Model 3

Charging 2019 Model 3 with a portable gasoline generator

I know the title sounds crazy, like why would you do that? Well last month we had an extended power outage due to a storm and I ran my whole house for several days off my Harbor Freight 8750kw gas generator. Its a cheap one, paid about $500 on sale, so I know its not an inverter or sine wave generator. I have seen so many YouTube videos claiming you can't charge a Tesla unless you use an expensive generator with an inverter.
So just to test that theory I decided to try charging my Tesla using my Tesla mobile charger that came with the car. At first I tried 120V 12A and I was surprised that it worked just fine! Left it charging for about 30 minutes. Next I got brave and tried 240V 32A. The generator is only rated at 28A and I was powering a number of things in the house at the time. To my surprise my Model 3 started charging and slowly ramped up to 16A and held there. It seemed to be fine charging until I disconnected after about 10 minutes.
So the expensive inverter sine wave generator theory is dis-proven. Seems you just need a steady power source. Did Tesla do something in software to improve charging and make it more tolerant of less than ideal power sources?

Has anyone else had any longer term experience using a gas generator?

Comments

  • interesting report
  • THD (total harmonic distortion), over a period of time, is what does in "sensitive" electronics. You should read up on THD.
  • From looking into this a year or so ago I found the key seems to be that the generator has to have a neutral to ground bridge. If not you will get a poor ground error and the car won't charge.

    I couldn't charge off my older portable 2004 16kW Generac. After finding a lot of information on the issue I made a neutral to ground bridge that plugs into one of the receptacles and the car would charge; although, slowly.
  • @larry.becque_98436954

    Thanks for sharing your experience. I sometimes wonder what could be done to charge my Model 3 in a pinch.
  • > @"Magic 8 Ball" said:
    > THD (total harmonic distortion), over a period of time, is what does in "sensitive" electronics. You should read up on THD.
    >
    >

    I think you're saying that the Tesla's electronics could be damaged over a period of time if this type of charging was used. Is that right? Not sure.
  • Yes, most electronics in your home can be damaged over time as well. We live in a digital age now with many things having the equivalent of a computer inside. Many of my wall switches and outlets are hooked up to wifi etc. I would never consider using anything but an inverter generator these days.
  • After some research, I've found an interesting video about charging a Tesla with a generator. I has a work-around about the grounding issue. https://youtu.be/4MR-uKp6u8M In this particular video he's using a Predator generator. A Honda inverter generator would be much quieter.
  • Inverter generators are not the total solution. A lot of the higher end Honda inverter generators don't include a neutral to ground bond, which is required in order to charge an EV.

    It's pretty well demonstrated below using a Generac, which supposedly had a bonded neutral to ground, yet still required an additional bridge.

    https://youtu.be/5J5QA8C3S5k?t=517
  • I am not sure anyone is trying to sell inverter generators as "a total solution". Inverter generators make cleaner (not greener) power which is important for many electronics commonly used by most these days and yes they typically run quieter.
  • One of the most common problems with using a generator was the lack of a solid ground. The car will check the circuit for a solid ground before allowing a charge to flow. Good report though, i am unaware of any software updates to be tolerant of other power sources however.
  • > @"Magic 8 Ball" said:
    > I am not sure anyone is trying to sell inverter generators as "a total solution". Inverter generators make cleaner (not greener) power which is important for many electronics commonly used by most these days and yes they typically run quieter.

    Exactly. This is "last resort solution", not a "total solution". Like if California has a major earthquake and the whole area is without power for 5 days. In the video I gave the link for, the guy made a bridge to connect the neutral to the ground in the 2nd AC socket. Now how about if in addition to how he connected that, what if he also ran a long wire out from that and connected that long wire to a metal pipe that went down into the ground? Would that establish a true grounded power source? I'm not sure.
  • > @in7_98388832 said:
    Now how about if in addition to how he connected that, what if he also ran a long wire out from that and connected that long wire to a metal pipe that went down into the ground? Would that establish a true grounded power source? I'm not sure.

    The neutral bus is connected to earth ground bus in the main panel of your house. My generator is setup to supply the whole house, through the panel, so in that configuration I am indeed connected to earth ground via neutral.
  • > @gmr6415 said:
    > From looking into this a year or so ago I found the key seems to be that the generator has to have a neutral to ground bridge. If not you will get a poor ground error and the car won't charge.
    >
    > I couldn't charge off my older portable 2004 16kW Generac. After finding a lot of information on the issue I made a neutral to ground bridge that plugs into one of the receptacles and the car would charge; although, slowly.

    You may be on to something about the neutral to ground connection. My generator says for the GFI outlets to work properly the generator must be connected to a grounding rod pushed into the earth. I haven't done that yet, however my generator is connected to a 4 wire system, (2 hots, ground and neutral) to the house. Therefore, the generator is connected to the house main electrical panel which bridges the neutral to an earth grounding rod outside the panel.

    So perhaps this worked for me because the Tesla was connected to the house wiring which in turn was connected to the generator. If I had connected directly to an improperly grounded generator directly without an earth grounding rod it probably would not work.
  • > @"Magic 8 Ball" said:
    > Yes, most electronics in your home can be damaged over time as well. We live in a digital age now with many things having the equivalent of a computer inside. Many of my wall switches and outlets are hooked up to wifi etc. I would never consider using anything but an inverter generator these days.

    My TVs, computers, wifi, cable router box, telephone, even air conditioning all worked fine on the generator for many days after the storm. I was kind of surprised because I have heard so much about 'sensitive electronics' not working on generators. I think part of the reason is having a big enough generator that you don't run it close to 100% and it can act as a very steady power source with no sudden voltage drops from overloading it.
  • > @"larry.becque_98436954" said:
    > > @"Magic 8 Ball" said:
    > > Yes, most electronics in your home can be damaged over time as well. We live in a digital age now with many things having the equivalent of a computer inside. Many of my wall switches and outlets are hooked up to wifi etc. I would never consider using anything but an inverter generator these days.
    >
    > My TVs, computers, wifi, cable router box, telephone, even air conditioning all worked fine on the generator for many days after the storm. I was kind of surprised because I have heard so much about 'sensitive electronics' not working on generators. I think part of the reason is having a big enough generator that you don't run it close to 100% and it can act as a very steady power source with no sudden voltage drops from overloading it.

    It only take one bad transient event to ruin a bunch of stuff.
  • > @in7_98388832 said:
    > After some research, I've found an interesting video about charging a Tesla with a generator. I has a work-around about the grounding issue. https://youtu.be/4MR-uKp6u8M In this particular video he's using a Predator generator. A Honda inverter generator would be much quieter.

    Here is a link to another guy that did the exact same thing and found he had to make a 'bonding plug' https://insideevs.com/news/369939/video-tesla-model-x-charging-generator/ .

    In my case I didn't have to do that because everything was bonded to house wiring system and properly earthed to a real grounding rod. So definitely, proper grounding is necessary for any generator used to charge a Tesla, inverter type or not.
  • I have a diesel 10k grounded generator as a back up to my hybrid battery back up solar. I’ve hooked the 3 up to it and got 2% after an hour. Also have a newer 2k Yamaha and it did not charge the Tesla at all.
  • > @in7_98388832 said:
    > > @"Magic 8 Ball" said:
    > > In the video I gave the link for, the guy made a bridge to connect the neutral to the ground in the 2nd AC socket. Now how about if in addition to how he connected that, what if he also ran a long wire out from that and connected that long wire to a metal pipe that went down into the ground? Would that establish a true grounded power source? I'm not sure.

    Absolutely that would establish a 'true ground' and would work. In fact, my generator manual says it should be earthed to a grounding rod pushed into the ground. Essentially I did the equivalent by hooking my generator with 4 wires to the main house electrical panel ground which is bonded to a grounding rod just outside the panel near the meter.
  • > @"Magic 8 Ball" said:

    > It only take one bad transient event to ruin a bunch of stuff.

    True. However, as I stated earlier, with a big enough generator not running anywhere near maximum, keeping the usage below 75% and disconnected from the power grid, there shouldn't be any transients. Unless the house gets hit by lightning or the generator runs out of gas. Funny in that video with the small inverter generator how you could hear its motor strain every time he increased the Tesla charging by 1-2 amps, and he could see the voltage sag on the charging screen. Mine doesn't do that at all, it barely notices additional loads coming on and just runs rock solid.
  • > @"Magic 8 Ball" said:
    > > @in7_98388832 said:
    > Now how about if in addition to how he connected that, what if he also ran a long wire out from that and connected that long wire to a metal pipe that went down into the ground? Would that establish a true grounded power source? I'm not sure.
    >
    > The neutral bus is connected to earth ground bus in the main panel of your house. My generator is setup to supply the whole house, through the panel, so in that configuration I am indeed connected to earth ground via neutral.
    >
    >
    Mine was connected to the whole house so it was the same setup, only the generator was different, mine being a large 8750 watt non-inverter.
  • @coleAK, "I have a diesel 10k grounded generator as a back up to my hybrid battery back up solar. I’ve hooked the 3 up to it and got 2% after an hour. Also have a newer 2k Yamaha and it did not charge the Tesla at all."

    That's similar to what I ran into a year or so ago with our 2004, 16kW portable Generac. Even though it was connected to the house through a 14-50 receptacle and that receptacle is directly wired to a breaker in the breaker box, which has it's own neutral to ground bar making a bond within the box, the M3 would give me the ground fault error whether I plugged directly into the generator or to our dryer receptacle in the house.

    I added a ground cable from the frame of the generator directly to a ground rod. I still got the error. I made a neutral to ground bridge and plugged that into one of the receptacles on the generator itself. That solved the issue, but it still would only charge at around 7 amps. If I adjusted it any higher on the car the generator would surge, the M3 didn't like it and would disengage the charging.

    During that trial and error time I tried my neighbor's Honda EU2200i 2200-Watt 120-Volt Super Quiet Portable Inverter Generator. It wouldn't charge the M3. I plugged in my homemade neutral to ground bridge and the car accepted it and charged up to 12 amps.

    At this point I feel that being able to charge at 7 amps in an emergency is better than nothing. We are in hurricane territory and I'm sure at some time I'll need it.

    There are also line conditioners on the market, many of them made for RVs with the same issue, that would probably resolve the problem for around $200.
  • @coleAK, Below are a couple easy to read articles on bonded and floating ground generators. They also explain the difference in transfer switches used depending on the type of generator. The second link gets into unbonding a bonded generator and bonding a floating ground generator with a bridge.


    https://generatorbible.com/blog/bonded-neutral-vs-floating-neutral/

    https://generatorbible.com/blog/bonded-to-floating-neutral/
  • Model 3 wins Rally by 10 minutes, portable chargers involved including a Kona V2V.

    https://www.teslarati.com/tesla-model-3-dominates-targa-west-rally-video/
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