200 Watt Inverter Doesn't Run 180 Watt Appliance

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DearMissMermaid

DearMissMermaid

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Joined
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I bought a 200 watt inverter. My house battery is small, it's crammed in literally, with the engine in my  Class C, so I figure at this point I don't need a big inverter which drains the battery rapidly. I surveyed the items I wanted to occasionally use while not plugged into the grid.

I won't be getting a bigger battery until I am ready for solar, as the current location for a battery is so teeny tiny, I will have to add the bigger battery elsewhere, more wiring, more expense, so nothing I am going to do anytime soon.

Sometimes when I am traveling, I stop somewhere scenic to make lunch, walk the dog, do some work which requires my laptop.  In the past, if my laptop battery died, I had to fire up the generator, just to recharge it. That seems like a big waste of gas, though I do exercise the generator monthly to keep it happy, but I don't want to use it needlessly just to power up a dead laptop battery.

Also, sometimes I am in a friend's driveway and want to be mindful not to overload their 15 or 20 amp circuit I am plugged into.  Since their power is already running my battery charger, I figured one way is to use my inverter rather than the 110 direct on certain items. 

Everything I wanted to use was under 200 watts, so I settled on a small 200 watt inverter.  It runs the laptop computers, the crockpot, the flashlight recharger, cell phone charger, I don't have a TV yet, but the TV I would get would be under 200 watts.

All works fine until I tried to use a 180 watt mattress warmer with it.That was the main reason I settled on a 200 watt inverter rather than a smaller one.  I was just testing it out, in case I did some boondocking, I was hoping on chilly nights to prewarm the bed which is over a cold basement area. The heat helps tremendously with my aches and pains. (Getting old ain't for sissies!)

The bed warmer won't work on the 200 watt inverter. The bed warmer controls blink and it won't heat up, yet the controls indicate it is only 180 watts (that's what the label reads.)

What does this mean?  Is my inverter really not 200 watts?

Amazon will take the inverter back, refund cost and shipping, well actually it was $31.67 with free shipping, they will pay return shipping, but since it works for everthing else, I am puzzled whether to return it or not. But not having the bed warmer option is a big downer. I was planning to be bookdocking some this summer in an area where the nights can get cold. I love my mattress warmer.  ;D

By the way, the inverter model I have is:
Wagan EL2402 SmartAC 200W Power Inverter with USB Port (It had great reviews, so I chose it over others)
Tiny link to it:
http://tinyurl.com/625vk57

Any technical savvy minds out there that can solve this mystery?
 
It's probably not your inverter, it's probably your bed warmer. I have heard time and time again about bed warmers and electric blankets will not work on a modified sign wave inverter. This has to do with the bi-metal switch used to control the temperature I think the modified sign wave (square wave) heats it up and causes the on off scenario you are seeing. If the inverter isn't shutting down then it hasn't any problem.

You can try another brand of bed warmer but the odds are against finding one that will work. You could buy a pure sign wave inverter but that's a costly solution, especially considering the time of year it is and the near future needs.

I'd remove the bed warmer and tell my husband or boyfriend or significant other a long sob story about technology abounding me, and solicit their help in warming the bed.
 
Is your inverter rated at 200/400 watts or 100/200, if the latter it is only good for 100 watts continuous and 200 start.  You would need a minimum of 200 watts constant / 400 watts start.
 
That inverter is rated for 200W continuous, 500W surge, so lack of power isn't the problem.  It's most likely the controller for the mattress heater.  If it's electronic, it won't work on the modified sine wave output of the inverter, and at worst, will be destroyed by the inverter power.

There are 12VDC mattress heaters, I would look for one of those and keep the inverter for the things it will run.
 
Also, sometimes I am in a friend's driveway and want to be mindful not to overload their 15 or 20 amp circuit I am plugged into.  Since their power is already running my battery charger, I figured one way is to use my inverter rather than the 110 direct on certain items.
Click to expand...
Power is power.  You'll not conserve your friend's power by using the inverter.  It gets its power from the battery which gets its power from the converter which gets its power from the shore power.  Actually, you will use a tiny bit more this way because inverters have some power consumptions themselves (that's why they get hot).
 
The problem is you controller fo the mattress pad.  The old ones with the bi-metallic strp worked fine as the worked on the heat of their resistance.  The newer ones are electronic and modified sign wave usually burns out the controllers.  I hope you did not damage yours.  Check it by trying it on house power.

I hope everything is OK,
 
Everything that uses electricity has an initial SURGE when you first turn it on  This surge can be quite large Some motors for example may need 4 to 7 times their label rating to start up, Light bulbs, about 2x bed warmers, closer to 1.25 to 1.5 x, This power is only drawn for a brief instant, but,, if the inverter can't push that much it won't work.

A Traditional generator can, usually, provide the power (Thanks to the flywheel effect) even though it can not maintain that power level long.

And then you have the other end of the calcultion.

The inverter may be rated 200 watts, but odds are that is a PEAK rating.  While I do not know your inverter I do know that there are inverters out there rated 1,000 watts which can only deliver a sustained power of around 760 watts. So your inverter may only be able to deliver 150-175 continous.

You need a bigger inverter.. Say 450 watt.

Next, we have the MSW/TSW issue..

If you go to the XANTREX web page and navigate to technical documents for the X-Power series (MSW) you will find a document titled something like "Things that may not work on an MSW inverter"  One of the things listed: Electric blankets.

If you then navigate to the tech-documents for the PROSINE (True sine wave) no such document

I will give you the list of things that will not work on a True Sine inverter here:
Any device that requires more power than the inverter can product

End list

If it works on shore power, it works on a True Sine inverter.

One final comment:  I always thought that the MSW's did a more efficient job of converting DC to AC than the TSW's... till I looked it up and found that the specs on the X-power and Prosine for efficiency... Identical.
 
I agree with John. If you want to run a 180 watt device then a 200 watt inverter is not a good choice. A 400 watt inverter doesn't cost that much more than a 200 watt.
 
The bed warmer won't work on the 200 watt inverter. The bed warmer controls blink and it won't heat up
Click to expand...

What is your inverter doing while this is happening?  Does the green pilot light stay on or is it also blinking on and off?

If the light stays steady, the problem is with the electric blanket not being compatable with the inverter's modified sine waveform.

But if the pilot light also blinks on and off, the problem is in the inverter. 

First thing I'd look at is the wiring between the inverter and battery.  Wire loses voltage in proportion to the amount of current you're trying to pull through it.  If you're just plugging the inverter into a convenient 12 volt outlet, it's very likely the wire between that outlet and the battery is too long and too small to pass the current needed to run the inverter at full power.  It may work OK at lower power levels, but when you try to pull a lot of power, the wire can't pass all the voltage to the outlet and the inverter shuts down from low voltage.  Once it shuts down the voltage goes back to normal and the inverter tries to restart, only to shut down again when it tries to draw a lot of current.

You may have to move the inverter close to the battery, connect it via it's own custom 12 volt outlet (with very short, heavy  wires going to the battery), then use a 120 volt extension cord to get the power where you need it.
 
DearMissMermaid said:
I bought a 200 watt inverter. My house battery is small, it's crammed in literally, with the engine in my  Class C, so I figure at this point I don't need a big inverter which drains the battery rapidly. I surveyed the items I wanted to occasionally use while not plugged into the grid.

I won't be getting a bigger battery until I am ready for solar, as the current location for a battery is so teeny tiny, I will have to add the bigger battery elsewhere, more wiring, more expense, so nothing I am going to do anytime soon.

Sometimes when I am traveling, I stop somewhere scenic to make lunch, walk the dog, do some work which requires my laptop.  In the past, if my laptop battery died, I had to fire up the generator, just to recharge it. That seems like a big waste of gas, though I do exercise the generator monthly to keep it happy, but I don't want to use it needlessly just to power up a dead laptop battery.

Also, sometimes I am in a friend's driveway and want to be mindful not to overload their 15 or 20 amp circuit I am plugged into.  Since their power is already running my battery charger, I figured one way is to use my inverter rather than the 110 direct on certain items. 

Everything I wanted to use was under 200 watts, so I settled on a small 200 watt inverter.  It runs the laptop computers, the crockpot, the flashlight recharger, cell phone charger, I don't have a TV yet, but the TV I would get would be under 200 watts.

All works fine until I tried to use a 180 watt mattress warmer with it.That was the main reason I settled on a 200 watt inverter rather than a smaller one.  I was just testing it out, in case I did some boondocking, I was hoping on chilly nights to prewarm the bed which is over a cold basement area. The heat helps tremendously with my aches and pains. (Getting old ain't for sissies!)

The bed warmer won't work on the 200 watt inverter. The bed warmer controls blink and it won't heat up, yet the controls indicate it is only 180 watts (that's what the label reads.)

What does this mean?  Is my inverter really not 200 watts?

Amazon will take the inverter back, refund cost and shipping, well actually it was $31.67 with free shipping, they will pay return shipping, but since it works for everthing else, I am puzzled whether to return it or not. But not having the bed warmer option is a big downer. I was planning to be bookdocking some this summer in an area where the nights can get cold. I love my mattress warmer.  ;D

By the way, the inverter model I have is:
Wagan EL2402 SmartAC 200W Power Inverter with USB Port (It had great reviews, so I chose it over others)
Tiny link to it:
http://tinyurl.com/625vk57

Any technical savvy minds out there that can solve this mystery?
Click to expand...
Borrow a larger inverter and test, will quickly see if it's your inverter size or mattress warmer.  I can't see how a mattress warmer would require pure sine-wave power, heat producers are usually happy with "dirty" power, no matter.  "Also, sometimes I am in a friend's driveway and want to be mindful not to overload their 15 or 20 amp circuit I am plugged into.  Since their power is already running my battery charger, I figured one way is to use my inverter rather than the 110 direct on certain items."  A 180watt item is like 1.44 amps....  amp draw is amp draw, if your plugged into there power its being used... in fact, if you use an inverter, your actually using MORE power than without. The inverter uses power during the conversion process.
 
jje1960 said:
I can't see how a mattress warmer would require pure sine-wave power, heat producers are usually happy with "dirty" power, no matter. 
Click to expand...

I don't think it is the heating element that is objecting to the modified sine wave, but rather the electronic control and thermostat on the warmer. As Ned mentioned:

Ned said:
That inverter is rated for 200W continuous, 500W surge, so lack of power isn't the problem.  It's most likely the controller for the mattress heater.  If it's electronic, it won't work on the modified sine wave output of the inverter, and at worst, will be destroyed by the inverter power.
Click to expand...
 
Our electric blankets would not work on a 1000-watt modified sine wave inverter but work fine on a 400-watt pure sine wave inverter. We tried three different NEW electric blankets after one of our old electric blankets gave up. They all had electronic controls. I purchased the 400-watt pure sine wave inverter specifically for the electric blankets and also use it for our computers.

Richard
 
I also ruined two brand-new electric blankets so gave up on that ($$$$).  We got a mattress warmer that runs on either 12v or 110v and haven't had any issues with it.

ArdraF
 
OK, WHERE did you get the mattress warmer that runs on 12 volt or 110 power?  I've searched all over for one of those.  Tell me quick before yours vanishes... tee hee hee   

(If yours turns up missing, check my wheel estate...)

As you know, once you get hooked on a mattress warmer, they are IMPOSSIBLE to give up.  :-\  One of the best things about them is that they can stay on the bed year round, no bulky blankets to store. In my mini-motorhome, which I live in fulltime, this is a huge consideration. (Especially since my puppy needs the room for his toys, sweaters, T-shirts, jackets, vests, coats, footballs, tennis balls, teddy bears, blankie, leash, tether, Frisbees, treats, food, raincoat and golf balls)  I never knew one six pound puppy could require so much stuff...

My other electronic gadgets run fine on the inverter as does the treasured crock pot (cooking underway can be handy) so I am miffed my mattress warmer balks.

Not sure who to borrow a larger inverter from...  I'm in this RV park,  a few more days, then it's time for a trip!  I need to exercise the engine, might as well change out the front yard while I'm at it.  I don't really have a need for a bigger inverter, unless I got a jumbo one for the microwave and coffeepot, but that is overkill, I have the generator for that.

I do like this little inverter, it was only $30 with free shipping, it runs everything but my beloved mattress warmer.

As for the other comment above, about my significant other, well it's just me, a slippery mermaid, I move and travel so much, I haven't been nailed down at the altar.  I almost got married, awhile back, but when I found out I had to quit dating, well that was a deal breaker...  :eek:
 
I almost got married, awhile back, but when I found out I had to quit dating, well that was a deal breaker...
Click to expand...

This is where a significant other with a proper attitude is handy. :)


Fixed quote
 
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