| Electronics > Projects, Designs, and Technical Stuff |
| Batteroo testing |
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| Brumby:
That's why I mentioned three. Three very similar results will give a very high degree of confidence. |
| FrankBuss:
--- Quote from: amspire on December 23, 2016, 06:01:36 am ---Frank, Some tests you could do. --- End quote --- Good ideas. But I shouldn't do it all by myself, then there is nothing left for Dave and others to test :) Dave could measure the temperature with his IR camera, and/or tape a thermocouple on the case with kapton tape. I have only one sleeve left, don't want to break this. The packet is now shipped to the next tester. I have included another cute little toy I ordered from eBay and just got today and didn't test so far, would be interesting to see it in a video. --- Quote from: EEVblog on December 23, 2016, 04:40:05 am ---Thought about getting two and running side-by-side but then people might complain the trains aren't identical. So will run two tests and then edit side-by-side footage with timer. Maybe add a lap counter? --- End quote --- A lap counter would be nice. I thought about this, too, but didn't have much time, always crazy time at the end of the year with client projects. An easy way would be a photodiode, and then an Arduino which measures it on an analog input, and a simple software high pass filter and hold-off, no need for calibration. Outputs each lap time on the serial port. Running two side-by-side is possible, just do two tests with four batteries, first test train A without sleeves, train B with sleeves, second test train A with sleeves and train B without sleeves, all in one shot. This should proof that there is not much difference. Then wait for a day so that the batteries can recover. Then a third test, using the two batteries from the tests without the sleeve: one in train A without the sleeve, one in train B with the sleeve. I guess the results will be really devastating for Batteroo. Don't forget to measure the open loop voltage of each battery at the beginning and the end of every test. --- Quote from: IanB on December 23, 2016, 08:46:41 am ---The number of tests for a significant result depends on the magnitude of the effect being measured. If the difference is something striking like 2:1, then only a couple of tests with a similar outcome is enough to start establishing confidence in the conclusion. --- End quote --- I'm pretty confident that the train tests are significant. I did now four tests, two with the sleeve and two without the sleeve, with two different battery brands. What I was thinking, after the second test you could argue that the train might have wear off, or getting dusty or something like this. But this is not valid anymore after the 4th test, and all tests are showing that with the Batteroo sleeves the time was significantly reduced, and the 4th test suggesting, that even the additional time for dead batteries with the sleeve is lower than without it (but maybe the train is running a bit faster for a very short time). Needs 6 tests as described above to compare all scenarios. |
| rollatorwieltje:
--- Quote from: Wytnucls on December 23, 2016, 08:24:53 am ---Here is an attempt to identify the DC to DC converter IC (I find it unlikely that they would have developed their own IC at that price point). There are no resistors to set the output voltage, so it is probably a fixed voltage output IC (~1.5V), which usually comes in a 6 pin package. This one has 8 pins. A 2.2uF inductor usually means a switching frequency of 2MHz for similar ICs. The picture is a bit blurry, but here my best guess for the PCB topology and pin functionality: Feel free to chime in if you spotted other connections --- End quote --- Not quite sure about the green Vout. If that was actually ground, the pinout matches the Monolithic Power MP3414 closely, except for the feedback pin of course. [conspiracy hat] Monolithic Power is about a 20 minute drive from Batteroo HQ [/conspiracy hat] |
| EEVblog:
--- Quote from: FrankBuss on December 22, 2016, 03:28:59 pm ---The MP3 player test is done. I used the method Dave described, just filming it, no measuring, to actually see when it turns off (looks like there was no low battery warning, maybe voltage jumped a bit). With sleeve a fresh battery worked 17.9% less long than without the sleeve and the additional time after using the sleeve on the dead battery from the first test with the MP3 player (which had a few days to recover) was 13.4 %. --- End quote --- And there goes the ball game. Typical passive device and typical active device FAIL :-DD And who was it that predicted maybe a 10-20% typical increase from a "dead" cell in their original video? And also the Oz university professor interviewed by the newspaper predicted the same thing. The odd device might be higher, but I'm pretty sure the results are not going to be pretty... |
| bktemp:
--- Quote from: Wytnucls on December 23, 2016, 08:24:53 am ---Here is an attempt to identify the DC to DC converter IC (I find it unlikely that they would have developed their own IC at that price point). There are no resistors to set the output voltage, so it is probably a fixed voltage output IC (~1.5V), which usually comes in a 6 pin package. This one has 8 pins. A 2.2uF inductor usually means a switching frequency of 2MHz for similar ICs. --- End quote --- Are there any boost converter ICs preset to 1.5V output voltage? I couldn't find one. 1.5V is an unusual output voltage for a boost conveter. Typically you need 3.3V or at least 1.8V for powering a microcontroller from a single battery. Therefore my guess would be it is a customized version, so even the pinout could be customized. Guessing from the high output ripple and the bad load regulation, it also doesn't seem to have a fixed switching frequency. Many ultra low power regulators turn the switch on until a peak current is detected, then turn it off until the output voltage is below a fixed theshold voltage. The output regulation will be bad, but the control circuit will be much simpler, consuming less power. |
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