF signal.

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