I'm trying to get an accurate calculation of the initial internal resistance of a charging battery. I'm working on a project that involves a DC power supply charging a 24V battery. The power supply is limited to 50A.
I fully drained the battery and measured the open terminal voltage at 13V. I then connected the charger, which immediately pegged at 50A. The charger drove the voltage to 22.5V. The simple calculations say:
R = (22.5-13)/50 = 190mOhm
Is that the whole picture? Or is there a resistance associated with the battery charger that I need to take into account as well? If so, is there a trick to expose that value?
I need to get an exact value because the design calls for two 24V batteries in parallel, but I only have the resources to test one right now. If I have a good estimate of the internal resistance when the battery is fully drained, I can predict the circuit behavior when the 2nd battery is added. Thanks!
I fully drained the battery and measured the open terminal voltage at 13V. I then connected the charger, which immediately pegged at 50A. The charger drove the voltage to 22.5V. The simple calculations say:
R = (22.5-13)/50 = 190mOhm
Is that the whole picture? Or is there a resistance associated with the battery charger that I need to take into account as well? If so, is there a trick to expose that value?
I need to get an exact value because the design calls for two 24V batteries in parallel, but I only have the resources to test one right now. If I have a good estimate of the internal resistance when the battery is fully drained, I can predict the circuit behavior when the 2nd battery is added. Thanks!