MM912_637 ? SOC / SOH Sensor for 2V Off-Grid Batteries

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MM912_637 ? SOC / SOH Sensor for 2V Off-Grid Batteries

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britesc
Contributor I

Hi,

I am trying to find a sensor capable of reporting the SOC / SOH of 2v Lead Acid Batteries as used in off-grid power solutions.

Does anyone know if a MM912_637 will fit the bill.

I would need 24 1 for each battery, with their input being fed into Arduino controllers, 2 x 12.

Any advice gratefully received,

 

Kind regards,

jB

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TomE
Specialist I

Interesting part. Very complicated though.

 

> I would need 24

 

They're $4.40 each in 10,000 quantity, so that's over $100 for the chips alone. They're 48 pin QFN packages.so would need fairly complicated PCBs to mount them on.

 

They may be overkill for what you want as they have internal CPUs.

 

They also assume 12V batteries and need to be grounded to the battery. I assume your 2V cells are in series, so that would be very difficult to arrange with each chip "grounded" to a separate cell in the stack and requiring separate 5V/12V power. That assumes they could be programmed for 2V cells. Then you wouldn't be able to communicate with this stack of chips either.

 

To measure SOC/SOH all you need is the current through the stack, the voltage of each cell, the temperature a a bit of calculation based on battery theory. If you're building a charger, then looking for chips dedicated to this and the associated App Notes might be a good start. Freescale only seems to make Lithium charger chips.

 

Tom