Power Considerations - AA Batteries in Parallel

[mstewart]

I am developing hardware for the nRF52840.  After testing our firmware, we are going to need somewhere around 6,000-7,000 mAh to run our hardware for the time needed.  We were looking at using (4) Energizer I91 which have a nominal voltage of 1.5V and 3500 mAh.  The nRF52840 has a wide input range of 5.5V to 1.7V.  

Would it be efficient to do a set up as below, utilizing 2 pairs of AA batteries in series and then in parallel with reverse current/polarity protection via schottky dioeds and still use the DCDC converter:

Or would it be better to use 2 C batteries in series and get roughly 7000 mah at a nominal voltage of 3V. 

[ketiljo]

Hi Morgan

 

You could just connect the batteries in parallel without the diodes. Most states in the manual that only equal batteries must be used, so it reverse chanrging shouldn't be an issue. You can use a mosfet in series with the battery pack to avoid the voltage drop over the diode. 

I'd go for AA instead of C, much easier to get hold of.

best regards,

Ketil Aas-Johansen