Last updated: · by Md. Arshadul Alam
Step 1: Add up what you actually want to run
A ceiling fan draws roughly 75–100W, an LED bulb 9–15W, a 32-inch LED TV about 60W, and a Wi-Fi router 10W. Four fans, six lights and a TV comes to roughly 500W — not the 1200VA unit you were about to buy.
Step 2: Convert watts to VA
Divide your total watts by 0.8 to get VA. 500W becomes 625VA, so an 800VA IPS gives comfortable headroom. Oversizing wastes money and undersizing kills the battery.
Step 3: Size the battery for the backup you want
Backup hours ≈ (battery Ah × 12 × 0.8) ÷ your load in watts. A 100Ah battery on a 500W load gives roughly 2 hours. Want 4 hours? You need either 200Ah or a smaller load.
Step 4: Choose the battery type honestly
Tall tubular batteries last longest and cost most. Flat-plate batteries are cheaper but need more water top-ups in Dhaka's heat. Pick based on how often you will actually maintain it.
Mistake 1: Running an IPS on a badly set charging current
A charging current set too high boils the electrolyte away; too low and the battery never fully charges. Both shorten battery life dramatically. Have it checked at installation.
Mistake 2: Ignoring ventilation
Batteries in a closed cupboard run hot, and heat is the main killer of battery life in Dhaka. Give the battery airflow and keep it off bare concrete.
Prices are indicative for Dhaka in 2026 and change with parts availability and brand. Call us for a current quote on your exact model.