Hello,
I am configuring a bq34z100 to provide fuel gauging for a large Lithium pack made up of 7S16P Sanyo UR18650FM cells, the pack is nominally 25.9v, 40Ah, and 1078Wh (154Wh/series level). I am currently using ChemID 0100, can you please run the attached discharge log through mathcad to confirm that this is correct. I think the temperature may be out of calibration by a degree or two, if this makes a difference please let me know and I'll find out what the exact offset is. 7282.WalkerChemIDdischarge27052014.log
The second thing I need some advice on is the correct settings for the design capacity and energy as this pack is too large to configure without scaling of some sort. Reading through some other posts, it looks like there is a problem with the passed charge counter, so the design capacity should be scaled so that it is under 16k. Since the load is most likely going to be constant power, do I need to keep the design energy under 16k too? or can this value be up to 32k?
If my calcs are correct I think I can either
- scale by 5x by applying 5A discharge and telling the system that it is 1A
- Enter the design capacity as 8000mAh
- Enter the design energy as 30800mWh
or
- scale by 3x and scale energy by 10x by applying a 3A discharge but telling the system it is 1A as well as setting design energy scaling to 10
- Enter the design capacity as 13333mAh
- Enter the design energy as 5133cWh
Do my calculations make sense? and will one of these approaches be more accurate than the other?
Thanks
