MAh to mA Conversion: How to Calculate Battery Capacity

  • Thread starter RestlessMind
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In summary, battery capacity is a rough guide and cannot accurately predict the battery life based on current draw. It is important to also consider the internal resistance of the battery and refer to datasheets for specific information. The Eveready website provides datasheets for their alkaline batteries, but it is a Flash-based website. Generally, a battery is tested at a 20 hr rate, but different rates may provide different results.
  • #1
RestlessMind
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mAh - mA "converstion"

If a battery has a capacity of (for example) 1000mAh, how many mA can it be considered to possess? I understand that it can give 100mA for 10 hours, or 10mA for 100 hours, etc. But, depending on what application you are putting the battery towards, how do you know how long the battery will last? Is it judged by how much FW current an application (such as an LED) uses/draws?
 
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  • #2


Draven said:
If a battery has a capacity of (for example) 1000mAh, how many mA can it be considered to possess? I understand that it can give 100mA for 10 hours, or 10mA for 100 hours, etc. But, depending on what application you are putting the battery towards, how do you know how long the battery will last? Is it judged by how much FW current an application (such as an LED) uses/draws?

Yes.

Battery capacity is only a rough guide, though. You can't infer that it will last 1000 hours if it is delivering 1 mA. And you can't say it would last 6 minutes delivering 10 amps.

You need to know more about the internal resistance of the battery before you can say if the battery is suitable for a particular application.
 
  • #3


I haven't been able to find datasheets at duracell.com, but the eveready.com website has datasheets:

http://www.eveready.com/

It's an obnoxious Flash-based website, so you have to click on the "Learn More" arrow at the bottom of the intro page, and then click on "Download Application Manual PDF" arrow for the alkaline batteries on the left.
 
  • #4


vk6kro said:
Yes.

Battery capacity is only a rough guide, though. You can't infer that it will last 1000 hours if it is delivering 1 mA. And you can't say it would last 6 minutes delivering 10 amps.

You need to know more about the internal resistance of the battery before you can say if the battery is suitable for a particular application.
Understood.

I haven't been able to find datasheets at duracell.com, but the eveready.com website has datasheets:

http://www.eveready.com/

It's an obnoxious Flash-based website, so you have to click on the "Learn More" arrow at the bottom of the intro page, and then click on "Download Application Manual PDF" arrow for the alkaline batteries on the left.
Thanks for the info.
 
  • #5


Draven said:
If a battery has a capacity of (for example) 1000mAh, how many mA can it be considered to possess?
Then 1 A-h is the "C" rate. Usually they test at a 20 hr (C/20) rate, which means 50 mA for 20 hrs. At C/100 you will probably get more than 1 A-h.
 

1. What is the difference between mAh and mA?

mAh (milliampere-hour) is a unit of measurement for battery capacity, while mA (milliampere) is a unit of measurement for current. mAh is used to measure the total amount of charge a battery can hold, while mA is used to measure the rate at which current is flowing.

2. How do I convert mAh to mA?

To convert mAh to mA, you need to know the battery's voltage. You can then use the formula: mA = (mAh * 1000) / voltage. For example, if a battery has a capacity of 3000 mAh and a voltage of 3.7 V, the conversion would be: (3000 * 1000) / 3.7 = 810 mA. Keep in mind that this conversion is for a fully charged battery and the current will decrease as the battery discharges.

3. Why is it important to know the battery's capacity in mAh?

Knowing the battery's capacity in mAh can help you determine how long a device will run on a single charge. It can also help you compare different batteries and choose the one with the desired capacity for your specific needs. Additionally, it can be useful in troubleshooting battery-related issues.

4. Is there a standard mAh to mA conversion rate?

No, there is no standard conversion rate for mAh to mA. The conversion will vary depending on the battery's voltage. As mentioned earlier, the formula to convert mAh to mA takes into account the voltage of the battery.

5. Can I convert mA to mAh?

No, you cannot directly convert mA to mAh as they are measuring different things (current vs. capacity). However, if you know the current (in mA) and the time (in hours) that the battery was discharged, you can calculate the battery's capacity in mAh using the formula: mAh = (mA * time) / 1000. For example, if a battery was discharged at a rate of 200 mA for 5 hours, the capacity would be: (200 * 5) / 1000 = 1,000 mAh.

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