Author Topic: ESR Meter Adapter Design and Construction  (Read 119171 times)

0 Members and 1 Guest are viewing this topic.

Offline Johnny10

  • Frequent Contributor
  • **
  • Posts: 778
  • Country: us
Re: ESR Meter Adapter Design and Construction
« Reply #250 on: May 08, 2020, 01:21:04 pm »
Great Thread !
Tektronix TDS7104, DMM4050, HP 3561A, HP 35665, Tek 2465A, HP8903B, DSA602A, Tek 7854, 7834, HP3457A, Tek 575, 576, 577 Curve Tracers, Datron 4000, Datron 4000A, uTracer, HP5335A, EIP534B 20GHz Frequency Counter, TrueTime Rubidium, Sencore LC102, Tek TG506, TG501, SG503, HP 8568B
 

Offline trobbins

  • Frequent Contributor
  • **
  • Posts: 380
  • Country: au
Re: ESR Meter Adapter Design and Construction
« Reply #251 on: May 15, 2020, 01:34:40 am »
I have powered up my variant of Jay_Diddy_B's ESR meter, and it is performing very nicely indeed.

The IA certainly allows easy setup up for 0 milliohm (+/- less than 0.1 milliohm) and 1.000V for 1 ohm 1%, and appears to be dead accurate down to the 47 milliohm 1% reference I have, when using a nice 30cm long Kelvin clip lead set with 4mm plugs.

I haven't yet played with the 555 oscillator, which is running at 18kHz, to see if the setup can support similar results at 100kHz.

Aiming to set up the IA gain for 1V/ohm and 0.1V/ohm to allow up to about 16 ohm max range (open circuit reads about 1.65V at the moment), and use switched fixed resistors and a trimpot for gain setup with sufficient offset trim range (which I aim to change to fixed and trimpot to reduce the present trimpot sensitivity when setting 0 ohm end).

I found a practical 'zero ohm' link to keep the Kelvin clip contact faces flat over their entire length, in the form of an 8mm wide, 0.9mm thick flat bar that had a previous life as a contact link bar in a high current contactor.  There are a few parts that show some temperature sensitivity (a few milliohm change when squirted), so packaging the circuitry to minimise local temperature changes seems worthwhile.

PS. it does work with capacitors, even the bigger ones with readings down around 10 milliohm, although ESR of a cap may be quite temp sensitive and so absolute ESR should really note the temp, and comparisons should use caps at the same ambient temp.

 

Offline ogden

  • Super Contributor
  • ***
  • Posts: 3474
  • Country: lv
Re: ESR Meter Adapter Design and Construction
« Reply #252 on: October 24, 2020, 09:05:03 pm »
As ESR Meter Adapter is safe to measure charged capacitors, most likely it can be used to measure ESR of the batteries too. I would love universal battery/capacitor ESR meter. Hint: LTC6900 as configurable by resistor(s), clock. Please do not hesitate to post if you are interested in measuring ESR of the batteries.
 

Offline Jay_Diddy_B

  • Super Contributor
  • ***
  • Posts: 2524
  • Country: ca
Re: ESR Meter Adapter Design and Construction
« Reply #253 on: October 26, 2020, 06:51:06 pm »
Hi group,

I have looked at measuring the ESR of cells before. You can find the message in this thread:

Link: https://www.eevblog.com/forum/projects/esr-meter-adapter-design-and-construction/msg2798498/#msg2798498

ESR Meter Adapter - Modification for 1 kHz (nominal)

Now I am going to share modifications that can be made to the ESR Meter Adapter to lower the frequency from the 100kHz, normally used for electrolytic capacitors, to 1 kHz for batteries and cells.

LTspice Model

[attachimg=1]


I have indicated the changes and addition on the LTspice schematic.

The LTspice model shows an output of 100mV /  \$\Omega\$

[attachimg=2]


This is nice and linear just like the 100kHz version.

Modified Circuit Board

[attachimg=3]


All of the parts will fit the original except for the 100uF electrolytic capacitor.

Testing

[attachimg=4]


Here I am using the test resistors described here:

Link: https://www.eevblog.com/forum/projects/esr-meter-adapter-design-and-construction/msg343855/#msg343855

to confirm the operation.

Attachments

I have attached a pdf of the modified schematic and the LTspice model.

Regards,
Jay_Diddy_B

[attachurl=5]
[attachurl=6]
 
The following users thanked this post: tom66, kripton2035, BravoV, ogden

Offline ogden

  • Super Contributor
  • ***
  • Posts: 3474
  • Country: lv
Re: ESR Meter Adapter Design and Construction
« Reply #254 on: October 27, 2020, 02:37:30 am »
ESR Meter Adapter - Modification for 1 kHz (nominal)

Now I am going to share modifications that can be made to the ESR Meter Adapter to lower the frequency from the 100kHz, normally used for electrolytic capacitors, to 1 kHz for batteries and cells.

Wow, you are so fast! Thanx. Any chances to have 200 mOhm or at least 1 Ohm range? 20 Ohm is good for CR2032 and similar low capacity cells.
 

Offline hugo

  • Regular Contributor
  • *
  • Posts: 157
  • Country: ca
Re: ESR Meter Adapter Design and Construction
« Reply #255 on: October 27, 2020, 07:49:31 pm »
It looks like the output voltage is not quite linear below 2 ohm ... ;)
 

Offline floobydust

  • Super Contributor
  • ***
  • Posts: 4278
  • Country: ca
Re: ESR Meter Adapter Design and Construction
« Reply #256 on: October 27, 2020, 08:09:04 pm »
I've often wondered why this meter intentionally has such high output impedance with R3  :-//
Usually you want to pump some current, several mA's or more through the DUT to swamp out wet effects. In the case of lead-acid battery ESR I would think the measurement is corrupted. Car battery ESR measurements are several amp pulses for this reason I think.
 

Offline Jay_Diddy_B

  • Super Contributor
  • ***
  • Posts: 2524
  • Country: ca
Re: ESR Meter Adapter Design and Construction
« Reply #257 on: October 28, 2020, 08:42:01 am »
Hi group,

Here are some test results using Li-ion cells.

Laptop Battery Pack

[attachimg=1]


I broke apart an old Asus battery pack and separated four of the cells.

[attachimg=2]


I have numbered the cells 1 to 4.

HP 4328A Measurement

This is a 1 kHz (+/- 100 Hz) sinewave ac coupled milli-ohmmeter.

Sample reading:

[attachimg=3]


1 kHz ESR Meter Adapter

[attachimg=4]


The adapter was read with a Fluke 289. The Fluke 289 has been set relative to remove the offset.

[attachimg=5]


Results

The two methods gave very similar results. The difference are probably from the connections made with the 4328A.


[attachimg=7]


Regards,
Jay_Diddy_B

« Last Edit: October 28, 2020, 08:54:38 am by Jay_Diddy_B »
 
The following users thanked this post: tom66, kripton2035, BravoV, ogden, Jacon

Offline ogden

  • Super Contributor
  • ***
  • Posts: 3474
  • Country: lv
Re: ESR Meter Adapter Design and Construction
« Reply #258 on: October 28, 2020, 04:38:43 pm »
I broke apart an old Asus battery pack and separated four of the cells.
Wow, very promising results. Difference between instruments below 10% and battery impedance spread below 10% as well - cell pack looks like well-balanced. Any chance for you to discharge one cell and measure ESR with both tools again? Asking to disassemble all the battery packs around until you find one with bad cell would be asking too much :)
 

Offline kripton2035

  • Super Contributor
  • ***
  • Posts: 2064
  • Country: fr
    • kripton2035 schematics repository
Re: ESR Meter Adapter Design and Construction
« Reply #259 on: February 12, 2021, 03:14:37 pm »
@Jay
is it possible to use the schematic for the 1KHz version (bigger capacitors)
and using a switch to change the oscillator frequency, still be able to use the 100KHz ?
this would allow us to have one device to measure both batteries internal resistance and capacitors esr.
thanks.
 

Offline Jay_Diddy_B

  • Super Contributor
  • ***
  • Posts: 2524
  • Country: ca
Re: ESR Meter Adapter Design and Construction
« Reply #260 on: February 12, 2021, 06:01:31 pm »
@Jay
is it possible to use the schematic for the 1KHz version (bigger capacitors)
and using a switch to change the oscillator frequency, still be able to use the 100KHz ?
this would allow us to have one device to measure both batteries internal resistance and capacitors esr.
thanks.

Hi,

You can add a switch in the oscillator so that it can do 1kHz and 100kHz. It will work fine.
The larger values of capacitors in the coupling network, will reduce the protection from applied voltage or charged capacitors. The coupling capacitors had a 500V rating in the original design.

Does this help?

Jay_Diddy_B



 

Offline kripton2035

  • Super Contributor
  • ***
  • Posts: 2064
  • Country: fr
    • kripton2035 schematics repository
Re: ESR Meter Adapter Design and Construction
« Reply #261 on: February 12, 2021, 06:25:09 pm »
yes it helps ! thanks.
I assume it is only for the first protection capacitor 10uF/500v would be pretty big. the second 100nF is already available @ 500v for the 100khz version.
may be a DPDT switch to change the protection capacitor, and the oscillator at the same time.
 

Offline zoltanh

  • Contributor
  • Posts: 23
  • Country: ro
Re: ESR Meter Adapter Design and Construction
« Reply #262 on: February 22, 2021, 09:49:56 pm »
Hi,

Do you have a STL of case for this ESR Meter Adapter? I would really appreciate if you share it to me. Thank you.
 

Offline kripton2035

  • Super Contributor
  • ***
  • Posts: 2064
  • Country: fr
    • kripton2035 schematics repository
Re: ESR Meter Adapter Design and Construction
« Reply #263 on: April 04, 2021, 05:25:41 pm »
as I just made the pcb for my shorty-with-display project, I also made a pcb for my jay_diddy_b esr meter variation
more to come in a few weeks. ;)

 
The following users thanked this post: ogden, BroMarduk

Offline m3vuv

  • Frequent Contributor
  • **
  • Posts: 833
  • Country: gb
Re: ESR Meter Adapter Design and Construction
« Reply #264 on: April 14, 2021, 06:46:09 am »
any chance someone can do a thru hole version of this for decrepid dinosoars like me?,my eyes aint what they used to be at 54yrs old!!
 

Offline kripton2035

  • Super Contributor
  • ***
  • Posts: 2064
  • Country: fr
    • kripton2035 schematics repository
Re: ESR Meter Adapter Design and Construction
« Reply #265 on: April 14, 2021, 09:48:27 am »
I'm planning on making either a pcb with all smd components already soldered (via jlcpcb) and sell them
or once the prototype pcb is fully working another pcb with thru holes.
but be aware that the adc is in sot323 only (can use a prebuild breakboard at least)
and the aop is only soic8. so the thru-holes will have still some smd parts.
 

Offline m3vuv

  • Frequent Contributor
  • **
  • Posts: 833
  • Country: gb
Re: ESR Meter Adapter Design and Construction
« Reply #266 on: April 19, 2021, 08:41:26 am »
Unfortunatly not a lot of help as to the question i asked,i hate smd stuff!!
 

Offline Gyro

  • Super Contributor
  • ***
  • Posts: 6645
  • Country: gb
Re: ESR Meter Adapter Design and Construction
« Reply #267 on: April 19, 2021, 04:55:43 pm »
any chance someone can do a thru hole version of this for decrepid dinosoars like me?,my eyes aint what they used to be at 54yrs old!!

At 54 years old, I would seriously recommend a visit to a decent optician to check whether you have any medical issues that need to be referred. They shouldn't be that bad.

Either that or you're not using any visual aids, a magnifier, even a pair of cheap reading glasses would help.
Chris

"Victor Meldrew, the Crimson Avenger!"
 

Offline Jay_Diddy_B

  • Super Contributor
  • ***
  • Posts: 2524
  • Country: ca
Re: ESR Meter Adapter Design and Construction
« Reply #268 on: April 19, 2021, 07:47:51 pm »
Hi,

The board that I designed uses 1206 and bigger components. The smallest parts are SOD123 diodes. Here is photograph of the board:



These should be relatively easy to solder. You need a good pair of tweezers. I put solder on one pad. Position the part, solder that end and then solder the other end.

The op-amp used, LTC6241 is not available in thru-hole.

Regards,
Jay_Diddy_B


 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf