Support Path: /Product/Development and troubleshooting/
SLUSBZ5B (revised July 2016) explains that the bq34z100-G1 now has flash settings to allow for the fact that charge efficiency in lead acid batteries decreases with state of charge and is influenced by temperature. However, there appear to be many errors in the coverage of this subject throughout SLUSBZ5B. Also, the values provided for charge efficiency calculations in this document (and probably also stored as default in the device's flash memory) are different from those popularly said to apply to real batteries. At full charge and low temperature they might work fairly well, but probably less so in other conditions. Users therefore may wish to change the stored values, and it would be easier for some of us to do this if conversion factors were provided, perhaps in the same form used for table 12 on p29 of SLUSBZ5B. My guess is that Pb Temperature Compensation (subclass 34 and offset starting at 5) would be converted from DF value using the formula 1280 * DF. If so, to convert from temperature increase in K or C (above 25 C) to charge efficiency reduction in something (maybe 0.01% per C) the temperature change is divided by 1280 then converted to Xemics floating point form before being saved in flash. Similarly, my guess is that Pb Reduction Rate (subclass 34 and offset starting at 10) would be converted from DF value using the formula 80 * DF. So, to convert from state of charge increase (above Pb Drop Off Percent) to charge efficiency reduction in something (maybe 0.1% per %) the SOC increase is divided by 80 then converted to Xemics floating point form before being saved in flash. (All these figures are decimal.) However, these guesses are probably completely wrong so I would welcome correction. Whatever information can be provided would be useful in any form, so if someone could just say what the default (or stated maximum) flash contents represent and in what units (0.1% or 0.01% or whatever) then it should be possible to sort out at this end how to make any necessary changes. Thanks for any help you can give. All best, Tim.
For other users (especially those not using the IT evaluation hardware and software) conversion to Xemics floating point is explained inHow EVSW Display the Raw Data V1.03.pdf
e2e.ti.com/.../How-EVSW-Display-the-Raw-Data-V1.03.pdf
There is VB script for conversion on page 4 of slva148a.pdf
www.ti.com/.../slva148a.pdf but the flow diagram on page 8 of SLUA640 should not be trusted.