By Steven Quan:
With over 10 years of experience at SignliteLED, Sales and Product Manager Steven successfully managed this custom LED module project.
In September 2025, we received a WhatsApp inquiry with a final line that would have discouraged most suppliers.The client was a specialized contractor in Serbia with his own factory and assembly lines. He manufactures linear lighting fixtures for local installation projects in Serbia. He manufactures the fixtures himself and sources only the LED modules from suppliers.
The main requirement was straightforward: the modules had to work with the drivers already used in his factory. He did not want to replace drivers or change the existing production setup in his factory.
I immediately understood the challenge behind the request.
He already had inventory in stock. Changing drivers meant changing cost calculations across his production line.
The Spec Sheet He Sent and the One Line That Changed Everything
This contractor was already manufacturing his own linear lighting fixtures in Serbia before he contacted us. He did not need product recommendations. He needed a supplier who could build modules around the drivers and dimensions already used in his production line.

The specifications themselves were manageable. The real problem was the driver condition: everything had to work with the existing drivers already sitting in his factory.
Why the Driver Condition Was the Real Problem and Why I Did Not Walk Away
A constant current driver outputs a fixed current. His existing driver ran at 350mA. The single row module draws 120mA. The triple row module draws 360mA. I had seen similar driver conflicts before, and most of them ended with the supplier recommending completely new hardware. The voltage specifications were easy to match. The real challenge was making both module configurations work with the same driver.
The easy answer was to tell him to buy a second driver. I did not give him an easy answer.
Before discussing solutions with engineering, I went back through the original specifications he had sent over WhatsApp.
This was the configuration we were trying to make work with the same existing driver:

| Параметр | Однорядный модуль | Triple Row Module |
| Размер печатной платы | 493 х 25 мм | 493 х 50 мм |
| Светодиодная кон | 20 серии, 1 параллель | 20 серии, 3 параллельные |
| Всего светодиодов | 20 | 60 |
| рабочее напряжение | 50-60В | 50-60В |
| Цветовая температура | Теплый белый | Теплый белый |
| расчетная мощность | Приблизительно 7Вт | Модуль 21 Вт, 23-24 Вт с драйвером |
| Материал печатной платы | Алюминий | Алюминий |
| Сертификация | CE ROHS | CE ROHS |
| ведущий | Existing stock — no new driver | Тот же существующий драйвер |
Before replying, I discussed the driver requirements directly with our engineering team. because I knew the project would move forward or collapse based on that one issue alone. The client was waiting for an answer before moving forward with production planning. At that point, the project could only move forward if the driver configuration worked correctly. I did not know yet which it was going to be.
The Solution That Kept His Existing Driver and His Budget Intact
Three single row modules connected in parallel each draw 120mA.
Combined, the three modules operate within the working range of his existing 350mA driver configuration.
That meant:
No new driver. No additional hardware. No extra cost in his production line.
The single row and triple row modules become interchangeable from the driver’s perspective, as long as the single row modules are wired in parallel groups of three.


How Parallel Connection Solved the Driver Problem:
| конфигурация | ток на единицу | связь | Total Current | Driver Change |
| 1x Single row | 120 мА | прямой | 120 мА | Yes — different driver needed |
| 1x Triple row | 360 мА | прямой | 360 мА | No — matches existing |
| 3x Single row parallel | 120 мА каждый | параллельный | Всего 360мА | No — matches existing |
After reviewing the current calculations and wiring configuration, his reply came back in two words:
“That’s ok.”
The client had carefully reviewed every technical detail throughout the discussion, that was effectively his approval to move forward.
He Did Not Ask for a Sample. That Tells You Everything.
Most buyers in this situation ask for a prototype first. That is the normal process when you are ordering custom LED modules from a factory you have never visited.
He never asked for one.
- No sample testing.
- No factory visit.
- No third-party inspection.
He placed the production order based entirely on our WhatsApp discussion, the engineering solution, and the PCB drawing we confirmed together.
That level of trust is built through technical communication and consistent follow-up before production begins.
From Payment Confirmed to PCB Drawing Before the Next Morning
After the specifications were finalized, the client confirmed the order and we immediately moved the PCB drawing into production review. I contacted engineering that same afternoon and flagged it as priority.

After one day of technical discussion, the PCB drawing was completed the following day and sent for confirmation. That speed mattered because his own production planning was already waiting on confirmation.
Hole positions, LED layout, and connector locations were all finalized in a single message exchange.
He reviewed the layout, confirmed the hole positions, and approved the drawing for production.


Final Specifications Locked for Production:
| Параметр | Один ряд | Тройной ряд |
| Размер печатной платы | 493 х 25 мм | 493 х 50 мм |
| Светодиодный счет | 20 | 60 |
| конфигурация | 20с 1п | 20 с 3р |
| рабочий ток | 120 мА на модуль | Всего 360мА |
| Driver Used | 350mA existing | 350mA existing |
| полная мощность | Приблизительно 7Вт | Примерно 23-24 Вт |
| подложка | Алюминий | Алюминий |
| Сертификация | CE ROHS | CE ROHS |
Why Aluminum and Not FR4
He asked about FR4 during the spec discussion. I recommended aluminum immediately because I have seen high-density FR4 modules fail early from heat buildup in commercial applications.
Aluminum PCB reduces LED junction temperature by 15 to 20 degrees Celsius compared to FR4, which directly extends module lifespan and improves long-term stability.
For a contractor installing these fixtures into commercial spaces under his own company name, reliability mattered far more than the small material cost difference.
Once the specifications and PCB drawing were confirmed, production could begin.
What Came Off the Production Line
This is what the first batch looked like before it shipped to Serbia.

He never visited the factory. Never saw these being made. He trusted a conversation and a drawing. Every module in that batch had to be exactly what the spec sheet described because there was no second chance to make a first impression.
The Shop in Serbia What the Modules Looked Like Installed
After the modules arrived, he installed them. He sent photos.

The finished installation matched the original specifications we discussed during the project.
The video footage is from a separate project a modern office installation the contractor completed using the same modules. He shared it alongside the shop photos.
Five Minutes After the First Batch Arrived

This contractor assembles fixtures himself. He knows immediately whether a module works dimensions, output, driver compatibility. When he says “All good” and asks for more within five minutes of delivery, For a contractor who assembles the fixtures himself, that response was enough to confirm the modules met his requirements.
My reply: “Sure. But we have to arrange it after our holiday.”
That was the second order. The double row module he added in that order 493x50mm was a new configuration he wanted for a different project. Same quality expectation. Same trust level.
Four Orders Later What This Partnership Actually Means
That second order was not the last.
Full Project Timeline:
| дата | What Happened | результат |
| Сентябрь 2025 | WhatsApp inquiry — spec sheet, website reference | Project started — no sample requested |
| Сентябрь 2025 | One day of discussion — specs confirmed | Triple row and single row specs locked |
| Сентябрь 2025 | PCB design confirmed next day | Инженерное подписание завершено |
| Сентябрь 2025 | Order confirmed and PCB drawing completed | Production review started |
| October 2025 | First batch received in Serbia | “All good” — zero issues |
| October 2025 — 5 minutes later | “Can we order more?” | Second order — double row added |
| Late 2025 | Third and fourth orders placed | Активное постоянное партнерство |
What Made the Difference:
| ситуация | Что сделало Signleteled | What It Produced |
| No sample — specs only | Engineered from WhatsApp conversation and spec sheet | Производство соответствует спецификациям |
| Driver compatibility conflict | Parallel connection solution — no new driver | Zero extra cost for contractor |
| Two module types needed | Both engineered in one session | Complete range from one supplier |
| Fast turnaround needed | Рисунок печатной платы готов до следующего утра | Нет задержки производства |
| First order with no sample | CE ROHS certified aluminum PCB delivered | “All good” on arrival |
| Четыре заказа с течением времени | Постоянные характеристики и качество каждой партии | Primary module supplier status |
He came with a condition that most suppliers use as an exit. We used it as a starting point. That is the reason there have been four orders.
If You Manufacture Your Own Lighting Fixtures
If you manufacture your own lighting fixtures and already have driver limitations or existing production standards, send the specifications before production planning begins.
Most problems in custom LED module projects start when these details are discussed too late.
На сайте SignliteLED, we prefer confirming compatibility before production starts rather than correcting problems after installation.
часто задаваемые вопросы
да. Этот проект является прямым примером. Подрядчик разместил заказ на основе спецификации и беседы WhatsApp — образец не запрашивался или отправлен. Это делает возможным точную спецификацию, четкую связь по электрическим требованиям и печатную плату, подтвержденную до начала производства. Когда все три на месте, физическая выборка добавляет время без добавления уверенности.
The process starts with knowing the driver’s output current. Once that figure is confirmed, we design the LED string configuration — series count, parallel count, and total draw — to match it. If a single module configuration cannot match the driver directly, parallel wiring of multiple modules is the standard solution. We work through this during the spec phase, before any drawing is produced.
Не прямо с одного выхода в стандартной конфигурации — токовые тяги разные. Однако три однорядных модуля, проводимых параллельно, берут тот же общий ток, что и один модуль тройного ряда. Если выход драйвера соответствует трехрядной тяге, параллельно соединенные однорядные модули будут работать от одного и того же драйвера без модификации. Именно так мы и решили эту проблему для этого подрядчика.
Parallel connection means multiple modules share the same driver output, with each module drawing its individual current simultaneously. The driver sees the combined draw. It applies when you need to run lower-current modules from a higher-current driver, or when you want to expand a lighting run without adding a second driver. The key requirement is that the driver’s total output current matches the combined draw of all parallel modules.
Алюминий рассеивает тепло от светодиодного соединения значительно быстрее, чем стекловолокно FR4. Алюминиевая печатная плата снижает температуру светодиодного соединения на 15-20 градусов по сравнению с FR4 в условиях высокой плотности, а низкая температура соединения напрямую увеличивает срок службы светодиодов. Для подрядчика, устанавливающего модули в светильники, которые будут работать в течение тысяч часов в коммерческих средах, эта тепловая разница приводит к меньшему количеству отказов и более сильной репутации продукта.
On this project, the PCB drawing was completed and sent for confirmation the day after the specifications were finalized.
The modules in this project were CE and ROHS certified. CE certification confirms compliance with European safety and electromagnetic compatibility requirements. ROHS certification confirms that restricted hazardous substances are absent from the product. Both are required for commercial lighting applications in European markets, and both were specified by this contractor from the first message.
It describes how the LEDs are electrically arranged on the PCB. “20 series” means 20 LEDs are connected end-to-end in a single chain — the voltage adds up across all 20. “3 parallel” means three of those chains run side by side, sharing the same current driver. The triple row module in this project had 60 total LEDs arranged as 20 series, 3 parallel — giving it three times the current draw of the single row 20 series, 1 parallel module.
Minimum order quantities for custom LED linear modules depend on the PCB configuration and tooling requirements. For projects involving a new PCB layout — as in this case — there is typically a setup cost that makes smaller runs less economical. The right starting point is to send your spec sheet: we will confirm quantities and costs based on your actual configuration, not a generic price list.
When no sample is available, the spec sheet does the work a sample would otherwise do. We confirm every parameter in writing before engineering begins — PCB dimensions, LED count, series and parallel configuration, operating voltage, current draw, substrate material, and certification requirements. The PCB drawing goes back to the client for sign-off before production starts. That drawing is the checkpoint. If anything is wrong, it is corrected before a single LED is placed.





