Thermos Cooking

[w32honu]

We are eager to try your methods as well as some of your recipes. After little use our thermos failed to keep any heat at all. Suspect cheap chinese manufacture.

Any brand recommendations?

[Normanby]

The thermos is use is made by Nissan, which is the brand recommended by The Boat Galley blog in their article on thermos cooking.
Using the numbers stamped element I calculated that in the 4 minutes it took to boil it consumed 6 amp hours (not 6 amps), at 12 volts (through the inverter) that was 60 watt hours.
Though I can't find my calculations at the moment - they could be flawed.

[mbianka]

Originally Posted by w32honu

I thought cooking rice in a pressure cooker risked clogging the valve?

Interesting thread. Have enjoyed reading it. All of this thermos talk reminds me of.......... What was it?

Oh yes, something to do with buckets.

Cooked rice in a pressure cooker many times never had a problem. Spray or dash of oil eliminates any foaming. Never had a clogged valve. Have used a bucket too never had a clog with that too. But, of course I wasn't cooking rice.

[sparrowhawk1]

6Ah for a four minute draw is a 90 amp power draw. My hot plate is rated at 750 watts which if you divide by12 is around 60 amps. And it will bring a cup of water to a boil in 4 min.

[StuM]

Originally Posted by sparrowhawk1

6Ah for a four minute draw is a 90 amp power draw. My hot plate is rated at 750 watts which if you divide by12 is around 60 amps. And it will bring a cup of water to a boil in 4 min.

Yep, that 6 amp hours in 4 minutes suggests that it is a 1 KW heating element.

[sparrowhawk1]

Well I guess I'll stick with my pressure cooker and insulated box

[Normanby]

Originally Posted by StuM

Yep, that 6 amp hours in 4 minutes suggests that it is a 1 KW heating element.

My knowledge of those ingenious electrons is sketchy at best, clueless at worst.
But surely if the element used 90ah as mentioned above, then that would have drained my little 100ah battery. It didn't.

Here's my dodgy electron mathematics:
Stamped on the element's casing is "300W".
At 240 volts, isn't that 1.25 amps?

Thus, at 12 volts, on the input side of the inverter, aren't we talking 25 amps (300 /12)? (plus inverter losses, let's say 30 amps).
So if run the element for an hour i'd consume 30 amp hours.

Run for only 4 minutes, isn't that 2 amp hours (there are 15 blocks of 4 minutes in an hour, so 30 amps divided by 15 equals 2)?

Where did i go wrong? (probably forgot to carry the 1).

Matt

[sparrowhawk1]

No that definitely makes more sense. But you changed it from a 6ah to 2ah draw. Thus 30amps instead of 90. Edit if you had your 100 amp hour battery and drew 90 amps off it for 4 minutes you withdraw 6 amp hours not killing your battery but little bit hard on it to be pulling that many amps at once.

[StuM]

> But surely if the element used 90ah as mentioned above,

It didn't. That was 90 amps, not 90 amp hours.

You said "Takes about 4 minutes to come to the boil, the element uses 6 amp hours at 12 volts (through the inverter)" which suggest roughly 1KW or around 4 amps @ 240v, 90 amps @ 12 volts.

Your calculations are correct. If it is labelled as 300W, the 2 amp hours is what I would expect. How did you come up with the 6 amp hours in your original post?

[sparrowhawk1]

So I'm back on board with this idea. does anyone know of a good brand of a 120 volt immersion heater?

[Normanby]

Originally Posted by StuM

> How did you come up with the 6 amp hours in your original post?

With a cunning blend of ignorance, misinformation, and what I suspect is early onset Alzheimer's.

What was the question?

[Normanby]

Maybe this element could work without an inverter:
http://www.my12voltstore.com/RoadPro...p/rpbh-012.htm

[sparrowhawk1]

Originally Posted by Normanby

Maybe this element could work without an inverter:
http://www.my12voltstore.com/RoadPro...p/rpbh-012.htm

Great idea I was going to order one right away but they want almost $15 for shipping. So I'm going to shop around a little. also there were no reviews. Update: amazon has it for $6.32 free shipping on orders over $35 but it only got a three star rating

[NornaBiron]

Originally Posted by Seaworthy Lass

This was the odd result with a runny white and cooked yolk after only half an hour in the thermos:

I had the most bizarre results today with boiled eggs in the thermos. I put 4 room temperature eggs in a 1 litre thermos and filled it with boiling water. After 2 hours I had one perfectly cooked egg, 1 nearly there and 2 with hard yolks and VERY sloppy whites - all the eggs were the same age. Odd!

[biker6977]

Here are a few neat sites I found- had never heard of this until finding this thread!!!

Vacuum Insulated 4.5 L Cook & Carry System | Thermos®

Thermos Cooking

http://thermalcooker.wordpress.com/2...hermal-cooker/