mank1234 Night time use
Your battery bank must be able to take care of this energy usage.
If you are going to use lead acid battery, you have to also consider the dept of discharge (DOD) that is acceptable to you since discharging too deep your battery will reduce its lifespan. Assuming 50% DOD, your battery should have capacity of 2 times your night time energy use.
Again, if you are in Southern Nigeria, you must must necessarily oversize your battery bank to take care of 3 days without sunshine. That means your battery bank should be 3 times your night time daily energy usage.
If you don’t want to do the above, you must have standby generator or a connection to the national grid.