The biggest technical support headache wasn't due to poor circuit design or buggy firmware. It was due to a misunderstood product feature - the LED Disable mode. But rather than remove the feature, I tried to make it work more reliably by adding additional code. Ultimately I failed and paid the price by having to test customer's units and even refund a few.
PWM5 firmware version 1.3 is here: http://256.uk/?p=113

By Julian

Youtuber, shed dweller, solar charge controller aficionado

12 thoughts on “Julian reveals: secrets of the pwm5 – #2 misjudgement”
  1. Avataaar/Circle Created with python_avatars Matt Miller says:

    Man… A little QR code on there which pops up a little video on your phone explaining the LED would’ve been great. 😅

  2. Avataaar/Circle Created with python_avatars David _1 says:

    yay enjoying this

  3. Avataaar/Circle Created with python_avatars Shrike DeCil says:

    Some sort of tiny note on the device label itself near the LED.
    "LED activity in XXX Mode Only"
    There's the underlying hint "Go find the darn manual".

  4. Avataaar/Circle Created with python_avatars vonries says:

    I don't know about anyone else, but I think it is a great feature. Sorry it bit you in the ass. I would say in your open source version just comment out that line don't remove it. If they can figure out how to uncomment the line in code then they should be smart enough to handle plugging it in correctly.

  5. Avataaar/Circle Created with python_avatars Browarus Pierogus says:

    hmmm why all this hassle if one small button would eliminate all problems

  6. Avataaar/Circle Created with python_avatars Robert Heal says:

    Those instructions were not very good. It is really not hard to say, very clearly, that to reset the device it has to be disconnected from both the battery and the solar panel. This is in fact quite non-obvious, since most devices are not supplied from both sides, and if you disconnect from the supply side, then people expect them to be off.

  7. Avataaar/Circle Created with python_avatars Anvilshock says:

    As the mechanical switch was ruled out due to the shrink tubing, did you consider an optical sensor, like an LDR? Cover another hole in the tubing = button pressed?

  8. Avataaar/Circle Created with python_avatars amandarosenberger says:

    New to your channel, but I have to say it surprised me how many people don't don't the manual. Your manual is 1000000x better than cheap Chinese ones. Some common sense helps people. Would love to buy one of these… can't find a reliable charge controller that I like. BTW… love the LED feature… got what it was by reading the label… ha ha… but then again I can read and understand electronics which is where people go wrong with electronics… not having a background or understanding the theory. Diode in the wire is a definite keep no matter what. I have seen diodes in panels fail epicly with whole house electrical fire as a result.

  9. Avataaar/Circle Created with python_avatars frill necked lizard says:

    I would love it if more people put a led disable function on their products, this is because every night there are about 10 led's on random electronics that are charging or doing stuff that are keeping me awake. allthough putting it on a solar charge controller?

  10. Avataaar/Circle Created with python_avatars Jake Abel says:

    I bet you had people that just put some electrical tap over the LED to remove the flashing.

  11. Avataaar/Circle Created with python_avatars Jar says:

    Very interesting series, Julian, thanks for posting. Hindsight is wonderful. Biggest secret to successful selling to joe public is keep it simple and show as little information as possible, and also make the technical help access as time consuming as possible for the customer (very difficult to do the latter if you are small, and no respectable ethical person wants to do that anyway). All big companies now follow this disgusting regime. But that LED feature, buddy, what were you thinking? Respect to you for admitting it here. LED disable = piece of black tape.

    I guess idiots think that if they can work something without reading a manual then it has proved their own intelligence. Ironic that the opposite is true, of course. To get the best out of any technical product, you must get as much information from the original designer as possible; that is intelligence. I think not reading the manual has come about because of this idiotic feeling of superiority and also all the useless crap that regulations and lawyers say must be in the manual which hides the odd useful bit of info amongst a tome of utter rubbish. Luckily, most of my customers have a PhD.

    You have not mentioned having temperature compensation. I hope there is!!

  12. Avataaar/Circle Created with python_avatars zx8401ztv says:

    Hmm shame that 🙁
    Too fancy for its purpose, keep it simple and foolproof.

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