BQ34Z100-G1: Lead Acid battery vs Pack charactoization

The chemistry data is stored and used on a cell basis in the gauge, so you do not have to re-characterize the cells. One issue that users have had with stacked PbA packs is the the resistance of the straps connecting batteries will contribute to the series resistance in Ra table updates. This resistance does not have the same linearity as the cells over current and temperature, so this can cause gauging errors. You may want to consider the bq34110 device. It uses a CEDV gauging algorithm and the straps have less impact on gauging accuracy.

Thanks Tom,
How accurate is bq34110 compared to BQ34Z100-G1.My application is UPS (48V battery pack & 800W load ).
Jagbir

Tom,
I need your opinion on this topic .Here are more details about my application.
Discharge current ~ 15- 18 A for 10 minutes only when mains power is not there. Battery chemistry : Lead Acid ,AGM , 48V :4 nos. of 12V batteries in series each rated 9Ah ,charging current ~ 1-2 A.. Which one of these two TI fuel gauge suits my application better : bq34110 or BQ34Z100-G1.
Waiting for your reply .
Thanks,
Jagbir Singh

Jagbir,
I cannot get to your request at this time, but I will answer it later tonight.
Tom

Jagbir,
EIther gauge can be used for PbA cells. I have already discussed the issues with connecting PbA batteries in series and the strap resistance contributing to Ra Table updates and causing gauging errors. The other problem with using PbA with Impedance Track gauges is that PbA cell voltages rest to a high value during the rest period after discharge. The IT gauge will run a capacity simulation about every 5 hours during rest and will update capacity based on the OCV. This could cause an empty pack to report up to 50% SOC. The SOC will then drop at the start of discharge. The gauge does have a feature that will prevent the jump, if the SOC is at 0% at the end of discharge, but this will not prevent the jump if the SOC is not 0%. The bq34110 is a CEDV gauge and it uses coulomb counting to update capacity, so it will not run the capacity simulations during rest. The SOC should remain stable until you start charging the pack. The disadvantage of the CEDV gauge is that the pack has to be discharged from near full charge to below 7% SOC to update FCC as the pack ages. I would use the bq34110 for this application, because I think that it will provide the best performance.

Tom

Thanks Tom!