The secret of cheap LED lamps

A visitor to the site Vladimir sent photos of the insides of a cheap Bellight 12W 1000 lm LED lamp, which he bought at the Leroy Merlin store for 98 rubles.

I tested a similar 10 watt bulb. She had a good color rendition index of 81.9, there were no ripples, the luminous flux exactly corresponded to what was stated, a pulse driver was used and the lamp could work with a significant decrease in the supply voltage without reducing the brightness.

So what's the catch?

There are 14 smd-LEDs on the board, which make up two parallel groups of 7 pieces each. Each LED has three crystals (when a small current is applied, three luminous points are visible). The voltage at the terminals of the board when the lamp is 63 V.

The body is plastic outside and aluminum inside. But there is no sense from aluminum, since there is practically no thermal contact between it and the board - the board is glued to the case with white sealant and almost does not touch aluminum. Inside the case on the plastic rails installed driver board.

In one of the wires, a protective resistor is hidden in the heat shrink tube.

The driver is made on a BP2832A chip. Capacitor C2, which was supposed to filter the supply voltage of the chip, is not installed - there is only a small ceramic capacitor on the bottom of the board.

Bottom view:

When the lamp was working (before disassembly), the case was barely warm, the heat from the LEDs just did not reach it.

The manufacturer gives a 24 month warranty for this lamp. How long it will live in reality depends on how “strong” the LEDs turn out to be and how much they can work with such minimal cooling.

© 2017, Alexey Nadyozhin


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