New LCR meters, Zoyi ZT-DQ01 and ZT-DQ02 (March 2025)

[RogerG]

Hi,

does the DQ-02 suffer from the same BMS problem as the ZT-703S/706S?
I mean, that the battery is overloaded in the ZT-703S/706S up to 4.35V due to a wrong BMS chip, just relying on the battery internal protection to stop the overloading.

Is this the same behaviour at the DQ-02, too?
At the teardown pics at the beginning of this thread I can't recognize the BMS chip.

Regards
Roger

[RogerG]

Hi all,
here is version 1.0 of my unofficial manual
"ZT-DQ02_AnengLM08_manual-ed1.0.pdf"

"ZT-DQ02_AnengLM08_manual-ed1.0-PRINTER.pdf" is A4 printer friendly (save toner version)

"ZT-DQ02_AnengLM08_manual-ed1.0-PRINTER-BOOK.pdf" printer friendly as above, but resized to A5 size booklet (obtained with 6 A4 sheets and 2-sided print) 

ciao
marco

Hi marco,

this part of the manual is a little bit confusing to me. Had to read a few times because I'm no native english speaker:

3.1.1
Whenever possible, with components with low load or high impedance load, it is recommended to use
the * clip input terminals, as it has lower stray parameters and provides more accurate results.

They all are clip inputs, the 4wire cable and the internal clip inputs.
Maybe an additional * "internal" is missing here to clarify?

Thanks for your good work!

Roger

[BillyO]

Hi,

does the DQ-02 suffer from the same BMS problem as the ZT-703S/706S?

There is no BMS problem with the ZT-703A/706S.  It is a misunderstanding by people that don't understand how the whole system works.

[SammysHP]

does the DQ-02 suffer from the same BMS problem as the ZT-703S/706S?

No, it uses a different charging controller.

There is no BMS problem with the ZT-703A/706S.  It is a misunderstanding by people that don't understand how the whole system works.

It seems like you're the one who doesn't understand how it works.

[BillyO]

I do.  There's a physics degree hanging on my wall that attests to that. 

[Skander]

I do.  There's a physics degree hanging on my wall that attests to that. 

A device that relies on the BMS constantly turning charging on/off (permanently cycling and flashing the indicator as long as it remains plugged) instead of the charge controller reaching a fully charged state has "no problem".

Very good.

The physics degree might need an electronics degree buddy to help it out.

Is there a fire hazard as some people claim? Lol no.
Is there a "problem" with the wrong charge chip being used by Zoyi? Well, yes.
Will slightly overcharging the battery every single time and relying on the BMS to cut it off reduce its lifespan? Yes.

[BillyO]

That's not even close to what we were talking about.  But go for it anyway. 

There is no problem with the Zoyi set up.  If yours is a blikin' light, then yours has a problem.  Mine does no such thing.

THis discussion probably does not belong in this thread though...

Oh, are you under the impression that electronics is anything other than applied physics, or that lithium cell design falls into electronics?  Never mind, that discussion probably does not belong here either.

[indman]

I think I should wait until they make the ZT-DQ03 with a 3.5 inch display. Similar to ZT-703S 

I never saw the ZT-DQ03 model with a large display, so I bought an analogue of the ZT-DQ02 called the Richmeters RM705B.
I haven't opened the case, but I'm almost certain that the hardware is 100% identical to the ZOYI version. The software version is 1.0.8
When the device is turned on, there is no ZOYI logo, but there is a modest "HANDLED LCR METERS" label.
I've been using this device for two weeks, and I want to share some thoughts and experiences with you. Perhaps they will help someone understand this complex device.I have attached photos of my version below, as well as the method I used to ensure a more stable position of the device on the table. To achieve this, I used the rubber case from the MY-65 multimeter, which has a very convenient and stable flip-up platform.

To be continued later....

[coromonadalix]

im sure the 1.0.8  is the same base version as the zoyi when they came out  ...    but some did start at v 1.0.5 ?

sadly  we can update them while putting a file in a temporay drive ... but no way to dump them in reverse and do a compare with the zoyi branded fw ??

there is some sw tools for the mcu ....

if your meter was mine, i would have pushed the zoyi 1.1.2 ...   and we know we can downgrade them ...

[indman]

but no way to dump them in reverse and do a compare with the zoyi branded fw ??

That's why I'm not in a hurry to update to version 1.12, because version 1.0.8 might get lost. Plus, I haven't seen any significant improvements in the latest version from ZOYI.

First of all, I would like to share my impressions of a feature that I plan to use frequently, as checking the quality of batteries is currently very important. I do not have any YR1030/35 devices, so I am glad that I did not purchase them earlier, as they would have been sitting on a shelf. The "BATT" feature in the RM705B is quite satisfactory in terms of its capabilities, and I would like to discuss it in more detail.
I don't have a reference AC milli-ohmmeter, but I do have a homemade DC milli-ohmmeter(20mA) in the form of a DMM add-on  I will use the ZT703S as the DMM.
The DC voltmeter in battery test mode is calibrated quite well, and I have shown the measurement results from the AD584 source.

[indman]

The AC milli-ohmmeter in BATT mode is also calibrated quite well for amateur radio tasks. However, there are some nuances.
I have shown in the photos that if you short-circuit the Kelvin probes, the display will show a value that is different from zero.
However, if you short-circuit the probes through a short copper piece, the display will show a value of 0.00. I have performed a short-circuit calibration in this position, and it has been successful. Interestingly, this calibration is almost identical to the factory calibration. In the DMM attachment, I also use this short copper bar and the REL function to ensure that the display readings are equal to 0.

[indman]

Now I will show the measurement of several low-resistance SMD resistors(3mohm,5mOhm,10mOhm) to check whether the readings in the battery test can be trusted.
For comparison, on the right side of the RM705B, I measured this resistor using the ZT703S (the display readings in millivolts correspond to the resistance in milliohms).
As you can see, the RM705B milliohm meter can be trusted. In the last photo on the right, I measured a 1Ω resistor and a 470Ω resistor.
This goes beyond the range (200Ohm) specified in the documentation. The real upper limit of resistance measurement in this mode is 499.99Ω, but the measurement error will be high.

To be continued...

[coromonadalix]

you're right 

maybe, just maybe,  the  RM705B  could have a more matured FW ?   i dont know if zoyi released their source code  ... wich i doubt

thks for the test you do  INDMAN

normally  you should be able to zero out the kelvin probes "short cal test" with the REL function

[indman]

maybe, just maybe,  the  RM705B  could have a more matured FW ?

Unfortunately, this is not the case. And I will show in the following posts the moments that greatly spoil the impression of this device, which is not badly designed in hardware, but the software often baffles me. 

[marco58]

Hi marco,

this part of the manual is a little bit confusing to me. Had to read a few times because I'm no native english speaker:

3.1.1
Whenever possible, with components with low load or high impedance load, it is recommended to use
the * clip input terminals, as it has lower stray parameters and provides more accurate results.

They all are clip inputs, the 4wire cable and the internal clip inputs.
Maybe an additional * "internal" is missing here to clarify?

Thanks for your good work!

Roger

Hi Roger,
I'm no native english speaker too, and thank you for this remark.
Yes, I'm referring to frontal clip (numbered 12 and 13 in figure at paragraph 2.1) so an added "internal" is a good suggestion.
I'll add in next revision...

edit:
pheraps better repeat the terminology used in the previous sentence:
"Whenever possible, with components with low load or high impedance load, it is recommended to use the front panel input clips, as they have lowest stray parameters and provides most accurate results."
(singular / plural and comparative modified also - I hope this version is correct... )

[indman]

Now I'm going to show you how I test batteries. To do this, I bought a low-cost charger and modified it slightly to make it easier to connect the Kelvin clamps. Of course, the quality of the contacts in this device is not as good as in expensive devices and special clips. However, it is still suitable for quickly checking the quality of the battery. I also slightly increased the tension of the spring to ensure a better contact with the battery.

[SammysHP]

For better results you want each prong of the clips touch the battery individually to eliminate the contact resistance. Some time ago I made my own jig for this:



There are better alternatives on AliExpress for only $10-20, but they often don't take anything longer than 18650.

[Cyclotron]

For better results you want each prong of the clips touch the battery individually to eliminate the contact resistance. Some time ago I made my own jig for this:



There are better alternatives on AliExpress for only $10-20, but they often don't take anything longer than 18650.

Brilliant!  Going to make one just to have on hand for the eventual need.

[mawyatt]

For better results you want each prong of the clips touch the battery individually to eliminate the contact resistance. Some time ago I made my own jig for this:



There are better alternatives on AliExpress for only $10-20, but they often don't take anything longer than 18650.

That' a nice DIY solution!!

Some time ago, we just took the easy path with an inexpensive Yaorea XS10-4. This can also serve as a SMD fixture for 4-wire Kelvin measurements with larger SMD components, altho somewhat clumsy. Here we are using an adapter for the Yaorea connector to a 4 banana jack for plugging into a standard 4 connection DMM input to measure the DCR of a SMD inductor.

Best

[indman]

That's a nice DIY solution.
Some time ago, we just took the easy path with an inexpensive Yaorea XS10-4. This can also serve as a SMD fixture for 4-wire Kelvin measurements with larger SMD components.

Yes, it's a good solution, but in my region, it costs $20, and the charger I use costs $1.5-$2.
So I've suggested a very budget-friendly option for enthusiasts..It may not measure internal resistance as accurately as more specialized clamps, but as I mentioned earlier, it is still useful for quickly assessing battery quality.

[mawyatt]

That's a nice DIY solution.
Some time ago, we just took the easy path with an inexpensive Yaorea XS10-4. This can also serve as a SMD fixture for 4-wire Kelvin measurements with larger SMD components.

Yes, it's a good solution, but in my region, it costs $20, and the charger I use costs $1.5-$2.
So I've suggested a very budget-friendly option for enthusiasts..It may not measure internal resistance as accurately as more specialized clamps, but as I mentioned earlier, it is still useful for quickly assessing battery quality.

Don't recall what this fixture cost, it was part of the Yaoera meter kit acquired long ago. If one has access to a 3D printer this could yield a similar type fixture as the spring loaded Pogo pins are available on AliX.

Best

[SammysHP]

I had trouble finding these pogo pin contacts at AliExpress for a reasonable price, so I made my own by drilling through a bolt and inserting a pogo pin insulated with heat shrink tubing. Total cost: a few cents in parts and half an hour of work.

[BillyO]

You should do a how-to video.  Sounds interesting.   

[RogerG]

A few days before my DQ-02 arrived. The additional kelvin clips I ordered as kit were missing. Surprise, surprise. The communication with the dealer Snakol was very tenacious. One stammered sentence per day. At the end he refunded 3,48€ for which, of course, I can't get clips anywhere else. So I wouldn't recommend to buy the full set there.

Did anyone measure the thickness of the 3 "blades" of the Ziboo kelvin clips? Or alternatives? The Zoyi included isolation bridge is 0,81mm. I don't want a kelvin adapter much thicker than this to avoid baggying out the contacts in my DQ-02.

Thanks Roger

[Skander]

A few days before my DQ-02 arrived. The additional kelvin clips I ordered as kit were missing. Surprise, surprise. The communication with the dealer Snakol was very tenacious. One stammered sentence per day. At the end he refunded 3,48€ for which, of course, I can't get clips anywhere else. So I wouldn't recommend to buy the full set there.

Did anyone measure the thickness of the 3 "blades" of the Ziboo kelvin clips? Or alternatives? The Zoyi included isolation bridge is 0,81mm. I don't want a kelvin adapter much thicker than this to avoid baggying out the contacts in my DQ-02.

Thanks Roger

You should push Snakol to either a) refund the same price as this: https://it.aliexpress.com/item/1005011907078136.html
or b) open a dispute and return the entire item, and purchase it from the official Zoyi store.

Anyway, I exclusively use the Ziboo clips despite my unit coming with the stock Zoyi 4 lead kelvin clips. I don't have them near me now to measure but they are a little thicker than the included isolation bridge.

I also use this for shorting during calibration if using the contacts: https://it.aliexpress.com/item/1005006236959254.html