You would have to add a generator for the rainy days. This can be a lost cost DC alternator belt driven by a single cylinder diesel pump engine. A Volvo single cylinder diesel pump engine only costs 14,000 PHP. Then you would purchase an automotive DC alternator and a bracket. This would charge up the batteries during rainy days.

 

I too am interested in battery technology, but only for brownouts and these batteries would be charged from the grid and only be used during brownouts... my concern is the battery itself, hearing complaints that batteries do not last in this hot and humid weather as they are very expensive and also not knowing how many KWH it would take to run the essentials in a brownout... I see there are Gel based batteries that I hear are superior both in capacity and longevity but not sure what the cost...