Page 1 of 2

12 volt electric blanket

Posted: 11 Sep 2008, 15:47
by adam2
These are available from Maplin
http://www.maplin.co.uk/Module.aspx?ModuleNo=224946

The price has recently been reduced from £25 down to £10, this reduction suggests that they did not sell well, and perhaps wont be stocked in future?

Might be a useful prep for cold weather and fuel shortages. For other than brief use a large battery will be required since the load is stated to be 3 amps.

EDIT I have now purchased one of these blankets, although the website states the consumption at 3 amps, the packaging states that it uses 4 amps.
I found the actual measured consumption to be a little over 4 amps.

I dont know how well made or safe these are and would advise caution in use, the law sets very high standards of safety for mains electric blankets, but I suspect that 12 volt ones may be exempt.

I dont normaly use an electric blanket, prefering ordinary woollen blankets, though I would regard a 12 volt electric blanket as prudent to have in case of severe weather etc.
(the last one I bought cost about $100, from the USA , since at the time they were not available in the UK)

EDITED with update re 4 amps used not 3

Posted: 11 Sep 2008, 17:32
by MacG
'Continental people have sex life: the English have hot-water bottles.' That was all. It has now become hopelessly out-of-date. How right was the kind (and to me unknown) lady who wrote to me in a letter:

'You are really behind the times. In this field, too, things have changed, and - this is the most important - techniques have advanced. We are using electric blankets nowadays.'

Posted: 11 Sep 2008, 19:01
by tomhitchman
And, for Adam2, you can by a 240v to 12v converter with car plug in type socket for the 12v for a tenner here:

http://www.m-99.co.uk/Electrical/240v_M ... verte.html

Woud this be safe to use warming up the bed in an unheated bedroom when the weather gets really cold?

Posted: 11 Sep 2008, 19:20
by JohnB
It's not a full sized blanket, and is advertised for keeping you warm in a car. Wouldn't a hot water bottle be better in a house?

Posted: 11 Sep 2008, 19:26
by tomhitchman
JohnB, last year did hot water bottles which actually was quite good but the top of my stove is only a few inches away from the roof of the fire so have to heat water in lots of little pans and is quite time intensive so getting a little bit lazy....

Posted: 11 Sep 2008, 19:59
by JohnB
tomhitchman wrote:JohnB, last year did hot water bottles which actually was quite good but the top of my stove is only a few inches away from the roof of the fire so have to heat water in lots of little pans and is quite time intensive so getting a little bit lazy....
Tom, I'm shocked at your laziness. But not half as shocked as you'll be if your electric blanket is faulty :lol: :lol:

Posted: 11 Sep 2008, 20:19
by RenewableCandy
JohnB wrote:
tomhitchman wrote:JohnB, last year did hot water bottles which actually was quite good but the top of my stove is only a few inches away from the roof of the fire so have to heat water in lots of little pans and is quite time intensive so getting a little bit lazy....
Tom, I'm shocked at your laziness. But not half as shocked as you'll be if your electric blanket is faulty :lol: :lol:
Are there stone blocks or slabs you can just rest on the top of the stove, then slip them into cloth wrappers when they're warmed up? Less hassle than messing about with pans, and won't leak in your bed. IIRC Tattercoats' (?) Chilli Penguin has them sort of built-in.

Posted: 11 Sep 2008, 20:35
by tomhitchman
RC I had thought about this last year but didn't get around to it. I have some unused paving slabs in the garden so may take a hammer to one to see if can break cleanly and give it a try.

Down south it is nowhere near cold enough just yet, lounge hasn't been beneath 19C as yet.

Posted: 11 Sep 2008, 20:56
by RenewableCandy
tomhitchman wrote:RC I had thought about this last year but didn't get around to it. I have some unused paving slabs in the garden so may take a hammer to one to see if can break cleanly and give it a try.

Down south it is nowhere near cold enough just yet, lounge hasn't been beneath 19C as yet.
Such consumate laziness...truly, I am in awe :D !

Posted: 11 Sep 2008, 21:00
by tomhitchman
Oh, two of you ganging up on me now!

The paving slabs only became spare in the summer, in my defence.

Posted: 11 Sep 2008, 21:21
by tomhitchman
So doing some research here are the reletive heat capacities of concrete and water:

Water 4186
Concrete 2060

(volumetric heat capacity, KJ/m³.k)

So would I have to have a concrete wrap double the size of the old hot water bottle method for the same heat?

Any ideas how best to make it cuddleable? Is this a new business idea in changing times?

Posted: 11 Sep 2008, 21:47
by RenewableCandy
tomhitchman wrote: Any ideas how best to make it cuddleable? Is this a new business idea in changing times?
Knock the corners off so it's vaguely round, then get some quilted cloth and stitch up a cover of roughly the same shape but a bit bigger, with 1-2 "sides" left open so you can put the stone in.

Now I come to think of it the stone's capable of getting hotter than water is, you'll have to make sure it stays below "Farenheit 451"...

Posted: 11 Sep 2008, 21:52
by JohnB
RenewableCandy wrote:you'll have to make sure it stays below "Farenheit 451"...
Only if he reads in bed :lol:

Posted: 11 Sep 2008, 22:17
by JonB
tomhitchman wrote:So doing some research here are the reletive heat capacities of concrete and water:

Water 4186
Concrete 2060

(volumetric heat capacity, KJ/m³.k)

So would I have to have a concrete wrap double the size of the old hot water bottle method for the same heat?

Any ideas how best to make it cuddleable? Is this a new business idea in changing times?
When I was a kid, we had a rayburn, but no CH for a while - (clean) housebrick in the bottom oven until v. hot then wrapped in a thick wool blanket. Put in bottom of bed - could barely put your feet near them to start with, but kept the bed warm for ages. Fantastic. Radiates the heat far slower than water HW bottle.

Posted: 11 Sep 2008, 22:49
by Keela
When I was a kid we had a Cleopatra (whatever THAT was).

The flue ran up the wall beside my bed. I lay up against the wall and was never cold. I don't remember it ever managing to get the radiators above a vague luke warm - such were the joys of uninsulated micro-bore pipework!