Multimeter Question

[gmf2010]

Hello,

I am new to the Li-ion aspect of flashlights, but just purchased a Nitecore NDI, 2x AW14500, and a WF-139 charger.

After reading numerous posts here, I decided to buy a cheap multimeter to test the batteries.

I know there are other threads somewhat similar to what I'm asking, but I don't want to take any chances based on misinterpretation, especially with something that is potentially dangerous.

My question is, can someone tell me exactly what I would have to do (settings and connection-wise) in order to test my AW14500s properly?

This is the meter I have purchased: http://www.amazon.com/dp/B001T3Y8XW/?tag=cpf0b6-20

One last thing, are these correct readings for approximate voltages? There seems to be a little variation in the charts I've found here.

4.2 volts aprx. 100%
4.1 volts aprx. 90%
4.0 volts aprx. 80%
3.9 volts aprx. 60%
3.8 volts aprx. 40%
3.7 volts aprx. 20%
3.6 volts aprx. empty for practical use
<3.5 volts over-discharged

Thanks a lot for the help, I appreciate it =)

 

[Norm]

How do you use a multimeter??

 

[old4570]

Pictured its on 20v Direct current or DCV 20

Positive to positive and negative to negative on battery will give voltage reading .

To measure AMP's set it to 10A , and move the positive lead to the 10ADC position ...

Com should be negative , so your moving the positive lead from far right to far left and the neg remains in the middle .

So to recap :

COM = Neg and does not need to move ...
+ is either far left [ 10A setting ] and for the rest of the settings far right .
Voltage measurements etc ...

You should only need to move the + when reading AMP's in the 10A setting .
To measure Amps , remove tailcap , place - on the end of the batt and + against the body where you have clean aluminum .

Hope this helps

 

[gmf2010]

That's exactly what I needed to know. Thank you very much =)

Pictured its on 20v Direct current or DCV 20

Positive to positive and negative to negative on battery will give voltage reading .

To measure AMP's set it to 10A , and move the positive lead to the 10ADC position ...

Com should be negative , so your moving the positive lead from far right to far left and the neg remains in the middle .

So to recap :

COM = Neg and does not need to move ...
+ is either far left [ 10A setting ] and for the rest of the settings far right .
Voltage measurements etc ...

You should only need to move the + when reading AMP's in the 10A setting .
To measure Amps , remove tailcap , place - on the end of the batt and + against the body where you have clean aluminum .

Hope this helps

 

[45/70]

One last thing, are these correct readings for approximate voltages? There seems to be a little variation in the charts I've found here.

Yes, there are some variations in estimating Li-Ion cell capacity by measured voltage. It is not an exact science, however most estimates I have seen, are actually pretty close to each other. That one will do. :)

The biggest variation, is when reading a voltage of around 3.80-3.85 Volts, or below. Due to different manufacturing techniques, and slight variations in the chemical formula, cells from different manufacturers won't have exactly the same voltage, at the same capacity level, below this voltage range.

Dave

 

[Billy Berue]

Although you didn't ask about this, I thought I would nevertheless point out that the spec's for this DMM indicate an accuracy for DC voltage of +/-0.5% + 5 counts. This means, for example, if you are tying to use this DMM to measure for proper termination voltage of a Li-Ion cell--let's say 4.20v--if that meter indicates a voltage of 4.20, then assuming the meter is performing to its claimed spec's, then you only know that the real voltage the cell falls somewhere in the range of 4.13-4.27v. This *may* not be accurate enough, depending on your own personal expectations. This topic has been debated before, but suffice it to say that some on these forums believe that this is not good enough *for them*. My own personal opinion is that 4.27v is pushing it a bit for charge termination voltage of a Li-Ion cell, and I personally would want a meter with better accuracy. But this is just my opinion. Others would argue that knowing the voltage to within the above range is good enough. There's really no right or wrong answer to this issue--it just depends on what you expect and need from your meter in terms of accuracy.