[zilax002]

Oh man, just recieved the new device yesterday; it was at 40% battery level. Played with it found it awesome.
I plugged it to charge it all night (with protection battery 80% on) and this morning the red lid was off, probably indicating it fully charged, and…ONLY 67% !!!!!
My charger is a standard 5v/1A charger so i don’t understand !
I charge all my devices on it fine ! The BTR and the rest…
I hope my Qudelix is not a lemon !

Bluetooth battery levels are always just estimates.

I suspect the Qudelix is conservative with its estimates. Other devices will show 30% and then just die. Not so with the 5K.

 

[Serge Bernamej]

Bluetooth battery levels are always just estimates.

I suspect the Qudelix is conservative with its estimates. Other devices will show 30% and then just die. Not so with the 5K.

Also i just charged it like 45 min ago (put the charging limit to 100%) and now it showed 100%!!!!
Does that mean the battery got to 80% during the night (i put the likit to 80%yesterday) and got drained during the night, thus giving me 67% this morning ?
Or is it maybe as you said?

 

[CactusPete23]

Also i just charged it like 45 min ago (put the charging limit to 100%) and now it showed 100%!!!!
Does that mean the battery got to 80% during the night (i put the likit to 80%yesterday) and got drained during the night, thus giving me 67% this morning ?
Or is it maybe as you said?

Many devices don't show % capacity properly until they complete a few charge/discharge cycles. Batteries also often perform a somewhat better after the first 1 to 3 cycles. So, I think no need to worry. Just enjoy the music and the new toy!

 

[Serge Bernamej]

Many devices don't show % capacity properly until they complete a few charge/discharge cycles. Batteries also often perform a somewhat better after the first 1 to 3 cycles. So, I think no need to worry. Just enjoy the music and the new toy!

Thanks my friend !

 

[sgtbilko]

Omg, thank you! Totally forgot this was a thing.

I can't believe I've been manually replicating my Peace presets on the phone when I could have just had a Chrome tab next to Peace and done it in like a tenth of the time.

Yep, I was was exactly the ssame. Good on Qudelix for making it happen.

 

[yaerb]

Also i just charged it like 45 min ago (put the charging limit to 100%) and now it showed 100%!!!!
Does that mean the battery got to 80% during the night (i put the likit to 80%yesterday) and got drained during the night, thus giving me 67% this morning ?
Or is it maybe as you said?

try setting 80% limit again, and if you didn't the first time, leave it plugged in when you check the percentage. that way you can see what the battery was doing without any power draw.

battery voltage will instantly drop quite a bit from that 80% limit if there is power being pulled from it. after mine peaked at 80% the charging disabled and the resting voltage ended up at ~71%.

if you unplug and replug it will charge to 80% again then disable when it hits 80% and the resting voltage/% will be a bit higher then last time.

as someone else said, its not showing a charge estimate, its the real voltage/% so I can understand the concern

 

[Serge Bernamej]

try setting 80% limit again, and if you didn't the first time, leave it plugged in when you check the percentage. that way you can see what the battery was doing without any power draw.

battery voltage will instantly drop quite a bit from that 80% limit if there is power being pulled from it. after mine peaked at 80% the charging disabled and the resting voltage ended up at ~71%.

if you unplug and replug it will charge to 80% again then disable when it hits 80% and the resting voltage/% will be a bit higher then last time.

as someone else said, its not showing a charge estimate, its the real voltage/% so I can understand the concern

Do you think it's a big deal the difference between 80% and 100% charging?

 

[CactusPete23]

More that you ever wanted to know! LOL Excerpt from https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries

Tables 2, 3 and 4 indicate general aging trends of common cobalt-based Li-ion batteries on depth-of-discharge, temperature and charge levels, Table 6 further looks at capacity loss when operating within given and discharge bandwidths. The tables do not address ultra-fast charging and high load discharges that will shorten battery life. No all batteries behave the same.

Table 2 estimates the number of discharge/charge cycles Li-ion can deliver at various DoD levels before the battery capacity drops to 70 percent. DoD constitutes a full charge followed by a discharge to the indicated state-of-charge (SoC) level in the table.

NMC	LiPO4
Depth of Discharge	Discharge cycles
100% DoD	~300	~600
80% DoD	~400	~900
60% DoD	~600	~1,500
40% DoD	~1,000	~3,000
20% DoD	~2,000	~9,000
10% DoD	~6,000	~15,000

Table 2: Cycle life as a function ofdepth of discharge*
A partial discharge reduces stress and prolongs battery life, so does a partial charge. Elevated temperature and high currents also affect cycle life.
* 100% DoD is a full cycle; 10% is very brief. Cycling in mid-state-of-charge would have best longevity.

Lithium-ion suffers from stress when exposed to heat, so does keeping a cell at a high charge voltage. A battery dwelling above 30°C (86°F) is considered elevated temperature and for most Li-ion a voltage above 4.10V/cell is deemed as high voltage. Exposing the battery to high temperature and dwelling in a full state-of-charge for an extended time can be more stressful than cycling. Table 3 demonstrates capacity loss as a function of temperature and SoC.

TEMPERATURE	40% CHARGE	100% CHARGE
0°C	98% (after 1 year)	94% (after 1 year)
25°C	96% (after 1 year)	80% (after 1 year)
40°C	85% (after 1 year)	65% (after 1 year)
60°C	75% (after 1 year)	60% (after 3 months)

Table 3: Estimated recoverable capacity when storing Li-ion for one year at various temperatures
Elevated temperature hastens permanent capacity loss. Not all Li-ion systems behave the same.
Most Li-ions charge to 4.20V/cell, and every reduction in peak charge voltage of 0.10V/cell is said to double the cycle life. For example, a lithium-ion cell charged to 4.20V/cell typically delivers 300–500 cycles. If charged to only 4.10V/cell, the life can be prolonged to 600–1,000 cycles; 4.0V/cell should deliver 1,200–2,000 and 3.90V/cell should provide 2,400–4,000 cycles.

On the negative side, a lower peak charge voltage reduces the capacity the battery stores. As a simple guideline, every 70mV reduction in charge voltage lowers the overall capacity by 10 percent. Applying the peak charge voltage on a subsequent charge will restore the full capacity.

In terms of longevity, the optimal charge voltage is 3.92V/cell. Battery experts believe that this threshold eliminates all voltage-related stresses; going lower may not gain further benefits but induce other symptoms(See BU-808b: What causes Li-ion to die?) Table 4 summarizes the capacity as a function of charge levels. (All values are estimated; Energy Cells with higher voltage thresholds may deviate.)

CHARGE LEVEL* (V/CELL)	DISCHARGE CYCLES	AVAILABLE STORED ENERGY **
[4.30]	[150–250]	[110–115%]
4.25	200–350	105–110%
4.20	300–500	100%
4.13	400–700	90%
4.06	600–1,000	81%
4.00	850–1,500	73%
3.92	1,200–2,000	65%
3.85	2,400–4,000	60%

Table 4: Discharge cycles and capacity as a function of charge voltage limit

 

[yaerb]

Do you think it's a big deal the difference between 80% and 100% charging?

if you don't need that extra 20% to get through the day it will have a longer useful lifetime. leaving batteries at 100% is how you end up with batteries bulging and puffing up, for example.
although left completely drained can be damaging as well that seems to be less of a problem unless left for longer periods.
maintaining above 20% and below 80% seems to be the general consensus for longevity.

 

[zilax002]

And it's worth emphasizing you don't want to run the device to the ground. The 80% cutoff feature is great but you also don't always want to be running it to 20% and below. That's as bad or worse as always having it at 100%

The most ideal range would be like 40 to 60% but that's a narrow band for many devices.

 

[DeJaVu]

Does that mean the battery got to 80% during the night (i put the likit to 80%yesterday) and got drained during the night, thus giving me 67% this morning ?

Proper Li-Ion charging involves 2 stages, CC(constant current) and CV(constant voltage). When it reaches the 100% full voltage(in 5K case 4.35v.) charging circuit continues charging and monitors the voltage not to overshoot 4.35v and it gradually decreases current till it gets to about 10% of the starting current and terminates, thus making sure battery is 100% full. When you limit the charging to 80% it skips the CV phase(probably a limitation of the charging circuit, or maybe by engineer choice idk), because of that you get higher voltage drop when charging terminates and thats why you get lower % charge after the device has rested for some time.
Its basically a mislabeled option, as it doesnt use the proper charging method and will never be actually 80%.
As a sidenote, batteries from different batches or if they switch supplier mid run, even with same capacity, can have different discharge curves and if the "voltage to percentage" ratio isnt calibrated to the specific battery, percentage display will never be 100% correct.

 

[Serge Bernamej]

Proper Li-Ion charging involves 2 stages, CC(constant current) and CV(constant voltage). When it reaches the 100% full voltage(in 5K case 4.35v.) charging circuit continues charging and monitors the voltage not to overshoot 4.35v and it gradually decreases current till it gets to about 10% of the starting current and terminates, thus making sure battery is 100% full. When you limit the charging to 80% it skips the CV phase(probably a limitation of the charging circuit, or maybe by engineer choice idk), because of that you get higher voltage drop when charging terminates and thats why you get lower % charge after the device has rested for some time.
Its basically a mislabeled option, as it doesnt use the proper charging method and will never be actually 80%.
As a sidenote, batteries from different batches or if they switch supplier mid run, even with same capacity, can have different discharge curves and if the "voltage to percentage" ratio isnt calibrated to the specific battery, percentage display will never be 100% correct.

Incredible answer. Thanks !
By the way i am completely still flabbergasted by this dac amp. Just the best audio purchase I made ever !

 

[Serge Bernamej]

And it's worth emphasizing you don't want to run the device to the ground. The 80% cutoff feature is great but you also don't always want to be running it to 20% and below. That's as bad or worse as always having it at 100%

The most ideal range would be like 40 to 60% but that's a narrow band for many devices.

Noted ! Thank you !

 

[Serge Bernamej]

Wouldn't it be good to have a notification (tone) when the battery reaches 20% so we don't need to keep on checking if we are dangerously draining it ?

 

[Hypops]

Wouldn't it be good to have a notification (tone) when the battery reaches 20% so we don't need to keep on checking if we are dangerously draining it ?

The app (or your phone) should tell you how much charge is left.