最近幾年，電動車普遍使用了所謂三段式充電器，第(di)(di)(di)一(yi)個階(jie)(jie)(jie)段(duan)(duan)(duan)叫恒(heng)流(liu)(liu)階(jie)(jie)(jie)段(duan)(duan)(duan)，第(di)(di)(di)二個階(jie)(jie)(jie)段(duan)(duan)(duan)叫恒(heng)壓階(jie)(jie)(jie)段(duan)(duan)(duan)，第(di)(di)(di)三(san)個階(jie)(jie)(jie)段(duan)(duan)(duan)叫涓流(liu)(liu)階(jie)(jie)(jie)段(duan)(duan)(duan)。從(cong)電(dian)(dian)子技術角度針對電(dian)(dian)池而言：第(di)(di)(di)一(yi)個階(jie)(jie)(jie)段(duan)(duan)(duan)叫充電(dian)(dian)限流(liu)(liu)階(jie)(jie)(jie)段(duan)(duan)(duan)，第(di)(di)(di)二個階(jie)(jie)(jie)段(duan)(duan)(duan)叫高恒(heng)壓階(jie)(jie)(jie)段(duan)(duan)(duan)，第(di)(di)(di)三(san)個階(jie)(jie)(jie)段(duan)(duan)(duan)叫低恒(heng)壓階(jie)(jie)(jie)段(duan)(duan)(duan)比較貼切。第(di)(di)(di)二階(jie)(jie)(jie)段(duan)(duan)(duan)和第(di)(di)(di)三(san)階(jie)(jie)(jie)段(duan)(duan)(duan)轉(zhuan)換(huan)時，面板指示燈相(xiang)應變換(huan)，大多(duo)數充電(dian)(dian)器第(di)(di)(di)一(yi)、二階(jie)(jie)(jie)段(duan)(duan)(duan)是(shi)紅燈，第(di)(di)(di)三(san)階(jie)(jie)(jie)段(duan)(duan)(duan)變綠燈。第(di)(di)(di)二階(jie)(jie)(jie)段(duan)(duan)(duan)和第(di)(di)(di)三(san)階(jie)(jie)(jie)段(duan)(duan)(duan)的(de)相(xiang)互轉(zhuan)換(huan)是(shi)由充電(dian)(dian)電(dian)(dian)流(liu)(liu)決定的(de)，大于某(mou)電(dian)(dian)流(liu)(liu)進入第(di)(di)(di)一(yi)第(di)(di)(di)二階(jie)(jie)(jie)段(duan)(duan)(duan)，小于某(mou)電(dian)(dian)流(liu)(liu)進入第(di)(di)(di)三(san)階(jie)(jie)(jie)段(duan)(duan)(duan)。這個電(dian)(dian)流(liu)(liu)叫轉(zhuan)換(huan)電(dian)(dian)流(liu)(liu)，也叫轉(zhuan)折電(dian)(dian)流(liu)(liu)。

    買(mai)新充電(dian)器(qi)要(yao)檢(jian)查三(san)段(duan)(duan)式(shi)充電(dian)器(qi)的(de)(de)三(san)個(ge)(ge)重要(yao)參(can)數(shu)，第(di)(di)一個(ge)(ge)重要(yao)參(can)數(shu)是涓流階段(duan)(duan)的(de)(de)低(di)恒(heng)(heng)(heng)壓值(zhi)，第(di)(di)二個(ge)(ge)重要(yao)參(can)數(shu)是第(di)(di)二階段(duan)(duan)的(de)(de)高恒(heng)(heng)(heng)壓值(zhi)，第(di)(di)三(san)個(ge)(ge)重要(yao)參(can)數(shu)是轉換電(dian)流。這三(san)個(ge)(ge)重要(yao)參(can)數(shu)與(yu)電(dian)池數(shu)目有(you)關(guan)(guan)，與(yu)電(dian)池的(de)(de)容(rong)量Ah有(you)關(guan)(guan)，與(yu)溫度有(you)關(guan)(guan)，與(yu)電(dian)池種類有(you)關(guan)(guan)。用(yong)(yong)戶一般可以自己測(ce)得(de)第(di)(di)三(san)階段(duan)(duan)的(de)(de)低(di)恒(heng)(heng)(heng)壓值(zhi)。方法是，不接電(dian)池，給充電(dian)器(qi)加市電(dian)，用(yong)(yong)數(shu)字萬用(yong)(yong)表的(de)(de)200V直流電(dian)壓檔測(ce)的(de)(de)輸出電(dian)壓。另兩個(ge)(ge)參(can)數(shu)高恒(heng)(heng)(heng)壓值(zhi)和轉折電(dian)流一般需要(yao)專用(yong)(yong)工(gong)具才能測(ce)得(de)。