Using A Volt Meter To Measure MAH ??????

[rupps5]

I charge with a polypro 4 charger that does not read mah. I would like to know how many mah I am putting back into the packs. So my question is can I use my volt meter to count how many mah are going back into my packs?

This is the volt meter I have.

http://i30.photobucket.com/albums/c303/rupps5/DSCN9752.jpg

[Pinecone]

Nope.

You can put something like a Eagle Tree flight data recorder inline and use that to measure and log the mAH.

[rupps5]

well how do chargers count the mah? There has to be something like a volt meter in there.

[Pinecone]

They start by measruing amps, then integrate over time. mAH = milli amps x hours. So you measure 100 mA for 1 hour = 100 mAH. But since the charge current changes over time, it has to measure it over small sections and add them up.

Some voltmeters will read milli amps, but you would have to take a reading every second and add them up.

[spork]

Try one of these. It does the integration for you.
http://farm1.static.flickr.com/6/9849017_2cae763a1d.jpg

Actually, this is an intersting problem. As mentioned, you'd have to sample the currently frequently. I'll think about it and see if something comes to mind. Meanwhile, kgfly probably has a good answer.

[Pinecone]

Actually many watt meter type devices measure mAH use, so sticking one in line while charging would read out the mAH added to the pack.

[write2dgray]

Current draw is usually measured in higher-end devices using principles of the "Hall Effect" so as to minimize observation effects.

http://en.wikipedia.org/wiki/Hall_effect

A standard voltmeter can't pull this off, but some of the products that can are:

Astro Flight Super Whattmeter 101N
Eagle Tree MicroPower V3 E-Logger
Medusa Research Oracle Data Recorder or Power Analyzer II
RC Electronics Watt's Up WU100 V2- David