Search for a lithium battery manufacturer in India and the first page is mostly lists: top ten this, leading five that. Almost none of them say how the ranking was decided, and a good number of the places on them were bought. That is not a reason to distrust every list, but it is a reason not to buy from one.
The useful alternative is a short set of checks you can run yourself, on any supplier, from documents they already have. Nine of them are below. They are the same questions our own engineers get asked by telecom operators and fleet buyers, and any manufacturer worth the order can answer all nine in a morning.
Three very different businesses describe themselves the same way. A manufacturer buys cells, designs the pack around them, assembles and tests it. An assembler buys modules and screws them into an enclosure. A trader imports a finished battery and puts a sticker on it. All three will say "manufacturer" on a website.
The question that separates them: where is the plant, and can I visit it? A manufacturer will name the address and let you walk the line. CLN Energy builds at Plot 18, Sector 140, Noida — the plant is also the registered office, and visits are by appointment because it is a working production line. The plant page sets out what is built there.
For stationary backup, telecom, solar storage and most Indian vehicle duty, lithium iron phosphate (LiFePO4) is the sensible default: it tolerates heat better than the nickel-based chemistries and has a higher thermal runaway threshold. The trade is size — an LFP pack is physically larger for the same energy, which matters in a phone and not in a 19-inch rack.
A supplier who cannot tell you the chemistry, the cell format and where the cells come from is selling you somebody else's decision.
The battery management system is what stops a pack being quietly destroyed. Ask what it protects against — over and under voltage, over current, short circuit, temperature — whether it balances cells, and what it reports. On a telecom site or in a data centre, a pack that reports state of charge and health over RS485 or CAN to the site controller is worth considerably more than one that does not, because nobody is standing next to it.
"6,000 cycles" means nothing on its own. Cycle life is measured at a stated depth of discharge, temperature and charge rate, and the same pack cycled shallower lasts longer. A specification that reads 6,000 cycles at 95% DOD, 25°C, 0.5C/0.5C can be checked; one that reads "up to 6,000 cycles" cannot.
Expect the number to differ across a range, too. Ours does: 3,000 cycles on the table-top residential packs and the 100Ah high-voltage racks, 6,000 on the wall, ground-mount, stackable and 314Ah rack ranges. A supplier quoting one figure for everything they sell has not read their own datasheets.
Four come up in almost every serious enquiry: UN 38.3 for transport, IEC 62619 for industrial cell and battery safety, IEC 61000 for electromagnetic compatibility, and UL 1973 for stationary safety, with UL 9540A where thermal runaway testing is required. Electric vehicle packs in India have their own regime under AIS 156, and telecom has T-SEC.
Ask which apply to the pack you are buying, not to the company in general, and ask for the report. What each standard actually covers is worth ten minutes before the conversation.
Warranty terms vary by duty, and a supplier who quotes one term across a catalogue is either simplifying or guessing. Ours run from 36 months on e-mobility packs to 60 on material handling, telecom and most stationary products, 84 on the liquid-cooled 100 kW/215 kWh unit and 120 on the 1 MWh BESS, because those duty cycles are not comparable. Get the term for your pack in writing, with what voids it.
A five-year warranty is worth what the company behind it is worth, and how fast someone can reach the site. Ask where the nearest service engineer is, what the response time is, and whether service is handled by the manufacturer or passed to a dealer. An imported pack with a warranty administered abroad is a different proposition from one built a few hours' drive away.
This is the check that cannot be faked cheaply. Ask for installations with the customer, the configuration and the year. Ours include 22,864 packs across BSNL's telecom network in 400Ah and 800Ah modules, 180 kWh of backup behind a 100 kW UPS at RailTel's Pondicherry command control centre — changed over inside a two-hour window without the centre coming off supply — and signalling backup for Southern Railway at Chennai. Each is on its own project page with the real numbers.
Many requirements are not a catalogue item: a different voltage, an enclosure that fits an existing tray, a protocol your controller speaks. A manufacturer can answer that; a trader cannot. If your requirement is bespoke, what a custom pack involves is set out separately.
If you only have one phone call: ask for the plant address, the cell chemistry, the cycle life with its depth of discharge, the test reports for the standards that apply to your application, the warranty term for your pack, and two deployments you can verify. The answers, or the hesitation, will tell you most of what you need.
Ask for the plant address and a visit, the cell chemistry and format, the cycle life with the depth of discharge it was measured at, and the test reports for the standards that apply to your application — typically UN 38.3, IEC 62619, IEC 61000 and UL 1973. Then ask for two deployments with the customer, configuration and year, and call one. A manufacturer can produce all of that; a re-badger will offer brochures instead.
For Indian stationary, telecom, solar and most vehicle duty, yes, on the grounds that matter there: it tolerates heat better and has a higher thermal runaway threshold than the nickel-based chemistries. The trade-off is physical size for the same energy, which is a fair exchange in a rack or under a vehicle floor and a poor one where space is the constraint.
Between roughly 3,000 and 6,000 cycles depending on the product, and the figure is only meaningful with its test conditions attached — depth of discharge, temperature and charge rate. Treat any specification that omits them as marketing rather than engineering, and ask for the datasheet of the exact model you are buying.
It depends on the pack and the volume, so compare on total cost rather than on the invoice: warranty length and who honours it, how quickly an engineer reaches the site, and how many times you replace the battery over the same years. Those are the numbers that decide what the battery actually costs you.
Become a
Partner
Comments: