LED driver delay

Good afternoon to all!
I'm a first time writer but a long time reader.
I'm facing a little problem with my led strips.
This is my current setup:

STRIP_1: 12V led strips, 24.5W/m, 5m
STRIP_2: 12V led strip, 24.5W/m, 1,2m

Both strips are identical, length is the only difference.

STRIP_1 is driven by a Mean Well RS-150-12 power supply (12V, 150W).
STRIP_2 is driven by a Mean Well RS-50-12 power supply (12V, 50W).

Both drivers are connected to the same switch (220V, 50Hz).

When I press the switch, strips are turned on with a different timing: STRIP_2 has a delay of a fraction of second compared to STRIP_1.
Moreover, if I switch off and immediatly switch on the strips, STRIP_2 delay is increased (about 2-3 seconds).
This is quite strange as I expected to be faster (capacitors should be still half charged).

Any clue?
Is there a way to synchronize the strips?

Thanks a lot and best regards!

The RS-150 is likely a two stage design and the RS-50 may be a single stage design. Two stage designs typically have longer startup times, each stage starting in sequence. You can do it fast, but it costs money.

The RS-50 controller may have a "kick-start" circuit that speeds up time to regulation from a cold start. When you switch it off and immediately back on (not normal operation) that circuit does not operate causing it to take time to bring the output into full regulation.

Not much you can do except use a secondary switch that only turns on after both are fully on.

Semiman

First of all, thanks for your reply!
The RS-50-12 has a rise time of 30msec while the RS-150-12 has only 20msec.

As regards the secondary switch, how can I make it?
Is it possible to use those power supplies in parallel with a common - and a diode on both the +?
Thanks a lot!