【正文】 to get the required current output. All positive plates are connected together as are all the negatives. Because each positive plate is always positioned between two negative plates, there is always one or more negative plate than positives.The resultant voltage of lead acid cell is normally 2 volts In order to achieve the voltage required for the application each cell is then connected in series by substantial metal straps to form a battery. In a typical monoblock battery, such as that used in a car for starting, the voltage required is 12 volts, achieved by connecting six cells together in series and enclosing them in one plastic box. Leisure batteries where a sustained current requirement is needed and a deep cycle, the ability to be discharged to 90%, have a different makeup to that of a traction battery that is used in a car.The cell containing the plates is filled with an electrolyte made up of sulphuric acid and distilled water with a specific gravity of at 60deg F ( C). Sulphuric acid is a very active pound of hydrogen and sulphur and oxygen atoms. Sulphuric acid is a very reactive substance and because of its instability it is able to distribute itself very evenly throughout the electrolyte in the battery. Over time, this action ensures that an even reaction can occur between all the plates. the lead dioxide at the positive plates turns the surface of both plates into lead sulphate. As this process occurs the hydrogen within the acid reacts with the oxygen within the lead dioxide to form water. The net result of all this reaction is that the positive plate gives up electrons and the negative plate gains them in equal numbers, thereby creating a potential difference between the two plates. Care and Maintenance of Flooded Lead Acid BatteriesThe most important aspects of care for these and all other types of batteries concern both charge and discharge as well as the mechanical treatment of the batteries . keeping them topped up with water etc.It is important to consider that lead acid (pb) batteries are, as we have seen above, quite delicate chemical factories.DischargeLead acid batteries should never be run flat. The maximum remended discharge is 75% of the total. This means that the battery should have a minimum of 25% of charge remaining when it is put on charge.Lead acid batteries once filled with electrolyte, should always be regularly charged even if they are not in use. When left idle a filled battery will self discharge because of its own internal resistance. Storage also affects the rate of discharge. A battery should never be stored directly on the ground and especially not on concrete. The best storage method is wooden pallets which do not conduct or allow damp paths and do allow good air circulation. During storage, most manufacturers remend a freshening charge once every two months or so.How to find the state of chargeTo easily see the state of charge accurately you should obtain and fit a battery condition instrument such as the E meter or Curtis 901, the former is easily the best but is not cheap. The most accurate way of checking a battery’s condition is with a drop tester but this is not a quick and easy method.The cost of an E meter or curtis may initially appear prohibitive, but you should consider how much its cost will save by preventing the premature failure of expensive batteries.It is extremely difficult to accurately measure the state of charge of a lead acid battery and to predict the remaining capacity.Battery capacity is not parable to a tank full of petrol. A filled petrol tank contains a finite amount of energy which can be used either slowly or fast according to the energy required. Battery capacity is not so simple.If you try to draw the battery down more quickly you cannot expect to get the same amount of Ah from it. For example if you draw it down over just one hour the ap。同時(shí)在設(shè)計(jì)的過程中得到了同學(xué)們的幫助，提出了許多寶貴的意見，在這里我要感謝你們的幫助。對(duì)于使用者來(lái)說，從外部來(lái)看，密封蓄電池是一個(gè)“黑箱”，至少是一個(gè)“灰箱”。蓄電池的放電過程是化學(xué)能轉(zhuǎn)變?yōu)殡娔艿倪^程，蓄電池的充電過程是電能轉(zhuǎn)化變?yōu)榛瘜W(xué)能的的過程。在定電阻放電狀態(tài)下，也可方便地測(cè)量出其準(zhǔn)確的蓄電池容量，且體積小、可靠性高、價(jià)格低廉、測(cè)量方便、具有很高的性能價(jià)格比，一定會(huì)得到廣泛的應(yīng)用。顯示最后一位 SETB CALL DELAY MOV A,0 MOV P1,A RETLEDMAP: DB 3FH,06H,5BH,4FH,66H,6DH,7DH,07HDB 7FH,6FH,77H,7CH,39H,5EH,79H,71H。顯示碼填入顯示緩沖73HCLR CLR CLR 。數(shù)字轉(zhuǎn)換成顯示碼(中間) ADD A,80H 。71H,72H,73H中為查表得到的顯示碼。選通通道1 CLR MOVX DPTR,AAA: POP DPLPOP DPHPOP ACCPOP PSWRERI 數(shù)字顯示程序設(shè)計(jì)本系統(tǒng)采用動(dòng)態(tài)顯示方式，LED為共陰極。延時(shí)10usSETB EX1 。開中斷 SETB IT1 。(6)讀A/D結(jié)果寄存器。(2)設(shè)置A/D中斷。如此反復(fù)。每次累加到360000A。Q= (53)式中： I— — 電池的放電電流；t—— 電池的放電時(shí)間。 原理圖圖44 A/D接口電路原理圖第5章 軟件設(shè)計(jì) 主要算法 電壓 (51a) (51b)式中： —A／D轉(zhuǎn)換IN1輸入端的8位輸出； —IN1輸入端的模擬電壓值； U —蓄電池的端電壓。地址選通端分別與三個(gè)地址線相連，用于選通IN0—IN7中的某一通道。ADC0809芯片內(nèi)部沒有時(shí)鐘脈沖源，可以利用單片機(jī)提供的地址鎖存控制輸入信號(hào)ALE，作為ADC0809的時(shí)鐘輸入。 設(shè)計(jì)方案ADC0809與單片機(jī)的硬件接口方式有：查詢方式、中斷方式和等待延時(shí)方式。START上升沿將逐次逼近寄存器復(fù)位。 Vcc：電源，單一＋5V。當(dāng)A/D轉(zhuǎn)換結(jié)束時(shí)，此端輸入一個(gè)高電平，才能打開輸出三態(tài)門，輸出數(shù)字量。ALE：地址鎖存允許信號(hào)，輸入，高電平有效。下面說明各引腳功能。(5)模擬輸入電壓范圍0～＋5V，不需零點(diǎn)和滿刻度校準(zhǔn)。：(1)8路8位A/D轉(zhuǎn)換器，即分辨率8位。 原理圖圖43 數(shù)字顯示電路原理圖 A／D接口電路的設(shè)計(jì) 設(shè)計(jì)思路本設(shè)計(jì)要進(jìn)行電壓采樣和電流采樣，因此涉及到A/D轉(zhuǎn)換器的應(yīng)用。這種顯示方法的優(yōu)點(diǎn)是使用硬件少，因而價(jià)格低；但占用機(jī)時(shí)多，只要單片機(jī)不執(zhí)行顯示程序，就立刻停止顯示。 數(shù)字顯示電路的設(shè)計(jì) 設(shè)計(jì)思路靜態(tài)顯示亮度高，編程容易，管理也比較簡(jiǎn)單，但占用的I/O口資源較多，為了簡(jiǎn)化電路，降低成本，數(shù)字顯示采用動(dòng)態(tài)顯示方式。由于檢查不同種類的蓄電池時(shí)，要求放電電流的大小不同，因此電路的放電電流值必須是可調(diào)的，該電路中調(diào)節(jié)基準(zhǔn)電壓E，則改變了Us與E的比較值，從而就改變了恒流放電的電流值。該電壓與基準(zhǔn)電壓比較并經(jīng)放大環(huán)節(jié)放大后，經(jīng)控制調(diào)整環(huán)節(jié)使電路電流恒定[8]。Q2與Q3三極管構(gòu)成調(diào)整環(huán)節(jié)。 原理圖圖41 采樣電路原理圖 恒流放電電路的設(shè)計(jì) 設(shè)計(jì)思路為了檢測(cè)蓄電池的容量，需要對(duì)電池進(jìn)行大電流放電，并且要保持電流的基本恒定。 設(shè)計(jì)方案電壓采樣時(shí)，電路采用分壓形式。圖31 內(nèi)部振蕩電路和外部振蕩電路由于外部時(shí)鐘信號(hào)是通過一個(gè)2分頻觸發(fā)器后作為內(nèi)部時(shí)鐘信號(hào)的。10pF。這個(gè)放大器與作為反饋元件的片外石英晶體或陶瓷振蕩器一起構(gòu)成自激振蕩器，振蕩電路參見圖31。石英晶體振蕩和陶瓷振蕩均可采用。XTAL1：反向振蕩放大器的輸入及內(nèi)部時(shí)鐘工作電路的輸入。如果微處理器在外部執(zhí)行狀態(tài)ALE禁止，置位無(wú)效。然而要注意的是：每當(dāng)用作外部數(shù)據(jù)存儲(chǔ)器時(shí)，將跳過一個(gè)ALE脈沖。ALE/PROG：當(dāng)訪問外部存儲(chǔ)器時(shí)，地址鎖存允許的輸出電平用于鎖存地址的低位字節(jié)。 P3口：P3口管腳是8個(gè)帶內(nèi)部上拉電阻的雙向I/O口，可接收輸出4個(gè)TTL門電流。這是由于內(nèi)部上拉的緣故。P1口管腳寫入1后，被內(nèi)部上拉為高，可用作輸入，P1口被外部下拉為低電平時(shí)，將輸出電流，這是由于內(nèi)部上拉的緣故。當(dāng)P1口的管腳第一次寫1時(shí)，被定義為高阻輸入。低功耗的閑置和掉電模式32位可編程I/O線數(shù)