How to Measure the Internal Resistance of a Battery

$2 for 5pcs 1-4 layer PCBs ;PCBA from $0 : jlcpcb.com/DYE
3D printing services as low as $0.07/g, 48hr build time
Support Ludic Science on Patreon:
/ ludicscience

[@kentherapy7022]

Helpful video. Although the internal resistance is a constantly changing value, it is enough for a basic explanation. Don't buy cheap batteries. Their resistance will take revenge on you....😂

[@ludicscience]

Too late.... i have some 50 chinese 😂, have to figure out what to do with them LOL

[@kentherapy7022]

@@ludicscience ........Damn...!....🤣...Shiva with you...👀

[@parviz5246]

Good job very helpful video
Thank you buddy

[@t1d100]

Good information and explanation.

[@ludicscience]

Thanks

[@akrampeace696]

Very nice explanation

[@constantinalexandru6627]

very intristing sir. Thankyou.

[@eili_04]

Hello
-batteries can be used to calculate the resistance of a cable (fault loop impedance)
and what would be different from the current video
- thank you and have a good day

[@JoeMcLutz]

Than You!

[@steadyfield]

The problem is, the internal resistance has many definitions. What you are measuring is long-term DC resistance (the DC internal resistance can be varying as well). The internal resistance measured by the common internal resistance meter is AC 1kHz resistance. There are huge differences between AC resistance, short-term DC resistance and long-term DC resistance (one of the root cause could be the nonlinearity of the chemicals such as polarization). The internal resistance (or to be more accurate, impedance) is a complicated topic and cannot be explained clearly with few words, you can search for EIS (electrochemical impedance spectroscopy) for more information, as well as some test standards such as HPPC (hybrid pulse power characterization).

[@Basement-Science]

I would argue that the method in the video is by far the most meaningful in practice. Ideally you would measure it this way over the entire discharge cycle, but this is often good enough.
I dont really get the point of the AC 1kHz measurements. In my view it would show more the transient response (but also badly) rather than anything else - which is never very good anyway and is vastly increased by adding some (electrolytic) capacitors in parallel, if it matters. On the other hand, the DC resistance actually tells you the voltage drop in most situations and therefore when your voltage may be too low etc.

[@steadyfield]

@@Basement-Science I don't think so. AC 1kHz resistance has become a de facto "standard" in battery industry and it is useful in practice. Lots of battery manufacturers (I mean rechargeable battery) give 1kHz resistance data in their battery datasheets. Therefore, by measuring the 1kHz AC resistance of your own battery, and compare the results with the one in the datasheet, you can know about the aging of your battery in most cases.

[@Basement-Science]

@@steadyfield I know manufacturers commonly give you this value, but that doesnt make it much more useful. The discrepancy between AC 1kHz and a DC measurement like in the video can be pretty big, and more importantly, the difference depends on the battery.
So just because 2 batteries have the same AC impedance doesnt tell you much about their DC internal resistance. It could still be vastly different.

[@schitlipz]

R[internal] = R[load] * ( V[open] / V[load] - 1 )
Use R[load] at about 10 ohms.

[@stefano.a]

With 10 ohms the battery is almost short circuited

[@schitlipz]

@@stefano.a So?

[@stefano.a]

@@schitlipz the battery discharges very fast, the voltage across the resistor vary also fast and the internal resistance measured is very different from the value provided by the manufacturer

[@schitlipz]

​@@stefano.a mfg spec sheet ... I'm not feeling like I want to argue. I'm too old for this kinda thing.

[@NemencioRas]

With this simplified equation,
V[load]-1 must have then an absolute value for V[load]

[@miroslavolopez7301]

We Miss High voltage experiments

[@ludicscience]

I will make a couple soon

[@armenvegas]

I always thought it was "Lucid Science"

[@mikefixescars]

Coolant equals current

[@stefano.a]

The load resistor in the example has too low resistance. The internal resistance variates according the load. Try with another load resistor and you will find another internal resistance value.

[@schitlipz]

No. That's wrong.

[@stefano.a]

@@schitlipz you have not made measures about internal resistance of batteries. Try before speak please. This is not a mistery: the internal resistance is provided from the manufacturer according to precise nominal load condition.

[@schitlipz]

@@stefano.a You do not know me.

[@schitlipz]

I don't know why my reply to you was removed. I said, "No, that's wrong." [Seems the comment was put back up.] If you want to prove it to yourself, try using a decade box and use the equation given. Don't complain when people correct you.

[@stefano.a]

@@schitlipz your reply means only that you haven’t made the measure. So, do not insist

[@SNIPER-69K]

Where are you from Russia? 😊