Not sure what has changed, but it is now taking a really long time to get my bed to 110C for ABS printing. I am talking 30 minutes to an hour, or forever! (see below):

A few observations:

1. The output at the Meanwell 350W PSU measures 12.00V under full load, so that does not seem to be the bottleneck.
2. At the relay board, the supply voltage has dropped to 11.65V. So I am losing 0.35V in the 16 AWG wires between the PSU and the relay board.
3. If I place a sheet of white copy paper over the glass on the bed, it heats in 20 minutes or less. I think it is blocking the drafts from the fan. (There is a sheet of cardboard below the heater).
4. The fan on my Hexagon hot end seems to play a major role in this. Once I left the extruder parked near the center of the bed, where the fan drafts hit more of the bed, and the temps topped out at 93C.
5. With the extruder in the home position the fan has less influence.
6. Have not measured the voltage drop across the lighter gauge supply wires from the relay to the bed heater, but based on the warming of the wires I think a fair amount of energy is being lost there, too.

My solution has been to use 105C for ABS, which is working fine for my prints. The extra time needed to go from 105C to 110C is significant.

I think I would have to change the fan mount on my hot end for 110C to be a routinely usable bed temp.

Anyone else have a similar experience?

Jim