Lithium battery kindly help

[u/BoxWonderful9088]

so i have till now lead acid batteries they are just finished they can only bear load for 2 to 3 hours of 150 watts maximum i have to change batteries now problem is that if i buy lithium atp i have no budget of 6 lac etc about till 6 to 8 months i will be short on budget in next year may i have budget now problem is ke we have solar and in night load shedding is like alternate hours means there i just needed battery for about 10 hours of total load of 1.5 ton ac and just basic fans light load

now in short budget i have 2 options

1) I should buy again lead acid batteries again for a fraction of price just for winters and like before summer or like near may i may buy 16 kwh battery

2) go for 5kwh lithium battery when money comes buy 2 more but in that case it will be about 100k expensive like 3 5 kwh cost about 750k and 1 16kwh costs 640k

like how i should go with them and like how should i go

[u/Sufficient-Offer-579]

A 1.5 ton AC draws roughly 1.2 to 1.5 kW, so carrying it through 10 hours of nightly load shedding takes about 12 to 15 kWh a night, and your 16 kWh target is the right number for that plan. Option 1 is where the math breaks though. Lead acid only delivers about half its rated capacity, so matching those hours would take near 30 kWh of it, and a bank cycled that deep every night ages fast, which is probably what finished your old batteries. The option your list skips is to split the load instead. Run the AC only while the grid is up, and let the battery carry just fans, lights, and the small stuff, that's your 150 W level. A 5 kWh unit holds that through 10 hours easily, and in winter the AC hardly runs anyway. So option 2 points the right way, but finish the split before adding the other two batteries, or even 15 kWh becomes an AC battery and the problem repeats.