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Let's say I have a 14.8V battery with capacity of 5200mAh. My load constantly draws 20 amps from it. I want to estimate the time it takes until the cell reaches let's say 10V. This is just an example, I dont't have this configuration. How would you calculate this time, to reach from one voltage level to an other?

Tage
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    This kind of question has, without exaggeration, been asked hundreds of times here. It's a) trivial and b) you can't tell me you didn't find at least an approach on this site. – Marcus Müller Feb 17 '19 at 13:50
  • … and a lot of others. – Marcus Müller Feb 17 '19 at 13:51
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    And it is very unlikely that a 2.6 Ah battery can deliver 20 A. – Transistor Feb 17 '19 at 14:36
  • Actually I am curious on how much time it takes to reach a certain voltage level, and not how much time it takes to empty battery. The answers in your linked question, does not answer mine. Or at least, I am missing something there. – Tage Feb 17 '19 at 14:42
  • Tage, the internal resistance of the battery would probably cause it to drop to 3V or below instantly when connected. A single cell Lithium battery is not designed for that level of output. – MadHatter Feb 17 '19 at 14:58
  • Yes, you are right! This was a bad example from me. I just want to know in general how should one calculate this time, to reach from one voltage level to an other. I guess temperature rise also affects this internal resistance and this makes it a bit more difficult, – Tage Feb 17 '19 at 15:04

1 Answers1

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The battery has a very flat discharge characteristic from 3.7V to 3.5V, so the discharge time to 3V is about the same as the full discharge time (2.7V?). but it must be borne in mind that when discharging with a current of 20A, the capacity of the battery will be less than indicated on the marking.

In addition, you must make sure that this type of battery allows the discharge current of 20A. Also, a long discharge with such a large current will cause a strong heating of the battery and a decrease in the working life

Electric_90
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Artur
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  • Welcome to EE.SE. A minor point: 'A' for ampere. All SI units named after a person have their symbols capitalised but are lowercase when spelled out. SI also recommend a space between the number and the symbol. You wouldn't write "5apples" but rather "5 apples". – Transistor Feb 17 '19 at 15:20