I pull most of my 18650 cells from old laptop batteries and I'd like to get a charger that can show cell capacity, resistance/impedance, to give me a better idea of the cells condition than the thumbsucking I do currently.
So far I have found an Opus BT - C3100 V2.2 Smart Battery Charger that seems it can do all that, currently $30 at Gearbest, which is a very decent price:
Liitokala li500 is dirt cheap, ~$16 if you have an adapter
I think the internal resistance measuring is not the best so I push cells 5 times so they disconnect and take the lowest.
Looking at the reviews, the IR function on the Liitokala just doesn’t work, while on the Opus it does appear to work. I think I’ve read the Opus capacity measurements are higher than actual, by a fixed fraction I presume, so keep that in mind. The Opus uses PWM to regulate charge and discharge current, with quite high pulses of ~2.5A. I imagine this can’t be good for charging some cells, but I could be wrong. Edit: it’s probably fine: Best bang for the buck charger? Anything on the horizon? - #26 by Speed4goal
Actually that compares to the 2.1. I have the 2.2 version and I think they made the fan quieter ,not sure of the other changes!
HKJ did not review the 2.2 version. I am sure others have.
EDIT: The thread I provided goes over my failed power supply for the 2.2 and the solution. This is covered in the last 2 weeks or so of the thread. Starting @ post #128.
I have had 3x Lii500. The IR in every one of them is useless. Otherwise a good charger. I use it often.
My Opus is a tad rough and variable for IR but serviceable. There is speculation that the pulse charging is not as good for cells, especially small ones. So far…no proof of that. My oldest and best charger uses pulse charging and I have cells over 10 years old still serviceable. The Opus is my most valuable charger.
There are extensive threads on both chargers with lots of opinions on both. HJK has reviews on both (see links above post).
Others that may be more accurate are 3-4x the price.
If IR is an important feature and you don’t want to spend like $90, the Opus is your only choice I know of. You can do IR without a charger but that’s another discussion.