1) he says he's using laptops, so the internal power circuitry is fixed: changing the external power brick will make little difference
2) I've yet to see a laptop with three internal drive connectors - quite simply there isn't room for three internal drives
3) several mentions of an "expansion card" - which makes little sense in the context of laptops. Is this a USB > SATA adaptor? A cardbus/PCMCIA > USB adaptor? An external USB hub?
4) Is the laptop USB2 or USB3? If the laptop is USB2, having a USB3 external hub will not speed things
5) as has already been asked, has the power saving features on the USB root hubs been disabled in the device manager?
6) If you have USB3 caddies plugged into USB2 sockets you may not be able to draw enough current to spin the drives. Remember USB2 caddies required the use of TWO USB sockets to achieve connectivity
it would help if we knew the make/model of all the hardware involved