Basic knowledge of household wiring is kinda required here, or at least the ability to use Google.

The 3 wires in a 3 prong household socket:
Line (black)
Neutral (white)
Ground (bare copper or green)

 

Does the safety plug have to be IN while charging with the pigtail? Or should I remove altogether?
Your procedure mentions charging it off-site. I'm connecting via pigtail in car that we created.
Wondering what is best/safest.

 

https://www.greenhybrid.com/forums/f...ry-jump-31056/

"When finished charging, remove the safety plug and fully reconnect the main relay and ECU. The two 8mm bolts connecting to the main plug should be 48 in-lb. The 10mm orange terminal bolts need to be a little tighter. I just used 48 in-lb and went a little further."

When the safety plug is out, it opens the circuit between cells splitting the battery into two disconnected batteries. No amount of voltage applied at the relay points will result in charging the battery.

 

So Safety plug IN while charging with pigtail?? Lock in place before or after plugging charger?
Sorry for being repetitive, I just want to make sure everything is in order since my procedure varies from your original method.

 

If you have diodes properly installed in the circuit, it doesn't matter.

 

Unfortunately I'm having issues with power supplies. I built two of them and everytime I try to connect to pigtail to charge, it blows the power supply. What could I be doing wrong? Worst case I'm going to remove battery from vehicle and start from scartch. I ordered another HLG-120H-C350A that should arrive early next week to problem solve again.

 

You have the polarity reversed, or diode(s) backwards?

 

those 2 eyelets are not the ones i would use (i had the same question when i was in the building stage - before getting into the relay);
those eyelets require you to completely remove the screw;
use "u" shaped or horseshoe shaped terminal ends - you only have to loosen the bolt and then you can slip the ends onto the loosened bolt (screw).

 

...which creates uneven pressure and torque that's not uniform vs. a ring terminal. I can't imagine someone finding removing and installing two screws that burdensome.

 

if one was going to leave it there as a permanent fixture, then Yes - rings should be used;
but only for the 3 or 4 hours just to charge - just easier, and could drop one (or two), also just something more to pick up.
i did drop a couple of screws that i had to retrieve; as i recall i had to go over to the driver's side and lift up on the entire battery
so the screws would roll to the area of the passengers side and i had to use a magnetic tool to get them out.