Products > Test Equipment

Test coin batteries

<< < (3/6) > >>

Psi:
A Keithley 2450 SMU would do it.   10 nA – 1 A range
but you wont like the price.

tszaboo:

--- Quote from: Psi on November 09, 2023, 09:44:13 am ---
--- Quote from: tszaboo on November 09, 2023, 09:32:44 am ---I have a Keithley 2380 for capacity tests. It doesn't do ESR directly, but you can either calculate it with a pocket calculator, or write a Python PYVISA script to measure it. It really depends on your definition of ESR, I've seen 10 different definitions already. I think it would fit your budget, though not sure how much it costs now.

--- End quote ---

Keithley 2380 current resolution is like 100uA.  That isn't small enough to do capacity testing on a coin cell discharge at 200uA.
The problem with the Keithley 2380, and a lot of similar things, is that they are designed for devices that draw up to like 200W.
They just don't have the resolution down in the sub-mA scale.

--- End quote ---
Well let's say a CR2032 coin cell is 200mAh, you don't want to test a battery for a thousand hours, you would set up like 2-10mA discharge current.
If you want to do lifetime measurements it's not the right tool, but for a generic "Is this 50mAh or 200mAh" test it's sufficient. It's definitely not as great as an SMU but it doesn't cost as much as well. If I would know there is a market for it, I could design a coin cell testing setup, since I already made a pretty extensive, ~0.03% (current) and 0.003% (voltage) accurate battery testers in my past job.

Fungus:

--- Quote from: Ian.M on November 09, 2023, 09:05:37 am ---See ATmega328P full datasheet section 28.6.1. Analog Input Circuitry and you will find the dynamic impedance of an active ADC input during sampling is under 100K (possibly by more than an order of magnitude) so could well be significant with respect to the cell load resistor. 

--- End quote ---

I think it's section 28.9 in the one you linked above.

Maybe if you're switching between analog input pins and have to keep charging the internal capacitor.

If you're not switching between channels the the charge on that capacitor will be steady.

Psi:

--- Quote from: tszaboo on November 09, 2023, 11:17:33 am ---
--- Quote from: Psi on November 09, 2023, 09:44:13 am ---
--- Quote from: tszaboo on November 09, 2023, 09:32:44 am ---I have a Keithley 2380 for capacity tests. It doesn't do ESR directly, but you can either calculate it with a pocket calculator, or write a Python PYVISA script to measure it. It really depends on your definition of ESR, I've seen 10 different definitions already. I think it would fit your budget, though not sure how much it costs now.

--- End quote ---

Keithley 2380 current resolution is like 100uA.  That isn't small enough to do capacity testing on a coin cell discharge at 200uA.
The problem with the Keithley 2380, and a lot of similar things, is that they are designed for devices that draw up to like 200W.
They just don't have the resolution down in the sub-mA scale.

--- End quote ---
Well let's say a CR2032 coin cell is 200mAh, you don't want to test a battery for a thousand hours, you would set up like 2-10mA discharge current.
If you want to do lifetime measurements it's not the right tool, but for a generic "Is this 50mAh or 200mAh" test it's sufficient. It's definitely not as great as an SMU but it doesn't cost as much as well. If I would know there is a market for it, I could design a coin cell testing setup, since I already made a pretty extensive, ~0.03% (current) and 0.003% (voltage) accurate battery testers in my past job.

--- End quote ---

Depends what the goal is I suppose, if a product is using the CR2032 at 2-10mA and you want to characterize it at that discharge then its fine.
But if the goal is to confirm it meets datasheet capacity spec you really have no choice but to discharge using what the datasheet says the capacity is measured at, which is ~200uA and takes like 45 days.
Might be able to push it up to 1mA and still get rated capacity, depending on brand, but much more than that and you will definitely measure it as under-capacity when its actually not.

In any case, for the OP situation the manufacturer isnt going to accept evidence of under performing cells unless the data shows them tested at the correct discharge current.

Stray Electron:

--- Quote from: swiss on November 09, 2023, 06:20:40 am ---Hello everyone,
We currently suspect that some of the cr2032 button batteries we receive do not meet the specifications. We would therefore like to buy a setup where we can check the capacity and internal resistance of individual cells.
The solution should not cost more than 2000 USD. Can you recommend something?

--- End quote ---

   Do you just want a load and a meter for a manual readout or are you looking to do data logging?  If logging then what interface? I have several HP 3437A voltmeters that would be great for an application such as this.  They only have three voltage ranges; 0 to .1 volt, 0 to 1 volt and 0 to 10 volts and they're only 3 1/2 digit so they're not very useful for other applications but they will take up to 5700 readings per second and output the results over HP-IB so they would be perfect for an application like this.

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod