It does seem to be related to button tops, though.
The circuitry and software in the C4-12 that determines the internal resistance is very finicky. Maybe more sensitive than other brands of chargers, hence why Miboxer might be doing these small software changes to improve this.
Also, I wouldn’t really say your other charger gets the resistance right, but that it gives a more stable and reliable reading then the C4-12. Accurate internal resistance is a very difficult thing to measure due to the tiny units we use, milliohms.
I have Liitokala chargers that I can set to 0.5A, 1A and 2A.
At least the indicator light stays permanently on those values. Obviously that’s no proof the charger actually uses those currents. I never use such cells but 2A would cook 900mAh cells.
Anyway my question was a bit unclear I think.
Which Liitokala charger has 3A output? I haven’t found one above 2A. And that’s for all cells combined. So only if there is one cell in the charger it gets 2A.
The only Liitokala charger I know that charges 2A is the Lii-402 only when used with single battery on the slot #4 and using a USB charger that can provide 2A.
I’m not sure of any others Liitokala charger that can charge at 2A… maybe someone can comment?
This C4-12 is the first charger I’ve seen with this much power, 12A. Maybe it will start a trend where other charger manufacturers will release high powered versions of their current models. Then we will have choices. :+1:
If I had choice I would go for something far more simple. No displays with settings. Just one button to set the current and that’s it. Just like the little LiitoKala and Basen chargers.
That brings me to another point. I’ve also bought a simple USB tester that shows me the current draw when charging. I learned something I knew for a long time but never got trough my thick skull.
A 2A (Basen) charger isn’t twice as fast as an 1A (LiitoKala) charger.
Sure 2A goes full throttle when the cell is (nearly) empty, but the more full it gets the lower the current.
I’m not saying that’s bad, or shouldn’t be that way, just that those high currents only matter in the beginning of the charging process. And when the cell isn’t completely empty, you won’t see high currents at all.
I have no way of doing an honest test but as a way to explain using fictive numbers I expect something like this.
3A: 15 minutes at 3A, 15 minutes at 2A, 1 hour at 1A and below. (90 mins)
2A: 45 minutes at 2A, 1 hour at 1A and below. (105 mins)
1A: 2:15 hour at 1A and below. (135 mins)
Your numbers are way off. Most Liion chargers use 2 main phases. The CC phase which is constant current and the CV phase which is the contact voltage.
The vast majority of time spent charging a battery (let’s say from 3.0 volt) is spent in the CC phase. Maybe 75% of the time.
Once the battery is charged up to around 4.1v or so the charger will shift to the CV phase. The voltage holds at 4.2 and the current starts to ramp down slowly.
The CV phase is always very slow for the amount of power it puts into the battery. This is why you see cell phones say they charge from dead to 80% in one hour. That is the CC phase. It might take another 30 to 40 minutes to get that last 20%.
Lithium tool battery packs usually only charge them up to 4v. This makes them charge faster and the battery life longer.
Same for electronic cars. Tesla only charges their battery packs to roughly 4.0 volt. Definitely not to 4.2v. That just adds charge time and reduces battery life.
In my experience, I weekly tend to run my 26650 cells down to around 3.7 volt. With my old 1A charger I’d be waiting about 5 hours. With a 2A charger it went down to about 3 hours. With a 3A charger it’s usually under 2 hours. So yeah, from 1A to 3A is not exactly 3 times faster, but it saves me over 3 hours of having to sit next to the charger either reading or watching tv, etc… which is huge. I get impatient. I’ll gladly pay more money for a faster charger. Lol