i'm looking for two li-ion charger recommendations meeting separate criteria:
1) gift for friend:
an inexpensive ($20?) one or two slot charger mostly for 18650. bells and whistles like adjustable charge current, storage voltage (~3.7V), etc would be nice, but not necessary. the main requirement is that it's not junk or finicky to use.
2) new charger for myself:
i'm currently using an Opus BT-C3400 V3.1, but i'm wondering what else is out there that could be better, cheaper, or just different.
firm requirements (which the Opus does have):
- ~4 slots
- long enough slots for unprotected 21700 (70mm) cell length, but protected 21700 would be a bonus as i think the Opus barely fits unprotected 21700
- adjustable charge current
- capacity testing (discharge and then charge back up)
- charge to storage voltage (~3.7V)
- display current and voltage while charging (not necessarily at the same time)
if it matters, i'm in the US.