# How to measure mAh?



## josean (Aug 18, 2006)

Hi there,

I am wondering about a reliable method to measure the real capacity (mAh) of a battery.

I have seen this site , in which (at the end of the page) they use a digital multimeter to measure the mAh of the batteries.

As that caught my attention, I did a bit more research. The multimeter seems to be a model named DT9205A (not sure, because image is fuzzy).

Searching on Google, such model seems to be a cheap ($20) chinese multimeter.

The question is the next one: Can I use a standard multimeter to measure mAh. If so, how is this done? Should I use a more specific and expensive equipement?


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## Anders (Aug 18, 2006)

Hello josean.

No, you can't use a multimeter to measure mAh, in your link they measured Volt. 
You can measure Li-Ion cells with a multimeter using the volt scale to determine the % of the charge, but this method is not exactly.
With Ni-Mh cells this method doesn't work at all. 

This is for Li-Ion cells:
[font=&quot]4.2V – 100%
4.1V – 87%
4.0V – 75%
3.9V – 55%
3.8V – 30%
3.5V – 0%[/font]

If you look at this thread maybe you find your answers, with info about ZTS MBT-1, Ansmann ENERGY CHECK LCD and CBAII, in your case, living in spain the Ansmann ENERGY CHECK LCD problaby would meet your demands, i just got mine from germany,52€ including freight. However this meter doesnt measure rechargeable Li-Ion cells. neither does the ZTS MBT-1.

https://www.candlepowerforums.com/threads/129308

Anders


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## JimH (Aug 18, 2006)

Are you talking total capacity, as in rated capacity, or capacity remaining.

If you are talking total capacity from a fully charged battery, the best way to measure mAh is with a CBA. Everybody I know on CPF that measures mAh uses one of these.


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## zelda (Aug 18, 2006)

It exits some rc-charger for less $$, they can measure the capacity. Most in the $$ Range have only 1 A max. discharge rate. 

I have a Multiplex LN 5014 It's worth the money.

zelda


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## Handlobraesing (Aug 18, 2006)

You can measure mAh using a multimeter with data logging capability


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## lrp (Aug 18, 2006)

Zelda, how much did you pay for the charger? Thanks!


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## zelda (Aug 18, 2006)

I payed 100$. 

Now its 82$

http://www.nesail.com/detail.php?productID=3780 

Zelda


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## josean (Aug 19, 2006)

Well, I understood that there is no way of measuring capacities (neither total nor remaining) easily and using just a cheap multimeter.

I use my batteries (NiMH) mainly for digital photo camera, several flashlights, wireless mouse/keyboard and a multiband radio receiver. You can consider all of them domestic gadgets, none of them being some tactical, in which I must rely on.

So, the measuring is not a real need, but just curiosity to confirm advertised capacity, and just to test a battery (sometimes stored for weeks) before putting either on a charger or on a gadget.


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## Handlobraesing (Aug 19, 2006)

josean said:


> Well, I understood that there is no way of measuring capacities (neither total nor remaining) easily and using just a cheap multimeter.
> 
> I use my batteries (NiMH) mainly for digital photo camera, several flashlights, wireless mouse/keyboard and a multiband radio receiver. You can consider all of them domestic gadgets, none of them being some tactical, in which I must rely on.
> 
> So, the measuring is not a real need, but just curiosity to confirm advertised capacity, and just to test a battery (sometimes stored for weeks) before putting either on a charger or on a gadget.



Actually, you can.. if you have the patience. Take a current measurement, record the reading exactly every 30 seconds. Plug them into computer, sum them up.


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## jugeh (Aug 19, 2006)

josean said:


> Hi there,
> 
> I am wondering about a reliable method to measure the real capacity (mAh) of a battery.
> 
> ...



I stumbled across this site some days ago too. Was very confused because according to the position of the knob the DMM is set to 20A DC. So they are actually measuring the short ciruit current of the cells. Also unusual they reversed the polarity in all measurements.

Seems all to be very doubtful.


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## lrp (Aug 19, 2006)

Thanks Zelda!


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