Modified Sine Inverter

acguy · **Posted:** Fri Jan 27, 2012 5:59 pm

Just wondering if anyone is using a modified dine inverter to run a LED tv. Wondering about the effects of not using a full sine. Will the modified wreck the tv?

ric · **Posted:** Fri Jan 27, 2012 10:44 pm

LED TV's (not standard LCD TVs) are actually 12v DC appliances like your household computer and use power supplies to reduce the 120v AC to the required DC 12v/5v/3.3v needed by the electronics. They don't give two craps about the wave pattern because it's converted back to 12v DC and the internal power supply's capciters make up for the crappy power by design. My 22" LED LCD 1080p at a maximum on turn on uses 42w, and running.. maybe 35? My $10 internet special 100w inverter runs it beautifully.

It would NOT run a standard LCD tv very well, since they use cold cathode (CFFL) tubes for backlight and they HATE modified sine waves as all neon lights do.

Paul I. · **Posted:** Fri Jan 27, 2012 11:21 pm

My 2 cents, I have both LCD & LED TVs & monitors. Some run with 110v right into them AND some have there own power supplies converting 110v to 12 - 18 volts. SO , some run on all DC input and some don't. I think they will care about the sine wave. They are built to run on 60hz, BUT I am sure + or - 1hrz is not going to do much.

I do have a 2000w inverter on board that is modifieded sine wave and it works both LED & LCD TVs (& the microwave) that I have had on board. A modified sine wave inverter is similar to a square wave output except that the output goes to zero volts for a time before switching positive or negative. I would stay away from the cheap inverters and try not to use any of them over 80% of there rating!! Remember too, the caps in the TV's power supply are made for (some are made for 50Hz or 60Hz for abroad) 60hz. in other words, as the sine wave drops, the cap discharges to keep the voltage up. Its a timing thing, if you will. If the wave slows down, than the cap in the supply needs to discharge more. Can it do it?? Or if the inverter is a cheap one, that is putting out more of a sq wave. Than the power supply will have the same problem.

Here is the unit I have, BUT more inportantly there are video's that explains a lot about inverters. http://www.xantrex.com/power-products/p ... rters.aspx

230 Mike · **Posted:** Sun Jan 29, 2012 10:31 pm

Any inverter will most likely run the TV. However, not all modified sine waves are the same, and many consumer electronics these days are designed on the ragged edge with respect to the capacitors used in their power supplies. Generally (and there are always exceptions), more money spent on the inverter will result in both higher efficiency (inverters are inherently inefficient) and a wave form that is closer to a true sine wave (i.e., it has more "steps" in the wave form). Bottom line, I wouldn't run a $1K television on a $40 inverter from the Wal-Mart automotive department.

acguy · **Posted:** Mon Jan 30, 2012 8:06 am

This is what I'm thinking of usuing. Going to mount it right behind the tv, Any Thoughts

http://www.xantrex.com/power-products/power-inverters/xpower-inverters-digital.aspx

230 Mike · **Posted:** Mon Jan 30, 2012 8:29 am

Xantrex and Tripp Lite are two reputable makers. What's the power consumption of your TV? Use an inverter rated for much more power than the anticipated load and you should be OK.

Paul I. · **Posted:** Mon Jan 30, 2012 10:02 am

Your link is pointing to two units, one 400w & a 800w unit. You may want to read PDF page 25 that shows the load rating on each unit. Also, since you are mounting the inverting behind the TV, you are going to need to do the math on what size cables you will need. I installed my inverter, just out side of the engine compartment in order to keep the cable size down. I had to use 1/0AWG at 8 feet. It is better to keep the DC cables short and make up the the rest with AC wiring. 12/3 wire is lighter, cheaper and AC will have far less of a voltage drop per foot of wire.

You may want to use this chart http://www.windsun.com/Hardware/Wire_Table.htm

If you pull, 240 watts using 16 feet of wire, you will need #8 wire. Most of these TVs use 40 to 80watts, but you may want to run bigger things. Or a DVD/Blu-ray player.

acguy · **Posted:** Mon Jan 30, 2012 7:31 pm

Not to concerned to much with wiring,I have already pulled a wire to the head #10 AWG. The tv is 66W max which is including the built in DVD. I'm think of just using the 400W. I really have no other need for the inverter. We don't anchor out very often over night as I have 2 young children and a 80 lb golden retriever that needs a piece of land and space!

Constant draw for the 400 W is rated for 320 W, in my eyes thats enough of BS factor!!

ric · **Posted:** Mon Jan 30, 2012 9:38 pm

An LED LCD DVD player tv (22in probably) should pull more then 45w.

acguy · **Posted:** Mon Jan 30, 2012 10:12 pm

ric wrote:

An LED LCD DVD player tv (22in probably) should pull more then 45w.

It's a 19" Toshiba LED/LCD/DVD 66 W.
Rating on the TV is 0.55A Max

Power = Volts x Amps
120 x 0.55 = 66 Watts

Correct?

ric · **Posted:** Mon Jan 30, 2012 10:41 pm

Yup.

Now this is just cool.
http://www.xantrex.com/power-products/p ... nitor.aspx

Paul I. · **Posted:** Mon Jan 30, 2012 10:45 pm

acguy wrote:

ric wrote:

An LED LCD DVD player tv (22in probably) should pull more then 45w.

It's a 19" Toshiba LED/LCD/DVD 66 W.
Rating on the TV is 0.55A Max

Power = Volts x Amps
120 x 0.55 = 66 Watts

Correct?

Plus, the load of the inverter and any voltage drop due to the wiring. You want to take a voltage check under full load. #10 wire should be fine!! In reading the manual from your link, the inverter uses 0.4 amps. if I remember right.

Now you are correct on your math with the AC side, but have you done it on the DC side of things?

Between the TV and the inverter, to keep things round. Lets say the both use 100 watts. On the DC side, thats about 9 to 10 amps. off the top of my head. Also, I would install a in-line fuse at the battery. If the wires at the inverter every shorted, you want that protection.

Paul I. · **Posted:** Tue Jan 31, 2012 10:08 am

ric wrote:

Yup.

Now this is just cool.
http://www.xantrex.com/power-products/p ... nitor.aspx

Yes it is!! I tried to download the installation manual to see how it is wired. The link is bad, I wanted to see how easy or hard it would be with a dual or tri-battery setup.

ric · **Posted:** Tue Jan 31, 2012 10:22 am

Paul I. wrote:

ric wrote:

Yup.

Now this is just cool.
http://www.xantrex.com/power-products/p ... nitor.aspx

Yes it is!! I tried to download the installation manual to see how it is wired. The link is bad, I wanted to see how easy or hard it would be with a dual or tri-battery setup.

It does two battery banks per gauge. So if you have a dual battery setup on a switch, each battery would be it's own bank. If you have 3 batteries, 1 starting and two deep cycle "house" batteries wired together, that's still only two banks. It's just a fancy voltmeter, but it would answer the question when I'm on the lake all day.. is my battery dead yet or can I blast music for another 2 hours??

I could be wrong but I read when it reads a low voltage on a bank, it can trip a relay and shut down that bank. Or just sound an alarm. Awesome!

Paul I. · **Posted:** Tue Jan 31, 2012 10:39 am

My self, I have 3 banks. Its measuring amps too, so (I could be wrong, heance I wanted to use the link) its more than a fancy voltmeter. I was thinking that a 3 way switch could be used between banks, I will just have to wait for them to fix the link, or call them.

www.iFourWinns.com

Modified Sine Inverter

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