Submitted by gongzhen2015 on Mon, 2017-12-04 13:29
Hello guys, I have a question that bother me a long time ago.
I was having this UMC came with the vehicle to charge my car on a NEMA 14-50 for years. Previously I didn't noticed my charging voltage which shows on my car is about 205-210 V. I recently went to my friends home and saw his MS is charging at 239 V constant, it brings me the question, why my UMC can only deliever 208 V to my vehicle.
I tried to use meter to measure the voltage from the hot to neutral on my nema 14-50 outlet, the number is about 121 V for both of them, which make me confused more. Previously, my guess was because my house is may be on the end of the power lane which the main cable have a lower voltage than others, but it shows me the voltage on my end is pretty solid and good which is above 120V. So in my mind, 120+120 should at least have 230 V or more.
However, I found something fun, if I turn the current down to about 5 A. the voltage will increase to about 215V-218V.
Please help me, is there possible something wrong with my UMC, are the input voltage which 121V is low. Thank you for any response!