At least 7 REI stalls showed a 125 kW, 261 kWh battery. Ask which job it does

What it means for youBattery storage for factories: four lines to check on every quote

If you are comparing battery quotes for a factory: check four lines on every quote. One, which job the system is for, from the three in the table above, ticked in writing. Two, how it connects to the solar you already have, and whether your present solar inverter can work with it. Three, how much power its own cooling and controls use, while running and while idle; that power comes out of what the battery saves you. Four, cycles (how many full charges and discharges it is rated for), round-trip efficiency and warranty, in writing. Round-trip efficiency is how many units come back out for every 100 you put in. Ask whether the figure is measured at the battery (DC) or on the AC side, where the system connects to your site (AC), which also counts the losses in the inverter.

Here is what lines three and four can look like in a catalogue. The UnityESS Aqua 4 we sell is this same 125 kW / 261 kWh size, built from 260 cells of 314 Ah, all in one chain. Its catalogue lists 2.63 kW for its own systems while operating and 0.05 kW while idle, a life of 8,000 cycles, and a round-trip efficiency above 94 per cent measured on the DC side, at the battery. Solentra sells battery storage for business and industry, Powered by UnityESS, and our BESS calculator asks about your site, your solar and your tariff before it works out a payback.

If your site is in Punjab: check your tariff category and the months before you buy a battery to cut peak-hour charges. The evening surcharge covers factories above 50 kVA and large commercial connections, and only from 16 June to 15 October, so there is none now. This year's tariff order runs to 31 March 2027, and the next one could keep or change the calendar; our time of day tariff story has the details. In Jammu and Kashmir, check whether your bill already shows time of day rates, because that depends on the meter.

If you want a battery for power cuts: say so in your enquiry, and ask for the transfer switch and the backup mode by name in the quote, with the time the switch-over takes. Ask which loads it will carry and for how long, and ask for the usable kWh, which can be lower than the rated figure. A 261 kWh cabinet at its full 125 kW lasts about 2 hours before losses; at a lower load it lasts longer.

If you are an installer or an EPC firm: an EPC firm designs and builds the plant for its client. Put the job on the first page of every storage quote, and if the customer wants backup, show the transfer switch and the backup mode as their own lines. Ask the maker for the own-use figures, the cycle life, the round-trip efficiency with DC or AC marked, and the warranty terms in writing, before you compare offers. When the boxes match, those lines and your service may be what a customer compares.

If you are a homeowner: these cabinets are built for business and industry and are far bigger than a home needs, but the first question is the same. Ask which job a home battery is for. A plain on-grid rooftop system switches off in a power cut, so backup needs a hybrid inverter, which can run the house from a battery, or an all-in-one unit with a battery built in. You can follow the scheme's Punjab numbers every day on our tracker.