Why are my brand new, daylight led bulbs flickering?

First I hope you return the flickering lamps. With no electronics switches you sound like you have lamps with questionable drivers.

Flickering lamps is a sign of component failure on the driver board. (They work for a while from an hour to a few weeks then start flickering)

I have become an advocate of DLC (design light consortium) certification these lights for the most part must have a 5 year warranty so they rarely fail and the few that I have had fail have been replaced with no issues.

DLC certified lamps and fixtures usually cost a little more as they are sold from more reputable sources (no I do not consider Amazon reputable) Amazon may have some quality lights including DLC but many are just junk from china.

I have found this problem with even brick and mortar home stores “big box” in the past and today will not purchase a led lamp if it is not DLC for this reason.

So I believe you are experiencing component failures and that is why the lamps start flickering.

Keep in mind that the LED bulbs made with Edison bases have the electronics in the base. They produce heat. Many fixtures out there mount the lamps upside down. So the heat concentrates in the base and overheats the electronics. Try one of those brand of bulbs that starts flickering in a table lamp (BEFORE it starts flickering of course) where the bulb is mounted in free air, right side up. I will bet it won't start flickering.

Electronic parts are manufactured to run at different temperature levels. Lower temp electronics are cheaper. While Ed is right about the certification, even certified LED bulbs will run with a far longer lifetime if the bulb has good air circulation and heat dissipation and is oriented so the heat doesn't concentrate around the driver. My preference would be that LED bulbs were certified in both "right-side-up-only" applications and "universal" applications. as the "right-side-up-only" ones would be cheaper and would allow the discerning consumer to save money. Unfortunately too many consumers are ignorant and that scheme likely would not work out so well.

I have tested a lot of LED bulbs. They have continuously gotten easier to use, have less dimming issues and perform with more variety of gear (switches/lamps/whatever).

I can tell you the number one issue I have seen is certain LEDs flickering at "almost" full power. Whether this is with a basic light switch or a none LED certified dimmer switch. This is by far the number one issue I run into with LEDs.

I am sure Harper or one of our resident electricians can go over this more technically but new LEDs can usually be successfully dimmed but seem to wig out around the 90% voltage rate - which is the dimmer turned all the way up. I have also noticed this in regular switches where the switch components had issues a slight voltage drop.

I have seen the phenomenon so many times I just put a new LED compatible dimmer switch in before I even bother troubleshooting. Just FYI if they continue to flicker like this the LEDs will eventually burn out their motherboard and this could just take a few days.

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.