Automotive parts factory · 480 kW BESS

The site and the problem

A tier-2 automotive supplier near Pune runs a 480 kW facility with two-shift operations. The site manufactures precision-forged components for OEM drivetrains, with peak loads hitting 480 kW during machine finishing. The DISCOM tariff structure penalised demand overshoot: 22% of the monthly electricity bill came from demand charges alone, even though actual energy use was moderate.

Before the BESS installation, the factory relied on a 60 kVA diesel backup set for peak-hour relief. The DG ran 3-4 hours daily to shave the afternoon peak before evening grid sags. This meant ongoing fuel costs, CPCB compliance overhead (emission testing every 6 months), and noise complaints from neighbouring residential clusters.

Sizing the system

We modelled twelve weeks of 15-minute load data and found the peak duration problem: the afternoon shift peak lasted 6 to 8 hours, with a mean load of 420 kW and bursts to 480 kW. A 480 kW / 960 kWh BESS (IZ-480K-3P) was sized to clip the top 60 kW for 4 hours each day and absorb midday solar generation. Pairing this with a 320 kWp rooftop array meant solar energy produced during machine downtime could be stored and re-used during the evening shift, when grid demand charges peak across the DISCOM.

The engineering trade-off was straightforward: pay ₹48 lakh upfront for the BESS+solar stack, or continue ₹8-10 lakh annual diesel + compliance costs. At 3.6-year payback, the numbers justified three-phase LFP chemistry with active BMS firmware tuning for the hot ambient (42 to 48°C in summer).

Engineering details

The IZ-480K-3P is a three-phase wall-mounted cabinet housing LiFePO4 cells in 48 V strings, managed by an in-house BMS firmware that monitors cell voltage, current, and temperature in real time. The cabinet includes a 480 kVA PCS (power conversion system) converting DC energy to 415 V, 50 Hz three-phase AC. Grid-to-island transfer happens in under 14 ms, allowing seamless islanding during a grid sag without triggering diesel startup.

The system was integrated into the factory's existing 320 kWp solar inverter via modular AC coupling. The cloud EMS (portal.infozeb.energy) aggregates load forecasts, PV generation, and battery state-of-charge every 5 minutes and optimises charge/discharge cycles via OCPP-compliant protocols. Thermal management was critical: the site reaches 48°C ambient during May-June, so the cabinet includes active cooling (6 kW refrigerated compressor loop) to hold cell temperature at 35-38°C.

Key technical features of this deployment:

• LFP chemistry, 6,000-cycle design life (16 years at daily use)
• Round-trip efficiency 95%+ on the cell, 91% system-level accounting for inverter losses
• Active cooling system maintains 35-38°C cell temperature in 48°C ambient
• Modbus and OCPP integration into existing SCADA architecture
• 14 ms grid-to-island transfer (vs 5-10 second DG changeover)

What changed after commissioning

Within the first 90 days, peak-hour demand dropped 38%, cutting the monthly demand charge by ₹22,000. The solar self-use ratio reached 94%, meaning almost all midday PV generation was either consumed directly or stored in the battery, avoiding net-metering export haircuts. Annual diesel spend fell from ₹9.6 lakh to ₹1.2 lakh. CPCB compliance overhead vanished: no more emissions testing, no fuel pilferage audits, no annual engine overhaul at year-5.

The factory floor team reported a secondary benefit: the 480 kW peak is now silent. Before, the 60 kVA DG set ran at 85 dB during afternoon peaks, creating workplace noise stress and neighbouring complaints. The battery system operates at under 45 dB (cooling fans and inverter hum only), invisible to shop-floor operations.

Lessons we carried into the next deployment

This was our second large industrial peak-shaving project, and we learned three critical lessons that shaped subsequent builds.

• Load profiling is non-negotiable. We had initially sized for a 400 kW system based on nameplate capacity. Actual 15-minute interval data revealed peak duration was 6 hours, not 2 hours. This changed the kWh sizing by 40%.
• Thermal management scales faster than power. At 480 kW discharge, the cells generate 15-20 kW of internal heat. Ambient temp swings from 28°C to 48°C meant cooling cost exceeded 4% of total OPEX. Cold-climate sites (Himachal, Ladakh) don't face this; coastal sites (Goa, Karnataka) do.
• DISCOM tariff structure drives ROI, not kW. The site's 22% demand-charge penalty made BESS ROI dramatic. If demand charges are only 8%, payback stretches to 6-7 years. We now run tariff impact modelling upfront.