Words such as "Fast" and "quick" have very subjective meanings. For example, once I went to see a doctor earlier than usual, the receptionist said that I came early, and I can quickly see the sick and leave. It’s good, I expect to be able to go back to work in time, and catch up with a meeting that I thought I couldn’t catch up. After reading a copy of People's Cars and a National Geographic impurity two years ago, I was called to the clinic.
Before I went to see a doctor, I even had time to watch two last year's Road & Track magazines. It’s enough to finish the meeting for so long... When I told the receptionist that the visit seemed to be longer than I expected, she said it was already fast enough. Ok, maybe my estimate is rapid, and the end result is fast. I think this is actually slow.
In the era of nickel-cadmium batteries, which are rechargeable batteries for most portable electronic products, we have different terms for different charging speeds and clearly defined them. At the "standard" charging speed of C/10, it takes about 12 hours for the battery to go from no electricity to full. The battery does not require a charge termination function at this rate. Then there is a "quick" charging of C/3, which takes nearly 4 hours from no electricity to full grid, which requires charging to terminate. Finally, the "quick" charging C/2 to C, the battery is full at a C rate in just over an hour. This charging rate requires a termination function and typically requires full charging before entering the maintenance charging mode.
As lithium-ion batteries become the first choice for portable charging power supplies, fast charging is now a good area of ​​innovation. The shift from devices to smartphones and tablets adds even more challenges. A more extreme example is Samsung's latest tablet Note Pro 12.2. The tablet uses a 9500mHr battery and comes with a 2A charger. This means that if the user does not plug in the power supply for a whole day, it will definitely charge for a whole night. From the comments, I should make the battery work for more than 10 hours, which is satisfactory.
Going back to the fast charging problem with this type of device requires setting consumer expectations. Terms such as "fast" or "rapid" can be used to set expectations. Figure 1 shows the time required from different state of charge (SOC) to full charge at different maximum charging currents. As can be seen from the figure, when charging from 75% of the SOC, it does not matter whether the adapter of 2A or 3A capacity is used. It takes more than 1.2 hours to fully charge. This is because charging in constant voltage mode. Therefore, consumers will be disappointed if they expect to use a fast or fast charger to fully charge the battery.
However, if charging starts from an empty charge, there is a difference of about 20 minutes between the 2A and 3A charging rates. This is entirely in the expected setting. In a paper by Botsford and Szczepanek, they provide parameters for slow, fast, rapid and rapid charging. Although this paper is about electric vehicles, it points out a consistent definition of these terms. In this article, the speed is slower than the faster, while the faster is slower than the rapid. This is consistent with other battery charging terms.
　　 Figure 1. Comparison of the time from different state of charge to full charge with the maximum charge current.
The paper cites the California Air Resources Board (ARB) directive. The command requires a fast charger to bring 100 miles of mileage after ten minutes of charging. Of course, this means that the car needs to have a battery that can travel more than 100 miles.
We can use the same concept to express the rapid or fast meaning in a portable device. For example, we can stipulate that the battery charge obtained by the rapid charger after 30 minutes of charging should be maintained for at least 5 hours. This is just an example, assuming a rapid charging current of 1C and the battery can support 10 hours of normal operation.
I know that the advantages of providing faster charging are greater than the difficulties of solving practical technical problems. If we can't set expectations to assess consumer perceptions, then rapid charging may not be as valuable as we think. Providing a wall adapter that is not much larger than the current 10W adapter, while providing double the power at a cost of less than twice the cost, will definitely keep us busy. In many cases, consumers want to charge their devices while they are using them, so they need more power. To solve the heating problem caused by charging at a double rate in very slim smartphones and tablets, a significant increase in conversion efficiency is required.
Fast or fast, it is actually the expected problem. Whether waiting in the doctor's office for waiting, waiting for family members to get ready to go out, or charging my new tablet, my slow speed is some people's haste. I want to know what you think about this issue and what challenges you think are fast or fast. By the way, I haven't mentioned the capacity degradation that can be caused by faster charging.
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Reference material
Charles Botsford, Adam Szczepanek, "Fast charging and slow charging: the pros and cons of the new electric car era", Norway's Stavage EVS24, May 13-16, 2009.
1U,8 Ways Aluminum Shell, Rackmount 19'' Inch 16A 250V PDU (Power Distribution Unit)
Features:
- 19" Horizontal/Vertical Mount Type
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Heavy Duty Aluminuml Body Or ABS- 1U,1.5U size
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Shell Material:Uninflammable PC modules,Aluminum/ABS Alloy Shell
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Type of Cable & Plug:3G*1.5mm2*2m,DIN49441 Plug
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Protection:Optional Security System To Avoid Accidental Disconnections.
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Certificates:CE-EMC;CE-LVD;RoHS;UL94-VO
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Different Types of Input Male Plug Top Options are available
Technical Specifications:
- Rated Current:16A
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Max Output Power:4000W
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Rated Voltage:250V,Household Voltage 240V 50/60Hz
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Switch:Red On/Off
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Color:Black Or Aluminum White
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Other Functions For Option
Application:
Used for power distribution for 19 inch 1 U server rack.
Product Images:
Power Distribution Unit
Intelligent Management System(Appdu),Appdu â… (Without Intelligent Management),Appdu â…¡(With Intelligent Management),Pdu (Power Distribution Unit)
Guangdong Steady Technology Co.LTD , https://www.steadysmps.com