Modding the TEC 06 for 4-Terminal Kelvin Measurement

[@dta116]

Have you completed Part 2? I am very interested.

Looking forward to part 2. Thanks for also sharing your mistakes.

[@diydsolar]

Hi, good videos about TEC-06. Do you get solution ? Thanks, I can't find "part 2" of this video.

[@pault6533]

Is the result any better than buying another unit that’s made better? I’ve already had to put a momentary switched capacitor on the input to avoid powerbank cutouts when starting a test, and adding a reset button when the unit gets stuck and needs a reset. I can’t imagine needing to do another mod. I’m quite happy with the ATORCH DL24 as-is and it does so much more. The TEC-06 is in a box somewhere, with English translation labels stuck to the PCB too.

[@BeetleJuice1980]

So no part two?

[@KainkaLabs]

The mod works and improves the accuracy but still the internal resistance measurement does not give very reliable values. They are jumping around by a factor of 2. So it´s not really worthwile to take the effort to make the mod.

[@BeetleJuice1980]

@@KainkaLabs I know you are doing a great job. So this unit is good only for capacity measure?

[@KainkaLabs]

Yes. For internal resistance measurement I wouldn´t use it. There are specialized devices for that like this one: www.elv.de/akku-ri-messgeraet-rim-1000-fertiggeraet.html You can also do that by yourself with a simple load resistor and 2 voltage measurents directly at the battery terminals (with and without load-resistor). Then the internal resistance is: Ri = (V2-V1)/R

[@BeetleJuice1980]

@@KainkaLabs i was searching KZbin for this diy project. Found some good builds. Do you suggest any specific diy project for this measurement? Thank you

[@KainkaLabs]

No, I don´t. Sorry.

[@gregsullivan7408]

So you never actually got it to work properly, correct? Just a thought - are you sure it is waiting long enough for the voltage to settle, when it turns off the load to measure the unloaded voltage? The reason I ask is that I notice that for NiMh, the voltage increases to about 1.2V after a capacity test has completed, even in the mode where it uses the open circuit voltage to test for the termination voltage. I'm using a 0.9V termination, so 1.2V seems high, but I'm no expert. If it's not waiting long enough, impedance measurements will be too low. I don't have an oscilloscope unfortunately.

[@manemojbe]

did you manage to solve the problem? for me, internal impedance is not important, but voltage difference is crucial because cutoff voltage is measured wrong and that leads to faulty battery capacity measurement.

[@KainkaLabs]

Yes, problem solved. But you shouldn´t worry about the cutoff-voltage as long as you set low enough. Take e.g. a 1,5V alkaline battery. The measured capacity is nearly identical with cutoff-voltages set between 0.1V and 0.9V. The remaining capacity below 0.9V discharge voltage is negligible. The capacity is much more dependent on temperature, discharge current, pauses during discharge (electrochemical recovery) etc. As long as you take thick enough leads for the current path so that the voltage drop over the leads is less than 0.1V with your chosen discharge-current there really is no need for the modification.

[@manemojbe]

I did some translations from Chinese manual that I received and found interesting information. It has two ways of capacity measurement: with 2 wires and 4 wires connected. In 4 wires connection test (like you did it in video) starting by clicking the button in AH led position, it uses pulses to measure open circuit voltage (that is the situation when the current drops on instrument). Than it uses that value to calculate internal resistance every few seconds. The displayed voltage value is open circuit voltage and that’s the explanation why it differs from measured. In 2 wires connection mode (connected to I+ and I-) which can be started by pressing the button when led is on batt voltage position, it gives a real time voltage value (in my case difference was 0.02V). If I understand it right I think it recommends 2 wires connection in regular use. Here is Google translate from Chinese, I’m not a native English speaker so you might better understand: The TEC-06 detector has two types of battery access: two-wire and four-wire. In the 4-wire access mode, the internal resistance of the battery can be measured, and the measurement result is displayed in real time. The measurement principle is as follows: During the discharge process, the detector will detect the line voltage in real time and generate a momentary off every few seconds. Break the pulse and measure the open circuit voltage during the pulse. The open circuit voltage is reduced by the on-line voltage and divided by the discharge current value, which is the internal resistance value. The measurement using the four-wire method considers that when measuring the on-line voltage, the voltage on the line is generated and the measurement accuracy of the on-line voltage is affected. For more accurate measurements, it is more accurate to use two wires at the root of the battery. This principle of detecting internal resistance is closest to the actual usage. Measuring the internal resistance needs to start with "mode 1" (in the "use step")

[@KainkaLabs]

That is a very valuable information. I will try to pin this for other users in the video-description of the main video about the TEC-06

[@alincristiancenan6986]

Hi, can u show an exemple on where to solder them and which resistence to solder?

[@alincristiancenan6986]

Hi , i have bought fews of this tec-06 and i would like to do the moding for 4 terminal kelvin mesurement As i couldn't see in this video witch pin to desolder from lm324 and how to solder the 2 resistance ,could u explain in a draw on how to do it please Thanks

[@exgenica]

What is preventing part 2 from being posted? Has the TEC-06 manufacturing company caused a problem for you because of the several problems you found with this design in your original video review? Have they instructed you to NOT post part 2 of your "Kelvin Mod"? It seems like part 2 would be a VERY quick bit of work to test your proposal and display your results once you received the new replacement LM324, but it's not yet posted 19 months later? You seem to have numerous other projects posted in the intervening months. Or, is this a KZbin search failure issue?

[@KainkaLabs]

If you scroll through the other comments I have already commented on this. The mod with a better OpAmp works and gives near perfect results. But you have to bend on pin of the OpAmp upwards and solder 2resistors directly to the pins. So it´s not very beginners-friendly mod and thus I didn´t do a supplementary video. Producing videos is also very time-consuming and sometimes a loose interest in some older things and have more ambition to do videos on things I am ATM "working" on. And of course nobody can "instruct" me to NOT post anything "critical" :-)

[@Adrian-Carstea]

Your drawing is wrong, voltage follower have negative feedback not positive.

[@KainkaLabs]

You are right of course. Stupid me. It was already quite late in the night when recording that video :-)

[@arthus1971]

Have you completed Part 2? I am very interested.

[@KainkaLabs]

Yes and it works.

[@arthus1971]

@@KainkaLabs wonderful!!! please where is it ?