I just saw another thread with a post showing photos of an Opus giving erroneously low capacity readings. The poster had another charger brand to verify the readings were too low - the other charger gave capacity readings much closer to the batt. manufacturer’s rating. This is the thread:
Then, there is the question about high charge amp pulses (not constant current) which ‘might’ shorten battery life - see HKJ’s review. Also some complain about fan noise.
Xtar chargers are highly rated but many suggest buying separate chargers for Li-on and NiMH batts since all-in-one smart chargers tend to have various compromises in their design to accomodate multiple battery types.
Some examples of complaints of all-in-one smart chargers include: charge current too low for Li-on or too high for Ni-MH or smaller batts; only use inner bays for smaller batts or bays #1 and #4 for quicker charging; if you use bays #1 & #3 or #2 & #4 at the same time, the charge current gets split between the two and its too slow; if charging small batts, don’t charge just the one batt but 2 batts minimum to lower charge current but remember to put the two batts in bay #1 & #3 or #2 & #4 but not #1 & #4; etc. and the list goes on…it can get confusing.
I think the overall favorite for Li-on batts on this forum and Candlepowerforums is the Xtar VP2 with adjustable volts up to 4.35V to accomodate some newer Li-on batts (VC series and VP4 does not have this feature). I don’t know what the favorite charger is for NiMH.