Emboldened by experiences reported in this list, I plugged my old Ti500 grey puck power supply into my 17"Al. Powers it up OK and (slowly) charges the battery (tho' I don't think it's ever going to get to full charge). I can't say the puck feels any hotter than it does powering the Ti500. I'm afraid my physics isn't good enough to appreciate the significance of the 45W/65W difference - tho' I rather guess that it wouldn't be wise to plug the 65W 17"Al power supply into the Ti500.