Car boiler

Hello. An order with Aliexpress came to me a couple of days ago - a 12v autocoiler with power from the cigarette lighter. Briefly: performs its function "on the verge", a mug of water heats up to a boil for 17 minutes. And really dangerous for a car. I haven’t written anything for a long time, so many letters
When Aliexpress once again sentA mailing list with goods that I really need (according to the Chinese) that you need to have time to buy while there are just incredible discounts, I quickly looked at the motley footcloth, and the mouse pointer reached for the "Delete message" button. But stopped halfway, as in the heada thought flashed that of all the advertising nonsense, only a 12v car boiler is at least of some interest to me. I was busy at that moment, and in a few clicks of the mouse I placed an order, without paying, in order to figure out in my free time whether I needed it or not.
Recently, I travel a lot and far oncar, and tea taken from the house in a thermos manages to cool. It is not always possible to go to a cafe and have lunch / dinner in a civilized manner. And although the use of such a boiler is rather doubtful, I decided to buy it for long trips, in case of, say, a wild night in the middle of a field / forest. It is not a fact that such a case will happen at all, but I will be ready for it. And I decided: I take it!
But before placing an order, I looked at othersoffers on Aliexpress, and as always, the boiler offered with a big discount on mailing turned out to be about one and a half times more expensive than the average price on the site. Therefore, that spontaneous order was canceled, and I ordered a boiler from another seller with a high rating and a large number of orders, and even with a 30% discount. Well, this calmed down.
An order came to me exactly 4 weeks later, and after testing the boiler, I decided to share information about its capabilities, take a break from work and try myself as a writer.

Workmanship, of course, is not so hot, sometimes onplastic hefty burr. The heating element itself is flimsy, the “spring” is easily deformed by the fingers, it is also loosely fixed in the housing, and moves without any special effort.

The wire is 80cm long.

The first inclusion was late at night, I justmade sure that the boiler is working. I have a 12v 7Ah battery left from the old halogen on-camera light, they put it in UPSs, and the “outlet” of this battery is just the cigarette lighter socket. As I recall, before moving to the LED flashlight for shooting, I dragged two of these batteries, each 2.5 kg ... It has become dusty since 2011, I use it very rarely to power various crafts ...

How are soldering irons checked in stores? - they stick it in the socket for a couple of seconds and shove it into your hands: “Here, it’s heated!” For about the same way I checked the boiler for the first time, put the plug into the cigarette lighter socket, felt the heat with my fingers, and was glad that it even works.
In order not to get any nasty surprisein the car, I decided to pre-test the boiler at home. First of all, I opened the case to check if the wires to the heating element were installed securely and if I would not expect a short circuit at the wrong time. Both in the car and in the "home" battery there is a fuse, but still ...

The wires to the heating element turned out to besoldered, but not too high quality. Surprised by the red color of the spiral, is it a plating, or a copper alloy spiral? It is interesting to compare the cross-section of the heater itself and the cross-section of the wire: even visually these are quite comparable values, and we can expect that the wire will also decently heat up.

Sometime out of children's interest, I completelythe Soviet burned boiler was broken, and in it the spiral inside the outer tube was flooded with some kind of light gray compound, so that there were no gaps between the spiral and the outer tube. Here, as you can see, the compound is absent, at least on the straight part of the tube and spiral. But whether he is in the area of ​​the "spring", I can not say. The spiral does not move inside the tube (pulled for it), so we can assume that there is still a compound there ...
No heating fixation elementsThere is no element and supply wire in the plastic case, the heater holds onto the wire, and the wire holds onto the heater. So if you accidentally pull the cord (or heater), the boiler can self-understand.
Next, the control passed the plug of the boiler. I came across devices in which a similar plug was made of some kind of thermosetting non-consumable plastic. Here, the non-consumable only front part of the plug with a movable contact was checked with a soldering iron. Better, of course, than the entire plug made of soft polystyrene.

I have a cigarette lighter socket and a plug in my carthey get very hot during the operation of the autocompressor, but rather the problem is in the socket itself, and not in the plug, there simply is nothing to warm in it, the wire is soldered directly to the pin. Apparently, the very place of contact between the socket and the pin of the plug is heating up, but nothing can be changed here.
And finally, the main full-scale test. A mug of water from a tap with a volume of about 200 ml, a boiler in it, and a plug in the battery. The supply voltage is about 12.2 volts, in a car with the engine turned off, it happens about the same. And with the engine running, I would not turn on such a boiler, it is not known how it will carry out a voltage of 14 ... 14.5v.
Yes, before that I measured the total resistanceboiler: exactly 1 ohm. Thus, the current consumed by the boiler clearly exceeds 10A, and I can not measure it: I have ammeters only with a measurement limit of 10A. The design power of the boiler, therefore, P = UxU / R = 12x12 / 1 = 144W. Wow, even more than 120W declared by the seller, but this, unfortunately, is not the power of the heating element itself, but the “total” power of the boiler, taking into account losses in the wires.
But even power is not the main thing. The main thing is the time during which this boiler will boil a mug of water. Unfortunately, the battery for the on-camera light turned out to be rather weak for this experiment, the voltage dropped sharply, and the "boiling" had to be stopped. Still, this battery is already more than 7 years old and its operating mode was far from the most favorable. The boiling process has stopped:

But since I also have at homecar "spare" battery, it was decided to use it. I armed myself with “crocodiles”, I hooked the wires from the crocodiles to the disassembled plug of the boiler somewhat, and the process started. I did not take a photo of this collective farm.
I had to be patient: the water in the mug was in no hurry to boil. I remember once using a mini-boiler 220v 700w - he heated the mug to a boil for a minute with a little. Therefore, I counted on 5, a maximum of seven minutes.
And here the wait lasted for 17 minutes! Ten minutes later, the mug was already scorchingly hot, but it was still far from boiling.
After 4 minutes:

After 7 minutes:

In 10 minutes:

After 15 minutes:

But now, finally, after 17 minutes, the long-awaited boil came!

Although the boiler eventually coped withhis task, oh how hard it was for him! While waiting for the boil, I periodically felt the connecting cord - the heating of the cord was so strong that I even wanted to interrupt this experiment. But before the melting of the insulation of the wires was still far away, and I still brought the matter to a conclusion, deciding that in a pinch the thin wire would work as a fuse. The heating of the wire is quite natural, its cross section does not exceed 0.75 sq. Mm (per eye), which is not enough for a current of more than 10A. With a full resistance of the boiler of 1 Ohm and a rated power of 144 watts, probably just about 20-30 watts is dissipated on the connecting cable, and we get the 120 watts promised by the seller that go to heat the water. These, of course, are rough estimates; measuring specific values ​​is simply not interesting.
The first thought was to replace the native cord with a cordmore suitable section, but is it worth it? The cord will take up more space than the boiler itself ... Moreover, when replacing the cord, the current consumed by the boiler will increase even more, and not the fact that the cigarette lighter in the car will cope with it ... But to attach “crocodiles” to such a boiler is absurd ...
Output: The boiler performs its main function, having a capacity of about 120 "pure" watts, it is able to bring a mug of water at room temperature to a boil in 17 minutes. In principle, it is suitable for rare cases of wild caravanning. True, I would not be surprised if he suddenly dies after a few cups of tea. Yes, there is still some chance to burn to hell and the car itself, without drinking a seagull.