nerys
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Re: charging on generator

Wed Oct 29, 2014 10:22 pm

Hmm something to do with how the unit makes the 220v?
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dsinned
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Re: charging on generator

Thu Oct 30, 2014 11:34 am

fooljoe wrote:I know that dsinned tried setting his JuiceBox all the way down to 6A to start the charge, but it still wasn't happening at 240V. Strangely enough, he reported that using the same generator at 12A and 120V (which in theory is the exact same amount of power as 6A and 240V) did work.

True. I was baffled by this, but the severe bogging of the generator at the instant when the JuiceBox switched on the load (RAV4 EV's OBC) was unmistakable. I was measuring the generator's output voltage, current and frequency at the time, and despite setting the JB's current limiter to <10A, as I recall the instantaneous load current inexplicably appeared to surge way higher while the voltage and frequency dipped way below nominal (240V/60Hz). This would explain the generator's behavior (i.e. badly bogging) causing it to temporarily fall out of regulation, or what I am describing as a "brownout condition".

Btw, I did this generator test a few months ago on a fairly warm day while it was at operating temperature. I would like to repeat the test this Winter to see if the generator's operating temperature had anything to do with this unexpected behavior, which is certainly doubtful.

If I can't get this to work, I essentially wasted my money on the generator (~$350), because using it to charge an EV at 120V only is really not worth the effort and high cost of gasoline to keep the generator running so long.
Last edited by dsinned on Sun Nov 02, 2014 10:38 am, edited 3 times in total.

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TonyWilliams
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Re: charging on generator

Sun Nov 02, 2014 9:48 am

fooljoe wrote:I know that dsinned tried setting his JuiceBox all the way down to 6A to start the charge, but it still wasn't happening at 240V. Strangely enough, he reported that using the same generator at 12A and 120V (which in theory is the exact same amount of power as 6A and 240V) did work.


If you setup the EVSE to send a pilot signal of less than 6 amps, then the car is looking for digital communication to accept DC charging.

Obviously, a LEAF does not have this capability through J1772.

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TonyWilliams
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Re: charging on generator

Sun Nov 02, 2014 9:55 am

dsinned wrote:If I can't get this work, I essentially wasted my money on the generator (~$350), because using it to charge an EV at 120V only is really not worth the effort and high cost of gasoline to keep the generator running so long.


I suspect your inexpensive generator has virtually no flywheel weight. That will certainly save money for the manufacturer, but not handle a change in load very well.

Also, there may be a way to adjust the governor so that it can more quickly react to the load.

muus
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Re: charging on generator

Sun Nov 16, 2014 5:25 pm

dsinned wrote:
fooljoe wrote:I know that dsinned tried setting his JuiceBox all the way down to 6A to start the charge, but it still wasn't happening at 240V. Strangely enough, he reported that using the same generator at 12A and 120V (which in theory is the exact same amount of power as 6A and 240V) did work.

True. I was baffled by this, but the severe bogging of the generator at the instant when the JuiceBox switched on the load (RAV4 EV's OBC) was unmistakable. I was measuring the generator's output voltage, current and frequency at the time, and despite setting the JB's current limiter to <10A, as I recall the instantaneous load current inexplicably appeared to surge way higher while the voltage and frequency dipped way below nominal (240V/60Hz). This would explain the generator's behavior (i.e. badly bogging) causing it to temporarily fall out of regulation, or what I am describing as a "brownout condition".

Btw, I did this generator test a few months ago on a fairly warm day while it was at operating temperature. I would like to repeat the test this Winter to see if the generator's operating temperature had anything to do with this unexpected behavior, which is certainly doubtful.

If I can't get this to work, I essentially wasted my money on the generator (~$350), because using it to charge an EV at 120V only is really not worth the effort and high cost of gasoline to keep the generator running so long.


Are you sure you are setting the pilot to below 10A? I used an upgraded Panasonic EVSE and setting it at 6A to 12A worked fine on a cheap Chinese propane generator charging my Leaf. 6A at 240v is the same as 12A at 120v so there's no reason why this shouldn't work. From you description, your car is pulling a lot more current than it is supposed to so either the pilot isn't set correctly or your car is pulling more current than it's supposed to. What car are you trying to charge?
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dsinned
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Re: charging on generator

Sun Nov 16, 2014 7:43 pm

RAV4 EV. It's possible the car just won't "accept" <15A from a 240V charge. On my next charge, I'll have to try it with my JB pulled in to the wall (at 240Vac). I will preset the JB to only draw 6A and see if the car actually honors it. Same for the JB as well. It may be that JB's range of current limit adjustability does not allow a setting as low as 6A from a 240V AC source. I believe it does, but I'll have to check again while charging from the wall just to be absolutely certain.

fooljoe
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Re: charging on generator

Sun Nov 16, 2014 10:42 pm

dsinned wrote:RAV4 EV. It's possible the car just won't "accept" <15A from a 240V charge.
In the course of testing charging efficiency at L1 vs L2, I took my Rav all the way down to 6A @ 240V and it charged just fine.

Interestingly (but not relevant to the generator issue at hand), the efficiency at 12A / 120V was much worse than 6A / 240V even though the power draw is identical...
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EV4Taos
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Re: charging on generator

Thu Feb 25, 2016 9:07 pm

Ingineer wrote:
QueenBee wrote:
Ingineer wrote:The easy way to make this work is take a screw-on plug (NEMA 5-15P) and install two 1/2 watt 100k ohm resistors. One from neutral (silver screw) to ground (green), and the other from hot (gold screw) to ground (green). Then simply plug this into one outlet on the generator, and your EVSE into the other. This will safely pass the ground detect on the Nissan (and our upgraded) EVSE, while not being a hazard in any other way.


Hey Phil, just thought of something. If charging from a 240 volt generator would it be beneficial to connect both hot legs and the neutral to ground via the resistors?
Yes, this is 100% correct. Then earth is then properly floating is in the "middle". This is also how we advise our European customers who have isolated grounds. (some places in Europe do)

Image

-Phil


hi

This question is for Phil. I know you want folks to ask question publicly so you don't have to answer the same question over and over. So here it is:

Is the above picture the same resistor 240v configuration for the USA or is this just for the EU? If its different how so? Is it still using 2 resistors?

Much thanks,

Jonathan

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Ingineer
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Re: charging on generator

Fri Feb 26, 2016 9:52 pm

Yes, it's the safest configuration.
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EV4Taos
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Re: charging on generator

Fri Feb 26, 2016 10:08 pm

Ingineer wrote:Yes, it's the safest configuration.


Wow thank you for responding so quickly! I know you are busy!
Just to clarify USA = EU configuration? Both pins go to ground with a resistor?

Jonathan

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