Coulomb Counter to Monitor Charge Flow

Nicolas L.

Part Number: BQ25570
Other Parts Discussed in Thread: BQ34110

We are currently using the BQ25570 Energy Harvesting IC with a solar cell in conjunction with simple link MCUs with great success. The VBAT_OK pin was used in the past to give a "battery low" warning.

For future designs, we'd like to improve the battery monitoring by evaluating the charge flows to adapt the system load to the environmental conditions (input power). We thought about a bidirectional coulomb counter / battery gas gauge for that. Are there any concerns with such a device in series with the battery on the VBAT pin? Could you recommend parts, alternatives or different concepts to achieve our goal? We're planning on using a LiFePO4 battery (approx. 1Ah) for storage.

Highly appreciate your suggestions / recommendations.

over 7 years ago

0 Onyx Ahiakwo over 7 years ago

TI__Guru* 76230 points

Hi Nicolas,
Since you are planning on using LFP, i would suggest looking into the bq34110 given that you will be mostly coulomb counting and then your host can interprete the passed charge data to tell how much capacity is in the battery.
thanks
Onyx

0 Nicolas L. over 7 years ago in reply to Onyx Ahiakwo

Prodigy 40 points

Hi Onyx,

thanks for your recommendation, I'll definitely check this one out. Do you see any general constraints with these devices in conjunction with the BQ25570? I was unable to find a reference that recommended against connecting an additional device to the VBAT/VSTOR pin so I'd say it's worth a try.

Thanks

Nicolas

0 Onyx Ahiakwo over 7 years ago in reply to Nicolas L.

TI__Guru* 76230 points

Hi Nicolas,

No I do not.

thanks
Onyx

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Coulomb Counter to Monitor Charge Flow