Checking Total HV Output

Disassembled battery casing and wanted to check outputs of each bright copper connections, two big orange cables. Assuming about 64V on one and the remainder on the other, 143 Volts. ( gen II ) There must be another common point in the HV Battery area, Is there? I'm assuming up front, the MG units. but running a neg line from the front of the car to the hatch area, even well insulated and a larger guage does not appeal to my living instincts.

 

Hi Pat, ty. The first 1/3 of battery modules read something less than 64 Volts, in increments of something less than 8,16,24,32,40,48,56 and then 64 volts. I then contnued measuring after some sort of break in the pack assuming a wiring change ( series/parallel) That total segment from the first neg in the latter 2/3rds read again something less than 143 Volts, I made the nice person-umption that the voltage was devided as such to the two copper terminals. Obviously that was incorrect. For convenience I was only measuring from the rear of the modules. I also measured a few modules on both sides, but considered this too cumbersom and subject to an accidental short. I don't really consider my measurement system as too accurate and believe that internal and cumulative resistances affect accurate readings. I was not about to disassemble any modules as my car works. Back to the subject: where can I find this relay to measure the HV, in fuse box area? is relay marked HV? What should I watch out for as far as shorting it out? Thanks much for your reply. Andy PS: You are right, I forgot the MG's are AC

 

Hello H* and Pat, Thanks much for your posts. Everything is totally clear now. Hobbit, your rundown is incredibly good, good info to reread and digest. To answer your question, I basically did the same thing you did as I was curious to see how everything worked and measured. I was not aware that the break at the 1/3 point was the HV switch interconnect, so my measurements were not quite kosher. I did not touch the ECU.

 

In reassy of the left rear seat ( 2 large bolts ), the inner bolt was extremely tight, maybe a burr on the female side. I finally used some more force and got it. Never identified the problem tho.