Complete Indoor LED Wall Procurement Guide: Size Calculation, Module Layout, Power & Receiver Card Configuration
Before you sign the PO, the numbers have to work — module counts that divide evenly, receiver cards with headroom, and power supplies that won't overheat. Here's the field-tested math, with a P1.86 example you can copy.
The order that looked fine until the crew hit site
The quote was tight, and the schedule was tighter. Then the install crew opened the crates and found the screen width didn't divide evenly into the module size. Someone grabbed a grinder. Three days later, half a module is cut, two receiver cards are running at 100% load, and a power supply is too hot to touch.
Now you're paying site labor by the hour to redo what the drawing should have caught in ten minutes. Every one of those problems was avoidable — with the same three calculations a good engineer runs before the PO is signed.
In this guide
1. The four calculations every integrator runs
Indoor LED wall engineering boils down to four numbers: size → module count → receiving cards → power supplies. Get these right and the rest is assembly. Get them wrong and the margin you quoted disappears on the install floor.
2. Three mistakes that eat project margin
These three errors show up in nearly every over-budget or failing indoor project — here's what they actually cost.
Forced module cutting
- Screen dimensions that don't divide evenly into the 320×160mm module are the #1 site problem.
- Forcing a cut gives broken pixels, a non-standard edge, and a wall that's harder to service — because that module no longer exists as a spare.
- Fix: design to whole modules, or adjust the frame to fit.
Receiver card at 100% load
- Running a receiving card at its maximum 512×512 load leaves zero headroom.
- Result: frame drops, instability, and no room for future expansion or a shifted layout.
- Fix: cap load around 80%, and keep the row/column grouping sane.
Power supply overloaded
- Pushing a 200W supply to 90–100% causes heat, voltage sag, and early failure.
- Result: flicker under bright content, and supplies that die in year two.
- Fix: stay under 80% — the standard is 6 P1.86 modules per 5V/40A supply.
3. Worked example: P1.86, 320×160 module
Let's run the numbers on a real screen. Module: P1.86, 320×160mm, 172×86 pixels, ~20W average power. Target wall: 3.84m × 2.08m.
| Step | Formula | Result |
|---|---|---|
| Width modules | 3840 ÷ 320 | 12 |
| Height modules | 2080 ÷ 160 | 13 |
| Total modules | 12 × 13 | 156 pcs |
| Resolution | (12×172) × (13×86) | 2064 × 1118 = 2.31M px |
| Receiver cards — full load | 2,307,552 ÷ 262,144 | 9 (risky) |
| Receiver cards — ≤80% load | 2,307,552 ÷ 209,715 | 11 (recommended) |
| Power supplies | 156 ÷ 6 | 26 + 2 spare = 28 |
Reference: MRV416-N receiving card = 512×512 (262,144 px) max load; one 5V/40A (200W) supply drives 6 modules.
See what the margin buys you: 9 cards versus 11. Two extra cards cost a few hundred dollars and give you stability, future headroom, and a wall that won't drop frames during the launch event. That's not cost — that's insurance.
4. COB / GOB / SMD: the engineering differences
The process you choose changes the configuration, not just the price. Here's what to check for each.
| Dimension | SMD | GOB | COB |
|---|---|---|---|
| Module spec | Standard 320×160 | Same as SMD | Size / resolution may differ — confirm with factory |
| Field repair | Single-lamp rework | Harder (glue removal) | Module-level swap only |
| Spare strategy | Lamps + modules | Modules | Whole modules |
| Power per m² | Higher | Similar | Usually lower — more efficient |
| Robustness | Low | Medium | High (sealed) |
For a COB LED display, the configuration math is the same — but two things change. First, confirm the exact module size and resolution with the factory; COB modules don't always follow the 320×160 convention. Second, plan spares as whole modules, because COB isn't field-repairable per pixel. A low-failure-rate COB wall needs fewer spares — but each spare is a full module, so get the aging-test data before you size the inventory.
5. What to ask the factory before you order
Before you sign, get these four deliverables in writing. A supplier who provides them is an engineering partner; one who doesn't is just selling you a box.
- Module layout diagram — the exact module grid, cabinet grouping, and where every module sits.
- System topology diagram — controller → receiving cards → cabinets, with port assignments.
- Power & signal wiring diagram — power supply count, wiring routes, and cable specs.
- Spare parts list — modules, power supplies, receiving cards and cables, with quantities and prices.
FAQ: Indoor LED wall configuration
How do I calculate the number of LED modules for a screen?
Divide the screen width and height (in mm) by the module size (e.g. 320×160mm) and round to whole numbers. 3.84m × 2.08m ÷ 320×160 = 12 × 13 = 156 modules. Never cut a module — adjust the frame instead.
How many modules per power supply?
The industry standard for P1.86 is six 320×160 modules per 5V/40A (200W) supply, keeping load around 75% or below. Confirm the exact number against your module's power spec.
What is a safe receiving card load?
Cap it around 80% of the card's maximum (e.g. MRV416-N's 512×512 = 262,144 px). At full load you get frame drops and no headroom — the margin costs almost nothing.
Does a COB LED display configure differently?
The math is identical, but confirm the exact COB module size/resolution with the factory (it may not be 320×160), and plan spares as whole modules since COB isn't field-repairable per pixel.
Get the numbers before you sign the PO.
Send us your wall dimensions and we'll return a module layout, receiving card and power supply calculation — with the safety margin built in.
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