Inventory and Purchase Order Management for Solar EPCs

Where Solar Stock Actually Goes

Solar inventory is unforgiving: panels arrive in batches, structures arrive in pieces, and cables and earthing material are consumed on site where nobody logs anything. Over a quarter, the gap between what was bought and what was used quietly becomes the difference between profit and break-even.

Structure Your Stock First

Group items the way the business thinks about them:

• Major components: panels, inverters, batteries
• Structures: mounting frames, GI structures, clamps
• Balance of system: ACDB/DCDB, connectors, fasteners
• Consumables: cables, wires, earthing material, lightning arrestors

Each item needs a unit of measure — pieces, metres, kilograms — because mixing units is how a "50" in a spreadsheet becomes meaningless.

Log Every Movement

Stock changes only two ways: in (purchases, returns) and out (project consumption, damage, transfer). Every change should leave a stock movement record — what, how much, when, against which project or order. Unlogged movements are invisible losses.

The Purchase Order Discipline

A purchase order should capture:

1. Vendor and agreed rates
2. Line items with quantities and units
3. GST treatment per line — panels at the concessional rate for solar PV goods, structures and services at their applicable rate
4. Expected delivery date against a project schedule

Close the Loop: PO to Invoice

When the delivery arrives and is verified, the completed purchase order should convert into a vendor invoice with the same line items and rates. If conversion is manual re-entry, quantities and prices will drift — and reconciling them later is far more expensive than preventing the drift.

This receive-then-invoice flow, with stock movements recorded at each step, is built into Doctor Solar Wala's ERP module; the wider system it feeds is described on the features page.