Liitkokala Lii-M4 charger doesn't charge AA battery past 10 hours

[flat-earther]

I have a Liitkokala Lii-M4 charger made for AA AAA 18650 21700 batteries.
When I charge AA Ni-MH batteries it never goes past 10 hours, charging finishes at exactly 10:00h shown on the display. I don't recall seeing this problem when charging 18650s.
Sometimes it can finish charging a battery in less than 10 hours, but it never goes past 10 hours. It's hard to believe my battery would coincidentally take exactly 10 hours to charge to 100%.
What do you think, is it just a trash charger with a design flaw, a 10 hour timeout which shouldn't exist, or am I not comprehending something here?

[CapLeaker]

It took 10hrs to get 0691 ma in there?

[flat-earther]

yeah it's too slow. don't buy this charger.

[CapLeaker]

There is something totally wrong. You can charge an old NIMH battery faster than this charger whatever it is. Man 69ma per hour? Dayum… might as well put a hand crank on there and get a faster charge! It takes a whole day to recharge one NIMH if it is fully discharged!? Smack it against the wall and get a real charger!
You aren’t trying to charge a full battery by any chance?

[flat-earther]

The cell was discharged in my flashlight.
This device sucks as a charger but I'll still keep it for the capacity test it has, it helped me identify several bad cells I had. The cell in the image for example tested above 2000mAh, so it should charge more than 691mAh.

[CapLeaker]

But let’s say 700mah per 10 hrs. That’s 2100mah taking you 3 resets and 30 hrs to charge for a NIMH AA. That’s utter garbage.

[harp]

So, what is specifications say on back label, or manual? My sanyo ni-mh charger take 250mA to charge 2x AA, and shutdown by design after about 14 hour... I think it is dumb model limited with time interval. In past, I charged ni-mh with smart, fast charger, and yes, it charge it in hour and half, the batterys are hot to touch, and very soon the battery is for trash... it is so smart that detect that battery is ruined, and wont start charging anymore... dumb charger is better I think, but with your is something wrong if the battery is good I guess...

[stj]

when a battery takes too long to charge - touch it.
if it's burning hot then it has an internal leakage problem.
i have had lithium cells get so hot i threw them onto a metal plate with a fan over them - throwing them out of a window was contemplated!

[flat-earther]

well here's the manual if it matters https://manuals.plus/ae/1005009422514462

This charger is so weak the cells never get hot...

[stj]

5v input? thats a bit lame.
try another psu and cable.

my older lit' uses a 12v 2.5A supply.

[flat-earther]

5v input? thats a bit lame.
try another psu and cable.

my older lit' uses a 12v 2.5A supply.

Thank you stj, how embarrassing, now I realize my fault, I overlooked the fact that I used my computer's USB3 port as the power supply and evidently it's not powerful enough, because now I used a 5V 2.1A AC adapter and it successfully charged 2 cells in under 10h.
I need to try charging 4 cells at once. I realize in my original post I created a worst case scenario, an unspeced PSU and 4 cells at once.

BTW I originally bought this charger because it has USB input so I could use it off grid from a power bank, but that's not practical because I found out that once the batteries are mostly charged, the draw is too little and the power bank goes to sleep... had this happen with two power banks.

[flat-earther]

I did some testing, I placed 4 batteries to charge with the 5V 2.1A AC adapter and used a USB power meter and it showed 5.16V 0.22A, I don't think that low current would overload my computer's USB port...
After that I plugged the entire thing to my computer and it showed 0.22A, but the voltage sagged to 4.96V.

In my original post I think I also used a 1 to 3 USB port splitter and I may have had something else plugged into it also, so it actually had to be worse than that because now I tested my USB splitter and with a 0.42A draw it had a 0.1V voltage drop across it.
I also tested my USB3 port with a 0.53A load the voltage sagged to 4.85V.

[CapLeaker]

Well… yeah…. Gotta use the correct PSU. lol
But still it’s a garbage charger. 250mah? Might as well put a hamster on a hamster wheel trying to charge the batteries and it will outperform that charger. Lol

[harp]

once the batteries are mostly charged, the draw is too little and the power bank goes to sleep... If you DIY... Power Bank Stay Awake! Here's A Circuit To Do That: https://www.youtube.com/watch?v=lOL3ic8msas

[stj]

still not right,
to avoid confusion charge a single cell at max current - 1A
see what the charger draws.
i think we need to see inside it.
are you using 1900mAH cells?

[flat-earther]

The Duracell cells I have are 2500mAh bought 12pcs over 3 years ago. when I used the capacity test on this charger months ago couple were dead, couple around 1000mAh ,most around 2000, highest one 2270.

This charger is 500mA for AA cells, the 1A option can only be selected if charging 18650s.

I now charged 4 Duracells at once and here are the results. The cells did get hot by the way, used the same AC adapter.
All these tested around 2000mAh when I tested them months ago, apart from the fourth on the right which was 1000mAh.

[stj]

allowing for losses from heat, those numbers look o.k.
i guess the charger works - just a bit poor compared to my "Engineer Lii-500" that lets me charge AA & AAA stuff at 1AH

[stj]

btw, you mentioned "off-grid"
i try to standardise all my stuff for 12v input.
in a SHTF scenario 12v will be a lot more common to find.
cars, portable solar panels etc.

even if your roaming, any alarm panel will have a 12v lead-gel battery inside it - so comercial buildings = 12v sources.