What about GFCI? Do I need an isolation transformer to charge my AC300 in Europe?

August 8, 2022.
In Germany. One AC300 and two B300 batteries. Built my own Critical Load (3X) circuit. Integrated into existing CB panel. 3 separate heavy gauge AC plugs. This way I can plug in energy monitor into each AC300 output. The plan is too charge 90% from solar and increase my self sufficiency from 30% to 60%. This will help amortize the expense. In addition I have Blackout protection on three circuits in house. A 3 KW propane generator can help charging in winter if needed during any blackouts.

Neutral from AC300 kept completely separate from House Neutral. Ground and Neutral are tied together to eliminate floating ground on AC300. My plan was Neutral separation to protect AC300 when charging from House grid.

3 ON-OFF-ON 2 pole switches. With this I can individually select feed source (House or AC300) to critical circuit. Useful in winter when less sun available. Two solar sources for charging. 3 KW south rooftop with existing inverter can be used to charge AC between 11:00 and 14:00. Additional 2x370 east/west watt panels on carport for direct DC parallel charging all the time. Circuits include basement refrigerator and freezer, living room lights, TV and router with telephone, kitchen refrigerator and lights. 4 pole GFI CB of course.


August 25.

Many Error code 0800 later with AC output shutting itself off with NO OUTPUT plugged in. Occurs after 2 to 12 hours. New AC300 no change. My Bluetti dealer stopped communicating with me.

My conclusion.
One can live with a dangerous floating ground output or buy an isolation transformer for house AC charging. If house ground is seen on output connected to Neutral AND you use a normal grounded AC charging input, the circuit breaker on the AC charge input will open, or the house GFCI breaker will open. The AC300 will suffer internally and start producing 0800 error codes.

I will not accept a floating ground on my output. It is against all code and dangerous when part of a normal house circuit in my opinion. Okay at the campground, but not in my house.

My solution was to buy a 3000VA isolation transformer and a house CB resistant to transformer surges. I added a separate charging circuit dedicated to the AC300.

I added a three phase 4 pole GFCI breaker with three phases tied together. I gave up on the three separate AC outputs for now. The GFCI does NOT work when tested. Nor did a second one. Still an open item.

The blue AC outlet on far left is the dedicated one. The two red outlets are supplied with heavy gauge (13AWG) 5 wire cable from the outside to supply propane generator power to the AC300. I used two wires to run 12 volt DC 13AWG 10 amps bidirectional to the carport shed where the generator is stored along with all the security cameras and recorder. This way I can use the DC UPS for something useful and in a pinch charge the batteries from the car or charge the car. 10 amp inline fuse.