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)(di)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)限定值時，也(ye)會使輸出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)過(guo)(guo)低(di)(di)。　維修方(fang)法∶首先用萬(wan)用表檢(jian)查—下(xia)高壓(ya)(ya)直流濾(lv)波電(dian)(dian)(dian)(dian)(dian)(dian)容是否變(bian)質、容量(liang)是否下(xia)降、能否正常充放電(dian)(dian)(dian)(dian)(dian)(dian)。如無(wu)(wu)以(yi)上問題，則測量(liang)一下(xia)開關功(gong)率管的(de)電(dian)(dian)(dian)(dian)(dian)(dian)極的(de)限流電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)以(yi)及源極的(de)過(guo)(guo)流保護(hu)殮測電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)是否變(bian)值、變(bian)質或(huo)開焊(han)、接觸不良。若(ruo)無(wu)(wu)問題，再檢(jian)查—下(xia)高頻變(bian)壓(ya)(ya)器的(de)鐵芯是否完好無(wu)(wu)損。除此z外還有可能就是輸出(chu)濾(lv)波電(dian)(dian)(dian)(dian)(dian)(dian)容容量(liang)降低(di)(di)，或(huo)開焊(han)、虛(xu)接;電(dian)(dian)(dian)(dian)(dian)(dian)源輸出(chu)限流電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)變(bian)值或(huo)虛(xu)接;電(dian)(dian)(dian)(dian)(dian)(dian)源輸出(chu)線虛(xu)接等困素(su)都(dou)不要放過(guo)(guo)，都(dou)應仔細檢(jian)查，確保萬(wan)無(wu)(wu)—失。

                                                                                                                                                                                                本文摘自于(yu)中國(guo)充電(dian)器網