MAh to mA Conversion: How to Calculate Battery Capacity

[RestlessMind]

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?

 

[vk6kro]

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.

 

[berkeman]

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.

 

[RestlessMind]

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.

 

[whome9]

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.