Learning about rechargeable batteries and there chargers?!?!?..

I’m trying to post a picture to make things easier but I can’t figure out how to do so. I have the nitecoreums4 battery charger. And bassically I’m trying to figure out what everything means on the charger and how to properly use it. I bought the Samsung 30Q 18650 3000mAh 15A - Button Top Battery for the Astrolux mf05 flashlight. It also requires another battery that the fan Handle requires which I bought the EFAN 21700 3750mAh 40A Battery. I guess first off are these are the right types of battery’s for the flashlight to make it work properly right? I’m all knew to this so please forgive my ignorance. Also I’m trying to learn everything about the charger and how it works and what everything means on it and how fast I should charge my batteries and how to do so? If I could post a picture it would be a lot easier to let you guys know what I’m trying to learn but bassically I need to know everything about what everything on that battery charger in Particular means, like all the little abbreviations and how to use it properly. I’ve actually read the manual and understand it somewhat just not what all the words and abbreviations on the charger itself mean. Also I heard that that charger can read m(and some weird looking circle thingy) high and it’s saying the 18650 batteries are poor. Idk what this means, does it mean they are used or is it just because the particular charger I have reads them higher than normal which is what I saw on one review on YouTube? Also I have the Miboxer C4-12 on the way also. I’m holding this fives a more accurate reading of what I was talking about and just becasue I heard it was a really nice charger I think and couldn’t live without it. Will that suffice with a better accurate reading or if not what electronic device should I invest in the read the health of my batteries and the voltage or whatnot. Thanks guys.

Well 30Q will be fine for the Mf05. The 21700 handle battery is fine also.

As far as charging, the USM4 has automatic modes, so really just stick the battery in it and go, no need for fiddling with current, etc. High drain 18650’s are okay to fast charge at 2 amps, but I wouldn’t go over that. The 21700 is the same, but you can quick charge those at 3 amps.

You can search this forum for HJK’s review of it that gives a really detailed look at the usm4 and c4-12.

Just so you have some perspective. Your request is about like getting a new car and wanting to know everything about it….at once. There are reviews on the batteries, the charger, and the light. Do some digging and reading.

Lol I realized that and I’ve already done a decent amount of digging to of gotten to the point of finding the right batteries and charger and coming across this forum. I was in a hurry and wanted some answers quickly and was hoping the kind folks of this forum could oblige me. And lol I catch your drift but comparing it to a car might of been a bit of a stretch…

Ok thank you so much. You answered exactly what I wanted to know basically. Appreciate that.

So I’ve ran into a problem. With my usm4 I was trying to charge my imr 21700 3.7v limn 3750 mah battery I use for my fan handle cooler for my mf05 flashlight. Thought that charger was supposed to automatically set everything correct but I’m pretty sure it charged it up to 4.2 V and liion. Which isn’t this wrong. Now I tried to put that batter in the fan and the fan only goes in low speed mode and I can’t get it out of it. Can anyone help me thanks.

Most li-ion batteries are called “3.7v” (I think the reason is that most of their capacity is when the battery is at around 3.7v).

These “3.6-3.7v” (sometimes they are called 3.6v, sometimes 3.7v) are fully charged when they reach 4.20v.

Unfortunately, I’m not familiar with the MF05 handle fan cooler (I understand it’s powered by a 21700 battery) though… whether the “low-speed” you’re encountering is an issue or some other issue that may not be related to the battery used…

(There are other types of li-ion battery like LiFePO4 which are called “3.2v”, but are actually around 3.6-3.7v when fully charged.

And there are “high-voltage Li-Ion” (not sure of the proper term, but sometimes also called Li-HV in some chargers that support them; these are nominally called “3.8 or 3.85v” li-ion batteries, but are actually fully-charged when they reach 4.35v)

IF the battery was charged to 4.2v, then the charger did it’s job properly. Check it with a DVM.
IF the MF05 handle fan cooler DOES have different speeds and you cannot change it:

  1. you may not be doing it properly.
  2. Something is wrong with it. (stuff fails)
    -Does it matter? Low speed good enough?