-3
\$\begingroup\$

Is it possible to damage a phone by charging it with an intermittent power source? For example, by using piezoelectric transducers in the soles of your shoes.

Assuming they're wired to a 5V regulator, will the constant oscillations between 0-5V damage the phone in any way?

\$\endgroup\$
  • 1
    \$\begingroup\$ Welcome to the site. Please quickly realise that this is not a free design house, homework-answering service or an on-line technical encyclopedia, copied out to you on demand. People will help you take the next step if your question shows that you've done as much as you possibly could on your own - which your post doesn't, I'm afraid. Please revise your question showing your work and findings so far, in considerable detail. Or delete the question if Internet searches give you your answer anyway. Again, a warm welcome to the site. \$\endgroup\$ – TonyM Jun 24 '17 at 17:38
  • \$\begingroup\$ Very warm indeed! I'm not sure what more I can say, I've wired a simple circuit of piezos to a 5V step up converter and into a micro usb cable. I can see on the scope that flexing the piezos generates rapid oscillations in voltage between 0 and 5V. I'm now looking for insight from the experts to tell me whether these oscillations could damage my phone or if it's safe to use. I've come across this question which doesn't address oscillations. \$\endgroup\$ – spontarelliam Jun 24 '17 at 17:56
  • \$\begingroup\$ Your step up converter might not even be able to start up with spikes from the piezos. You'd probably need energy harvesting ICs, and even then you wouldn't "charge" your phone. \$\endgroup\$ – Wesley Lee Jun 24 '17 at 18:17
  • 1
    \$\begingroup\$ Quite. But you realise that the site's for specific design questions. The downvotes and vote to close suggest others may expect more details, too. Please can you edit your comment into the question, so no-one has to piece together the question from it all. And the welcome couldn't be warmer or more genuine. \$\endgroup\$ – TonyM Jun 24 '17 at 19:26
0
\$\begingroup\$

Is it possible to damage a phone by charging it with an intermittent power source?

Probably not. Lithium batteries have no memory effect have no problem handling a bit of charging followed by a bit of discharging.

For example, by using piezoelectric transducers in the soles of your shoes.

Now, this is interesting. If you somehow manage to create a 5V supply with enough current, then the phone will start charging.

Since the power generated by these piezo elements will be ridiculously small, it is highly likely that as soon as the phone starts drawing current to charge itself, your device's output voltage will collapse, and the phone won't charge at all.

However, the screen will light up for a few seconds and display "charging..." and this will most likely use a lot more energy than what your piezo elements can provide.

Therefore, the net result will be that the phone's battery will discharge quicker (due to the backlight) than if it had not been plugged into the sneaker-charger ;)

\$\endgroup\$

Not the answer you're looking for? Browse other questions tagged or ask your own question.