Inverter and TV

[brholt]

This weekend I installed a digital TV/DVD in the camper. On AC it worked well, pulledin lots of TV stations and the DVD worked well. However, when I switched to 12 volts I had some problems. I have two different inverters, both I suspect are modified sine wave inverts as they didn't cost much and just plug into the lighter socket.

The 150 watt fanless one played the DVD but the TV had a hard time getting signals. Only the strongest channels came through and the others had pixelation or the TV complained about a weak digital signal.

The 140 watt one has a fan that runs all the time (very annoying). Everything worked fine with it however.

My questions,
- Are some msw inverters better than others? How do you know?
- I suppose I could get a pure sine wave inverter but most of these seem to be overkill as the whole TV unit only draws 65 watts. I was hoping for something small, quiet, and inexpensive.

- bottom line, any recommendations for this situation?

Thanks

[big_whitey]

mena661 wrote:

smkettner wrote:
I recommend GoPower 150w or 300w sine wave. $150 - $180
http://www.boatandrvaccessories.com/gopoin.html

I have and use the 300w. Low idle draw, provision for remote switch, temperature controlled fan that never comes on with my 19" tv/dvd. You can wire it into the 120v circuit with a small transfer switch if you get bored with the connection logistics.

X2, I have a 300W Go Power hard wired to the batteries in a basement compartment. Yellow box is my inverter.

X3 on the 300w go power.

[time2roll]

Almot wrote:

smkettner wrote:
No need to disconnect converter if just the branch circuit to the tv is connected. Assuming the converter is a different breaker 😉

Wait a second. These are parallel branches. 120V in any branch will find its way to 120V input of converter, unless you do something to prevent this.

I always assume a transfer switch would be used. Nothing will go backfeeding the main panel if the transfer switch serves one branch circuit.

[brholt]

camperguy99 wrote:
I wonder if the problem really is the modified sine wave inverter? Everything worked when plugged into the 120V AC but not the inverter? Where was the antenna getting it's power from. You know the little switch you have to push before you can get any channels? I'll bet the antenna doesn't have any power.

No, the antenna is directly powered by the 12-volt powe system. When turned off I get nothing.

Based on the recommendations here I ordered a 150 watt pure sine wave inverter.

[Almot]

smkettner wrote:
No need to disconnect converter if just the branch circuit to the tv is connected. Assuming the converter is a different breaker 😉

Wait a second. These are parallel branches. 120V in any branch will find its way to 120V input of converter, unless you do something to prevent this.

[camperguy99]

I wonder if the problem really is the modified sine wave inverter? Everything worked when plugged into the 120V AC but not the inverter? Where was the antenna getting it's power from. You know the little switch you have to push before you can get any channels? I'll bet the antenna doesn't have any power.

[mena661]

64thunderbolt wrote:
I have bought 2 300w pure sine wave inverters from "the inverter store" on ebay and they both have performed flawlessly. Very reasonably priced also. TV works just like on shore power.

Great info!!

The Inverter Store Ebay

[wa8yxm]

brholt wrote:
This weekend I installed a digital TV/DVD in the camper. On AC it worked well, pulledin lots of TV stations and the DVD worked well. However, when I switched to 12 volts I had some problems. I have two different inverters, both I suspect are modified sine wave inverts as they didn't cost much and just plug into the lighter socket.

I have seen this many times in the forums.. The MSW inverters are very "noisy" electronically, they may have "Harmonics" that extend into the television band but more likely they are hitting the digital decode frequency (What we computer types call baud rate) and interfering with digital decode.

You might be able to filter.. But a True Sine inverter is highly recommended.. AS I TYPE this I'm watching a TV show recorded via a TRUE SINE WAVE inverter.

[64thunderbolt]

I have bought 2 300w pure sine wave inverters from "the inverter store" on ebay and they both have performed flawlessly. Very reasonably priced also. TV works just like on shore power.

[time2roll]

Almot wrote:
SMK, what for is the transfer switch that you mentioned - for disconnecting the converter from 120V?

No need to disconnect converter if just the branch circuit to the tv is connected. Assuming the converter is a different breaker 😉

Transfer switch would allow utility power to flow through when plugged in and use as normal. Then switch to inverter when needed. Transfer switch prevents back feeding the panel and causing a hazard.

http://www.bestconverter.com/Xantrex-Prowatt-SW-Inline-15-Amp-Transfer-Switch_p_457.html#.Ua2BO6fn_L...

[Almot]

SMK, what for is the transfer switch that you mentioned - for disconnecting the converter from 120V?

[Golden_HVAC]

I second the idea of putting the inverter closer to the battery, and running a small 16 gauge extension cord. With less than 3/4 amp on the cord, the voltage drop is insignificant.

I have not noticed a signal strength problem with either of my inverters, but might check it out next time I am dry camping.

I have a booster, and it seems to get in the weak signals much better.

I use the G3 booster found at this website. http://antennadeals.com/HD2605.html

Fred.

[mena661]

smkettner wrote:
I recommend GoPower 150w or 300w sine wave. $150 - $180
http://www.boatandrvaccessories.com/gopoin.html

I have and use the 300w. Low idle draw, provision for remote switch, temperature controlled fan that never comes on with my 19" tv/dvd. You can wire it into the 120v circuit with a small transfer switch if you get bored with the connection logistics.

X2, I have a 300W Go Power hard wired to the batteries in a basement compartment. Yellow box is my inverter.

[time2roll]

I recommend GoPower 150w or 300w sine wave. $150 - $180
http://www.boatandrvaccessories.com/gopoin.html

I have and use the 300w. Low idle draw, provision for remote switch, temperature controlled fan that never comes on with my 19" tv/dvd. You can wire it into the 120v circuit with a small transfer switch if you get bored with the connection logistics.

[Almot]

brholt wrote:

- Are some msw inverters better than others? How do you know?

You don't. Now that most items are made in China, even with a well known brand there is a risk to get poor MSW, with RF noise or poorly filtered wave.

brholt wrote:
I suppose I could get a pure sine wave inverter but most of these seem to be overkill as the whole TV unit only draws 65 watts. I was hoping for something small, quiet, and inexpensive.

Samlex 120W PSW costs $100 on Amazon. Not sure about "quiet", very few inverters in that range are fan-less and those cost more. Place it closer to battery, ex. in through-storage, then you won't hear the noise. Inverter actually has to be close to battery. You can add a remote switch in the room somewhere, though small inverter can idle 24/7, its idle draw is low.