Hey everyone! I'm currently working on a lighting project where I've got a circuit board that controls a bunch of addressable LEDs. It's a 12V system and can draw up to 15A, powered by a large LiFePO battery. Unfortunately, I ran into some trouble and ended up frying my board. After chatting with the manufacturer, we think it was due to inrush current when I connected the battery. To fix this, I decided to use an inrush current limiter (ICL) and installed a 1 ohm NTC thermistor in line from the battery, along with an on/off switch. While this setup seems to prevent the issue, the thermistor gets really hot! Since this board will be placed in a non-ventilated enclosure to keep out dust, I'm looking for alternative solutions that might not overheat as much. Would adjusting the size of the ICL help, or are there better components I could use? I've seen some 12V voltage stabilizers meant for car electronics that might do the trick. Any ideas?
3 Answers
One thing you could try is using the switch as a bypass. Basically, wire the switch in parallel with the NTC thermistor. When you first connect the battery, the switch would be open and the thermistor would handle the inrush. After that, you close the switch to bypass the thermistor. Just make sure your ICL can handle the current you're pulling, though!
You might also want to consider adding a small timer and relay that would bypass the ICL after a few seconds. This way, the thermistor only needs to manage the inrush for a brief moment rather than all the time. It could keep things cooler!
That sounds like a smart solution! I'll definitely look into it, thanks!
Another alternative is to use a power FET in a soft start circuit. This might help you manage the inrush current more efficiently. Check out this resource I found: https://www.ti.com/lit/pdf/slva156
Thanks for the suggestion! I’m still trying to get my head around it. The switch has 3 wires (V-in, V-out, and GND), and the NTC has two leads on the battery positive wire. How should I actually wire them to get this parallel setup?