Why can’t I use a heated blanket or heating pad?

[Wandererrr]

I have 200w of solar panels, 300ah of batteries, a 12v system, with a 3000w inverter making it 110vAC.
When I try to use a heated blanket someone gave me, that’s like 120w-ish, nothing happens.
When I try to use a heating pad that’s about 52w, 120v, the light flashes that’s supposed to be solid and it doesn’t heat up.
When I tried to use a brand new heating blanket that’s 180w, 120v, it started smoking. I bought a replacement. It started smoking too. I plugged them in somewhere else outside of the bus and they worked fine.
What’s causing issues with anything related to heat no matter the wattage?

 

[Checkthisout]

I have 200w of solar panels, 300ah of batteries, a 12v system, with a 3000w inverter making it 110vAC.
When I try to use a heated blanket someone gave me, that’s like 120w-ish, nothing happens.
When I try to use a heating pad that’s about 52w, 120v, the light flashes that’s supposed to be solid and it doesn’t heat up.
When I tried to use a brand new heating blanket that’s 180w, 120v, it started smoking. I bought a replacement. It started smoking too. I plugged them in somewhere else outside of the bus and they worked fine.
What’s causing issues with anything related to heat no matter the wattage?

Double-check the output voltage.

Is it a pure sine wave inverter?

 

[Wandererrr]

Double-check the output voltage.

Is it a pure sine wave inverter?

Yes. Already double checked

 

[sunshine_eggo]

We have an electric blanket at the ranch. On the Predator generator, it refuses to function with the flashing light as you describe. The frequency of the generator wanders between 58 and 62Hz. However, on the Quattro with it's 60±0.1Hz signal, it works perfectly.

My theory is that the unreliable frequency prevents the timer from functioning (has automatica 10 hour turn off).

Are you 1000% certain you have a true PSW inverter?

If they work running on grid, but not on your inverter, something is likely wrong with your inverter.

 

[#40Fan]

Link to the inverter??

 

[Checkthisout]

Yes. Already double checked

Ok. Only a couple things it can be.

1) high voltage

2) sine-wave impurity

3) You're so hot the blanket is catching on fire whenever it touches you.

 

[Wandererrr]

We have an electric blanket at the ranch. On the Predator generator, it refuses to function with the flashing light as you describe. The frequency of the generator wanders between 58 and 62Hz. However, on the Quattro with it's 60±0.1Hz signal, it works perfectly.

My theory is that the unreliable frequency prevents the timer from functioning (has automatica 10 hour turn off).

Are you 1000% certain you have a true PSW inverter?

If they work running on grid, but not on your inverter, something is likely wrong with your inverter.

Turns out it’s actually a “modified” sine wave inverter. Never realized. Learning a lot, thank you.
Is that the sole cause of all of these issues related to heat?

 

[Wandererrr]

Ok. Only a couple things it can be.

1) high voltage

2) sine-wave impurity

3) You're so hot the blanket is catching on fire whenever it touches you.

Turns out it’s actually a “modified” sine wave inverter. Never realized. Learning a lot, thank you.
Is that the sole cause of all of these issues related to heat?

 

[Wandererrr]

Link to the inverter??

https://www.amazon.com/Inverter-Modified-Converter-Outlets-Emergency/dp/B0BXL6QP8M/ref=mp_s_a_1_4?crid=3SV8SAUTZ3E6R&keywords=homkeep+inverter&qid=1699335197&sprefix=homkeep+inverter%2Caps%2C183&sr=8-4

 

[Solarcabin Channel]

I have an electric blanket made by Rellorus on Amazon and it has a timer and works fine off modified or pure sine wave but most with digital controls will only work on pure sine wave.

I am running it off a Weize 1200 watt pure sine inverter right now.

 

[Checkthisout]

Turns out it’s actually a “modified” sine wave inverter. Never realized. Learning a lot, thank you.
Is that the sole cause of all of these issues related to heat?

Probably.

I don't know why exactly.

 

[Tomthumb62]

Turns out it’s actually a “modified” sine wave inverter. Never realized. Learning a lot, thank you.
Is that the sole cause of all of these issues related to heat?

In general, there are a few use cases where a modified sine wave inverter is just fine. They’re so cheap so if you don’t need a pure sine wave, you can save a nice chunk of money.

However, I can’t tell you exactly what those use cases are. If you have only one inverter, go with pure sine to have it just work.

 

[SeaGal]

I had to look up what "modified sine wave" meant exactly, and judging by the images on Google, if it only has 3 different output levels (as the pictures show), then no way should that be called a modified sine wave! It's just a square wave which reverses its polarity

 

[Solarcabin Channel]

Depends a lot on the inverter. Some mod sine produce square wave that cause anything with digital readouts, ballasters or a thyristor to overheat or not work at all. Some mod sine have much smoother outputs close to pure sine and will run those fine.

On the other side some cheap pure sine are not producing pure sine and may also cause the same problems as a mod sine.

Here is a good article that explains what appliances work with each type:

https://www.altestore.com/blog/2015/10/pure-sine-wave-vs-modified-sine-wave-whats-the-difference/

 

[Lt.Dan]

In the last few years, pure sine wave has become so affordable, that there is almost no use case for modified anymore. Modified sine wave isn't AS cheap as it used to be.

I vaguely remember the higher quality MSW inverters being more of a "step" sine wave, so it was a little smoother, but not completely.

 

[Solarcabin Channel]

In the last few years, pure sine wave has become so affordable, that there is almost no use case for modified anymore. Modified sine wave isn't AS cheap as it used to be.

I vaguely remember the higher quality MSW inverters being more of a "step" sine wave, so it was a little smoother, but not completely.

When I first went off grid all we could get was modified sine wave inverters and they worked for about 80% of appliances but things like microwaves, some fridges, anything digital and compressor motors would not work right or worse would over heat and kill them.

 

[Tomthumb62]

I had to look up what "modified sine wave" meant exactly, and judging by the images on Google, if it only has 3 different output levels (as the pictures show), then no way should that be called a modified sine wave! It's just a square wave which reverses its polarity

Yeah but "modified" sounds a lot less harsh than "square". Are you old enough to remember that being called a "square" was a little social death?

 

[Checkthisout]

Yeah but "modified" sounds a lot less harsh than "square". Are you old enough to remember that being called a "square" was a little social death?

Does it cause overvoltage because the peak voltage point of a modified sine-wave is higher for a longer period of time?

 

[Tomthumb62]

Does it cause overvoltage because the peak voltage point of a modified sine-wave is higher for a longer period of time?

Lol, you have me mistaken for someone who understands Greek. Seriously though, I too would be interested in learning more about how modified/square sine wave is different/why.

 

[CoolWill]

Lol, you have me mistaken for someone who understands Greek. Seriously though, I too would be interested in learning more about how modified/square sine wave is different/why.