Is there a way to tell how full a battery is with a DMM?

[Brian321]

Ok so i read the sticky on how to use a DMM, But i am wondering if there is a way to tell how much juice a battery( CR123a, RCR123, 18650, 26650) has left in it? Or should i return this Multimeter and just buy a ZTS Mini? ( Its a cheap $20 Multimeter from walmart.)

 

[Mr Happy]

Ok so i read the sticky on how to use a DMM, But i am wondering if there is a way to tell how much juice a battery( CR123a, RCR123, 18650, 26650) has left in it? Or should i return this Multimeter and just buy a ZTS Mini? ( Its a cheap $20 Multimeter from walmart.)

If you are going to use lithium ion cells safely like 18560 or 26650, then you need to own a multimeter.

Yes, you can tell the state of charge of lithium cobalt ion cells by measuring their voltage, but it does not work equally well with other kinds of cells.

For lithium cobalt cells, the table is something like this:

4.2 V ... 100%
4.0 V ... 80%
3.9 V ... 60%
3.8 V ... 40%
3.7 V ... 20%
3.6 V ... 0%

 

[45/70]

From what I understand, a voltage reading is just as accurate, or possibly more accurate than a ZTS for estimating LiCo capacity. Using either, is just an estimate. I think ZTS just added the Li-Ion test, as a convenience.

Dave

 

[Brian321]

If you are going to use lithium ion cells safely like 18560 or 26650, then you need to own a multimeter.

Yes, you can tell the state of charge of lithium cobalt ion cells by measuring their voltage, but it does not work equally well with other kinds of cells.

For lithium cobalt cells, the table is something like this:

4.2 V ... 100%
4.0 V ... 80%
3.9 V ... 60%
3.8 V ... 40%
3.7 V ... 20%
3.6 V ... 0%

Thats good to know, Is there something silimar for primary CR123's?

 

[Ragiska]

Thats good to know, Is there something silimar for primary CR123's?

nope

 

[nodoubt]

If you are going to use lithium ion cells safely like 18560 or 26650, then you need to own a multimeter.

Yes, you can tell the state of charge of lithium cobalt ion cells by measuring their voltage, but it does not work equally well with other kinds of cells.

For lithium cobalt cells, the table is something like this:

4.2 V ... 100%
4.0 V ... 80%
3.9 V ... 60%
3.8 V ... 40%
3.7 V ... 20%
3.6 V ... 0%

so is it the same table for aw 18650s also ?

 

[45/70]

so is it the same table for aw 18650s also ?

Yeah, pretty much. There are about three tables like this floating around. They are all pretty close to each other. Keep in mind that the voltage measuring method for estimating the capacity of Li-Ion cells is not 100% accurate, it's just an estimate. Also, at voltage readings below about 3.80 volts, accuracy tends to fall off some, as the exact chemical mix used in cells from different manufacturers varies a bit.

Dave

 

[skatenut]

If you are going to use lithium ion cells safely like 18560 or 26650, then you need to own a multimeter.

Yes, you can tell the state of charge of lithium cobalt ion cells by measuring their voltage, but it does not work equally well with other kinds of cells.

For lithium cobalt cells, the table is something like this:

4.2 V ... 100%
4.0 V ... 80%
3.9 V ... 60%
3.8 V ... 40%
3.7 V ... 20%
3.6 V ... 0%

Good to know, thanks
Just ordered a DMM yesterday and look forward to using it. I don't really need one, but the road to being a flashaholic is becoming more slippery and the downhill gradient is increasing. :huh:

 

[fnsooner]

Good to know, thanks
Just ordered a DMM yesterday and look forward to using it. I don't really need one, but the road to being a flashaholic is becoming more slippery and the downhill gradient is increasing. :huh:

And getting darker if you don't have the proper flashlight.