BQ series gas gauges with IT: Max Error calculation questions

Kelsey Fitzgerrel

In regards to Max Error % for BQ impedance tracking fuel gauges.
How is Percentage RSOC calculated with max error %?
Is it multiplied or added?
i.e:. %RSOC * max error%

Assuming it is multiplied:
If RSoC% is 50% and max error% is 10%:
RSoC error calculated: 0.5 * 0.1 = 0.05 (100%) => 5%

How is that 5% calculated with RsoC%?
Is it 5% +/-? Such as: 47.5% to 52.5%? or 45% to 55%?

Application notes, technical reference, and data sheets do not clearly specify this.

Also, does max error % affect or point to any other parameter other than RSOC... such as calibration?

Thanks,
Kelsey

over 7 years ago

0 Kelsey Fitzgerrel over 7 years ago

Prodigy 60 points

"... MaxErr will increment by 1 for every 20 cycles that a Qmax update does not occur. The MaxErr value does not add or subtract from the SOC percentage. It is just a figure of merit to indicate that SOC is less accurate. It will reset to 1 after Qmax has updated."

I found this answer under another thread. A figure of merit that is not added or subtracted.
Please define this parameter.

Thank you

0 Onyx Ahiakwo over 7 years ago in reply to Kelsey Fitzgerrel

TI__Guru* 76230 points

Hi kelsey
The max error is just an indication o f how much accuracy to expect. If you have chosen your chem id correctly and completed learning cycle, the max error will be 1%. So it means you expect your gauge to be close to being 99% accurate. pls see blog post on how to evaluate the accuracy of a gauge.

e2e.ti.com/.../how-accurate-is-your-battery-fuel-gauge-part-2-2
thanks
Onyx

0 Kelsey Fitzgerrel over 7 years ago in reply to Onyx Ahiakwo

Prodigy 60 points

Thanks Onyx!

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BQ series gas gauges with IT: Max Error calculation questions