Individual cell resistance

[Garry Hallam]

What I am wanting to know is if it is possible to check each individual cells resistance once it is part of a made up pack?

Is it just a case of touching onto that cells + & - or do the other cells connected influence the value?

 

[sjpt]

You won't measure a cells resistance with a conventional meter. A meter's resistance settings are for measuring 'passive' resistance; the voltage from the cell will totally confuse things.

The only way would be to measure the voltage across the cell when under load. Unless you knew the exact load current that wouldn't give an absolute measure, but if you measured all the cells that way any 'bad' cells with high resistance would stand out as having a lower voltage than the others.

 

[saneagle]

What I am wanting to know is if it is possible to check each individual cells resistance once it is part of a made up pack?

Is it just a case of touching onto that cells + & - or do the other cells connected influence the value?

You need one of these type meters. You can't measure any cells that are in parallel, except as a group because any current will take a path through all cells in the parallel group.

RC3563 4Wire 18650 Battery Voltage Internal Resistance Tester High-precision Trithium Lithium Iron Phosphate Battery Tester True - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

 

[Garry Hallam]

You need one of these type meters. You can't measure any cells that are in parallel, except as a group because any current will take a path through all cells in the parallel group.

RC3563 4Wire 18650 Battery Voltage Internal Resistance Tester High-precision Trithium Lithium Iron Phosphate Battery Tester True - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

I had this in my Amazon cart. Looks like the same thing

https://www.amazon.co.uk/gp/aw/d/B0D3TLM83M/ref=ox_sc_act_image_1?smid=A27UHW7CNU42FR&psc=1

 

[saneagle]

I had this in my Amazon cart. Looks like the same thing

https://www.amazon.co.uk/gp/aw/d/B0D3TLM83M/ref=ox_sc_act_image_1?smid=A27UHW7CNU42FR&psc=1

£35 vs £12. Both a waste of money. I bought one 12 years ago, and I've never used it. It's normally pretty obvious when a battery is knackered. Internal resistance causes sag. You see the sag on your LCD. You can either put up with it or not.

What's your objective in measuring internal resistance?

 

[Garry Hallam]

I get what you are saying! "If it gets the pig clean, then use it"