電動車充電器直流電壓輸出過低，根據維修經驗，除穩壓控制電路會引起輸出電壓過低外，還有以下幾點原因：
   （1）輸出電壓端整流三極莒、濾波電容失效，可以通過代換法進行判斷。
   （2）開關功率管的性能下降，導致開關管不能正常導通，使電源的內阻增加，帶負載能力下降。
   （3）開關功率管的源極通常接一個阻值很小但功率很大的電阻，作為過流吳護檢測電阻。該電阻的阻值—般在0.2～o.8ω。如該電阻變值或開焊、接觸不良也會造成輸出電壓過低。
   （4）高頻脈沖變壓器不良，不但造成輸出黽壓下降，還會造成開關功率管激勵不足從而屢損開關管。
   （5）高壓直流濾波電容不良，造成電源帶負載能力差。
   （6）電源輸出線接觸不良，有—定的接觸電阻，造成輸出電壓過低。
   （7）電網電壓過低。雖然充電器在低玉下仍然可以輸出額定的充咆電壓，但當電網電壓低于充電器的(de)最(zui)低(di)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)限定值(zhi)時，也會使輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)過低(di)。　維修方法∶首先用萬用表檢查(cha)(cha)—下(xia)高(gao)壓(ya)直流濾波電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)是(shi)(shi)否變(bian)(bian)質(zhi)(zhi)、容(rong)量(liang)是(shi)(shi)否下(xia)降、能否正常充放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)。如無以(yi)上問(wen)題(ti)，則測量(liang)一下(xia)開關(guan)功率管(guan)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)的(de)限流電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)以(yi)及源極(ji)的(de)過流保護殮測電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)是(shi)(shi)否變(bian)(bian)值(zhi)、變(bian)(bian)質(zhi)(zhi)或開焊(han)、接(jie)觸不(bu)良。若(ruo)無問(wen)題(ti)，再(zai)檢查(cha)(cha)—下(xia)高(gao)頻變(bian)(bian)壓(ya)器的(de)鐵芯是(shi)(shi)否完好(hao)無損。除(chu)此(ci)z外還有可(ke)能就是(shi)(shi)輸(shu)出(chu)濾波電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)容(rong)量(liang)降低(di)，或開焊(han)、虛接(jie);電(dian)(dian)(dian)(dian)(dian)(dian)源輸(shu)出(chu)限流電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)變(bian)(bian)值(zhi)或虛接(jie);電(dian)(dian)(dian)(dian)(dian)(dian)源輸(shu)出(chu)線(xian)虛接(jie)等困素都(dou)不(bu)要放(fang)過，都(dou)應仔細(xi)檢查(cha)(cha)，確保萬無—失(shi)。

                                                                                                                                                                                                本(ben)文摘自于中國充(chong)電器網