liitakala 26650 battery first build

Motofox

100 µW
Joined
May 19, 2019
Messages
8
Hi, recently built my first battery using new liitokala 26650 li ion 5000ma batteries, 15s 4p

Just curious as to what tempature people see with there batteries and what is normal for these ? my bms has two temp sensors ive placed either end of the pack in the middle and the highest ive seen so far is about 28 degrees C under long loads of 40amp draw, pack was 17degrees C before, does this sound okay ?

also the liitokala li ion batteries say 2.7v to 4.2 whats a safe valtiage to drop the cells down too ?

heres the pack i built before i wrapped it
 

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Can you keep your hand on it . It should npt melt candle wax. Maybe soften not melt wax
What's the internal resistance of the cells ? What c-rate or amp rating ? Important stuff.
 
Yes I can keep my hand on it and it’s slightly warm. I believe these cells are 20a constant and 50 burst. Not sure of the resistance. Was just curious what other people’s experience is with the same cells. 28 degrees C doesn’t sound too bad ?
 
Off topic, but I don't like how your sensor wires run over the nickel strips. You need to solder them to an edge point and bring them together over the top away from the nickel. A small amount of chaffing, and you have a dead short =fire..
On topic. Discharge your pack at your controllers Max amps and see if it tolerates the draw. Anything over ~60c I'd be unhappy with but check the Mfr specs for details.
For longevity never go below 3v and charge to 4.1
 
i agree about the sensor wires, i plan on shortening them and rerouting them, the the battery only reaches around 27c on long full power drawing 40amps, so the battery is a lot more capable than the hub controller with is limited to 40a unfortunatly its intergrated into the hub which is nice and neat but i really wanna upgrade the controller now :( i guess that would mean taking the hub apart :(
 
Looks good but I would also keep sensor wires on top away from nickel strips
 
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