One type of low frequency flickering ( it is more a series of single light flashes f.e. every 4 sec. or 20 sec. or every 3 minutes) is caused by the power cable net. It is not so much a question of the quality of the LED. On the other hand, nowadays many manufacturers would know about this effect and should add some electronics or change the driver to avoid this flashing.

The wires in one conduit and/or the wires in Romex or similar cable types run close together for some distance, f.e. 10 or even 30 meters with only a few millimeter distance.

If a LED lamp is switched off, still some current can flow through the capacitors between the wires which are inevitable with the usual power cables.

A lamp switch is some kind of bridged by those between - wire- capacitors.

This is a very tiny current, which also flows through switched-off old style incandescent bulbs. But no effect is visible, no low frequency flashing is possible, since these bulbs can not store energy.

But some LED drivers have huge capacitors - elcos- for smoothing out the rectified net voltage.

The tiny currents in switched- off state will slowly accumulate voltage in those elcos. If the voltage is still low enough, the driver electronics can not start working. But if a certain threshold is reached, the electronics starts working and thus discharges the energy stored in that elco in a short flash of LED light. Now the elco has much less charges or is even empty and the cycle starts again.

Especially lamps which can be switched from different switches have a higher probability to produce these flashes, since there are more parallel cables involved. F.e., between 2 switches 3 wires run, of which one is always hot, another wire is directly connected to the switched-off lamp. Even if switched off, some tiny current flows between the hot and the floating wire.

Another reason for flickering not yet mentioned are tiny discharge indicator lamps which can be found in some light switches. Although those indicator lamps (meant to find the switch in darkness, f.e. in childrens' rooms) use only a tiny current, they sometimes also do some kind of bridging the switch like the capacitors between wires do.

And with more wire capacitors the flash frequency will increase.

One type of low frequency flickering ( it is more a series of single light flashes f.e. every 4 sec. or 20 sec. or every 3 minutes) is caused by the power cable net. It is not so much a question of the quality of the LED. On the other hand, nowadays many manufacturers would know about this effect and should add some electronics or change the driver to avoid this flashing.

The wires in one conduit and/or the wires in Romex or similar cable types run close together for some distance, f.e. 10 or even 30 meters with only a few millimeter distance.

If a LED lamp is switched off, still some current can flow through the capacitors between the wires which are inevitable with the usual power cables.

A lamp switch is some kind of bridged by those between - wire- capacitors.

This is a very tiny current, which also flows through switched-off old style incandescent bulbs. But no effect is visible, no low frequency flashing is possible, since these bulbs can not store energy.

But some LED drivers have huge capacitors - elcos- for smoothing out the rectified net voltage.

The tiny currents in switched- off state will slowly accumulate voltage in those elcos. If the voltage is still low enough, the driver electronic can not start working. But if a certain threshold is reached, the electronic starts working and thus discharges the energy stored in that elco in a short flash of LED light. Now the elco has much less charges or is even empty and the cycle starts again.

Especially lamps which can be switched from different switches have a higher probability to produce these flashes, since there are more parallel cables involved. F.e., between 2 switches 3 wires run, of which one is always hot, another wire is directly connected to the switched-off lamp. Even if switched off, some tiny current flows between the hot and the floating wire.

Another reason for flickering not yet mentioned are tiny discharge indicator lamps which can be found in some light switches. Although those indicator lamps (meant to find the switch in darkness, f.e. in childrens' rooms) use only a tiny current, they sometimes also do some kind of bridging the switch like the capacitors between wires do.

And with more wire capacitors the flash frequency will increase.