LiPo battery support in A13 SOM?

[siriusf]

Could you power the A13 SOM with a LiPo battery? the A13 SOM has a built-in charger for LiPo batteries? could you make that the A13 SOM automatically switches from the LiPo battery to DC power when is available?

[dave-at-axon]

Looking at the schematic for the SOM there is no battery charging circuit built into the module and supply to the board is 3.3V.

To use a LiPo battery you will need an external circuit to generate the 3.3V from the 3.7 battery. To allow the battery to go to a lower voltage and still provide 3.3V output, you need to use a buck/boost regulator. This will increase the voltage when the input is lower than the output and automatically decrease the voltage when the input is higher than the output. So far all of the Olimex boards I have used are using buck regulators only which means they can't be used with battery voltages close to the output voltage.

What out for LiPo chargers on the internet as most are standalone and means they can't power your board at the same time. What you need is a "Power Path" based design that can power the load and charge the battery at the same time. They also control the battery charging preventing over charge and avoid the types with trickle charge. I've used the LiPo Rider Pro from Seeed Studio and it kills the battery after about 6 months use on standby. The charger used with the Olimex designs doesn't seem to suffer from this.