Building my first pack, need some help.

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Oberfail

Member
Joined
Jun 22, 2021
Messages
103
hey @Oberfail @Wolf @floydR I just bought an used Liitokala Lii 500 from a guy. I want to ask what current rate should I use to test my 18650s in Normal testing mode? I used 700mA but they are getting pretty hot and the charger is also getting very hot, and after finishing discharging they arent charging up to 4.20 not even over 4.00v two of them got to 3.56v & 3.45v and the IR rating is changing every time. Am I doing something wrong or this charger is faulty?

Edit - The IR im getting from these cells are 27,43,52 and the cells are from 1680 to 2869 and one NCR18650A got 3045 but the cell is rated at 3000mAh.
250mA charge -> 250mA discharge
500mA charge -> 250mA discharge
750mA charge -> 500mA discharge
1000mA charge -> 500mA discharge

The LiitoKala Lii-500 charges at set current till 1.5/4.2v and stops to charge, once the current going into the cell is less than 50mA. This results in the cells not having the full 4.20v when you take them out the charger. The lower the voltage after you take them out, the lower the capacity in general aswell. But it can also be, that the cell didnt sat in the charger correctly.

Personally, i go for 750mA charge if its cold and the cells are good, if its warm or the cells are just of average used quality, i go for 500mA charge.
Also go for Normal Test and not Fast Test.

You can ignore the mR value the charger gives you. Its highly inaccurate which has been proven many times. All consumer grade chargers have a unprecise mR meter.

All i did was to test them once with the LiitoKala-500 to know their capacity and let them sit 2 weeks on a full charge. Then I took out 2 cells that dropped their voltage below 4.1v. Now 448 of 512 cells sit in a 14s32p configuration in our garden, being discharged with a 20w bulb for 7 days (168hours) to test the capacity. After that i will charge the whole pack up to 4.2v again to test if sustains the high voltage. If it does, i'll apply my lower voltage limits to it, put the pack into a corner and let it stay there for months being connected to our DIY garden shed 12v grid with solar panels to test it trough the winter long-term.
 
Last edited:

floydR

Member
Joined
Aug 23, 2017
Messages
1,328
The Liitokala Lii 500 can discharge at either 250mA or 500mA
The manual for Liitokala Lii 500 https://org-info.mobi/manual/lii500.htm
Hard to do a NOR test wrong. but if the cell is self discharging while charging it will give a higher capacity than it really is with the NOR test.
Wolf has many great write ups on IR compared 4 slot testers etc.

You could try a fan mod like the Opus fan mod to keep the Liitokala Lii 500 cooler.

Later floyd



If the cells get hot over 50ºc which is too hot to hold on to for long. while charging or discharging I wouldn't use them. even if that is within the specs.
 

pankajdas

New member
Joined
Sep 24, 2021
Messages
14
250mA charge -> 250mA discharge
500mA charge -> 250mA discharge
750mA charge -> 500mA discharge
1000mA charge -> 500mA discharge

The LiitoKala Lii-500 charges at set current till 1.5/4.2v and stops to charge, once the current going into the cell is less than 50mA. This results in the cells not having the full 4.20v when you take them out the charger. The lower the voltage after you take them out, the lower the capacity in general aswell. But it can also be, that the cell didnt sat in the charger correctly.

Personally, i go for 750mA charge if its cold and the cells are good, if its warm or the cells are just of average used quality, i go for 500mA charge.
Also go for Normal Test and not Fast Test.

You can ignore the mR value the charger gives you. Its highly inaccurate which has been proven many times. All consumer grade chargers have a unprecise mR meter.

All i did was to test them once with the LiitoKala-500 to know their capacity and let them sit 2 weeks on a full charge. Then I took out 2 cells that dropped their voltage below 4.1v. Now 448 of 512 cells sit in a 14s32p configuration in our garden, being discharged with a 20w bulb for 7 days (168hours) to test the capacity. After that i will charge the whole pack up to 4.2v again to test if sustains the high voltage. If it does, i'll apply my lower voltage limits to it, put the pack into a corner and let it stay there for months being connected to our DIY garden shed 12v grid with solar panels to test it trough the winter long-term.
I figured it out. actually, I didn't know how to use the charger then I watch some videos and I got to know that if the "end" is blinking on the display it means only discharging is done not the test. I thought the test was finished when the "End" on the display was blinking, my bad.
Im currently using 750mA as well. lets hope I get some good cells. And yeah Thank you once again. :)
 

pankajdas

New member
Joined
Sep 24, 2021
Messages
14
The Liitokala Lii 500 can discharge at either 250mA or 500mA
The manual for Liitokala Lii 500 https://org-info.mobi/manual/lii500.htm
Hard to do a NOR test wrong. but if the cell is self discharging while charging it will give a higher capacity than it really is with the NOR test.
Wolf has many great write ups on IR compared 4 slot testers etc.

You could try a fan mod like the Opus fan mod to keep the Liitokala Lii 500 cooler.

Later floyd



If the cells get hot over 50ºc which is too hot to hold on to for long. while charging or discharging I wouldn't use them. even if that is within the specs.
they are getting hot while discharging. I think it is because of the charger. I have now placed the charger vertically so the heat goes through the top and not through the cells. after placing it vertically the cells arent getting very hot like before but they are still getting hot just not like before.
 

Oberfail

Member
Joined
Jun 22, 2021
Messages
103
How about putting an old pc fan under the charger to cool it down?
You can just connect it to 12v, preferrably 5v so its quieter. No controller needed.
 
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