#1 - DIY
Added 2025-08-31 18:26:32 +0000 UTCI recently got the ZB2L3 battery capacity tester from Aliexpress. Overall it is an awesome device, but the resistors it comes with got really hot (not touch safe) during operation. I decided to quickly construct this MOSFET load with an NTC resistor bias at the gate. Basically as it get hot, the gate voltage bias decreases (due to NTC resistance dropping) and thus the current decreases. Now I got increased discharge current of 0.5-2.0 A and it is no longer extremely hot, just warm.
NOTE: The issue is, that it is still a non-linear load (just like a resistor), so as the battery discharges the gate voltage bias goes down and the current drops. In the future I might add a Zener diode or TL431 or use the voltage bias from the ZB2L3 board.
