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.

[Mputelli]

ok, this was extremely helpful, i want to run 2 mattress pads at 2, we are camping with a 12YO and a 9 Month old on our side of the popup, with running the 2 mattress pads and a bottle warmer in the middle of the night, periodically, not continuously. Using ohms rule.. a 400w bottle warmer on 120V would draw 3.3amps, could i run 2 matress pads, and the bottle warmer efficiently through the night without drawing the battery dead? I have 1 70ah deep cycle battery with an additional under the hood of the truck in the spare slot, haven't wired them in parallel yet. Might go with LifePO4 batteries, but then would i need to change my converter?? also, running just the 2 pads and the warmer, what size INverter would i be looking at? lots of ?s sorry

[tomkatb]

Likely your car battery of 70 ah would provide about 40 ah. Discharging more is hard on them.

The bottle warmer would use about 1/2 ah per minute. Watts=12.5 volts X amp hours.

So find the literature on the blankets. Keep in mind 3 amps ac is 30 amps dc.

A 50 watt pad would consume 400 watts in 8 hours. Roughly 32 ah or less.

So, two pads plus the bottle warmer expect the battery to die before breakfast. It would be so low it will not live long. 32+32+8=72 ah.

Is there no furnace?

[bikendan]

Originally Posted by Mputelli

ok, this was extremely helpful, i want to run 2 mattress pads at 2, we are camping with a 12YO and a 9 Month old on our side of the popup, with running the 2 mattress pads and a bottle warmer in the middle of the night, periodically, not continuously. Using ohms rule.. a 400w bottle warmer on 120V would draw 3.3amps, could i run 2 matress pads, and the bottle warmer efficiently through the night without drawing the battery dead? I have 1 70ah deep cycle battery with an additional under the hood of the truck in the spare slot, haven't wired them in parallel yet. Might go with LifePO4 batteries, but then would i need to change my converter?? also, running just the 2 pads and the warmer, what size INverter would i be looking at? lots of ?s sorry

Without any information on the year, make and model number of your RV, some of your questions can't be answered, like your converter questions. Especially when you reawaken a 5 year old thread, before Lithium batteries were common in RVs. Older RVs will not fully charge a LiPo battery.

[TacomaJoe]

Originally Posted by Mputelli

ok, this was extremely helpful, i want to run 2 mattress pads at 2, we are camping with a 12YO and a 9 Month old on our side of the popup, with running the 2 mattress pads and a bottle warmer in the middle of the night, periodically, not continuously. Using ohms rule.. a 400w bottle warmer on 120V would draw 3.3amps, could i run 2 matress pads, and the bottle warmer efficiently through the night without drawing the battery dead? I have 1 70ah deep cycle battery with an additional under the hood of the truck in the spare slot, haven't wired them in parallel yet. Might go with LifePO4 batteries, but then would i need to change my converter?? also, running just the 2 pads and the warmer, what size INverter would i be looking at? lots of ?s sorry

You need more power. The 400W bottle warmer will pull 3.3A at 120V which equates to 33A at 12V. Your 70Ah battery would run that 2 hours and be dead, pretty dead after 1 hour.

Bottle warmer and a couple of mattress pads would run on a 1000W inverter pulling over 50A with the load. I would suspect the pads and warmer have some sort of switching thermostat so it wouldn't be a constant load.

LifePO4 batteries have more capacity per pound. I have 830Ah in my trailer and use the mattress pad but haven't measured what the current draw of the pad is. My total battery usage runs about 150Ah per day. Your converter will probably charge a LifePO4 battery, just not 100% so you need another source (solar or LFP specific) to run the battery up so the BMS can do its balancing thing.

[Aussieguy]

Originally Posted by Mputelli

ok, this was extremely helpful, i want to run 2 mattress pads at 2, we are camping with a 12YO and a 9 Month old on our side of the popup, with running the 2 mattress pads and a bottle warmer in the middle of the night, periodically, not continuously. Using ohms rule.. a 400w bottle warmer on 120V would draw 3.3amps,

If it is on an inverter 120v = 3amp BUT battery drain will be 33 amps --- without taking into account losses for the inverter


could i run 2 matress pads, and the bottle warmer efficiently through the night without drawing the battery dead? I have 1 70ah deep cycle battery with an additional under the hood of the truck in the spare slot, haven't wired them in parallel yet.


Might go with LifePO4 batteries, but then would i need to change my converter??

keep your converter until you decide if you have to have the faster charging ...
if you plugin the converter to 120v then it will charge the lithium but will take a long time... BUT most people will be able to plugin shorepower long enough to achieve the charge

Use a small lithium charger to top it up and balance once in a while, every 2 weeks or so


also, running just the 2 pads and the warmer, what size INverter would i be looking at? lots of ?s sorry

Inverter sizing
calculate all your appliances in watts
they usually come with a wattage on the product sticker ...
work out which are you going to use at the same time

eg 400w for heater + 200w for warmer = 600Watt
go to the NEXT popular size inverter 1000w

Then you got to work out battery size to be able to power that for enough time

600w average use = 50amps @ 12v battery will be dead in about an hour
@ adults and a couple of kids take a fair amount of power
you will more than likely need a smallish generator as popup won't be real good for solar

you might get away with solar on a popup
when it warms up and you don't need the heating stuff
1 or 2 panels on the roof and maybe a ground panel or two

200ah lithium + 400w of solar would be a good starting point
but everything depends on HOW long you intend to camp (weekend or weeks)
how often can you use generator or shore power.

[Mputelli]

Originally Posted by bikendan

Without any information on the year, make and model number of your RV, some of your questions can't be answered, like your converter questions. Especially when you reawaken a 5 year old thread, before Lithium batteries were common in RVs. Older RVs will not fully charge a LiPo battery.

Thank you! its a 2016 jayco Jay 1207UD

[bikendan]

Originally Posted by Mputelli

Thank you! its a 2016 jayco Jay 1207UD

OK, since that RV is not a Forest River product, you're going to need to provide more information since this isn't a Jayco owners forum. We have no idea what converter Jayco puts in their RVs. So getting the make and model number of the converter will help.

Are you talking about a mattress PAD or a heated mattress? Forest River puts heated mattresses in their popups, not heated pads.
Are you sure that it doesn't have heated mattresses?
Also you didn't answer whether it has a furnace or not.
Bottom line is that you will need to upgrade the battery setup, at least at minimum, a pair of 6v golf cart batteries.

[tomkatb]

We have set up our fifth wheel to avoid using ac as much as reasonable. Gas fridge. Go-Jo coffee maker etc. No solar. 2200 watt Honda generator. 400 ah of battery.

Inverters have a standby power loss of 1-2 ah per hour.

Most are about 80% efficient. More money gets somewhat higher efficiency.

So, they consume a lot of battery.

SOK makes a fairly small 280 ah battery with all the options included. About $1000. Temp monitoring, heaters and a blutooth battery monitor. 7 year warrantee.