[RE-wrenches] EG4 and Bolt Car Charger

[Dave Tedeyan]

Hi All,

I've got an acquaintance with a somewhat kludged together off grid system
within his grid tied house. (We do not need to get into the random design
decisions that went into that...)

It is an EG4 3kw 120v off grid inverter, with one of the EG4 server rack
batteries. The system runs most things just fine. We plugged a 12A heat gun
into an outlet run by the inverter and it did just fine. He has a Bolt, and
the EV charger complains when it is plugged in. The red light on the
charger indicates that "System is not properly grounded" but gives no other
info than that. When plugged into a house outlet the charger works fine. It
even works pluged into an outlet run by the EG4 inverter when the inverter
has grid power present. But when grid power is removed from the inverter,
then the charger complains about the grounding.

I've tested the outlet and am getting 120V L-N, and getting about 2 Ohms
from Neutral to ground. The inverter has a ground terminal for the AC input
ground. For the output ground, there is just a lug on the inverter Chassis
which runs to the backup loads panel. I've tried connecting the ground bar
in the backup loads panel to the GEC directly when the inverter is in off
grid mode, and removed the wires from the AC input. But still no change. If
the house grounding was not good enough, then I would expect the charger to
never work. But when only connected to the EG4 inverter, and also connected
to the same grounding system, the charger does not work.

Has anyone seem anything like this, or have any ideas?
Cheers,
Dave

-- 

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Dave Tedeyan, P.E.
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