NiMH is a fantastic technology, but there are still advantages to using NiCad. NiMH batteries are notoriously fickle because it is very difficult to detect their charge state based on their voltage. Many chargers will just charge at something like 1.5V / 1A for an hour or two and expect you to drain the batteries between charges.
NiCad batteries handle 'trickle charging' much better than NiMH ones, which usually degrade significantly with overcharging. So NiCads are still used in places like alarm backups, power tools, or off-grid applications where they might be connected to a charging circuit for long periods of time between discharges.
And 18650 cells are great, but I would think carefully about using li-ion or li-po chemistries in areas where they will be exposed to the elements and unsupervised.
NiCad batteries handle 'trickle charging' much better than NiMH ones, which usually degrade significantly with overcharging. So NiCads are still used in places like alarm backups, power tools, or off-grid applications where they might be connected to a charging circuit for long periods of time between discharges.
And 18650 cells are great, but I would think carefully about using li-ion or li-po chemistries in areas where they will be exposed to the elements and unsupervised.