Even in equatorial Africa 48h is not enough. Neither for actual usage, nor for battery life (and no one ever got marketing-leaflet-aka-datasheet-stated lifetime out of them batteries). Two years max, and hope either the project dies, or the company dies, or someone steals the batteries.
Source: been there maintaning solar offgrid.
And then --- geodiversity can only make it worse, never better.
But you are right. I would downvote if I was wrong and laughed at.
we added a wind turbine as well which was great since some of the rainy stormy days had lots of wind. I don't understand my original posts parent's comment about (geo) diversity not helping.
To make it work, it's cheaper to throw away about 2/3rds of your energy than to build 150 hours worth of storage. Some amount of "curtailment" is going to be optimal, and in my case, because solar is so cheap and my starting assumptions allowed no other energy sources, a LOT of curtailment is used. Literally most of the energy is unused.
If you ignore massive curtailment as a possibility, then yeah, haha, it's not going to work.