jimbo69ny
1 W
- Joined
- Feb 9, 2018
- Messages
- 52
Hello Everyone,
I recently picked up a bunch of laptop batteries and I had a few questions.
How does internal resistance relate to voltage? Does it?
I want to test to see what happens when you put a low resistance cell and a higher resistance cell, in parallel, in a circuit. Lots of people have opinions on it but I wanted to test it in a test circuit. So I tested all of my cells for internal resistance. Most of them were between 700 and 850 ohm. A couple were in the 600's. About 8 of them were near zero ohms. As my meter was connected to the near zero cells the ohm rating slowly climbed. I was surprised to see that the battery was absorbing voltage from my meter and the ohm rating was increasing. (in case you didn't know, a multi meter sends a small amount of voltage through a circuit when you are testing resistance)
I was surprised to see that internal resistance seems to change as voltage is increased. Is that normal? I thought each cell had a nominal internal resistance.
Also, does capacity relate to voltage? Capacity is inherent to the cell regardless of voltage right? For example, if you have a 3500 mah cell and a 2600 mah cell in parallel, both healthy new cells, at the same voltage, they can have different capacity right? Capacity doesn't merge when in a parallel circuit like voltage right?
Thanks!
I recently picked up a bunch of laptop batteries and I had a few questions.
How does internal resistance relate to voltage? Does it?
I want to test to see what happens when you put a low resistance cell and a higher resistance cell, in parallel, in a circuit. Lots of people have opinions on it but I wanted to test it in a test circuit. So I tested all of my cells for internal resistance. Most of them were between 700 and 850 ohm. A couple were in the 600's. About 8 of them were near zero ohms. As my meter was connected to the near zero cells the ohm rating slowly climbed. I was surprised to see that the battery was absorbing voltage from my meter and the ohm rating was increasing. (in case you didn't know, a multi meter sends a small amount of voltage through a circuit when you are testing resistance)
I was surprised to see that internal resistance seems to change as voltage is increased. Is that normal? I thought each cell had a nominal internal resistance.
Also, does capacity relate to voltage? Capacity is inherent to the cell regardless of voltage right? For example, if you have a 3500 mah cell and a 2600 mah cell in parallel, both healthy new cells, at the same voltage, they can have different capacity right? Capacity doesn't merge when in a parallel circuit like voltage right?
Thanks!