That’s a lot of explaining to try and do, but they’re all very useful features. Have a look through this brief but well-done manual for the Maha charger. It doesn’t do li-ion cells but the features are similar and they give a little explanation of each one. Also, you could look around on Battery University to learn the basics, although it’s a bit of a labyrinth with lots of articles…but it’s all very well explained if you want to take some time to read and learn. Basically NiMH has some best-practice care if you want them to perform their best and last as long as they can….li-ion is more robust but some of these charger features are useful to tell you things that lesser smart-chargers can’t, and the discharge feature is really handy for long term storage of cells if nothing else. Keep in mind that all of our rechargeable cells have a finite cycle life, so if you’re using things like the capacity and refresh (i.e. “loop”) features then you scrub off a little of the battery lifetime in the process (plus they can take a long time to complete, depending).
Discharge kind of overlaps with the capacity function somewhat. A little difficult to say for sure since the EBL doesn’t give important specs/methods, but it’s surely similar to what the Maha is doing, and will no doubt change parameters based on what cell chemistry it detects. Discharge can tell you a little bit, but maybe not the truth as far as actual capacity goes. The “loop” mode should do this, assuming it’s doing a charge/discharge/charge again cycle with rest periods like the Maha does…when that’s all finished you have a number for actual capacity, but of course that can vary a little depending on what low voltage the charger cuts off at. Like with lithium cells, most everyone calls 4.2v the fully saturated charge termination, but depending on manufacturer some may call anywhere from 2.6v to 2.8v the lower cutoff (how they determine and advertise mAh capacity…with a pretty slow charging rate from empty to full). Discharge can be handy for lithium cells for storage, too, since storing them at full charge can shorten their life and capacity a little bit…storing them around 50% capacity (around their nominal voltage) is best practice, and the discharge function can get you there without having to just run the cell down in a light or something & check voltage with a meter.
The “loop”….break-in….refresh….functions are what will give you the better capacity figures and they kinda overlap a bit. Along with the internal resistance measurement, this can tell you a little about a cell’s health as it goes through more and more use cycles, or if it’s been perhaps abused with a higher current drain or allowed to run down far below an acceptable low voltage cutoff. Some people really geek out over this and keep detailed records on their cells but the function can be helpful even if it’s not what you want to do all the time. But the discharge-only is much faster, since it’s doing one half of a full cycle and nothing else. Doing the “loop” stuff can take a couple days or more.
With NiMH it usually pays to keep them charged and used, rather than sitting unused self-draining over time, or worse, sitting half charged for long periods. Better cells can handle some of that but it’s pretty rough on NiMH and will usually shorten their lifespan and usable capacity, sometimes dramatically. Those “loop” cycles can help combat that or recover a little magic…often/sometimes. Sometimes the cell just ages and gets tired and there isn’t much you can do about that except continue to use it smartly, maybe relegate it to low drain lights or devices to squeeze some more life out of it before it really dies. At some point the charger will probably refuse to accept a worn NiMH cell when it senses really high resistance, and then you can either recycle the cell or try to keep it going by using a low-rate dumb charger that is only applying a very slow current for that ridiculous 16 hours or whatever…those can be hell on nice new cells but they come in handy for old cells.
I don’t know about this EBL charger but I would imagine that its internal resistance readings should be taken with a large grain of salt and may not give repeatable/same results on the same cells…kinda typical for almost all chargers that offer that measurement. But it gets you in the ballpark and can be handy to know - especially with NiMH but sometimes with li-ion, too. If you put a cell in and it’s showing preposterous numbers (like a 20ohm cell is showing 500ohms or 999ohms) it could just be that it isn’t making great contact in the slot. Good practice to wipe clean the charger contacts and ends of the cells before inserting, or at least once in awhile. And if you get weird numbers like that you can wiggle/rotate the cell and that might set it right (or remove and reinsert).
One more note on capacity. What the manufacturers spec and how they test may be different from how the charger goes about it, which may yet be different from what you see in real life use depending on the driver in the flashlight and what kind of drain is being put on the cells.
So it’s a lab spec vs theoretical measurement vs boots-on-the-ground. Could argue that the latter is the most important. If you’re draining a cell at a higher amp draw for a nice bright light beam, you’ll get less mAh capacity with most cells than if you run them at a lower current. So Samsung says 5000 but the charger does things slightly different and suggests 4600 but in your light and how you use it you actually get something closer to 4200 or less. It’s all relative and those numbers can vary a lot based on several factors.
Also, the “capacity” that may show on the charger screen for normal charging is usually just how much juice it put in to the cell on that round. That’s different than the actual capacity/refresh/loop cycle functions that are attempting to give you a number closer to the truth. Discharge is the same way…it’ll only show you how much drained out, but that doesn’t mean the same thing. If that all makes sense?
But……the process goes like this: charge at a slow rate until full……rest/recover….discharge at a slow rate until low voltage cutoff….rest/recover (or not)……recharge at a slow rate until full. That’s how the factories do it and that’s generally how the chargers do it for that function. You can do it yourself, too, with just a light, a less-featured but reliable basic charger, and a multimeter…can come pretty close that way but smart-chargers sure are more convenient.
Thanks so much. You are a great credit to this community. I noticed pressing on the contacts dropped some of my cells from 50mohm to 25mohm. I really appreciate your detailed info. It helps me a lot. Thanks !