Hello chaps,
Dimmer 2 succeeds and replaces Dimmer 1; Dimmer 1 is discontinued but many retailers hold residual stock.
Dimmer 1 utilised a triac to dim and thus only supported leading edge loads; Dimmer 2 is adaptive (supports leading and trailing edge loads). When you connect a Dimmer 2 it runs through a range of tests to determine what kind of load it is connected to, and calibrates itself accordingly.
Dimmer 1 was Z-Wave; Dimmer 2 is Z-Wave Plus (“series 500”). That means better encryption, increased range, over-the-air firmware updates and slightly reduced power consumption from the radio (the latter point is pretty negligible though really).
Dimmer 2 has active power monitoring built in (reports the power consumption of the attached load to 2DP). Dimmer 1 allowed you to declare a power consumption, and tot up the amount of time it was turned on, but it wasn’t true power monitoring.
Dimmer 2 also uses the power monitoring feature to notice sudden voltage drops from broken bulbs, damaged circuits, etc. and report them.
Dimmer 2 has larger terminals for up to 6mm sq cross section wire. Dimmer 1 only accepted 4mm.
Dimmer 2 has a max load of 250W. Dimmer 1 was 500W.
Some small physical differences, e.g. Dimmer 2 has an LED indicator built in, which provides visual feedback when including it to a network. Dimmer 2 is a bit fatter.
Any further questions, let me know.
PS. - hope to see full support soon, as Fibaro devices are the only ones which do not require a neutral at the switch. Aeon Labs, Qubino, etc. all require a neutral at the switch, meaning (in the UK at least) they are a “retrofit” product that can’t be retrofitted… 