How to see what capacity a fully charged rechargeable battery is holding? AA/AAA

pfpf

i have/had this:
https://www.amazon.co.uk/gp/product/B08CKCZMT1/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

i would go for another if available but can't seem to find anything that does the same.

i have battery chargers and i have a little unit that tells me green/amber/red for current state but not the actual current capacity.

is there such a thing that can read the capacity of a fully charged battery or does it need to go through a charge/de-charge/measure sequence like my unit above?

to be clear, i don't want to know what the battery "should" be holding, the battery tells me that but what it is holding on a full charge.

thank you.

sevenhills

A multimeter will tell you the voltage of a battery.

https://www.ebay.co.uk/itm/404768905899?hash=item5e3e1b5aab:g:tiEAAOSw4yhlrmXp&amdata=enc:AQAIAAAA8Os0V98UX6jaa6c6UgSXKc39zl/mO7sf4yE2DQo3Oo0pW8Pj9QJ+hNYGH/2cdymkbgPp0KrCOQihXbHKTrn7co1UaMyyvaPdcVX1LkDUqS0JvbppDH8PrBFCPnv7W2UAnW2GUkA0/XIp/e1sFRH0E/AiM7R3EKvJnmzH4mKGuBnztBdXjpOv9GmnvMw0QsJdOsQuxQXtnr0MABKQBkPwD1m2GAu/oz3y2qPHufIXGcqv21dJd4/HYw50xyDA4qUOF+8kHftWsqbqSM4WkVsEcDC7n1FSYa1GkhGGNrSuMaW/BAl/4zCJ9OzdsCwsz7deMQ==|tkp:Bk9SR8Cy_42vYw

matelodave

The only way to check the capacity of a battery is to do a discharge test and thats what the magic device does that the OP already has - it measures the voltage and current through a load over time and calculates the energy delivered. It doesn't and cant tell you the state of charge

The voltage doesn't really tell you all that much unless you you put a load on the battery as well, but even that wont tell you the state of charge or capacity remaining.

pfpf

matelodave said:

The only way to check the capacity of a battery is to do a discharge test and thats what the magic device does that the OP already has - it measures the voltage and current through a load over time and calculates the energy delivered. It doesn't and cant tell you the state of charge

do you have any idea what will do this job now as mine is no longer available.

and is what i am looking for the best way of determining the condition of a battery from the POV of how long it will power something? i am looking to weed out poor batteries from a large pool of batteries i have.

once "fully charged" they are all showing green as in full power on my cheap little tester but some are not lasting as long as others from that full charge.

edit: i think this is the same?
https://www.amazon.co.uk/dp/B08W3W15GB/ref=sspa_dk_detail_0?psc=1&pd_rd_i=B08W3W15GB&pd_rd_w=DJmjF&content-id=amzn1.sym.7b0d8b34-54be-4fd2-9baf-2d658b11dc53&pf_rd_p=7b0d8b34-54be-4fd2-9baf-2d658b11dc53&pf_rd_r=5J6C0ACYA8PPARBY85Z2&pd_rd_wg=2ulfy&pd_rd_r=64308a6a-c8c9-4e09-96d3-ba2df7657170&s=diy&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWxfdGhlbWF0aWM

sevenhills

matelodave said:

The only way to check the capacity of a battery is to do a discharge test and thats what the magic device does that the OP already has - it measures the voltage and current through a load over time and calculates the energy delivered. It doesn't and cant tell you the state of charge

The voltage doesn't really tell you all that much unless you you put a load on the battery as well, but even that wont tell you the state of charge or capacity remaining.

I have just tested a couple of AA batteries with my multimeter, they range from 1.1v to 1.3v so it does indicate a level of charge.

https://www.instructables.com/How-to-check-AAAAA-alkaline-battery-voltage-using/

ballyblack

https://www.amazon.co.uk/D-FantiX-Digital-Battery-Checker-Batteries/dp/B014FEM21G/ref=sr_1_8_sspa?crid=1R0AUAZ0KZEPZ&keywords=battery+tester&qid=1707137725&sprefix=battery+tes,aps,258&sr=8-8-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9tdGY&th=1

matelodave

sevenhills said:

matelodave said:

The only way to check the capacity of a battery is to do a discharge test and thats what the magic device does that the OP already has - it measures the voltage and current through a load over time and calculates the energy delivered. It doesn't and cant tell you the state of charge

The voltage doesn't really tell you all that much unless you you put a load on the battery as well, but even that wont tell you the state of charge or capacity remaining.

I have just tested a couple of AA batteries with my multimeter, they range from 1.1v to 1.3v so it does indicate a level of charge.

https://www.instructables.com/How-to-check-AAAAA-alkaline-battery-voltage-using/

It doesn't really, it checks the voltage not the remaining capacity or capability to provide current.

The best way to check an alkaline AA or AAA is to connect the multimeter probes to measure amps and set the meter to measure AMPS (usually 10 or 20A), do not use Ma or you'll blow a fuse or damage the multimeter - you should be able to pull around 3-4 amps for a few seconds if the battery hasn't died.

However as the OP is asking about rechargeable batteries the info about alkaline batteries isn't relevant.

matelodave

pfpf said:

matelodave said:

The only way to check the capacity of a battery is to do a discharge test and thats what the magic device does that the OP already has - it measures the voltage and current through a load over time and calculates the energy delivered. It doesn't and cant tell you the state of charge

do you have any idea what will do this job now as mine is no longer available.

and is what i am looking for the best way of determining the condition of a battery from the POV of how long it will power something? i am looking to weed out poor batteries from a large pool of batteries i have.

once "fully charged" they are all showing green as in full power on my cheap little tester but some are not lasting as long as others from that full charge.

edit: i think this is the same?
https://www.amazon.co.uk/dp/B08W3W15GB/ref=sspa_dk_detail_0?psc=1&pd_rd_i=B08W3W15GB&pd_rd_w=DJmjF&content-id=amzn1.sym.7b0d8b34-54be-4fd2-9baf-2d658b11dc53&pf_rd_p=7b0d8b34-54be-4fd2-9baf-2d658b11dc53&pf_rd_r=5J6C0ACYA8PPARBY85Z2&pd_rd_wg=2ulfy&pd_rd_r=64308a6a-c8c9-4e09-96d3-ba2df7657170&s=diy&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWxfdGhlbWF0aWM

Its similar to the one you've got, it will discharge the cell over a period of time and calculate the capacity from the voltage and current.