Quickest way to boil a kettle, in a car?

[Rob Morley]

So stick a CO detector on the roof.

[Tim Downie]

'Tis just a sign of her loving devotion. She just happens to be intelligent

*and* devoted. (Please ignore any sounds of hysterical laughter in the backgorund).

Tim

[[news]]

so to recap, the OP needs the following:

a 3Kw generator domestic kettle a trailer net curtain baghat to keep the wee beasties off his heed a 'dip it in the liquid' element + lifetime of waiting three (3) heavy duty 12V barreries a voltage drop detector protector a 3000W inverter a gas burner to remove the back seats a heat exchanger device let into the cars cooling system

AND NOW A *fecking* CO detector !!!!111!

stainless.steel.flasks.

RT

[The Natural Philosopher]

You will be misted up and fugged up with H2O and CO2 long before the stove starts to produce significant CO.

I have DONE THIS.

In fact and in practice. It works. Usually we left the back doors open. In pouring and driving rain we kept the engine running and removed the engine cover. No heater or fan on that van in those days. :-)

Failure to do either resulted in HUGE condensation. We even did that too, for a quick cuppa parked up in torrential rain. We certainly didn't die of CO posoning. It only takes a few minutes to boil a camping kettle.

[Phil Addison]

Delighted to hear it, so perhaps she'll veto the idea (which I appreciate did not originate from you). Have a search for Peter Parry's views on CO detectors before you rely on them for safety, and don't forget the fire risk, which is probably the greater hazard.

A quick google threw up

containing this report from USA:

"Deaths from motor-vehicle-related unintentional carbon monoxide poisoning ... 3) use of auxiliary fuel-burning heaters inside a passenger compartment or in a camper ... describes the investigation of deaths associated with multiple motor-vehicle-related CO poisonings ... These findings indicate that deaths from motor-vehicle-related unintentional CO poisonings increase during winter months and that death rates from CO poisoning in stationary motor vehicles are highest in states with colder average winter temperatures."

(... my abridging ...)

Phil

[Phil Addison]

But she is expected to stay inside until the soup is hot.

Is that a recommendation or a warning?

But the spec for this discussion is that all the doors and windows stay shut to keep out mosquitos.

How long does it take to get brain damage from CO?

Phil The uk.d-i-y FAQ is at

Google uk.d-i-y archive is at NOSPAM from address to email me

[Old Bill]

I don't have direct experience of this but surely its a non-starter? Even running a 12v car fridge for a few hours will flatten a car battery if the engine is not running. Whats the average car battery, 50Ah? times 12 volts = 600watt-hours Say 3Kw kettle boils in 10 minutes, thats 500watt-hours Oh dear, battery practically flat

[John Stumbles]

I knew you'd like it, Mary!

(I think SWMBO would too: she's an ardent - maybe even militant - and practicing La-Leche Leaguer)

[mike ring]

Phil Addison wrote in news: [e-mail]:

It never did me any have you got any ride tandem

mike

[Bob Eager]

[The Natural Philosopher]

and don't

The greatest risk is scalding, in cars with soft susponsion and large mobile occupants.

[The Natural Philosopher]

But it doesn't. It boils in about a minute at 3Kw. Less if half full.

[Andy Wade]

Bzzzt, you only need to bring the water up to 100 deg., not boil it all away. The energy needed to 'bring to the boil' is very little more than you need to get to 95 deg.

[Dave Plowman (News)]

There's no point in inverting 12 volts to 230 to heat something. And a 2kW invertor - needed for the smallest domestic kettle - would be *very* expensive, and would draw the best part of 200 amps.

I'm not sure what 12 volt kettles are available, but be prepared for them to be very slow in operation. Unless plugged direct to the battery. One which works off the cigar lighter type take off is restricted to about 10 amps - so about 120 watts. A domestic kettle is as I said about 2000 watts, so it will take 20 times longer to boil the same amount of water.

Personally, I'd use thermos flasks.

[The Natural Philosopher]

One liter is 1000cc is 1000gm which takes 1000 calories per degree C. Lets start at 20C and get 80C rise, so 80,000 calories.

mutiply by 4.2 and its 336KJ or 336 kilowatt seconds.

At 12v thats 280,000 amp seconds, or 7.8 Ah

So it takes 7,8 ampere hours out of a 12v battery to bring one liter of water to the boil from 20C starting point. Excluding losses of course.

One liter is at least 6 cups of coffee, or 4 mugs.

So with a 50A/h battery there's enough energy to make about 28 mugs of coffee.

The 7.8A/h that each litre takes to boil is rpelaced by charging the battery (typically at about 10A average, more when nearly flat up to maybe 30A) in about 45 minutes of running.

Now for gas stoves. It takes about 30 times the volume of air to properly burn a given volume of butane gas (less for propane) and the calorfic value of butane is 21000 BTU per lb, and a lb of butane is 6.5 cu ft of gas, and so its about 3.23 KBTU per cu ft of gas, or about 100 BTU per cubic foot of air used.

A BTU is roughly a kilowatt second, and we need 336 of those to boil the kettle, so its between 3 and 4 cu ft of air needed to do that.

I reckon teh average peole carrier atea is 7 x5 x 3ft roughly, so about

100 cu ft. So about 3-4% of the oxygen is used by the stove. Assuming zero ventilation.

Of course the heat is nowhere near 100% going into teh kettel, but even so, it doesn't take much ventilation to feed a small stove for a few minutes.

[Dave Plowman (News)]

But this is normally to protect the battery from being run flat, which lead acid types don't like. Are you *sure* there would still be enough charge left to start the car?

Then you've got the problem of the car not being 'sealed' to the outside, as the OP wanted. Unless you do some serious re-wiring.

Few are more than 100 amps. So say about a kilowatt. A domestic kettle takes twice this. And a 2kW invertor will cost serious money. Better to tow a generator. ;-)

[doozer]

The point I was trying to make was that you only need to make the water (very) hot. Continuing to heat the water to its boiling point (as per the scientific definition) is a waste of energy. In fact tea made with water that hasn't been boiled tastes better according to many people so you get a double reward.

[<Dave]

In article , Dave Plowman (News) writes

£250 for a 2000w from mds, lot of cuppa's to pay that back!

[Lobster]

Oh I have, once (deliberately) many years ago.

My little sister had got her gerbil stuck inside it...

David

[Owain]

Thank you for sharing that with us.

I am not sure whether to worry more about the health of the gerbil or the sanity of your sister.

Owain