Internal impedance/resistance of batteries

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.

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?

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: Review of Vapcell Internal Resistance Meter YR1030

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?

I wonder who the manufacturer is of YR1035?

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

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

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.

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

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

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

No.

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

I only know of hobby charges.

Thanks HKJ!

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.

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 :

Both ACIR and DCIR are sensitive to temperature.

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

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

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

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.