Credit to Author: Yasemin Borg| Date: Wed, 25 Mar 2020 17:36:57 +0000
Probably we all experienced the same situation several times trying to find a charging point wherever we are as a matter of emergency. 10 years ago, the situation was more or less the same with only a difference of technology. Since 2015 we are seeing more options to power up our devices. The majority now is using USB (universal series bus), leaving its place to wireless charging sooner or later.
As of the 1st of April of 2020, another change is happening that we need to adapt and adopt with respect to the Ecodesign Directive 2009/125/EC. This especially concerns USB socket outlet manufacturers who will be required to design and manufacture products with efficiency in mind. They will be mandated to publish active power efficiency levels in user guides, as well as on the product where possible.
This new legislation primarily highlights the importance of reducing the energy usage and provides greater insight to empower electricians and consumers to improve efficiency.
Yet awareness remains one of the greatest challenges facing our industry. Low-efficiency products undermine performance, shorten the life-cycles of installation and in extreme cases, fail or become hazardous. It is therefore vital that installers and owners are aware of the efficiency of all products throughout their life-cycle and act appropriately.
Key Factors of USB Charging Performance
1- Power Level
The power level of a device is important to choose the correct charging adapter with the right voltage and ampere level. Whereas it can go up to 100W laptops, it varies from 30 to 45W for tablets and can be up to 18W for new smart phones.
2- Charging Protocol
There are different types of protocols which also have an impact causing these limitations.
a- BC1.2: Battery Charging 1.2
Low power devices (5V, max 150mA)
High power devices (5V, max 1.5A)
b- Proprietary Protocols
These are developed by phone companies for their own devices. (Apple 2.4A, Samsung 2.1A)
c- QC: Quick Charge defined by Qualcomm QC3.0
This can be used with USB type A or C (3.6V to 20V, max 3A)
From QC4.0 version the protocol will align with PD (power delivery)
More Android phones will be introduced with Fast Charging
d- PD: Power Delivery defined by USB-IF organization 3.0
This can be used with USB type C only (5V to 20V, max 5A)
Apple and Google devices with Fast Charging
3- Charging Cable and Device’s Age
The quality of charging cable is also affecting the charging time. When you use a 3rd party cable you might realize it requires a longer charging time and connections might heat up pretty quickly.
When the device itself is new it is charged more efficiently as well. As the battery capacity is high, battery discharging rate is lower. In contrary when the device gets older the discharging rate becomes higher.
Taking into account that the device is with a fast charging feature and battery capacity together with the charging cable are the same, it can take over 2 hours with a 2.1A charger whereas over 3 hours with a 1A charger to fully charge the device from 0% to 100%.
4- Energy Efficiency
When it comes to charging one of the most important things we tend to neglect is charger’s efficiency.
The USB socket outlets are usually installed in walls, furniture or housings which cause undesirable heating on the back box and therefore makes it difficult to perform efficiently.
The required efficiency levels are clearly stated in the regulations (No 2019/1782 on External Power Supplies) referred as active power efficiency.
Common low-cost USB chargers in the market tends to have a lower level efficiency below 75% whereas Schneider Electric has the highest efficiency leading the USB charging market by far from its closest competition.