One cell phone app, on playstore, claims 55% charge does zero damage to cell [...]
Moreover, isn't there a 3 year shelf lifespan on Lithium Ion Chemicals in the cells?
What the voltage of two 18650 ..........is it more than 9 volts ?
LOL.....I know nothin
I have a Malkoff M-61 drop in that I want to use in a two 18650 batt body ...........can I ??
Generally using shallower cycles will prolong life, but it certainly won't completely eliminate cycle degradation. .
I would prefer to have protected cells in my collection because they protect from overcharge and overdischarge by disconnecting the battery
This is one *huge * advantage of running 1x18650 lights off *un* protected cells since you will get a long, gradual decline into the sunset.
It depends on the light. Some lights have built-in low-voltage protection. However, those lights usually have a period of step-downs, which give you plenty of warning. For example, Zebralights have a low-voltage protection at 2.7v, but they also step-down well before you're left in the dark. In the case of Zebralight, the built-in LVP would kick in sooner than the 2.5v LVP of a protected cell.
With most 1x18650 lights that don't use boost drivers, it would be tough to actually be left in the dark with a protected cell. The voltage is just too low for the forward voltage of the LED.
The cell declines to the voltage where the PCB is triggered and you go from xxx lumens to zero lumens in a nanosecond.
That is how every protected cell has worked with every Lego light with every P60-drop-in module I've had in the last 10 years. This is kind of good as it protected the cell from overdischarge, that's the point of it. It's not so good if you critically need light that very second. Case in point, you are an LEO holding a suspect or suspects in a dark basement. Your lights go out as the cell hits the threshold for cutting out, whatever it is, 2.5V I assume, and that jeopardizes things. I can think of 100 and 1 situations like that.
Interesting point you make. I've always thought the same thing also. I agree.
On the one hand, you don't want many recharge cycles but it appears that shallow cycles are better than discharing the thing down to 2.5V - beyond empty.
I've never experienced any issues with topping off my 18650 and similar cells. One of the biggest things is not to use a fast-charger. Might be annoying waiting 5 hours to charge up one 18650, but patience is worth it. Last thing you want is an 18650 becoming the world's greatest hand-warmer the instant you take it off of a charger.