Charging with Portable Generator?

Discussion in 'Cooper SE' started by mikeg0305, Sep 23, 2023.

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  1. mikeg0305

    mikeg0305 Active Member

    Anyone have any experience charging their Mini with a portable generator?

    We have the ability to hook our portable generator up to our house via a transfer switch in our main panel. But our current generator (no pun intended) is only 6500 watts and 30 amps, and our Juicebox 40 does not like it. I am looking at upgrading for several reasons, one of them being the ability to charge the Mini when we lose power for extended periods of time. Not looking to fully charge the Mini, but the ability to add 20-30 miles of range gets me access to DC Fast charging if needed

    Looking at 10k or more watts and 40-50 amps. Which should be enough to handle the house and the Mini, but not at the same time of course.

    Anyone have any experience??

    Oh and don’t go down the solar rabbit hole as that is in our future, just a couple of years away.

    Thanks - mike

    Sent from my iPhone using Inside EVs
     
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  3. insightman

    insightman Well-Known Member Subscriber

    Not a great solution, but I'm wondering, does your included charging cord work with your current generator? I'm wondering if my 120-V only charging cord would work with my 2,200-Watt generator. Of course, if it did, I'd be adding 2-3 miles rather than 20-30 miles.
     
  4. mikeg0305

    mikeg0305 Active Member

    I’ve never tried direct as I was afraid of breaking something, in the Mini.


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  5. insightman

    insightman Well-Known Member Subscriber

    I don't know what you mean by "direct." Isn't the job of the EVSE (wall-mounted or charging cord) to protect the car (and the people using the EVSE?)
     
  6. teslarati97

    teslarati97 Well-Known Member

    Before you go out to spend more money, did you try derating the Juicebox 40 to 20A or lower? Alternatively you could also derate the MINI to 15A if you don't want to mess with the Juicebox settings.
     
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  8. mikeg0305

    mikeg0305 Active Member

    I have not plug the Juicebox directly to the generator. I’ve only hooked up the generator to the house and then turned on the breaker for the Juicebox but it did not like that. As others have suggested it’s because the JB was looking for more amps than the generator could supply.

    I’ll try de-amping and see if that works.

    Btw, I am getting a larger generator no matter what, as I mentioned in my op. But just wanted to know what size I should target to kill a couple birds with one stone.


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    insightman likes this.
  9. you may find this interesting..
    not exactly what you're looking for, but it may help ... given what is done here, your solution should work. Set things up correctly. Level 1/Level 2, everything along the path needs to adjust to the rate/amp presented. The suggestion to bring the JB down to 20 sounds good, as it would need to know the max that can be drawn from the source. You may also want to try the mini's charger in your generator.
     
  10. Not all generators are the same, and you didn't mention the kind of generator you are using. I would never try to run sensitive electronics on an open-frame generator because they do not produce a clean sine-wave. It is what is often called "dirty" power. I would use an inverter style generator since they produce a much cleaner output power, but also produce much less noise.
     
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  11. teslarati97

    teslarati97 Well-Known Member

    Since we are going down the clean sine wave path, I'd also add total harmonic distortion. :)
     
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  13. pictsidhe

    pictsidhe Well-Known Member

    The problem is not dirty power. It is the grounding scheme on generators not passing muster with the EVSE. The car will rectify the input to DC, so square wave is actually absolutely fine.
    The ground issue is that portable generators have a floating output. They do not have neutral tied to ground. You can 'fix' that by tieing ground to one output leg. But now you have a potentially hazardous system if anything other than an EVSE is plugged in... You should also connect the ground to a ground rod to have something safe. Obviously, this is tricky as a portable installation...
    I have run into lack of ground a couple of times and noped out of Jerry rigging it. Other people were also using power.
     
  14. ENirogus

    ENirogus Active Member

    Tie one output to ground? No!
    If you have a a 240 volt evse there is no neutral connection so it should not care about neutral.
    It is a power issue, simple as that. 40 amp EVSE requires nearly 10kw to run. THe OPs generator is not large enough for that
    It would be cheaper to buy a smaller EVSE rather than a larger generator
     
  15. DJCoopster

    DJCoopster Well-Known Member

    I just ran into this yesterday. I wanted to run my generator under some load but couldn't get either the 120V 'travel EVSE' or 120/240V Flexible Fast charger to send power due to a fault light on both. I had the same thoughts (I have a heavy electrical/engineering background) but decided to just let it idle for a bit like normal.

    It's funny, the car isn't grounded, the generator isn't grounded, but the EVSEs care. lol
     
  16. insightman

    insightman Well-Known Member Subscriber

    For use with only a Level 1 EVSE, why not make an "adapter" extension cord that ties the ground and neutral wires together? Make the adapter cord very short and label it well so there's never a temptation (or a mistake) to use it for an actual extension cord.
     
  17. Rexsio

    Rexsio Well-Known Member

    On you tube guy charge bmw I 3 with portable generator 4 miles in1/2 hr IMG_1073.jpeg
     
  18. Rexsio

    Rexsio Well-Known Member

    IMG_1074.jpeg IMG_1076.jpeg
    Shopping at Costco I see generator with triple Gas/ LP/NG with starting Amps 52 Amp.Running Amps 39.5 Amp .for $699 get this baby hook up your EV charger have NEMA 14-50 receptacle too ,if you worry you have no power to your house ,looks like you can run charger on 32 amps /16 amps.
     
  19. Rexsio

    Rexsio Well-Known Member

     
  20. Rexsio

    Rexsio Well-Known Member

    Install Generac 26kW standby Generator system if you have LP/ NG gas
     
  21. ENirogus

    ENirogus Active Member

    I cannot think of something household that runs on 120/240 and figures it out by itself, so it seems probable that an EVSE so setup needs power and ground to be tied, perhaps as part of its startup procedure. My EVSE is 240 only I will have to try to run it next time I start my generator for testing
     
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  22. pictsidhe

    pictsidhe Well-Known Member

    Please don't do this.

    EVSE test the supply ground for safety reasons. That is why they nope out of working on portable generators, which have a floating output. If you want to do this properly, you need neutral and ground tied together, AND A GROUND ROD. At which point, it's not very portable.
     
  23. pictsidhe

    pictsidhe Well-Known Member

    OK. Some of you are going to kludge something anyway. So here is the safe kludge, not sure if it is legal, though.

    Take a portable generator. Remove ALL receptacles. HARDWIRE a cheap EVSE to it. Tie neutral to ground while you are doing that. This means it can only be used for charging EVs. Anything with receptacles, plugs and the ground and neutral tied somewhere will have a way to zap people if something unsafe is plugged in.

    Minis max out at 16A on 120V, btw. I'd be looking for a 230 genny.

    If you have an off-grid location. One way to safely use a portable genny would be a small grounded panel with GFCI outlets. Genny has a single outlet. Neutral and ground are tied at the panel and an 8' ground rod is installed. Now plug the panel to the genny, and the car to the panel.
     
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