Inverter Battery Warranty Explained: Full Replacement vs Pro-Rata
What 36+24 months really means, what pro-rata actually pays you, and what quietly voids the warranty.
Quick answer
An inverter battery warranty has two parts, printed on the label — for example 36 + 24 months. The first number is full free replacement; the second is pro-rata, where you pay a share of a new battery that grows as the old one ages. It runs from your date of purchase, so keep the stamped warranty card and invoice, and don't let low water or wrong charging void it.
How the warranty is structured
Almost every tubular inverter battery in India is sold with a two-part warranty, and the total is printed on the label — you'll see it written as something like 36 + 24 or 48 + 24 months. The first figure is the free-replacement period; the second is the pro-rata period. The exact split varies by brand, model and price band, so the only number that matters is the one on your battery.
Read it like this
- Warranty = free-replacement months + pro-rata months (e.g. 36 + 24). Read the figure on your label.
- Free-replacement: a genuine manufacturing defect gets a brand-new battery at no cost.
- Pro-rata: you pay a share of the current price toward a replacement, rising as the battery ages.
- The clock starts on your date of purchase — keep the invoice and the stamped warranty card.
- Low electrolyte, wrong or faulty charging, physical damage and non-authorised service commonly void it.
Free replacement vs pro-rata — the part people miss
During the free-replacement months, a genuinely defective battery is swapped for a new one at no charge — this is the cover most people think they have for the whole period. They don't. Once you cross into the pro-rata months, the brand only contributes a portion of the cost of a new battery, and that contribution shrinks the longer you've owned it. A failure near the end of pro-rata may get you very little.
How a pro-rata claim is worked out
The principle is straightforward even though each brand words it differently: the older the battery at the time of failure, the less you're compensated, and the more you pay toward the replacement. The calculation is tied to how much of the pro-rata period is left and the brand's applicable price at the time — so two batteries that fail at different ages get very different settlements. Your warranty card states the exact basis; read it before you assume a free swap.
| When it fails | Which period | What you get |
|---|---|---|
| Within the free-replacement months | Free replacement | A new battery at no cost, for a genuine defect |
| During the pro-rata months | Pro-rata | A discount on a new battery, smaller the older it is |
| After the warranty ends | None | Full price — but ask about exchange value for the old one |
What you actually get, by when it fails (illustrative — your card states the exact terms)
What quietly voids the warranty
- Letting the electrolyte (water) drop below the plates on a flooded tubular battery.
- Charging from a faulty or wrong-rated charger, or chronic deep discharge.
- Physical damage, opening the case, or tampering with the terminals.
- Removing, defacing or losing the serial number / label that identifies the battery.
- Service or repair by a non-authorised person, or installing a flooded battery in a sealed cabinet.
- No proof of purchase — a missing invoice or unstamped warranty card can sink an otherwise valid claim.
How to claim without friction
Keep the invoice and the stamped warranty card together from day one, and register the battery online if the brand asks you to. When something goes wrong, go back through the authorised dealer who sold it: they test the battery, confirm whether it's a genuine defect, and process the claim with the manufacturer. Going direct without paperwork is where most claims stall.
Where to next
Frequently Asked Questions
What does pro-rata warranty mean on an inverter battery?
It means partial cover. After the free-replacement period, if the battery fails you pay a share of a new one, and that share grows as the battery ages. The exact amount depends on how much of the pro-rata period is left and the brand's applicable price.
Does the warranty start from manufacture or from purchase?
From your date of purchase, as shown on the invoice — which is why you must keep the invoice and the stamped warranty card. Without proof of the purchase date, a claim can be refused.
What can void my inverter battery warranty?
Common voiders are letting the water level drop below the plates, charging from a faulty charger, physical damage or tampering, defacing the serial number, and service by a non-authorised person. Good maintenance and authorised service keep the cover intact.
Need help choosing?
Share your requirement and our team will recommend the right product and size for your home or business. Genuine stock, home installation, old-battery exchange, and on-site service & AMC across Delhi NCR — in business since 1998.