0

I accidentally charged one cycle and the toothbrush still works. But is it safe to use it in this voltage? What's the effect on the battery? Does it charge in half voltage or is there any in built voltage regulation?

electric toothbrush charger

Shamal Karunarathne
  • 101
  • 2

1 Answers1

1

This will fry the magnetic coil from twice the excitation voltage and possible saturate the core and melt it. try it out and post the Youtube video for proof of concept (j/k);) It will be far more than twice the temperature rise when the inductance (reactance) drops to just the wire resistance.

I suspect the small gauge wire inside will self-fuse.

It reminds me when in 1970 when my older brother borrowed a $5k portable tape recorder from CBC and smoked it on 230Vac during his trip thru Africa with a Land Rover. ( He majored in Political Science not engineering)

added

However consider the very low VA rating of this device, it would be perfect candidate for a 2:1 stepdown voltage transformer inside a USA bathroom junction box and receptacle for shavers and toothbrushes alike that run off 120Vac. enter image description here Although with the price of e-toothbrushes, it may be a thing of the past.

Tony Stewart EE75
  • 1
  • 3
  • 54
  • 185
  • "He majored in Political Science " Well, he had lots of "smoke" to go around then.. ;D – Trevor_G Jan 30 '18 at 13:27
  • 2
    It's made in Germany. It probably won't catch fire. – Jeroen3 Jan 30 '18 at 13:27
  • It may not have a coil though Tony, it's a charger and may be just a simple AC-DC convertor. Still, it will likely fail, and isolation maybe compromised. – Trevor_G Jan 30 '18 at 13:39
  • 2
    It is Braun's first Wireless magnetic charger with 50% efficiency and low power. Its just a transformer with the toothbrush having the secondary winding. I know these products. – Tony Stewart EE75 Jan 30 '18 at 13:50
  • 1
    A family lady friend banjaxed her husband's shaver. She reckoned that 110 V was for ladies and 230 V for men. (By that reckoning "real men" probably need 400 V.) – Transistor Jan 30 '18 at 15:16
  • Thankfully, The toothbrush is charging, And working fine so far. That's why I was wondering what really happens at charging? does it charge with lower voltage? And whether to keep using this way? – Shamal Karunarathne Jan 30 '18 at 15:19
  • 1
    So you are applying 230V~/50Hz when it is rated for 110-130V~50/60Hz Then twice the V is being applied to Primary and Secondary must decide how to regulate perhaps by DC Vref then temperature – Tony Stewart EE75 Jan 30 '18 at 15:38