It's not acceptable for commercial products to explode just because the consumer connects things up the wrong way round. Reverse polarity protection sounds dull, but it provides the perfect excuse to blow things up!
By Julian
Youtuber, shed dweller, solar charge controller aficionado
Fast forward 9 years and all mppt controllers have reverse polarity protection on the battery (or output) side. My question is: just how much protection is this? I accidentally reversed polarity from mppt to battery. Nothing melted or smoked, no error messages, no fault lights, but it is no longer working correctly. Basically it does not realize that it has been damaged somehow. It now seems to be unable to sense the correct voltage of any battery connected, eventually showing them as full, which prevents charge from initiating.
Wish I'd known this before I blew the diode on my buck boost converter lol!
You probably already know this, but 9 v batteries vary their voltage a Lot over their life, and start out north of 11 volts, no load.
Juilian. Is there any documentation on your MPPT project ? Trying to figure out what it would take to mod a Decent size (20A) Buck converter to function as a MPPT.
That is really nice. I like polyfuses. The paralleling isn't the best thing, but it does work. The problem is some of the polyfuses will blow first and the last one will see higher current (it will blow too very quickly, but momentarily will see higher current, i.e. 10A rated fuse, will be happy below 10A, trip over 20A, and whitestand up to 100A without damage; but in some spec sheets, I see that even at higher than trip current, lets say 50A, it can take 15 seconds for it to trip. Smaller devices are usually much faster, of about half a second max). It could make it last shorter.
I wonder how the life time of these polyfuses is determined. Can they survive 1000 cycles?
Can't you just put another diode in series with the output to block any current can't flow backwards?
So apparently that like 10A diode cant handle hundreds of amps
Wait… the current isn't going through the inductor, it goes through the diode since it's directly polarized. The inductor isn't connected in parallel to the diode, so no current flows.
you should have put the diode in parallel with the fuses to see witch went first! where can I find these fuses? I haven't seen them for sell anywhere. though I have seen them. I think some can look like capacitors. correct? great ol video
make a unit to hook up first that tests circuit before final hookup that has tiny fuze and a switch – few amp fuze not blown – everything OK
I appreciate how tidy your wiring is! – And I'd be happy to find that blown out diode. No test equipment needed to spot that!
better to use a p mosfet on the positive rail with the gate tied to negative
Let me say that your video is informative but the buck boost alone cannot be mppt I suggest you put a dc to dc converter before your rig that gives you more current gain
Rather interesting video that, might look into these to protect some of my solar setup
Hi Julian, I've started watching this series yesterday with great interest. I think you are looking to idiot-proof the electronics, and although polyfuses seem like an elegant approach, I always look for the most simple solution. Why not use a fuse for the output as well as the input? Fuses are inexpensive, readily available and should provide better protection without causing an inefficiency penalty. Cheers, Richard.
Didn't bother watching the video. Clicked off at the advertisement.