Lipo generic Long Life 4.1V

[BorisFF]

I'm coming from an Hyperion that goes full Amps for C asked rating
up to 4.1V 90%, once 4.1V is reached, it stops.

With PL8v2 when asking 4.1V 'only', why is there a large
amount of time spent at low curent at the end
(all cells already have 4.1V) ?

Preset is a copy of "Lipo generic Long Life 4.1V" with
Amps set to 1C.

[Gregor99]

The LiPo program on all chargers has two phases, the high current phase and the tapering current phase. The high current phase is called the "constant current" phase and operates at current set by the user. This phase runs until all cells reach 4.2v per cell. (4.1v for the long life preset). Then the charger switched over to the tapering phase which is called the constant voltage phase. In the constant voltage phase (or CV), the current is slowly tapered down while keeping the cell voltage at the set point.

The charge cycle terminates when the CV current reaches a predefined threshold. The default for many chargers is 10% of the set current. On the Powerlabs, the fast preset and the high power preset use 10%. The accurate preset and the long life preset use 5%.

The TCS setting on the Hyperions alters the termination current, not the end voltage like the long life preset. To get similar behavior to the Hyperion's TCS feature, raise the termination current. Use one of the first two presets and change the C/? termination setting from the default to C/5 or C/3 depending on what you are after.

More background on charging.

http://www.tjinguytech.com/charging-...-chargers-work

[RedOctobyr]

Greg, I've been told that 4.1V to 4.2V is about a 10%-of-the-pack difference. I haven't tried to test this myself.

Any sense of how much easier it is on the packs (that is, how much you might extend their lifespan, such as in terms of cycles) if you're charging to 4.1V, vs 4.2V?

I've been charging to 4.18V. I might try dropping that to 4.15V. I could even try 4.1V. I don't care that much with my 450 packs, but for my larger ones, if I could help meaningfully extend their lifespan, that would be nice. I don't do deep discharges (typically just to around 3.75-3.8V).

[Gregor99]

Sorry, I don't have hard numbers to give you. I believe I have seen the test results in the long distant past, but cannot find them now. There are likely many other factors such as depth of discharge, rate of discharge, storage levels and voltage levels at colder temps.

Lacking controlled tests with modern packs, I would use the termination voltage as a contributing factor to achieving longer pack life. If you are not getting acceptable pack life this is one of the many things that can help. As "acceptable pack life" varies by individual, its hard to make blanket statements which apply equally to everyone's scenario.

[BorisFF]

Thanks, Gregor99.