On Monday, October 29, 2018 at 9:53:34 AM UTC-4, Tim R wrote:
I had the ballast in an old two tube T12 fluorescent fixture go bad.

The local big box had direct replacement LED tubes on sale, so I tried them. They wire directly to line current, no external ballast, but the tubes fit in the old tombstone connectors.

They work fine; they start at full brightness even when the room is cold, unlike the old fluorescents they replaced. BUT there is a long delay between flipping the switch and seeing them start. It's on the order of 1 - 2 seconds, I haven't tried measuring yet.

We've been discussing this on another forum. Why would there be a delay? It's not unique to mine, either, others have noticed similar results.

I picked up some 8' LED bulbs to retrofit the fixtures at my store, and they start immediately.

https://www.amazon.com/CNSUNWAY-LIGH...be+replacement

But, they do have an input range between 100 and like 270VAC. There is some sort of circuitry inside that keeps the current consistent as LEDs act a lot like zeners when it comes to over-volting them.

Do you have a link to the lamps you bought?