What meter reads volts and mAH?

[bigchelis]

I want to test not just the voltage, but the milliamps per hour. I know that the other meter that reads the % of the batteries charge is good, but it doesn't tell you the mAH.


I want to know the when I purchase a cr123 3.7v 1300mAH battery it produces what it says. I bet it doesn't.

 

[Marduke]

A meter won't tell you capacity (mAh). To get that, you have to do a discharge test.

 

[Mr Happy]

milliamps per hour

By the way, it is milliamp-hours. You get the value by measuring milliamps over a period of hours and multiplying the two numbers together(*), so it is milliamps times hours rather than milliamps divided by hours.

* Technically you have to integrate them, but that is getting complicated.

 

[gillestugan]

Yes, you can do it manually by for example writing down the mA reading every 10 minutes. If you plot the values in a graph you will get the capacity by calculating the area under the line.

Or you can buy an advanced charger which does it all for you.

 

[bigchelis]

Yes, you can do it manually by for example writing down the mA reading every 10 minutes. If you plot the values in a graph you will get the capacity by calculating the area under the line.

Or you can buy an advanced charger which does it all for you.

I have a volt meter and it has mA, but they only go as high as 200 mA. All these batteries are in close to 1000mA and the 18650's are closer to 2k mA. Do I need a charger that can read up to that many mA?

 

[Chodes]

I think your need describes an HID. The bulbs have very long life and are tough. You'll get the 1000L and throw.

To stick with LED choice , a Malkoff triple dropin ? Mag body , Malkoff dropin , cells and charger for $200-$300.Gives you flexibility for body choice - anywhere from 1.5D with 2 x AW LION C Cells or 6D with 6 x D Nimh.

edit: Clearly , this reply was for another thread.

 

[Marduke]

I have a volt meter and it has mA, but they only go as high as 200 mA. All these batteries are in close to 1000mA and the 18650's are closer to 2k mA. Do I need a charger that can read up to that many mA?

You're confusing current and capacity. Current is mA, capacity is mAh. They are two different (but related) measures.

Perhaps the best method is to simply not worry about the cheap questionable cells, and purchase those which have been tested by the battery gurus here on CPF and are of known quality (ie. AW's cells)

 

[bigchelis]

You're confusing current and capacity. Current is mA, capacity is mAh. They are two different (but related) measures.

Perhaps the best method is to simply not worry about the cheap questionable cells, and purchase those which have been tested by the battery gurus here on CPF and are of known quality (ie. AW's cells)

I think purchasing the AW is probably my best bet since the quality has already been spoken for. Thanks

 

[Norm]

Here is a link to one of the hadiest pieces of test gear I own.
http://www.maxamps.com/Watts-Up-Meter.htm

Check battery condition, charger effectiveness, cell balance, ESC cutoff values, peak currents, stalled servos and more. "Watt's Up" measures mAh, Amps, Volts, captures peak Amps & Watts and low voltage events only thousandths of a second long. Easy hook-up -- like jumper cables. Best combination of features on the market. It has 1% or better accuracy, high resolution measurements and is small enough to take anywhere. Up to 60 Volts, 100 Amps, 65,000 mAh, 6500W!

 

[scott1981]

Yes, you can do it manually by for example writing down the mA reading every 10 minutes. If you plot the values in a graph you will get the capacity by calculating the area under the line.

Or you can buy an advanced charger which does it all for you.

I think that the area under the graph that you refer to would not give you the mAh, but mWh, since you would be plotting V against time and the current would be constant therefore you can calculate V x h (which comes from the graph) x A and it will give you mWh.


EDIT: My mistake, I misread your post. You are right, you are talking about plotting the current reading, and if it was constant, you can time it from beginning to end, eg V = 1.00 V / 0.9 V. By doing this you will have a squared area, and the only measurable variable would be time, and voltage would tell you when to stop. Using a resistor is also another approach, however you are now playing with 3 variables V and A and time. I am working on a circuit that starts a clock and it stops it after discharging a cell under a constant current once it reaches 1.00 V
It is not very sophisticated however I am sure that it can provide very accurate results. At the end of the test you have to multiply current (fixed variable) by elapsed time.