最近幾年，電動車普遍使用了所謂三段式充電器，第(di)(di)一(yi)(yi)個(ge)(ge)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)叫(jiao)(jiao)(jiao)恒(heng)流(liu)(liu)(liu)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)，第(di)(di)二(er)個(ge)(ge)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)叫(jiao)(jiao)(jiao)恒(heng)壓階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)，第(di)(di)三(san)個(ge)(ge)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)叫(jiao)(jiao)(jiao)涓流(liu)(liu)(liu)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)。從電(dian)(dian)子技術角度針對電(dian)(dian)池(chi)而言：第(di)(di)一(yi)(yi)個(ge)(ge)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)叫(jiao)(jiao)(jiao)充(chong)電(dian)(dian)限流(liu)(liu)(liu)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)，第(di)(di)二(er)個(ge)(ge)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)叫(jiao)(jiao)(jiao)高(gao)恒(heng)壓階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)，第(di)(di)三(san)個(ge)(ge)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)叫(jiao)(jiao)(jiao)低恒(heng)壓階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)比較貼(tie)切(qie)。第(di)(di)二(er)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)和第(di)(di)三(san)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)轉(zhuan)換(huan)時，面板指示燈相(xiang)應變換(huan)，大多數(shu)充(chong)電(dian)(dian)器第(di)(di)一(yi)(yi)、二(er)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)是紅燈，第(di)(di)三(san)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)變綠燈。第(di)(di)二(er)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)和第(di)(di)三(san)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)的相(xiang)互(hu)轉(zhuan)換(huan)是由充(chong)電(dian)(dian)電(dian)(dian)流(liu)(liu)(liu)決定(ding)的，大于某電(dian)(dian)流(liu)(liu)(liu)進(jin)入(ru)第(di)(di)一(yi)(yi)第(di)(di)二(er)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)，小于某電(dian)(dian)流(liu)(liu)(liu)進(jin)入(ru)第(di)(di)三(san)階(jie)(jie)(jie)(jie)段(duan)(duan)(duan)(duan)(duan)。這個(ge)(ge)電(dian)(dian)流(liu)(liu)(liu)叫(jiao)(jiao)(jiao)轉(zhuan)換(huan)電(dian)(dian)流(liu)(liu)(liu)，也(ye)叫(jiao)(jiao)(jiao)轉(zhuan)折電(dian)(dian)流(liu)(liu)(liu)。

    買新(xin)充(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)要(yao)檢查(cha)三(san)段式(shi)充(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)的(de)三(san)個(ge)重(zhong)要(yao)參數(shu)(shu)(shu)，第(di)(di)一(yi)個(ge)重(zhong)要(yao)參數(shu)(shu)(shu)是涓流(liu)階段的(de)低恒壓值，第(di)(di)二(er)個(ge)重(zhong)要(yao)參數(shu)(shu)(shu)是第(di)(di)二(er)階段的(de)高(gao)恒壓值，第(di)(di)三(san)個(ge)重(zhong)要(yao)參數(shu)(shu)(shu)是轉(zhuan)換電(dian)(dian)(dian)(dian)流(liu)。這三(san)個(ge)重(zhong)要(yao)參數(shu)(shu)(shu)與(yu)(yu)(yu)電(dian)(dian)(dian)(dian)池(chi)數(shu)(shu)(shu)目有(you)關，與(yu)(yu)(yu)電(dian)(dian)(dian)(dian)池(chi)的(de)容(rong)量(liang)Ah有(you)關，與(yu)(yu)(yu)溫度(du)有(you)關，與(yu)(yu)(yu)電(dian)(dian)(dian)(dian)池(chi)種類有(you)關。用戶一(yi)般可以(yi)自己(ji)測得第(di)(di)三(san)階段的(de)低恒壓值。方法是，不接電(dian)(dian)(dian)(dian)池(chi)，給充(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)加市電(dian)(dian)(dian)(dian)，用數(shu)(shu)(shu)字萬用表的(de)200V直流(liu)電(dian)(dian)(dian)(dian)壓檔測的(de)輸(shu)出(chu)電(dian)(dian)(dian)(dian)壓。另兩個(ge)參數(shu)(shu)(shu)高(gao)恒壓值和轉(zhuan)折電(dian)(dian)(dian)(dian)流(liu)一(yi)般需要(yao)專用工具才能測得。