Wireless Power and the Water Tank

May. 2018

When people see our demos, one of the first questions they ask is: will it charge _____ ? (or can it power _____ ? )

The answer depends on the average and peak power consumption of the product in question, but we typically see three categories:

The first category includes products like a toy train or a speaker. The Wi-Charge receiver can consistently deliver enough power to operate the device.

The third category includes products like a Tesla electric vehicle. If the question is “Can you power a Tesla?”, then the answer is “No”.

The second category is the most interesting. These are products where theirĀ peak power consumption might be more than what a Wi-Charge receiver can deliver today. But, theirĀ average power consumption is less, and often much less, than what we can deliver.

For instance, a smart door lock may be idle most of the time but when a human approaches, that smart door lock might want to analyze fingerprints, or to recognize a face, or to upload access data to the cloud. That takes a lot of energy, but perhaps happens just few or just dozens of times a day. The peak power consumption is much higher than the idle power consumption.

Similarly, a security camera might have a proximity sensor that then senses an nearby moving object. That sensor triggers recording or analysis. But recording and analysis don’t happen all the time – just several times each day

The solution there is to include a small rechargeable battery or other energy storage in the device. That battery can provide the peak power when needed, but charges when that peak power is not needed. It’s almost like a water tank for a toilet. Water fills for a couple of minutes, but then provides a lot of water during a short time when flushing.

If the peak and idle power consumption is known and if the usage pattern is known, we can calculate what size energy storage is required. We can also determine how many such products can be powered at the same time from the same Wi-Charge transmitter.