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Harold Gough
20th February 2017, 03:19 PM
Some day we may have this for cameras and flash guns?

https://www.ffx.co.uk/tools/product/Bosch-Gal1830W-3165140818469-18V-Wireless-Charger-And-Docking-Frame-Kit

Harold

DerekW
20th February 2017, 04:15 PM
already have it for my mouse

Jim Ford
20th February 2017, 05:19 PM
They can keep it at that price!

Jim

drmarkf
20th February 2017, 05:52 PM
I'd just settle for in-camera USB charging of E-M1ii batteries...

Naughty Nigel
20th February 2017, 07:41 PM
Wireless charging is little different to a transformer. All you have is two coils of wire placed closely together. An alternating magnetic field created by one coil is reproduced in the other.

This works well enough in a transformer where the two coils are in intimate contact with one another, and usually have the benefit of a soft iron or ferrite core. However, the system described here is highly inefficient, with the waste energy creating a lot of unwanted heat. Charging is also slow as a result.

Induction hobs use much the same principle, but of course heat is not such a handicap when cooking.

To the individual wireless charging may be a price worth paying for the convenience that it affords, but if we scale it up a few million times it means yet more CO2 emissions for very little benefit. Just like electric cars really. :rolleyes:

Otto
21st February 2017, 09:26 AM
My electric toothbrush uses this principle, and takes seventeen hours for a full charge! It is a highly inefficient process as Nigel says, and how often when you're out photographing would you get to put the camera down in the same place? It might be OK in a studio but not out in the field. Just keep a spare battery handy.

That said, having to unscrew and remove my E-M5's grip to get at the battery to charge it is a darned nuisance!

Naughty Nigel
21st February 2017, 09:36 AM
I think the idea is to introduce wireless charging in places like airports to avoid the need for charging cables and so forth. I can see the logic but it is a very wasteful technology.

Alternatively, Apple could improve the battery life of its devices, as there is always a sea of white chargers and cables around sockets in airports. One rarely sees other brands on charge. :rolleyes:

Ricoh
21st February 2017, 11:10 AM
Wireless charging is little different to a transformer. All you have is two coils of wire placed closely together. An alternating magnetic field created by one coil is reproduced in the other.
:rolleyes:

For efficient transfer, the transformer is effectively cut in half, one half in the charger base station, the other in the device to be charged. The problem as correctly mentioned relates to perpermeability, and efficiency falls off with air gap between the two halves. A plot of frequency against efficiency using ferrite cores shows a dependency.

Naughty Nigel
21st February 2017, 01:47 PM
A plot of frequency against efficiency using ferrite cores shows a dependency.

Efficiency may be improved at higher frequencies, but this would heat up surrounding metal objects and would probably cause unwanted interference.

Just don't use china cups with gold bands around them. :)

Ricoh
21st February 2017, 02:17 PM
Photon is the mediator and falls off as per the inverse square law. Need to complete the magnetic circuit, hence the dependency on air gap.