Battery life with heated mattress pad

[comfun1]

How long will a battery last if you use a heated mattress pad? Does anyone do this?

[bikendan]

I thought heated mattress pads and heated mattresses are 110v AC, not 12v DC.
If there are some 12v DC ones, a battery won't last long.

[comfun1]

I saw some 12v pads and blankets on the internet which caused me to think about this. They were aiming the advertising at truckers and as comfort blankets for people traveling in cars. I thought it might provide an alternative to heating the entire camper during the night.

[KyDan]

Using a battery to produce heat is typically a big drain...

We cold weather camp a few times a year and with flannel sheets (an absolute MUST) and a down comforter or down sleeping bag opened up like a comforter, we are ok down into the low 50s.
It's rough getting out of bed but it's all part of the adventure. I typically jump up and turn on the LP furnace and get dressed while standing over the floor vent.
Then I put the stove top coffee percolator on a burner and light the oven to pre-heat for biscuits or sweet rolls.
The trailer heats up quickly and I don't use that much battery in the process.
Then it's a hearty breakfast and a hike in the woods if we're lucky and the weather cooperates.

[upflying]

Originally Posted by comfun1

I saw some 12v pads and blankets on the internet which caused me to think about this. They were aiming the advertising at truckers and as comfort blankets for people traveling in cars. I thought it might provide an alternative to heating the entire camper during the night.

Trucker and travel heating pads implies they are used while the engine is running and the alternator is charging the battery.
Using 12 volt accessories in this situation is fine.

[TitanMike]

I've considered using my mattress heating pad, running it on an inverter.

Here's what I've come up with.

Mattress heating pad draws 120 watts when on full. At an average battery voltage of 12.5 volts that would be 9.6 Amps. Because a pure sine wave inverter is 90-95% efficient that would mean the actual current would be 10.1 to 10.6 amps. That's at the highest setting.

I find that a setting of 2 keeps me toasty warm with a furnace T-Stat setting of 60 degrees. A setting of "2" is 1/3 the max so actual current would be around 3.5 amp.

If one spends 8 hours with the mattress pad set at 2, using a good pure sine wave inverter the heating pad will draw down the battery by 28 amp hours.

Now the issue is "can your battery handle that?". For me it would be no issue if I wanted to do this as I have a pair of 100 amp Battleborn batteries and could run the heating pad for 6+ nights if that was the only draw.

When boondocking I don't use my heating pad. If I's expected to be real cold I just wear some "sweats" to bed.

For anyone running a single 12 volt battery they would most likely be able to get one night using the above method but would be charging the battery every day.

One note, if one merely wants to go to bed and have it pre-warmed, they could run the heating pad for an hour before bedtime and then turn it off. A lot less power use and just make sure to have a good blanket or opened up sleeping bag on top of the bed when they snuggle in.