If I am understanding the issue you describe, it sounds like you just need the appropriate outlet wired correctly. GM literature says you need a NEMA 14-50 outlet as shown below.

 

So, even with the 120v connection from the generator it will not allow power to flow from the generator to the EV. I read online that it has to do with mains power being grounded or something and the generator power is not.

 

Not sure how it is with the GM twins, but with my Lightning I charged off a 38kw diesel generator multiple times. I just hooked up the mobile charger directly to the generator. I did have to buy an adapter for it to fit the unique generator plug if I wanted 30 or 50amp charging. I don't see any reason why you couldn't charge from generator to the truck via it's J-connector.

Amazon.com

I even got a heavy duty extension cord:

Amazon.com: GearIT 50-Amp Extension Cord for RV and EV (50 Feet) 4-Prong 250-Volt, Tesla Model 3/S/X/Y, NEMA 14-50P to 14-50R 6/3, 8/1 STW AWG Gauge Outdoor Auto Power Cord : Automotive

Amazon.com: GearIT 50-Amp Extension Cord for RV and EV (50 Feet) 4-Prong 250-Volt, Tesla Model 3/S/X/Y, NEMA 14-50P to 14-50R 6/3, 8/1 STW AWG Gauge Outdoor Auto Power Cord : Automotive

www.amazon.com

 

When you get to the bigger generators they often do not come with a pure sign wave inventor on them. I have a large 11,000 watt peak and 10,000 watt constant generator with the proper plug but it does not produce a pure sign wave power coming out of the outlets. The generator cost around $1000 and if it had a pure sign wave inverter it would have been more like $10,000 for the generator. More than likely your generator cannot produce a pure sign wave electricity at the 240V level which your truck will not accept as it is basically a big electronic device which needs a pure sign wave clean electricity.

 

I have a Honda 7000is which is 'pure' sine and and very quiet - plus it's a Honda one pull start and quality (it has electric start though). It has 7kW peak - enough for a common 6kW charger, and 'only' costs some $4k or something (I got it when it was cheaper). I haven't tried charging with it yet but will, there are some trips I'm looking at where this would be a backup.

Meets California CARB emissions standards too - Honda generators are the gold standard basically.

 

You need to size a generator based on its continuous rating, for charging a vehicle, and then take 80% of that to actually use for charging.

 

Ordered and on the way! Thank you very much for the suggestion. Hopefully I have more luck with this than I did with the 120v connection.

 

Eu7000 is rated for 4800 continuous, we run them a little less becuase 4800 can still overload.

 

I tried my 9900W(running) Inverter generator and it worked fine with the 14-50 and 32A.
The problem with the GM charger is that if you have the 14-50 it assumes 32A, 14-30 it probably assumes 24. So if you need to limit it to less than that you'll need a less dumb charger.

 

The generator has a floating neutral and you need an adapter to make it a bonded neutral. That will work for 120v. The bonded neutral adapter in a 120v outlet will most likely bond the 240v. I made an adapter for my Eu2200i. Here’s an explanation.
Link

 

Thank you Suburban, ordered one as well - will let you all know what works.

 

Yeah I bought one of those bonded neutral plugs for that reason. Otherwise you can ground the generator, mine has a grounding point. Just drive a stake or attach to something, maybe the car should work …

Neutral is the return feed, the chassis ground is for safety only and should carry no currents normally, it’s just in case something gets loose and touches the chassis

 

Received the bonded neutral plug and it does indeed work for 120v but not for the 240v, any idea why this might be the case? I am thinking they are possibly on a separate circuit?

Any thoughts on a workaround for this issue? Right now I am only able to get 1.5kw out of my generator to charge the sierra as it is limited to a standard 120v outlet.

 

Level 2 EVSEs don't use a neutral whatsoever. However in order to test for the presence of a ground connection they will measure the voltage from hot to ground. If the ground is floating (like on an unbonded generator) the EVSE won't see 120V between hot and ground and will probably throw a fault.

 

This is very useful information, any thoughts on how I could circumvent this fault so I can charge my EV with 240V? The plug only works for the 120V outlets.

 

I know this thread hasn’t been updated in a bit but thought I’d add to it instead of starting a new one.

The power went out here about 2.5 hours ago. No big deal as I have a 19kW whole house standby generator that doesn’t get enough usage. Power goes out just as the family is about to watch a movie. Generator kicks in and they are happy to watch. I’ve seen the movie a few times so I opt to work in the garage fixing a carb on an old bike. Got the tv playing music for me, lights are on, all is good. I finish up and start thinking about how the generator will handle the truck. I get on the app and turn the charge up to 85% from the 80% it hit earlier in the day. I can hear the generator tone change. Current (no pun intended) is 20a on the charger. I turn it up to 40a and get another tone change on the generator. All seems good, the truck is happy, no lights in the garage flickered. Then I turn the truck charge back down to 80%, generator unloads a bit and still no flicker. I assume the house would be consuming 5-10a for fridge, freezer, clocks, chargers, tv, stereo, etc.

Having done this test, I would be confident to charge the truck from the generator if needed. I don’t have the bidirectional charger but I could have tuned on the power base and back fed the house to have silent power. Would have been easy enough to tie into a breaker and kill the main house breaker so I don’t back feed the utility.

Generator is a Generac Honeywell stationary unit.

 

Makes sense. Unless you are running heavy loads like AC, your house is probably drawing less than a kW. Your generator is obviously on an automatic transfer switch so the generator doesn't feed the grid. A bi-directional charger would also need to automatically island the home in an outage. The ones available do that and will use your solar power. You can use battery storage in an outage, including the vehicle battery. However, so far I haven't found a bi-directional charger/battery system that also automatically manages an ICE backup generator to provide power for charging the home and vehicle power when they get low during an outage.

 

Charger is the Grizzl-E mini. I’ve been turning the charge rate down to keep it under my solar production early and late in the day then max power mid day.

 

Inverter is essential as is 240V with a 50 AMP NEMA plug.
Doesn't mean the generator will produce 50 AMPS, but both legs energized doubles the rate of charge I think. I vaguely remember anything since suffering a stroke.

Harbor Freight is about to release a 11.500 W inverter closed-frame any day now.
I'll be the first to buy one.

When we take our next lap around the USA pulling a travel trailer it'll be in the bed of the Sierra for charging where their is no charging.
No range nor broken charger anxiety for this driver.

A long stroke engine usually means a low exhaust note and quieter with the generators on the market now or at least last I was checking them out and buying.

Charging with the GenMax 7200 Watt:

Charging with the Powerhorse 7500:

I love electricity and own dozens of generators purely because I like them.

When the recent fires hit a 6 mile radius around us was blacked out for the better part of a week.

With our Starlink and Tesla solar and Powerwall we were good to go.
100 Gallons of gasoline on hand and loaned out generators our neighbors were good to go too.

 

Inverter is essential as is 240V with a 50 AMP NEMA plug.
Doesn't mean the generator will produce 50 AMPS, but both legs energized doubles the rate of charge I think. I vaguely remember anything since suffering a stroke.

Harbor Freight is about to release a 11.500 W inverter closed-frame any day now.
I'll be the first to buy one.

When we take our next lap around the USA pulling a travel trailer it'll be in the bed of the Sierra for charging where their is no charging.
No range nor broken charger anxiety for this driver.

A long stroke engine with the lowest RPM usually means a low exhaust note and quieter with the generators on the market now or at least last I was checking them out and buying.

Charging with the GenMax 7200 Watt:

Charging with the Powerhorse 7500:

I love electricity and own dozens of generators purely because I like them.

When the recent fires hit a 6 mile radius around us was blacked out for the better part of a week.
With our Starlink and Tesla solar and Powerwall we were good to go.
100 Gallons of gasoline on hand and loaned out generators our neighbors were good to go to.

I have a 2-71 Detroit Diesel that was used on a generator. I’d like to find a generator head and charge my truck with it.

 

On a separate, but related note, has anyone been able to recharge with a generator while driving? In an emergency situation ( I.e. grid down and need to evacuate) it sure would be nice to throw my 12kw closed frame inverter generator (already used to charge the truck during a power outage) in the bed and get charge while driving.

 

It's a frequently asked question. I've yet to hear of someone pulling that off in a way that can be easily replicated by the lay-person.