I have a bunch of 18-18.5v batteries I need to test to see how much capacity they have and I figured the best way is to put a load on it and test, but I don't have anything that will work as a test load but I have a lot of ceramic/cemet resistors (100's) from 2w up to 20w. I just don't know what resistance I should put on the battery nor how many watts I should use.
I do have a couple 12v LED's that are "3w" but are more like 1/2w that I could put inline if that would help at all.
I know that if I put resistors in parallel they 1/2 the resistance (if same ohm rating) and double if put in series, but do the wattages stay the same, IIRC, they do.
So what ohm rating and what wattage should I be looking for, or what combination should I make to test these properly. I plan on taking the V reading then running the test for X amount of time and checking the V. I may take a reading every minute or so and keep track that way as well.
Any suggestions on this? Thank you for any help you can suggest!
I do have a couple 12v LED's that are "3w" but are more like 1/2w that I could put inline if that would help at all.
I know that if I put resistors in parallel they 1/2 the resistance (if same ohm rating) and double if put in series, but do the wattages stay the same, IIRC, they do.
So what ohm rating and what wattage should I be looking for, or what combination should I make to test these properly. I plan on taking the V reading then running the test for X amount of time and checking the V. I may take a reading every minute or so and keep track that way as well.
Any suggestions on this? Thank you for any help you can suggest!