battery state of charge study

Check out http://www.electronicsteacher.com/battery-tutorial.php

thanks a lot...

This tutorial is very much a layman's guide. He (it is unattributed) doesn't mention by name or effect Peukerts exponent. His self drain figures are also rather brutal. I would be very dissatisfied if any battery that I sold auto-discharged at that rate. If this contributor is trying to design a battery capacity monitor I would think she would be well above this level.

Everyone so far has assume that the question refers to lead acid batteries. Is this the case? There are many other types out there and they all have differing discharge characteristics. Are we looking at button cells or submarine batteries?

On the asumption that she(?) is making a specific monitor function for a specific battery I would suggest she looks up the actual discharge curves from the manufacturer. Failing satisfactory information from the manufacturer she could take several batteries and carry out her own discharge curve experiments to ascertain the characteristics at differing discharge rates and tempertures.

Some possibilities that exist for monitoring:-

• Count out / count in (using peukerts if appropriate),
• test for change in internal resistance by loading and a dV/dI calculation
• test for O/C terminal voltage by removing all current.
• Continous densiometry of electrolyte if cells are of suitabe size, construction and chemistry

I hope this may help Roza.

Give us some more info please.

Regards Chas

Call Odyssey Battery and speak with Bruce Essig or Kalyan Jana

www.odysseybattery.com

thanks...