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.
Thanks for the quick response
. I will have to study the OP more closely to learn about what the error may be.
meant for capacitors but does ok for batteries.once you get the feel for good esr readings for a certain cell go/nogo tests are fast.like when grading laptop pack salvage cells.
http://www.amazon.com/Anatek-Corporation-blueesrkit-Blue-ESR/dp/B005NB6CKS
i have one of the original kits from 15+ years ago.great tool.
I’m new to all of this but would like to replicate this set up. Would you be able to explain how the resistance/capacitor boxes were built.
I bought a Reed R5001 LCR meter for measuring impedance. Can I use that with this set up?
Thanks!
That is just resistors/capacitors connectors to the binding posts. When doing a lot of different test setups this is much easier than soldering the wires each time.
Even though I have a bunch of electronic loads, I uses that resistor box all the time.
Probably not, the problem is the battery voltage. When measuring the internal resistance you are not going to work on a voltage free circuit, due to the battery it will have about 4 volt.
@HKJ
1: while measuring internal resistance , do we need to be concerned with the wattage rating of a resistor ?
2: how can we conclude some usefull information from internl resistance figure ? like how good/bad is it ? how much int r is good how is bad ? bad would mean it cant supply great amperagess ?
3:Battery is pretty much dc source so how does ac comes into play ?
pardon me for those bunch of questions as it has been long time i studied electronics/circuits.
Yes, but if you are fast, you might get away with some overloading of the resistor.
Yes, but I do not have a table with good/bad values for different batteries.
Probably because it is easy to make a device that can measure impedance in-circuit, i.e. you can check the battery without disconnecting it. AC and DC gives different values, but in both cases the battery will be bad when the value has increased significantly from the initial value.
how much should be the battery charged (ideal no load voltage ) to do this test .
There is no rule about that, but you want the same charge each time to get the best comparison.
One charge level that is easy to get each time is fully charged.
Only lead acid batteries needs to be tested fully charged (and rested ideally).
IR of li-ion batteries does not change with state of charge (only very slightly) and can be neglected for practical reasons.
HKJ, I always love checking out your posts. You have some of the coolest toys. Do you have a stereo microscope yet? I just bought one… :nerd_face:
No stereo, only a flat view for me.
that chart while interesting is depicting a lousy battery.if the ohmic value were preceded by a decimal it would be close.
in my experienc at room temp the rise is not as bad as depicted.probably old data.
Nice to see this topic
I have a few questions.
My Liitokala gives a value in mR and I think this is the internal resistance of the cell
When I receive a cell I charge it, do discharge mAh test and connect/disconnect the cell in the charger to see what the lowest mR is (how a cell is placed affect the mR sometimes and I want to rule that out)
I then write the mAh and mR on a small piece of paper and stick it on the cell with tape.
I use my KeepPower 2200 measured 2300mAh for most testing and they got used the most of my cells.
They all three read 53mR when first tested.
Now the two most used (a lot of charge cycles went into the thorfire tests) now read 75mR and the third 61mR.
The two I always use together, if not in series then in a SRK never alone.
I have cheap rubbish cells that measure 125mR from the start and not getting used, and a 26650 Ultrafire that gives 35mR and 1646mAh that I use the first run of single 26650 flashlights since it is the only 26650 I currently own (2 good ones in transit)
Non of the cells become warm when charging or discharged.
When should I do a new mAh test on the KeepPowers? ( though at 100mR)
When used in serie I always put cells in the Liitokala and only use cells with same brand and mR even if the mAh is little (max 25) off, so if I have 4 Panasonic’s
1 3345mAh 61mR
2 3345mAh 70mR
3 3296mAh 65mR
4 3327mAh 61mR
I use cell 1 and 4 in series.
Not 1 and 2. Since mR is easy to measure and mAh takes a lot of time)
Is this good practice?
At what value is a cell considered written off?
the repeatability of the Liitokala test is poor.
anything over 150mohm is poor.decent laptop cells average 100.
i would keep the originally paired cells in service as they have in the past.its normal to see i.r rise with cycle count.1 and 4 are decently matched.
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.
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.
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
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?