12 thoughts on “Autopsy: faulty pwm5 solar charge controller”
I have the same experience – sun heating the hot glue just a bit to allow a bit of a wiggle from cable, no problem in summer. But then the small room allows water to get in over Autumn, resulting in moisture inside. And in winter, the water expands as it freezes and suddenly you have big opening – next Spring your circuit is dead. I started to pain all over the PCBs with nail polish on top – that helps a lot.
Hello julian! 👍 Do you have any remaining stocks to sell? However, I would prefer a button switch that shows volt and amperes on a small display than this strange flashing! I don't like counting this disco light, it's just an estimate of iron. I also like kine SMDs and components should be military or marine grade. This is a few cents / penny more expensive for the parts, but it lasts forever! Greetings from Austria!
use silicon – real silicon neutral setting gel for sealing. (dont use clear polymers either, they can go brittle in the sun / weather ) hot melt glue is bad for sealing as you see. only good for quick fixes in hobby use, not commercial sealing. 🙂 cheers for interesting series on your experiences in prototyping to production too
yup, hot glue is not good around anything that gets hot ive noticed, hehe. noticed your melted banana plugs, thats alot of heat. thinking the wire just got warm for too long and managed to open up the hot glue just enough for some moisture to sneak in.
Tks Julian , I think Your videos is what have let me understand most from Youtube. I start with no education at all on lectronics and now I have done a lot of experimenting on transistorcontrols and what I find as the most common problem on pwm controllers for brushmotors is the too big value on serial resistors to protect the outputcurrent of 555 timers, typically 300ohm. I find with sthandard mosfets capasitive inductance will need maximum 50ohm to be controlled perfect shape for input pwm. When I come across Your pwm5 design, I find there is a differenc between Your handwritten values and the values on the part-list. Both contain the total of 7 resistors, and for the handwritten it seems like 4.7K as serial resistor into the transistor. Then I wonder if this is really correctly and what is the pwm frequency ? The transistors data of 0,2A will be able to handle a 50ohm serial resistor I think. Please correct me. How is the shape of the signal into the the transistor on the oscilloscope ?
I have the same experience – sun heating the hot glue just a bit to allow a bit of a wiggle from cable, no problem in summer. But then the small room allows water to get in over Autumn, resulting in moisture inside. And in winter, the water expands as it freezes and suddenly you have big opening – next Spring your circuit is dead.
I started to pain all over the PCBs with nail polish on top – that helps a lot.
I forgot you designed that to be reopenable! Awesome! Great idea, Julian. 🙂
Hello julian! 👍
Do you have any remaining stocks to sell? However, I would prefer a button switch that shows volt and amperes on a small display than this strange flashing! I don't like counting this disco light, it's just an estimate of iron. I also like kine SMDs and components should be military or marine grade. This is a few cents / penny more expensive for the parts, but it lasts forever!
Greetings from Austria!
I'm a bit puzzled as to why you didn't uncover the back side of that board…?
probably been said but I reckon the heat from the bad connections caused the glue to melt
use silicon – real silicon neutral setting gel for sealing. (dont use clear polymers either, they can go brittle in the sun / weather ) hot melt glue is bad for sealing as you see. only good for quick fixes in hobby use, not commercial sealing. 🙂 cheers for interesting series on your experiences in prototyping to production too
yup, hot glue is not good around anything that gets hot ive noticed, hehe. noticed your melted banana plugs, thats alot of heat. thinking the wire just got warm for too long and managed to open up the hot glue just enough for some moisture to sneak in.
When in doubd, hot glue filled heat shrink tubing!
Another interesting video.
I would have thought a lacquer would have been your choice for sealing, perhaps shilac or similar, the water would run off 🙂
Tks Julian , I think Your videos is what have let me understand most from Youtube. I start with no education at all on lectronics and now I have done a lot of experimenting on transistorcontrols and what I find as the most common problem on pwm controllers for brushmotors is the too big value on serial resistors to protect the outputcurrent of 555 timers, typically 300ohm. I find with sthandard mosfets capasitive inductance will need maximum 50ohm to be controlled perfect shape for input pwm. When I come across Your pwm5 design, I find there is a differenc between Your handwritten values and the values on the part-list. Both contain the total of 7 resistors, and for the handwritten it seems like 4.7K as serial resistor into the transistor. Then I wonder if this is really correctly and what is the pwm frequency ? The transistors data of 0,2A will be able to handle a 50ohm serial resistor I think. Please correct me. How is the shape of the signal into the the transistor on the oscilloscope ?
Did you do a tutorial on that PWM5 circuit?