6 Questions You Must Ask Before Buying an Inverter Battery in India

2026 Update: This buyer checklist was first published in 2022–23. Three years later, not one of these gaps has been addressed by industry or regulators. The questions remain just as necessary — and just as unanswered at the point of sale.

I have spent 30 years inside India's power backup industry — as a manufacturer, as an entrepreneur, and now as someone who has no reason to protect any brand. What I am going to tell you is what every dealer knows and no manufacturer will publish.

Before you buy any inverter battery in India, ask your dealer these six questions. If they cannot answer them, walk away.

1. Is the Ah Rating Printed on the Battery — or Only a Model Number?

Ampere-hours (Ah) is the only number that tells you how much energy the battery stores. A 150Ah battery stores more than a 100Ah battery. Simple.

But today, many local and regional manufacturers in India have stopped printing the Ah rating on the battery itself. Instead, they print only a model code — "HT-200", "XB-150", "PX-220" — something that means nothing to you as a buyer. You cannot compare it. You cannot verify it. That is the point.

Before buying: Look at the battery physically. The Ah rating must be printed clearly on the label. If you see only a model number, ask why. If there is no satisfactory answer, do not buy.

2. What Is the Maximum Charging Current This Battery Can Accept?

This is the most dangerous missing piece of information in India's battery industry today.

Every battery has a limit — the maximum current at which it can be safely charged. Exceed that limit, and the battery overheats. Hydrogen gas builds up inside. The battery bulges. In worst cases, it explodes.

Solar PCUs and inverters available in India today can charge at 20A, 30A, even 40A. Many tubular batteries are only designed for 10–15A charging. Nobody checks whether the two are compatible. This information is not printed on the battery. It is not required by any standard. And it is the reason battery fires are increasing across India, especially in solar installations.

Before buying: Ask your dealer the maximum charging current this battery can safely accept. Then check what your inverter or solar PCU will deliver. They must match. If your dealer does not know the answer, that is your answer.

3. What Kind of Water Must Be Used — and How Often?

Every lead-acid tubular battery needs water refilling. This is not optional. It is the single biggest maintenance activity that determines how long your battery lasts.

The water must be distilled water — nothing else. Not RO water. Not filtered water. Not water from your refrigerator's ice tray. Not tap water. Only distilled water, available at chemists and battery shops, with a TDS (Total Dissolved Solids) level near zero.

RO water seems pure but still contains trace minerals. Those minerals react with the battery's electrolyte over months, coat the plates, and cause permanent damage that looks exactly like age-related wear. Your battery dies in three years instead of five. You never know why.

Water levels should typically be checked every 45–60 days, more frequently in summer.

Before buying: Ask your dealer whose responsibility water refilling is under the warranty. Ask whether the service network will check water during visits. Get it in writing if possible.

4. What Exactly Does the Warranty Cover — and What Voids It?

The warranty period printed on a battery — 36 months, 48 months, 60 months — is not a guarantee. It is a legal document with conditions.

Common reasons Indian battery manufacturers void warranties include water not maintained at correct levels, battery installed in a non-ventilated space, charging current exceeded (even if the buyer had no way to know the limit), physical damage to casing or terminals, and installation by a non-authorised dealer.

In practice, most warranty claims in India are rejected or partially settled at a "pro-rata" rate — meaning you get only a fraction of the battery's value back based on how many months have passed. This is standard industry practice, not a scam. But most buyers do not know this until they make a claim.

Before buying: Ask specifically what voids the warranty. Read the warranty card before paying. Understand that a 60-month warranty does not mean 60 months of full replacement.

5. What Is the Cycle Life — at What Depth of Discharge?

Battery manufacturers often claim "500 cycles" or "1200 cycles" of life. This number is meaningless without one critical detail: at what depth of discharge (DoD)?

A cycle means one full charge and one full discharge. But "full discharge" can mean different things. Discharging to 20% remaining (80% DoD) gives fewer total cycles. Discharging only to 50% remaining (50% DoD) gives significantly more cycles. A battery rated for "500 cycles at 80% DoD" may last twice as long if you only discharge it to 50% each time. No manufacturer explains this on the label. No dealer will tell you unless you ask.

Before buying: Ask for cycle life and insist on knowing at what depth of discharge that figure applies.

6. How Will You Know If the Battery Is Degrading?

A new 150Ah battery powering a 300W load gives you roughly 4–5 hours of backup. After two years of use, the same battery might give you 3 hours. After four years, perhaps 2 hours. This is normal degradation — but how do you know if your battery is aging normally or dying prematurely?

No manufacturer gives you a degradation benchmark. No dealer will test this during a service visit unless you insist. The only practical way is to note your backup time when the battery is new — time it yourself with a specific fixed load — and compare it annually.

Before buying: Note your backup time on day one. This is your baseline. Anything dropping more than 20% per year is abnormal and worth investigating.

The Bottom Line

India's battery industry sells on trust — the trust that the Ah rating on the label is accurate, that the warranty will be honoured, that the battery will last. That trust is not always justified.

The questions above are not technical. Any dealer can answer them. The ones who cannot — or will not — are telling you something important.

Buy from someone who answers all six.

Kunwer Sachdev — known as the Inverter Man of India and Solar Man of India — has 30+ years of experience in India's power backup and solar industry. He founded Su-Kam Power Systems, one of India's first inverter companies, and built it into a national brand. He is no longer associated with Su-Kam Power Systems in any capacity and bears no responsibility for Su-Kam warranty claims, product support, after-sales service, or any business dealings. He writes on inverterindia.com independently, with zero affiliate relationships, zero brand sponsorships, and zero commercial bias.