DIY, Notebook AC adaptor 用作 12V 充電器
再來一個 DIY, Notebook AC adaptor 用作
12V 充電器
xiao_laba@yahoo.com.cn
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何謂 DIY?! 某年某月某日, LECTURER 給同學的訓話,共勉之,
you, 書又讀吾好,
you, 字又體吾到,
you, 軟又吾識做,
you, 硬又怕爆煲,
簡單而言, 吹水最容易. you, 吹水最 O力.
用途警告:
本人學術研究之用, 諸位有無Ｘ用, 與本人無關; 了解何謂ＤＩＹ；
唯眾卿欲抄襲作非商業用，不用來函相告. 可交流；
唯眾卿欲抄襲作商業用，請不吝嗇來函相告. 可協助；
若諸位欲試之，任何損傷或損失，與本人無關；
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再來一個 DIY, Notebook AC adaptor 用作 12V 充電器;
材料: Notebook AC adaptor一個, 鐵釘兩口, 舊電話線盒, 舊電線兩條, DIY精神小小
工具: 螺絲批, 式士, 剪鉗, GAS燈, 錫線, 20蚊針表一個
adaptor 輸出電壓 : 19V, no load
初始充電電壓 : 低於 12V
一小時後充電電壓 : 13.1V
充電電流 : < 4A
Specification of the Battery
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An epilog
Textbook never tells how to fix the real problem, because of it could be nothing
to put down in writing. It does not tells how to DIY either, because of no one
has exact problem you encountered.
DIY is about thinking, doing and to learn new things by reviewing old things as
someone likes to do.
DIY is not the blame, not the scoff, not the sarcasm whatever.
This DIY gave her proof about everything can be done with confidence of try,
based on the knowledge obtained as some old things.
It was not guilty of illiteracy, but people show most appreciation for anyone
who try to learn and must respect.
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Some reading about the knowledge
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Valve regulated lead-acid (VRLA, 要加水的電池)
The charge voltage setting on VRLA is generally lower than SLA. Heat is a killer
of VRLA. Many stationary batteries are kept in shelters with no air
conditioning. Every 8°C (15°F) rise in temperature cuts the battery life in
half. A VRLA battery, which would last for 10 years at 25°C (77°F), will only
be good for 5 years if operated at 33°C (95°F). Once damaged by heat, no
remedy exists to improve capacity.
Charging lead-acid batteries with a power supply
Lead-acid batteries can be charged manually with a commercial power supply
featuring voltage regulation and current limiting. Calculate the charge voltage
according to the number of cells and desired voltage limit. Charging a 12-volt
battery (6 cells) at a cell voltage limit of 2.40V, for example, would require a
voltage setting of 14.40V.
The charge current for small lead-acid batteries should be set between 10% and
30% of the rated capacity (30% of a 2Ah battery would be 600mA). Larger
batteries, such as those used in the automotive industry, are generally charged
at lower current ratings. Cells constructed of a non-antimonial lead grid
material allow higher charge currents but have a lower capacity. The cylindrical
Cyclone is sealed and can sustain a pressure of up to 3.5 Bar (50 psi). A
pressurized cell assists in the recombination of gases.
Observe the battery temperature, voltage and current during charge. Charge only
at ambient temperatures and in a ventilated room. Once the battery is fully
charged and the current has dropped to 3% of the rated current, the charge is
completed. A good car battery will drop to about 40mA when fully charged; a bad
battery may not fall below 100mA.
After full charge, remove the battery from the charger. If float charge is
needed for operational readiness, lower the charge voltage to about 13.50V
(2.25V/cell). Most chargers perform this function automatically. The float
charge can be applied for an unlimited time.
State-of-charge reading based on terminal voltage
The state-of-charge of a lead-acid battery can, to a certain extent, be
estimated by measuring the open terminal voltage. Prior to measuring, the
battery must have rested for 4-8 hours after charge or discharge and reside at
room temperature. A cold battery would show slightly higher voltages and a hot
battery would be lower. Plate additions of calcium and antimony will also vary
the open terminal voltage. Furthermore, AGM has a higher voltage plateau than
the flooded lead acid and the readings on Figure 3 may not apply.
Theory of 蓄電池, Lead-Acid battery
蓄電池能夠充電再生，當其放電時，發生自發反應，它起一個原電池的作用；
充電時發生電解反應，起電解池的作用，可使原來的反應物再生。
汽車上所用的鉛蓄電池是最常用的蓄電池之一。
它是由間隔的海棉狀的鉛板和二氧化鉛所構成，並浸在硫酸溶液中。
當電池放電時，發生下列反應：
負極（Ｐｂ）：Ｐｂ＋ＳＯ4２－－２ｅ→ＰｂＳＯ4
正極（ＰｂＯ2）：ＰｂＯ2＋４Ｈ＋＋ＳＯ4２－＋２ｅ→ＰｂＳＯ4＋２Ｈ2Ｏ
總反應：Ｐｂ＋ＰｂＯ2＋２Ｈ2ＳＯ4→２ＰｂＳＯ4＋２Ｈ2Ｏ
由上可知，兩電極上都生成硫酸鉛，由於其難溶性，沈積在電極上而不溶解在溶液中。
由於反應中硫酸被消耗，有水生成，所以可用測定硫酸的密度來確定電池放電的程度，
當硫酸的密度降到１.０５ｇ·ｍＬ－1或電壓降低到１.９Ｖ時，就要充電。
當電池充電時，就是通以直流電，鉛板與電源負極相連，二氧化鉛板與電源正極相連，
在電解過程中，上述電極反應都逆向進行：
陽極（ＰｂＯ2）：ＰｂＳＯ4＋２Ｈ2Ｏ－２ｅ→ＰｂＯ2＋４Ｈ＋＋ＳＯ4２－
陰極（Ｐｂ）：ＰｂＳＯ4＋２ｅ→Ｐｂ＋ＳＯ4２－
總反應：２ＰｂＳＯ4＋２Ｈ2Ｏ→Ｐｂ＋ＰｂＯ2＋２Ｈ2ＳＯ4
故該蓄電池的反應可表示：
Ｐｂ＋ＰｂＯ2＋２Ｈ2ＳＯ4 <--> ２ＰｂＳＯ4＋２Ｈ2Ｏ
充電後，單個鉛蓄電池的電動勢約 2.1V。汽車上用的是將６個蓄電池串聯起來，電動勢約 12V。
Some illustrations about this DIY
