I'm trying to power a heated lunch box I got from Amazon (this one) via this - 12 V 20000 mAh Li-ion battery pack, which appears to be 6x 18650s.
When I plug it in, the battery heats up significantly, though it's enough to heat up my food, I'm worried if it's a bad idea or not.
The battery specs are - battery discharge requirements:
Input/output: two 20# line, 150 mm long
Maximum instantaneous current: 10 A
Maximum working current: 5 A
The lunch box has two PTC heater elements such as this one.
Can anyone help or explain if this is safe to continue or maybe introduce some current draw limits?