Solis FlexCore ID 20kWh Stackable HV Battery

The FlexCore-ID-BAT20kWh is the building block of SolisStorage's indoor stackable battery for commercial and industrial sites: a 20.09 kWh lithium iron phosphate pack of twenty 314 Ah cells in series, rated at 64 V. Packs stack in columns and are wired in series, so each one added lifts the cluster voltage by 64 V.

A cluster holds 3 to 13 packs under one high-voltage control box, giving 60 to 261 kWh, and up to six clusters can work in parallel. Every pack carries its own aerosol fire suppression; the IP20 system belongs in a dry plant room.

The 20 kWh pack in figures

Building a cluster from 3 to 13 packs

Nominal cluster voltage rises from 192 V with three packs to 832 V with thirteen, and the operating window moves with it, from 168–216 V up to 728–936 V. Solis recommends charging and discharging at 157 A, a 0.5P rate, which rates a three-pack cluster at about 30 kW DC and a thirteen-pack cluster at about 130 kW.

The control box forms the top layer of one column. Three or four packs make a single column, five to nine are split across two, and ten to thirteen spread over three. Bases sit 100 mm apart, the minimum Solis gives for heat to escape between rows.

Parallel clusters and the inverter

Where one cluster is not enough, the datasheet allows six in parallel, taking a site past 1.5 MWh. Each cluster keeps its own control box, chained box to box on the DC side.

The FlexCore datasheet sets the battery beside Solis S6-EH3P three-phase hybrids from 30 kW to 125 kW at 230/400 V. Their battery windows differ, 150–800 V on the 30–60 kW models and 300–950 V on the 80–125 kW ones, so confirm the pack count for the chosen inverter with Solis before ordering.

Fire protection and the room it needs

Fire suppression is built into each pack as an aerosol unit. The manual still treats the room as part of the safety design: indoors only, in a fireproof room free of ignition sources, with its own fire alarm and extinguishing equipment. The floor has to be dry, level and able to carry the full weight of the stack.

A single cluster wants 500 mm clear above it, 600 mm at the front and right-hand side, and 100 mm behind. Ambient limits are −20 to 55 °C discharging and 0 to 55 °C charging, and with fan noise rated below 75 dB, a plant room suits it better than an office.

Handling a 154 kg pack

At 154 kg, a pack is a job for lifting equipment rather than hands. Solis has the installer hook all four corners and stack the packs layer by layer, four bolts each. The manual names no particular lifting tool, leaving it to be sourced for the site; its tool list includes a hydraulic lifting cart, and it calls for at least four installers.

Once packs are installed, the rack is not to be moved or lifted. Solis also asks for commissioning no later than six months after the system arrives, and for stored packs to be recharged every three to six months.

In the box

Order alongside

• Solis FlexCore-ID battery control box

  The 250 A high-voltage box that heads every cluster and talks to the inverter over CAN. One per cluster.

• Solis FlexCore-ID accessory kit for 3–4 batteries

  For a single column: one base, four feet, the main leads, the 120 Ω terminating plug and an RJ45 adapter.

• Solis FlexCore-ID accessory kit for 5–9 batteries

  For two columns: two bases, a top cover and the jumper leads between columns.

• Solis FlexCore-ID accessory kit for 10–13 batteries

  For three columns: three bases, two top covers, and upper and lower jumpers.