WiTricity Article on Wireless Charging

[HuntingPudel]

WiTricity recently published an article comparing their modified MME's wireless charging to a J1772 L2 plug-in charge. ??

In the video, they do get an SVS notification on the dash, so I don't know if that's an issue related to the charge rate. ?‍

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[Murse-In-Airy]

No mention of how much power came from the outlet versus how much made it to the car. Call me doubtful.

 

[kodiakng]

No mention of how much power came from the outlet versus how much made it to the car. Call me doubtful.

they have another post addressing the efficiency - they claim similar loss compared to a L2 EVSE + on-board charger.

 

[Murse-In-Airy]

they have another post addressing the efficiency - they claim similar loss compared to a L2 EVSE + on-board charger.

They make it sound pretty. But I’m going to remain skeptical until I can see a side by side comparison. I hope for everyone’s sake that my skepticism is misplaced. I just know that my iPhone, plugged in, chargers a lot faster than my iPhone, not plugged in, and with a lot less waste heat. Maybe they’re using something more akin to iPhone MagSafe, which is admittedly a good magnetic charger but requires much closer distances.

 

[kodiakng]

They make it sound pretty. But I’m going to remain skeptical until I can see a side by side comparison. I hope for everyone’s sake that my skepticism is misplaced. I just know that my iPhone, plugged in, chargers a lot faster than my iPhone, not plugged in, and with a lot less waste heat. Maybe they’re using something more akin to iPhone MagSafe, which is admittedly a good magnetic charger but requires much closer distances.

current phone charging is done by electromagnetic induction; Qi is the dominant standard and both android and apple use it. the piece apple added to the system with MagSafe is a mechanism to keep the coils aligned using magnets (surprise ?) to keep efficiency high and reduce heat losses.

the WiTricity system uses magnetic resonance which works differently - a good explainer is here from Undecided with Matt Farrell. this method doesn't have the thermal loss or close proximity issues of induction but does still need relatively precise alignment for highest efficiency.

the biggest issue they'll have is getting manufacturers to integrate it into cars since, for mass adoption, it will be an additional system to include and maintain over time. they talk about not needing the on-board charger with their system but that is only true if manufacturers forego the current AC EVSE option; i don't see that happening anytime soon no matter what plug they put on the in-let port.

 

[Jimrpa]

current phone charging is done by electromagnetic induction; Qi is the dominant standard and both android and apple use it. the piece apple added to the system with MagSafe is a mechanism to keep the coils aligned using magnets (surprise ?) to keep efficiency high and reduce heat losses.

the WiTricity system uses magnetic resonance which works differently - a good explainer is here from Undecided with Matt Farrell. this method doesn't have the thermal loss or close proximity issues of induction but does still need relatively precise alignment for highest efficiency.

the biggest issue they'll have is getting manufacturers to integrate it into cars since, for mass adoption, it will be an additional system to include and maintain over time. they talk about not needing the on-board charger with their system but that is only true if manufacturers forego the current AC EVSE option; i don't see that happening anytime soon no matter what plug they put on the in-let port.

I could see high-end manufacturers putting in the system because it makes home charging a no-brainer. Also, if there's any type of wide-spread adoption, I could see putting something like this in instead of conventional L2 chargers. From what I gather, it wouldn't handle L3 currents.

 

[kodiakng]

I could see high-end manufacturers putting in the system because it makes home charging a no-brainer. Also, if there's any type of wide-spread adoption, I could see putting something like this in instead of conventional L2 chargers.

agree. it would be very useful for an autonomous application.

From what I gather, it wouldn't handle L3 currents.

they don't say where the limitation is that they haven't gone with a higher current system but since the input sequence converts DC to high frequency AC it may be possible in the future.

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