Solar · storage
The cheap battery is the dear one
A lead-acid bank costs roughly half as much as lithium on the day you buy it, then wants replacing around year four and again around year eight. Over ten years lithium is the cheaper battery, with nearly double the usable capacity throughout. Either way, storage adds PKR 250,000 to 600,000 to a solar quote — decide it before the inverter is chosen, not after.
Last reviewed
| Lead-acidThe cheaper receipt | LithiumThe cheaper decade | |
|---|---|---|
| Price today | The lower bill | Two to three times more |
| Capacity you can use | Roughly half the label | Nearly all of the label |
| Working life here | 3–5 years | 8–15 years |
| Looking after it | Water top-ups, terminal care, airflow | None to speak of |
| Where it lives | A ventilated corner of its own | A wall bracket |
| Deep discharge | Shortens its life every time | Designed for it |
| Recharge speed | Slow — often unfinished before the next outage | Fast |
| The ten-year bill | Highest, once replacements are counted | Lowest |
Ten-year model
One decade, two banks
Illustrative, for a bank sized to carry lights, fans, a fridge, the router and a CCTV recorder through an evening outage. Your figures will differ; the shape of the comparison will not.
Lead-acid
- Year 0Bank purchasedPKR 210,000
- Year 4Bank replacedPKR 210,000
- Year 8Bank replaced againPKR 210,000
- Year 10Third set already tiring—
Ten-year totalPKR 630,000
Plus top-ups, terminal care and a ventilated corner it will not share.
Lithium
- Year 0Bank purchasedPKR 480,000
- Year 4Still in service—
- Year 8Still in service—
- Year 10Inside its design life—
Ten-year totalPKR 480,000
No maintenance, and more usable storage in every one of those years.
Choosing what stays on
The bank is sized from this list — never the other way round. Putting the whole house on backup is what empties a bank in an hour and convinces people they were sold the wrong battery.
We walk the circuits with you at the survey, breaker by breaker, before a single figure is quoted. Offices usually put the CCTV recorder and network cabinet first; houses start with fans.
- LightsUsually on
- Ceiling fansUsually on
- RefrigeratorUsually on
- Router and CCTV recorderUsually on
- Phone and laptop chargingUsually on
- Water pump (1 hp)Usually off
- Air conditionersUsually off
- Electric geyser or ovenUsually off
Battery questions
Is lithium worth the premium in Islamabad?
Across ten years, for most households, yes. Lithium costs two to three times more at purchase, lasts two to three times longer, and gives nearly double the usable capacity from the same label rating. Lead-acid is the cheaper receipt and the dearer decade.
Can one tired battery in a bank be replaced on its own?
No. A series bank performs at the level of its weakest unit, so a fresh battery dropped among old ones is pulled down to their level and its life wasted. Banks retire together — which is the strongest argument for buying the right chemistry once.
How do you size a battery bank?
List what must survive an outage, multiply by the hours it must survive, then double the figure for lead-acid because the second half of its label is off-limits. Lights, fans, a fridge and the router make a modest bank. Add an AC and the arithmetic changes completely.
How much does storage add to a solar quote?
PKR 250,000 to 600,000 on top of the on-grid figure, covering the hybrid inverter and the bank. Chemistry and how much of the house you want riding through the outage decide where in that band you land.