Other Parts Discussed in Thread: GPCCHEM
Hi Team,
Can you have a look at the following customer inquiry, please?
I have a Fuel Gauge (bq27z561-R2), which should be able to measure currents between 10mA and 1.5A. Now I have a little problem.
Our minimum current is somewhere around 100µA, because we put our controllers into sleep mode when there is nothing to do.
The nominal operating current in non-sleep is about 10mA.
Maximum peak 1.5A can flow, if the user executes a certain action.
So we should actually be able to measure between 100µA and 2A, which of course is not so easy.
What do you do with your fuel gauges in such a case?
1. dimension them for 2A and the 100µA are not recognized as a discharge, but the intelligence of the device should still give a reasonable value for the RSoC and RemCap, even with many hours in sleep?
2. or is the system rather dimensioned for the 100µA (so 10µA resolution or so) and over-saturated the CC-ADC? Is that allowed at all? What about the 1.5A then?
I would prefer 1. but I have tried that with moderate success. The following chart was recorded with Battery Studio with 47kOhm as load (about 85µA):
Somehow everything fluctuates a bit too much. I have already read the whole technical manual what to do, but didn't find a solution.
The fuel gauging is also somehow quite a science in itself, so I hope that you can help me.
The learning cycle I have successfully performed, so the parameters for it are set, although of course the limits are all relatively low.
Only problem with the leanring cycle was that I obviously had a broken cable lying in the drawer, which led to a high resistance to the cell.
Unfortunately I only noticed this later because I had four things to do at the same time.
The measurement above is then done with this learning cycle as a basis with reasonable cables everywhere.
Can that only be due to the somewhat flawed learning cycle that the values jump around? I would have expected that they should be motionless at quasi-0-current anyway, right?
Timeline is btw. still in milliseconds because I hadn't converted them, the whole thing was just lying around for about 4 days over the weekend with the small load.
Thank you,
Franz
