USB power meter/tester thread - YZXStudio, Power-Z, RDTech and more.

I’ve not yet encountered the “Fail” message yet when updating the KM001, I’ve been able to update it a number of times already.

Does the KM001 that “Failed” work properly, except it does not want to update firmware?

Can you try changing a different micro-USB cable when you’re trying to update the firmware? (just guessing — it could be the USB connector does not properly connect with that specific KM001 meter maybe due to connector contact issue or something — or connect/reconnect a few times and try again)

Also, maybe try to do a Factory Reset on the meter (it’s in the last page of the Settings screen of the KM001 meter)

Hope some of the above suggestions might work.

Thanks for the suggestions, I went back and gave it a go but still getting a failed on the update unfortunately. One will have to do me for now.

How can I know if my YZXstudio ZY1270 has bluetooth or not?
If not, how can I connect it using microUSB to pc to read serial data? Any help for Windows, macOS or Linux would really help.

To see if it has Bluetooth or not look at the back of the main PCB of the unit, it should have pogo pins that connect to a smaller blue board that has a zigzag copper trace on it (which serves as the antenna), that’s the Bluetooth chip.

Ok what I did is to remove the screws at the back of the YZXstudio ZY1270 with a PH00 screwdriver. In fact there were only 3 on them, one missing, and were barely loose. One of the copper cylindrical separators was a little bit unscrewed, so tightened it up, in case the bluetooth module pins (they are retractable) didn’t touch the pads. Set the serial update to 1 seconds and no bluetooth device is found by the smartphone right away, but if I use “hcitool scan” on linux it does find the “SPP-CA” device instantly. For the device to be found on the Galaxy S10 it takes about 40 seconds to find it and you have to press “Scan” twice on bt settings, so if you are eager you may think it’s not working.

Now what’s left is how to read the data from either the smartphone or Linux or Windows. Do I have to pair the bluetooth device or does the app just have a device selector? How can I do it?

EDITED: found how to do it. You have to pair the smartphone to “SPP-CA” with PIN 1234. Then I used the app Serial Bluetooth Terminal from Kai Morich. Then click on menu - Devices and choose the paired device. Then on Terminal tab click on connect icon and that’s it, will output the time, voltage and amperage. It has option to save, share and Log. Probably the way to save everything is to enable “Log”, otherwise after a while toasts the error:
Hint: Receive buffer truncated. Try ‘Settings -> Receive -> Buffer size’

You can click home button on phone to open other apps and it will continue working in the background.

Yeah that’s how :slight_smile: , then the values are saved on a txt file which you can export to excel and transform to proper V and Ah numbers.

The Ah are not very reliable, specially if voltage fluctuates a lot, say you use quick charge and moves from 5 volts to 9 volts. You must use Wh, I presume you have to go adding up, since the meter does not output that value.
What you have is to divide Wh by desired voltage, say 3.7 volts or whatever, then you get flat Ah.

From my experience, even if you use a long interval like 10s the resulting Ah total from the sum of Amp readings will be within <5% of the real capacity value from the meter itself. Same goes for Wh. This method works unless the device being measured drops in and out of QC, but this rarely happens.

Is it possible to read serial data of YZXstudio ZY1270 over microUSB cable and not only bluetooth? So I can read from computer. I would like to do that because I get BT disconnect after a while, and I want to log for several hours. Looks like bluetooth connection is very weak and you have to keep the smartphone very next to meter. I’ve contacted f-t-2000 seller but no answer. No idea if he’s already present on eBay.

Finally got the bluetooth connection with the YZXstudio ZY1270 working for hours. You just have to put the meter and the phone very close (less than half a meter) because connection is so weak.

I have another question: what is the purpose of the micro-usb input of the ZY1270? I’m trying to use it as external power for the meter, but for some reason it sends power to the output, and it’s also counted in statistics. Is the female micro-usb in this case just another input like the male USB-A? Can’t be used int he same way as TC66C?

What’s the difference between ZY1270 and ZY1280? Does the latest have bluetooth option?

I think there’s quite a number of generations that went from 1270 to 1280.

here’s a features chart for 1270 to 1276. The 1280 basically has all features of the 1276, and then adds some more (like min/max, a micro-USB HID external port, more resolution, etc) (the translation is not so well done…)

Compare my reviews of them:

https://lygte-info.dk/review/usbMeter%20YZXStudio%20ZY1270%20UK.html
https://lygte-info.dk/review/usbMeter%20YZXStudio%20ZY1280%20UK.html

No mention to datalogging methods with practical examples.

I did show these two examples:


Albeit the second one was not done by me.

Still not satisfied with the answer. Does the ZY1280 have bluetooth? Is it an extra or all models have it?

The model I reviewed to not have Bluetooth, the backplate with the Bluetooth module is missing.

Checking the official YZXStudio website (Taobao, in Chinese), it seems there’s a slightly upgraded ZY1280M model:

https://item.taobao.com/item.htm?id=38401794937

(courtesy of Google Translate)

So how do yo datalog, using micro-USB interface?

Using the connector marked PC