In the BQ25504 datasheet it is suggesting that a load is typically connected to VSTOR.
In my situation I would prefer an always on, reliable 3.3V supply. This would drive an MCU/SoC. I would need the 3.3V on all the time and then rely on the MCU low power modes to bring energy consumption down to avoid wasting energy. Of course I'm prepared to put a 3.3V regulator in there to get the target voltage.
With a load connected to VSTOR it seems that you would lose this supply if your energy harvesting disappeared - that is not great. Solar energy harvesting is typically cyclical with long periods when you can harvest, and long periods when you can't harvest anything worthwhile.
Why not connect the load to VBAT and in that way the supply would always be there - provided you didn't completely drain the battery of course. I know that in this arrangement the battery protection features offered by the bq25504 (OV, UV, short ?) would be lost. However, a lot of LiIon and LiPo cells have built in protection to cover this anyway.
So my question is why don't you use VBAT as the load source rather than VSTOR ?
