Hello,
For our UPS application we'd like to estimate the end of service of our battery using the method provided by the bq34110.
One of our difficulties is for the cell resistance calculation. In the technical reference document, it says that we need to calculate initial RCELL values ("The Rcell High & Low Temperature Coefficients are obtained during a pre-production test whereby the customer initiates Initial Rcell calculations at temperatures of 5°C, 25°C, and 40°C", 2.11.1.6 Cell Resistance Calculation). The problem is that our battery may not be fixed (choosen by our client). Actually we know that the battery with be a Valve Regulated Lead Acid Battery 12V with float voltage=13.65 @20°C, but the capacity and the manufacturer could be different from our test battery that we would use to obtain the RCELL values. Do you think that we could consider these values as independant of the capacity and the manufacturer or these should fit perfectly the battery in use ?
Our second concern is with the threshold decision (2.11.1.7.1 Direct Resistance Decisioning). We would like to say our battery is no more "good" when the capacity is no more high enough. Is there a way to link the cell resistance with the battery capacity. So when the Rcell goes below the threshold we would say the capacity is below the acceptable capacity threshold and our battery should be replaced.
Thanks and regards,
Axel
