Internal impedance/resistance of batteries

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The Miller
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Ah OK 150mR means discard then for my future actions?

The cell data was made up
When I want to use a series light I grab the SRK with 4 panasonic cells in it ( use it as battery holder, place 4 fully charged cells then use it for 10 mins and put it away locked out)
And measure the mR and pick the two that are equal.
I measure all cells several times since how they are connecting makes a difference three times the same lowest mR is the one I think closest to reality.

Ronin42
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HKJ wrote:

photon1k wrote:

I think I remember seeing an iCharger 208B in one of your many informative posts. Have you looked at its IR measurement function, and if so, what do you think of it?

Yes, I have a iCharger 208B or two. They can measure IR, but I have not really used it or analysed it. It uses two wire and will give an error due to that.

very useful topic.
i am not an ee but use the LiitoKala chargers that offer a “similar” function.

i think we should press charger mfg to incorporate and improve this functionality.

(“It’s good that most people can’t remember their previous lives. Otherwise
things would be a lot more complicated than they already are.”
Ajaan Lee Dhammadharo)

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peakelec ESR70 measuring battery internal resistance?

Hello I have peakelec ESR 70.

I ask if it’s true 100khz meter:

peakelec replies

1. I can confirm that the Atlas ESR (models ESR60 and ESR70) do measure the true ESR at 100kHz. It applies a test signal of exactly 100kHz and measures the true ESR and ignores the capacitor’s reactance (unlike many other ESR meters).

I ask if it’s possible to measure battery internal resistance

peakelec replies

2. It is possible to measure the ESR of batteries if a series capacitor is used. See attachment.

I have made the circuit to measure ers of batteries.
I’ve used 10uF 35V Rubycon cap (ESR 0.30), and 47K resistor 5%.

Questions:

1. How to zero out the wire resistance? The Atlas meter is zeroes out OK, but that can’t be done while meter is connected to this circuit. What am I doing wrong?

2. Is 5% resistor OK, do I need 1%?

3. The internal resistance of typical lead acid batteries is 4.22 milliohm, that’s 0.00422ohm
The ESR70 resolutions is only 0.01ohm so how can peakelec claim it can measure internal resistanceo of batteries????

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Why not use small non polarized cap? peakelec ESR70 can’t measure those the capacitance and resistance is too small i guess. This way nothing needs to be subtracted except the lead resistance. hmm.

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ESR 70 measured internal resistance seems to be wrong:

0.06; 0.08ohm
60mili ohm; 80mili ohm;

When measured with proper battery tester it show
18mili ohm (manufacturer new battery is 16mili ohm)
http://www.yuasabatteries.com/pdfs/NP_12_12_DataSheet.pdf

That is huge difference. Any ideas?

HKJ
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smile wrote:
That is huge difference. Any ideas?

There can be 2 factors:
1) The circuit with a capacitor affecting the result
2) The frequency. The standard battery IR test is at 1kHz, the ESR70 is probably more like 100kHz

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

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HKJ wrote:
smile wrote:
That is huge difference. Any ideas?

There can be 2 factors:
1) The circuit with a capacitor affecting the result
2) The frequency. The standard battery IR test is at 1kHz, the ESR70 is probably more like 100kHz

I don’t know how capacitor (that alone gives stable results) in the circuit can have influence?
The frequency ESR70 is 100kHz, but how is this related to unstable measurements furthermore if the frequency is so critical then how ESR70 or Anatek Blue ESR meter can even claim they can measure battery resistance?

What do you know about YR1035 battery resistance meter, it’s quite well made? What is the com port for?
English manual would be nice. I did not find anything in this price range better then YR1035.

HKJ
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smile wrote:
HKJ wrote:
smile wrote:
That is huge difference. Any ideas?

There can be 2 factors:
1) The circuit with a capacitor affecting the result
2) The frequency. The standard battery IR test is at 1kHz, the ESR70 is probably more like 100kHz

I don’t know how capacitor (that alone gives stable results) in the circuit can have influence?
The frequency ESR70 is 100kHz, but how is this related to unstable measurements furthermore if the frequency is so critical then how ESR70 or Anatek Blue ESR meter can even claim they can measure battery resistance?

What do you know about YR1035 battery resistance meter, it’s quite well made? What is the com port for?
English manual would be nice. I did not find anything in this price range better then YR1035.

If you use a capacitor with very low impedance and ESR at 100kHz it will probably not affect the result much.
You can measure the battery impedance at any frequency you want, but do not expect the same result at different frequencies.
Sometimes scientists measure IR at many frequencies when testing batteries.

I do not know the YR1035 only the YR1030: http://www.lygte-info.dk/review/InternalResistanceMeterYR1030%20UK.html

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

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Thank you for the link, YR1035 is logically higher version of the same device the YR1030.
The YR1035 uses aviation connector vs. USB for YR1030.

How USB can be precise is beyond me, the worst connector you can get is USB, but it’s the cheapest and has 4 wires as required for this device. So the YR1035 is way better in this regard.

The YR1035 has also what looks like com port. I wonder for what, logging to PC?

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I wonder who the manufacturer is of YR1035?

HKJ
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smile wrote:
Thank you for the link, YR1035 is logically higher version of the same device the YR1030.
The YR1035 uses aviation connector vs. USB for YR1030.

How USB can be precise is beyond me, the worst connector you can get is USB, but it’s the cheapest and has 4 wires as required for this device. So the YR1035 is way better in this regard.

With 4 terminal connection you do not need a connector with low impedance, the usb will work perfectly.

smile wrote:
The YR1035 has also what looks like com port. I wonder for what, logging to PC?

Or for controlling a a sorting device, the YR1030 has functions to sort cells.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

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HKJ, maybe I just don't understand it well, but in this thread you mentioned that the health of a battery can be determined by monitoring internal impedance such as with a SM8124 meter, but in other threads, I thought you said that measuring internal impedance with a meter such as the SM8124A is only good when first receiving batteries and that only the DC method can measure the true IR as the battery ages?  If I understood it correctly and the DC method that chargers use to measure IR are what we should be looking at, then what is the maximum recommended IR of a lithium battery with protection circuits before they would need to be recycled?

 

Maybe there is no correct answer to my question either as protection circuits add all that extra resistance and from the batteries I have with the same part #, IR has varied greatly as well and left me a little doubtful as to when I should not use them anymore.  Right now, the only sane method I trust is if they heat too much whilst charging, then they go to the recycle bin and I'm done with them.

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Henrik, do you think that impedance values from the SM8124A can be converted to approximate resistance values, e.g. by using a conversion factor?

HKJ
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klrman wrote:

HKJ, maybe I just don’t understand it well, but in this thread you mentioned that the health of a battery can be determined by monitoring internal impedance such as with a SM8124 meter, but in other threads, I thought you said that measuring internal impedance with a meter such as the SM8124A is only good when first receiving batteries and that only the DC method can measure the true IR as the battery ages? 

The DC method is the best, the variation with AC is not as large.

klrman wrote:
If I understood it correctly and the DC method that chargers use to measure IR are what we should be looking at, then what is the maximum recommended IR of a lithium battery with protection circuits before they would need to be recycled?

The problem with chargers is that they all use different test parameters and the results is not completely comparable.

Lux-Perpetua wrote:

Henrik, do you think that impedance values from the SM8124A can be converted to approximate resistance values, e.g. by using a conversion factor?

No.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

klrman
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HKJ wrote:
The problem with chargers is that they all use different test parameters and the results is not completely comparable.

 

Is there a reasonably priced DC IR meter that is available then?

HKJ
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klrman wrote:

HKJ wrote:
The problem with chargers is that they all use different test parameters and the results is not completely comparable.

 


Is there a reasonably priced DC IR meter that is available then?

I only know of hobby charges.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

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Thanks HKJ!

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HKJ, thank you for this article! I now know much better how my SM8124A (pictured below) works. 

I've used it extensively and am impressed with the way that IR reading are repeatable - unlike my analyzing chargers. I purchased mine on ebay for around $53 (including shipping), but it it can be found on Ali for about $10 less. See the Found a Quality Battery Resistance Tester thread for more discussion on the SM8124A impedance tester. 

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Here is table for comparing ACIR and DCIR values for various cells. Cells are new from nkon.

Internal resistance is affected by DOD, see values of new LG MJ1.

Here is link :

https://endless-sphere.com/forums/viewtopic.php?f=14&t=73701

Both ACIR and DCIR are sensitive to temperature.

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HKJ wrote:
klrman wrote:

HKJ wrote:
The problem with chargers is that they all use different test parameters and the results is not completely comparable.

Is there a reasonably priced DC IR meter that is available then?

I only know of hobby charges.

Can you recommend an affordable and reliable hobby charger to measure DC IR of lithium-ion batteries?

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I don’t know if this is a ‘gold standard’ for IR but I’ve found it to be significantly more consistent and accurate than any of my analyzing chargers. If you don’t NEED a hobby charger, and are OK with just discharge and IR testing I’ve found this to be good.
ZH-YU ZB106+ v1.3
Note – there are a number of similar testers available with varying prices, power, and cooling options. This one goes from 0.1A > 2.6A. I use and external PC fan to cool it on higher settings.

You’ll need a good cell holder, and a power source. Many charger power bricks will work. Some units are USB powered.
I use this one. There are similar, but it HAS to have the 4-wire capability for IR.
4-Wire Battery Resistance Capacity Test Holder

To Air is Human, to Respire….Divine.

HKJ
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Lux-Perpetua wrote:


Can you recommend an affordable and reliable hobby charger to measure DC IR of lithium-ion batteries?

No, chargers are generally not very good at measure resistance (DC or AC), because there is a significant amount of contact resistance.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

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Thank you flydiver and HKJ! I just wish there was something available that is ready-to-use out of the box, i.e. 4-wire cell holder, resistor and powersource...all in one kit.

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flydiver wrote:
I don’t know if this is a ‘gold standard’ for IR but I’ve found it to be significantly more consistent and accurate than any of my analyzing chargers. If you don’t NEED a hobby charger, and are OK with just discharge and IR testing I’ve found this to be good.
ZH-YU ZB106+ v1.3
Note – there are a number of similar testers available with varying prices, power, and cooling options. This one goes from 0.1A > 2.6A. I use and external PC fan to cool it on higher settings.

You’ll need a good cell holder, and a power source. Many charger power bricks will work. Some units are USB powered.
I use this one. There are similar, but it HAS to have the 4-wire capability for IR.
4-Wire Battery Resistance Capacity Test Holder


Interesting tester, but I can’t find it on ebay or aliexpress….
EDIT:
Oh, wait, here it is:
https://www.ebay.com/itm/Battery-Capacity-DC-12V-Tester-Lithium-Test-Lif...
https://www.aliexpress.com/item/32795334108.html

Both parts 16 USD shipped? Not bad, though not great either. Wink
I wonder if ZB2L3 is any good, it’s much cheaper.

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Lux-Perpetua wrote:
Can you recommend an affordable and reliable hobby charger to measure DC IR of lithium-ion batteries?

The Xtar Dragon VP4 Plus will do IR testing, it works well enough for me Smile

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The ZB2L3 is not constant current, using resistors for the job. As the voltage runs down, the amp draw decreases. That will make some difference in the capacity (it will read higher), but I prefer constant current.
Does not appear you can do IR with them. I checked them out as a possible extra cheap dis-charger to have and decided it wasn’t worth it, at least for me.

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The EBD-M05 is a nice, affordable battery tester. Does DC IR nicely with the help of its PC software, which among manuals is downloadable from the ZKE website (chinese, translated).

Needs to be paired to a 4-wire battery holder, a couple affordable links to a ZKE holder in AliExpress here and there (like the one linked by flydiver).

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flydiver wrote:
The ZB2L3 is not constant current, using resistors for the job. As the voltage runs down, the amp draw decreases. That will make some difference in the capacity (it will read higher), but I prefer constant current.
Does not appear you can do IR with them. I checked them out as a possible extra cheap dis-charger to have and decided it wasn’t worth it, at least for me.

I see. No constant current = no good.

Thanks for setting me straight. Smile

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It’s really not too hard to use the links, pick out the necessary items, and purchase. We’ve done most of that homework for you.

When you get to this stage you take a step into Do It Yourself. It’s satisfying, as well as educational and useful. My understanding of my batteries took a BIG step up. A bunch of batteries that ‘seemed’ to be OK using capacity only from an analyzing charger got recycled when IR was found to be (very) high, and they would not sustain amp draws that were reasonable, but the analyzing charger could not achieve.

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