VAC at the TV outlet

[fraim]

So the TV outlet is powered by either shore power (gen) or from the Dimensions 300w inverter.
Shore /generator runs the TV. When I turn on the inverter (no shore/gen power) the TV comes on & shuts off after a few seconds. I was thinking power surge & TV shuts down to protect it's electronics. I got my volt meter & checked the VAC at the TV's outlet. Sure enough I'm getting 164.5VAC. Huh?? I looked at the inverter but not familiar with them but do see a "output breaker" (picture attached) but don't know what it does or if it's a fuse how to access it. I'm not sure if that's the fix but it's a starting point. Anybody familiar or have this prob before?
Thanks

 

[Rene T]

So the TV outlet is powered by either shore power (gen) or from the Dimensions 300w inverter.
Shore /generator runs the TV. When I turn on the inverter (no shore/gen power) the TV comes on & shuts off after a few seconds. I was thinking power surge & TV shuts down to protect it's electronics. I got my volt meter & checked the VAC at the TV's outlet. Sure enough I'm getting 164.5VAC. Huh?? I looked at the inverter but not familiar with them but do see a "output breaker" (picture attached) but don't know what it does or if it's a fuse how to access it. I'm not sure if that's the fix but it's a starting point. Anybody familiar or have this prob before?
Thanks

Are you getting the same reading on shore power and generator? If you are, try taking a reading inside your house on another outlet.

 

[Gizmo100]

If your inverter is a modified sine wave inverter and you are using a digital volt meter you may be getting a incorrect reading.

You will need a meter that says True RMS. I don't know a lot about it but I ran into the same problem a few years back

 

[Lou Schneider]

The Dimensions 300 is a modified sine wave inverter, so unless your meter measures True RMS voltage your meter won't accurately measure modified sine wave voltage. True RMS is only found on more expensive meters and is usually indicated on the meter.

When the TV shuts down, does the inverter stay active? If the inverter also shuts down (maybe momentarily until the TV sheds it's load) it may be from low input voltage when the TV starts drawing current, most likely from a loose or corroded connection between the batteries and the inverter.

 

[John From Detroit]

There are two types of inverters for this post. MSW and PSW also known as TSW. meters may or may not read properly on MSW inverters. I would think the MSW's would read low (Ie 100 volt instead of 120) but without testing
1: I do not know
2: it may depend on the meter.

But that said I'd sure say that inverter is suspect.

 

[fraim]

I haven't looked at the inverter status while the tv was powering off. But the green light is on after the tv powers off.
I'm thinking that even of it's MSW & I don't have a MSW meter wouldn't i expect to see different voltages at different measurement times & not the same 164.5vac at each measurement?
@ReneT... I'm pretty sure even without measuring while on shore power/gen that the voltage is correct or the tv would power off.
Anyone know what "Output Breaker" does or how it operates? The manual says to "reset the output breaker" for different reasons but that button doesn't push in & stay in. Rather it seems a bit loose. Also the manual says it's a 5 amp fuse but how do you get to the fuse?
The tv is new as of December & worked with the inverter at that time. The rig has been sitting at the storage yard since that time.

Thanks

 

[NY_Dutch]

Some power supplies don't do well with stepped square wave MSW inverters. More than one RV'er has found that out the hard way when their electric blanket and other electronics let out the "magic smoke" when turned on. The lucky ones found that some devices just didn't work, which may be the case with your TV.

 

[Isaac-1]

The simple solution here is perhaps to replace it with a Pure Sine Wave inverter, they are getting cheap enough these days, and if you have a modern flat panel TV, a 100-150 watt model would be plenty big. perhaps something like https://smile.amazon.com/AIMS-Power-PWRI30012S-Inverter-Continuous/dp/B0007911Y8 or even Amazon.com: BESTEK 300Watt Pure Sine Wave Power Inverter DC 12V to AC 110V Car Plug Inverter Adapter Power Converter with 4.2A Dual USB Charging Ports and 2 AC Outlets Car Charger, ETL Listed: Car Electronics

 

[Gary RV_Wizard]

The Output Breaker is simply a standard circuit breaker that protects the inverter from overload ( too many amps drawn from it). No different than the other circuit breakers in your load center in the RV or at home. On a 300W inverter, the breaker probably trips at about 2.5-3.0 amps.

The voltage you are reading looks suspiciously like peak voltage rather than RMS (average) value. Try a different voltmeter before making any conclusions.

I suggest you follow the advice in Lou's reply.

 

[fraim]

Thanks for that explaination gary. Next question...could you explain the difference between the "output breaker" & the gfci that is also on the inverter?
Last year my wife plugged in a vacuum cleaner into the 300w outlet and tripped the gfci on the inverter & all i had to do was reset that gfci but did nothing to the output breaker.
Trying to get a bit of education here.
Thanks

 

[Lou Schneider]

GFCI detects an imbalance between the currents on the hot and neutral wires and trips if there's even a slight difference between them, since the difference could be flowing through someone to ground. The amount of lost current needed to trip the GFCI is very small, and an inductive load like a vacuum cleaner motor can confuse the GFCI and cause it to trip even without any leakage to ground.

A circuit breaker simply monitors the amount of current flowing through a wire and trips if the current goes beyond it's rating to keep the wire from getting too hot.

 

[fraim]

Yeah, so after more research (including asking my friend who's an electrical engineer) based on what y'all were saying, i think it's an incomparability issue between the stepped square wave inverter & the new technology tv that I've just installed. A few of you had come to that conclusion already . So now I'd like to find a pure sine inverter that will somewhat fit the dimensions of where the old inverter sits.
Y'all are great for helping me out with your ideas & explainations. Much thanks!! I'll keep you posted on the progress.

 

[Isaac-1]

We might be able to help here if you tell us the measurements of the old inverter, also are you powering anything other than a TV with it (DVD player, etc?) This is a case where some brands are better than others, and some so called pure sine wave inverters are not very "pure"

 

[fraim]

LxWxH, inches = 13x6.25x3.25

 

[Lou Schneider]

A Google search will turn up a dozen or so possibilities, here's one to get you started. $45 on Amazon.

Amazon.com: BESTEK 300Watt Pure Sine Wave Power Inverter Car Adapter DC 12V to AC 110V with 4.2A Dual Smart USB Ports: Electronics

Buy BESTEK 300Watt Pure Sine Wave Power Inverter Car Adapter DC 12V to AC 110V with 4.2A Dual Smart USB Ports: Power Inverters - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

Edit: This is the same inverter Isaac-1 mentioned above. He probably did the same Google search I did.

 

[Isaac-1]

Actually the one I linked to was the metal case Bestek and costs about $5 more. Bestek seems to get good reviews overall, and it is hard to beat their price, though if you want nicer you can get a similar rated Samlex with GFCI outlets for about 3 times the price https://smile.amazon.com/Samlex-Solar-PST-300-12-Pure-Inverter/dp/B00H8N97E2/ or a Go Power for a bit more Amazon.com: Go Power! GP-SW300-12 300-Watt Pure Sine Wave Inverter: Automotive All of which have slightly smaller footprint than your old one.

 

[fraim]

Not a fan of the Bestek as far as it's dimensions & needed mods to the existing opening. But here's the thing I'm not seeing on those. There's no bypass for when connected to shore power that I can see or maybe I'm just not seeing it.

 

[Isaac-1]

These do not have integrated transfer switches I would be surprised if your original has one, but you really don't tend to need one on inverters this small, just let your converter charge the battery bank and let the inverter convert back to AC when plugged into shore power. Though if you really want to go that route you might add an external transfer switch box like Amazon.com: Xantrex 8080915 PROwatt SW Auto Transfer Switch: Automotive

 

[fraim]

Thanks Isaac.
If you look at the picture in my original post it shows the green led "external power". When I'm plugged into shore power the inverter is turned "off" & the "external power" led is on. Does that mean it has an integrated transfer switch?

 

[JayArr]

Wait a minute here. You haven't proved that the TV works! Before you go replacing the inverter try plugging a lamp into the TV outlet and see if it stays on. then run a long extension cord from the TV to the house and prove that the TV works on pure sine AC. Maybe your new TV has just failed.

Most (not all) switched mode power supplies in electronics do NOT object to modified sine wave input because the first stage is rectification to a DC bus. This was phased in about 15 years ago, along with Power Factor Correction (PFC) circutiry, to allow a single power supply to operate anywhere in the world. The power supply no longer cares if the input is 50hz or 60 hz (or anything close) and it doesn't matter if the voltage is 100, 110, 120, 220 or 240VAC. (you can even run them on two legs of a 208VAC three phase line.)

Previous to these design changes manufacturers had to build different power supplies for North America, Europe, Asia, Japan etc. The new universal design simplified the manufacturing and parts supply chain and reduced costs considerably.

I have earned my living repairing Switched Mode Power Supplies, inverters and motor drives for 25 years.