Heated Mattress Pad Safety

[Kellycanoe]

Hi Folks --

This might not be the right place for my question, but who would know the answer better than the people who gravitate to this forum?

I just bought a Sunbeam heated mattress pad for my 2015 22FB Sport, and I see in the user manual the following: "Do not use with generators, power converters or inverters." Why would it be unsafe to use with the inverter when off shore power? How is that different from plugging in directly to an AC source?

Of course, this is one of over 20 warnings in the first two pages of the manual. Is it just something the lawyers (who DON'T understand all things electrical) insisted on?

I've read all the threads I could find regarding heated mattress pads and found nothing on this topic. Hence my tug at your shirtsleeves for guidance.

Thanks in advance!

Kelly

[dznf0g]

I can't think of a safety reason, other than Sunbeam would have less comfort with consistent, stable voltage outputs from a wide variety of products than they would with federally regulated grid power supplies.

[cwf]

The blanket, being solid state controlled won't work with generator because the power output can be "dirty". This is why PC's and other sensitive electronics prefer full wine wave, clean power which usually you get from the power grid.

We put reflectix between the base and mattress.. all the best we need once warmed up.

[dznf0g]

Originally Posted by cwf

The blanket, being solid state controlled won't work with generator because the power output can be "dirty". This is why PC's and other sensitive electronics prefer full wine wave, clean power which usually you get from the power grid.

We put reflectix between the base and mattress.. all the best we need once warmed up.

Possibly, but I don't think this is true with a pure sine wave inverter generator.

[Zugbug]

I assume this has a safety certification, and it is probably a requirement for that certification.

[Kellycanoe]

Originally Posted by Zugbug

I assume this has a safety certification, and it is probably a requirement for that certification.

That was my guess, too, but I'd like to be sure!

I would be running the pad on a low setting off the batteries, so my question is mainly about the fact that an inverter would be between the power source and the device. Is there any risk at all of excessive power reaching the heating element and causing a fire hazard? Is it possible the device's thermostat would be damaged by a less precise and consistent power supply than would be provided plugging into shore power? And when the batteries are fully- or nearly fully-charged, is their output (via the inverter) significantly poorer quality than shore power?

Thanks, everyone, for your advice!

Kelly

[moosetags]

Admittedly, I don't know very much about the electronic technology involved with using a heated mattress pad in an Airstream or any RV. What I can comment on is long term use of a heated mattress pad in an RV.

We have had three Airstreams over the last twelve years. Two had queen beds and our current Airstream has twin beds. We have had Sunbeam heated mattress pads in each of our Airstreams, and have used them extensively both on shore power and generator power.

Brian

[Adventure.AS]

The newer AS use memory foam in the mattress top. Heated pads are not recommended because of the heat sensitive nature of the foam. https://tempurpedic.ca/product-info/product-care

[cwf]

Originally Posted by dznf0g

Possibly, but I don't think this is true with a pure sine wave inverter generator.

Agreed! If the inverter style generator you should be ok!!!

[quietguy]

If you're running it "off the batteries" via your inverter, I'm quite certain that your battery(ies) will be very dead long before the morning. How many watts is this heating pad as it could potentially draw more watts than your inverter is rated for!?!

[pcskier]

Originally Posted by quietguy

If you're running it "off the batteries" via your inverter, I'm quite certain that your battery(ies) will be very dead long before the morning. How many watts is this heating pad as it could potentially draw more watts than your inverter is rated for!?!

Inverter is likely 1000 watts, but even if only 500 watts will be no problem. Heated blankets/pads draw as little as 100 watts. Times two sides for a larger one that's 200 watts. And many people keep them set at level 5 out of 10. That's 100 watts total which is .83 amps. 10 hours would draw as little as 8 amps, or as many as 16 if it's pulling 200 watts. Two fully charged, healthy Interstate 24 Batteries provide 84 amps before depleting to 50%. Plenty of power for an electric blanky off the inverter for the night.

[16595]

Electric Blanket here.

It is a Sealy (queen) and has two controls. Each is rated at 180 watts.

We have tried using it on generator but get no heat output. Maybe due to lack of ground? Or that it is digital? The controls do light up but that is all.

Dwight

[mtcw]

I have used a DC 12 volt heated mattress pad for years--No Problems
Just watch your battery charge level.

[cwf]

Originally Posted by 16595

Electric Blanket here.

It is a Sealy (queen) and has two controls. Each is rated at 180 watts.

We have tried using it on generator but get no heat output. Maybe due to lack of ground? Or that it is digital? The controls do light up but that is all.

Dwight

Dwight.. does the heater work when plugged in your home electricity? Just a quick check...

[quietguy]

Originally Posted by pcskier

Inverter is likely 1000 watts, but even if only 500 watts will be no problem. Heated blankets/pads draw as little as 100 watts. Times two sides for a larger one that's 200 watts. And many people keep them set at level 5 out of 10. That's 100 watts total which is .83 amps. 10 hours would draw as little as 8 amps, or as many as 16 if it's pulling 200 watts. Two fully charged, healthy Interstate 24 Batteries provide 84 amps before depleting to 50%. Plenty of power for an electric blanky off the inverter for the night.

That's not correct at all. AC amps don't equal DC amps. (amps x volts = watts).

You're using 12 volts to create that 100 watts via the inverter (also remember your inverter isn't 100% efficient...it uses power to "make" power). Your inverter uses roughly 10 amps DC to make that 100 watts AC. Running that alone for a night will SERIOUSLY deplete your battery bank, assuming you start at 100% charge and use nothing else power wise. (The math looks something like this: to get 100 watts AC from 12v DC and assuming 85% inverter efficiency...100 divided by 12 divided by .85 = 9.8 amps; 100/12/.85=9.8; watts/volts=amps less the loss of power while inverting it.)

I stand by my original statement.

[quietguy]

Originally Posted by quietguy

That's not correct at all. AC amps don't equal DC amps. (amps x volts = watts).

You're using 12 volts to create that 100 watts via the inverter (also remember your inverter isn't 100% efficient...it uses power to "make" power). Your inverter uses roughly 10 amps DC to make that 100 watts AC. Running that alone for a night will SERIOUSLY deplete your battery bank, assuming you start at 100% charge and use nothing else power wise. (The math looks something like this: to get 100 watts AC from 12v DC and assuming 85% inverter efficiency...100 divided by 12 divided by .85 = 9.8 amps; 100/12/.85=9.8; watts/volts=amps less the loss of power while inverting it.)

I stand by my original statement.

Now once you understand the above you'll understand two more things:

1.) why your two 55 watt low beam headlamps will drain your car battery in just a few hours.

and

2.) why it was so important not to sleep through my physics classes back when you were in high school...

[Trailbob]

We have the Electrowarmth RV queen, 120V AC mattress pad. In the instructions it specifies that you must use a pure sine wave inverter, if powering it from a 12V system. I bought a 300W Samlex pure sine wave inverter to power it when we are boondocking. For now, the inverter plugs into a Blue Sea 12V outlet connected to 10ga marine duplex that I ran to the back bedroom.

We normally just turn it on to warm up the bed if it is cold, but have also left it on low during the night without depleting our 2 6V batteries too much. It does not run constantly, but cycles on and off.

In our truck camper, we have the Electrowarmth 12V version for a twin bed. I sometimes wonder if I shouldn't have put the same thing in the center of our AS's queen bed just to warm it up, thus eliminating the inverter.

I first heard of using heated mattress pads on Handybob's Solar site. He said he has used them for years off an inverter without depleting his batteries.

[Zugbug]

Having worked for a large well known safety certification laboratory I would not use this with an inverter if the labeling says it is not recommended.

Also, if something bad were to happen Insurance may not cover you because the device was used in a manner the documentation indicated was inappropriate.

[Lily&Me]

You can perhaps avoid all of these machinations by going non-electric for your warmth..i.e. Down comforters and microfleece.

Maggie

[Minno]

We have an electric mattress pad, but only run it when we're plugged in. However, I also do wilderness camping, and use an air mattress. I have found it to be cold (outside air temp is the temp under you). I have started packing a piece of polar fleece to use under the sleeping bag on top of the mattress, and it works wonderfully. Might be an option for you instead of an electric mattress pad. Might be an option for me too.....

Kay