Cisco Catalyst 3750 PoE Issue

we have a 3-switch stack (1x WS-C3750V2-24PS-S    48-port w/no PoE on top, and 2x 3750 48-port PoE underneath). We have PoE IP phones that are all functioning. I recently acquired 2 Engenius EAP9550s to add as repeaters for an expansion of our office. When I connect the APs (in PoE mode on the switches), the indicator for each AP turns green and the APs power up, briefly.

After about 10 seconds, the indicator LED on the switch turns amber. At this point, almost all of the indicators are amber on this bottom switch, they all changed to amber after I tried the APs in them. We have about 5 PoE phones connected to it (the remainder are on the middle PoE 3750)

The device specs state that each AP runs at about 18W (48 VDC x 375 mA)

I can't imagine that I am hitting my wattage limit per switch with the small number of phones that are connected to that particular switch, but the indicator code seems to imply the switch is denying PoE for these ports due to the 350W limit. I don't see any voltage limits in the spec sheet for the switch so I am at a loss.

So, when the switches are stacked, is there a different limit? Or does each switch have its own individual limit? Do I need a booster? I was under the impression the APs would function fine, we have a separate AP on a different physical network with the identical switch setup and it works just fine. PoE is enabled in the port specifications for every port on all of our PoE switches (its the default but I double-checked to be sure).

Do you actually need Power over Ethernet for all of the ports that have it active? If not turn off the extras as you don't need the power drain...

Are these switches connected to a UPS system and is that system throwing any warnings or errors? It could be that you are actually running out of available power with all the ports and switches and such connected in the same place...

Also, how is the power getting into the switches? You're not trying to chain feed it from one to the next right? They each have their own AC adapters correct?

We need the option since the IP phones we have are pass-through switches for our non VoIP traffic - i.e. VLAN 9 - VoIP, VLAN 8 Data, both through the same port and it needs PoE for the phone to power on and provide the passthrough switching.

We have 3 UPSs running at 30% capacity each according to the management consoles, no warnings. That was the first thing I checked, each switch is plugged directly into a PDU and it is all load balanced, no chaining at all.

If there is a non-PoE (or no device at all) plugged into the PoE switch, does it drain more power than designating the port as non-PoE? I thought the switches automatically determined power requirements.

I figured the same thing regarding the circuit, but there is nothing else plugged in to this particular switch aside from 5 PoE IP phones and the 2 APs.

Switching the positions of the switches would be a task, so I haven't tried it. I picked up 2xGb PoE Boosters for cheap to see if they fix the problem. Thinking about the stack, they are all trunked, but they each have dedicated power supplies so I can't imagine the stack would have a more limited Wattage than the sum of the 3 switches  WS-C3750X-24P-S  . We shall see, thanks for helping me brainstorm!