A rather odd device that leaves me wondering how many people use these to heat their meals at work on a daily basis. My first thought was about the risks of holding food at a medium temperature for long periods of time, particularly the common food poisoning villains like rice, pasta and potato. But used properly this unit does seem to bring the food to a high enough temperature to limit that risk. The instructions do suggest adding a small amount of water before heating, and I guess that may be to allow the steam to couple the heat throughout the food.
My test was perhaps a bit unfair in that I put a high mass of water in the unit. With a portion of loose food the heating time would be much faster, and especially so in a warmer environment. Yes, I do keep my home at a really low temperature in winter. I prefer a cool dry environment to a hot stuffy one.
Electrically this unit is very simple. Just a couple of self regulating PTC (Positive Temperature Coefficient - resistance rises as they get hotter) heating elements on an aluminium heat spreader. At plug in if the unit is very cold the current will peak at about 3A on a 240V supply before rapidly falling to a power dissipation of about 40W (20W per element). When it reaches its highest temperature the current drops to a passive level determined by the cooling effect of the external environment.
I suppose that something like this could also have other uses than heating food. It could also be used for various workshop applications where it's useful to heat something slightly before use.
One thing worthy of note is that the figure-8 cable supplied is copper coated aluminium, so it's possibly worth swapping it for a better locally sourced cable.
Here's a generic eBay search link to these type of units. You'll have to substitute your local voltage in the search box:-
https://www.ebay.com/sch/i.html?_from=R40&_nkw=electric+lunch+bento+box&_sacat=0&LH_TitleDesc=0&LH_BIN=1&_sop=15
I plugged this 220V unit into a 110V supply and it still stabilised at 40W so it may be capable of a wide voltage range. But I've not tested that under actual food heating conditions.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.

14 thoughts on “Inside a chinese electrically heated lunch / bento box.”
  1. Avataaar/Circle Created with python_avatars John Shaw says:

    Ive got a 60w one ,its a pelltier corcuit!
    Takes about am hour to warm a meal up and its ok.
    Put the food in it hot, when the unit is clean, and only turn it on about an hour before eating.
    Granted Rice is dodgey pasta seems ok!

  2. Avataaar/Circle Created with python_avatars Constantinus says:

    British pounds sterling has a higher value in the purchase. So $12.00 here in the states would be equivalent to 7 or 8 British Pounds and a few quid in England.

  3. Avataaar/Circle Created with python_avatars Devyansh Sareen says:

    Where to put water before heating ?

  4. Avataaar/Circle Created with python_avatars Frank Smith says:

    So… you think it was the rice? You dont think it had anything to do with the raw ass fish?

  5. Avataaar/Circle Created with python_avatars Shannon's Staffys says:

    Mine stopped working so I took it apart. It's almost exactly like yours inside, but metal tape (like tape for air ducts) keeps the orange plastic in place. I took apart the heating elements and read 12v DC between the two of them when plugged into my car socket. So why is it not heating up? Any ideas?

  6. Avataaar/Circle Created with python_avatars Chloe Hennessey says:

    Clive,
    8 chicken drumsticks
    1 cup Apple Cider Vinegar
    1 Cup Kikkomans Soy Sauce
    Half a small bottle of Pickling Spice (usually a handful).

    Mix all together in pot, bring to boil with chicken in the fluid.
    Bring it down to simmer and cover it.

    Chicken Adobo- SE Alaska fisherman’s style.

  7. Avataaar/Circle Created with python_avatars Paul Wood says:

    you have your house at 8deg because you're a typical sweaty sock, as tight as a nats chuff….. and that's coming from a like-minded Yorkshire man, be Froogle be proud….👍👍

  8. Avataaar/Circle Created with python_avatars Hic Svnt Dracones says:

    I feel your pain. On my first trip to Sydney ever, completely alone.. I grabbed some pre-made sushi at LAX before my connecting flight. Something like 18 hours later I got to Sydney, walked around a bit then made my way to Bondi beach, got a Chicken sandwich from some fast food type place, like a mcdonalds or something on the beach.. After the first bite my stomach started going, I got like hot cold, sweaty, thought I was going to die. I actually booked a hotel at Bondi, one right next to the place I got the sandwich, and forgot about my hotel in Sydney I was that sick, just curled up in bed for about 4 days, couldn't keep anything in my stomach. Ugh that was so horrible, alone in a foreign country with food poisoning… luckily it was a native English speaking country.. ALWAYS be very wary of Sushi that isn't freshly made.

  9. Avataaar/Circle Created with python_avatars 12345 6789101112 says:

    Your house temperature is about the lows we have here in winter. I'm getting cold just thinking of a house that temperature.

  10. Avataaar/Circle Created with python_avatars Ralf van de Ven says:

    For the sushi I'm not convinced the rice was the problem. The raw fish slightly fermenting the van for a while is the more likely culprit for the projectile vomiting.

  11. Avataaar/Circle Created with python_avatars Diddy boy says:

    I got it and it is amazing. I used canned meat and it even started boiling . But it depends on ambient temperatures how hot it will heat. I have 12v and 220V version .

  12. Avataaar/Circle Created with python_avatars Storm Trooper88 says:

    the label on the bottom… not dishwasher safe.

  13. Avataaar/Circle Created with python_avatars garbo says:

    Before you place your life & safety in hands on lack of quality control lying cheating scum bag communist electrical product made in china make sure that you have several working fire extinguishers , a lot of fire insurance , smoke & CO2 Detectors on every floor , . They cut every corner and good luck trying yo get a penny from any of the millions of defective made in china products. Great example people who had made in cheating china extremely toxic sheetrock in their homes. It was so toxic that all of the copper wire, plumbing fixtures & pipes, insulation etc had to be replaced at an average cost of $80,00 a house. Ten years later all cheating china said was they are investigating it & no money for cheated honeowners.

  14. Avataaar/Circle Created with python_avatars Jules Ann says:

    If you got food poisoning from sushi im sure it wasnt because of the rice! Blame the raw fish, lol! 🙂

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.