Use of Portable Generator to Charge the Battery in an Emergency

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Brharding

Member
Joined
Apr 7, 2017
Messages
7
Location
Folsom, CA
The LEAF User's Manual states:
"• Only charge using a standard 110 - 120
volt, 15A dedicated electrical outlet
(For example do not use an electric
generator). Failure to do so may cause
charging to fail and could cause damage
to the Li-ion battery charging
equipment due to power surges.
• NISSAN recommends using genuine
NISSAN charging equipment to charge
the vehicle. Using non-NISSAN equipment
could cause the Li-ion battery to
not charge correctly and may damage
the Li-ion battery." (Page CH-12)

Is is possible, say in an emergency, to charge the car with a portable generator without damaging it? I was thinking it might be a good idea to throw a small generator (roughly 3000 W) and a can of gas in the back of the vehicle on a trip that I was not sure if I either had a recharge station available and/or ran out of power before I could get to one. It would take some time, but it may be quicker and less hassle than having to call a tow truck.

(also would be an interesting idea to tow a small trailer with a running generator as a range extender for long trips -- but for another topic)

The manual goes on to say:
"• Trickle charging is performed using an AC 110
- 120 volt, 15A dedicated electrical outlet using
the EVSE (Electric Vehicle Supply Equipment)
provided with the vehicle.
• The genuine NISSAN EVSE (Electric Vehicle
Supply Equipment) charging equipment or
trickle charge cable performs a communication
function with the vehicle before Li-ion charging
starts. If this communication does not occur
because other equipment is used, the Li-ion
battery will not charge."

If the genuine NISSAN EVSE or trickle charge cable was used with to connect the LEAF to the generator, wouldn't the needed communication indeed occur? Doesn't both the 120 V wall plug-in as well as generator plug-in perform the same function; i.e. providing a source of electrical power for charging? Unless I have a really bad generator, wouldn't the condition of the supplied electrical power be the same?
 
There are several threads about this like the one BrockWI mentioned and it had been done successfully several times.

Basically you need to get around the lack of ground on a generator by adding some resistors between ground and hot and ground and neutral. Otherwise the EVSE will notice there's no ground and will not allow the car to charge.

Also it seems only pure sine wave inverter generators work well. These deliver a clean, surge-free power source. Other types of cheaper generators might work but there really hasn't been enough testing to confirm that they'll work ok.
 
I strongly recommend that only a single resistor be used between neutral and ground to create the necessary ground reference. That way the generator returns to floating operation if the connection comes loose. If resistors are connected between the line terminal(s) and ground along with the neutral terminal to ground connection, then a loose connection on the neutral could result in unwanted voltage levels between neutral and ground.
 
GerryAZ said:
I strongly recommend that only a single resistor be used between neutral and ground to create the necessary ground reference. That way the generator returns to floating operation if the connection comes loose. If resistors are connected between the line terminal(s) and ground along with the neutral terminal to ground connection, then a loose connection on the neutral could result in unwanted voltage levels between neutral and ground.
That seems to make the most sense. Seems like I read somewhere that that works too.

Also another option would be, if you are going to get your EVSE upgraded by Phil, is to have him install a ground ignore switch on the EVSE.
 
Good information in the referenced threads about inverter generators and bonding the neutral/ground (via resistor).

Also for self or non-professional assisted rescue, make sure you have one of the screw in recovery hooks that you could be towed with as well as a 12V booster pack.
 
Brharding said:
...

If the genuine NISSAN EVSE or trickle charge cable was used with to connect the LEAF to the generator, wouldn't the needed communication indeed occur? Doesn't both the 120 V wall plug-in as well as generator plug-in perform the same function; i.e. providing a source of electrical power for charging? Unless I have a really bad generator, wouldn't the condition of the supplied electrical power be the same?

Yes, basically. It's JUST electricity, electrical energy.

John Kuthe...
 
1- Make a grounding plug (covered in other threads)

2- Make sure the generator is operated at the "continuos load" amp setting and not above (it may be called a 2kW genset, but only capable of 1.6kW continuous). Divide the kW by the voltage (120/240) to get how many amps you can pull. So, 1.6kW / 120 volts = 13.3 amps. With such a limit, you could operate at the typical stock 120 volt - 12 amp setting of the EVSE. If you have your EVSE so modified, you could select the exact amperage of the EVSE to match the generator limits.

3- Hauling gasoline in a passenger compartment is potentially deadly and illegal. Consider storing your gasoline in a small, sturdy container under the hood, strapped or bolted down. Or, add a trailer hitch receiver and use a simple external rack to place the generator and gasoline.
 
JohnKuthe said:
Brharding said:
...

If the genuine NISSAN EVSE or trickle charge cable was used with to connect the LEAF to the generator, wouldn't the needed communication indeed occur? Doesn't both the 120 V wall plug-in as well as generator plug-in perform the same function; i.e. providing a source of electrical power for charging? Unless I have a really bad generator, wouldn't the condition of the supplied electrical power be the same?

Yes, basically. It's JUST electricity, electrical energy.

John Kuthe...
I've only seen where pure sine wave inverter generators work (after the grounding issue is resolved). With construction type generators this is the only test that I know of and it didn't work:

VitaminJ said:
It does not work :( No matter what I do I cannot get a charge more than 1 - 1.5kw. My home 7kw EVSE does not charge at all on the generator, only the modified Nissan EVSE works and only at a low rate. Generator is putting out 240v I tested independently. I will look around maybe there is a magic box that can make the generator signal cleaner for the EVSE. I know that my plug adapter is correct because I use it at work and I get 2.5 to 2.8kw charge with my Nissan EVSE. It was posted in this thread that a true sine wave generator was needed but I just had to prove it to myself, luckily it was my friend's and free to test.
 
IssacZachary said:
JohnKuthe said:
Brharding said:
...

If the genuine NISSAN EVSE or trickle charge cable was used with to connect the LEAF to the generator, wouldn't the needed communication indeed occur? Doesn't both the 120 V wall plug-in as well as generator plug-in perform the same function; i.e. providing a source of electrical power for charging? Unless I have a really bad generator, wouldn't the condition of the supplied electrical power be the same?

Yes, basically. It's JUST electricity, electrical energy.

John Kuthe...
I've only seen where pure sine wave inverter generators work (after the grounding issue is resolved). With construction type generators this is the only test that I know of and it didn't work:

A "pure" sine wave? How does whatever knows the difference won't work if it's NOT a "pure" sine wave? And what's the metric and allowable level of impurities from a "pure" sine wave?

John Kuthe...
 
JohnKuthe said:
IssacZachary said:
JohnKuthe said:
Yes, basically. It's JUST electricity, electrical energy.

John Kuthe...
I've only seen where pure sine wave inverter generators work (after the grounding issue is resolved). With construction type generators this is the only test that I know of and it didn't work:

A "pure" sine wave? How does whatever knows the difference won't work if it's NOT a "pure" sine wave? And what's the metric and allowable level of impurities from a "pure" sine wave?

John Kuthe...
I don't know. All I know is that there seems to be a lot of pessimism that it won't work, and the few tests that have been done seem to confirm this.

Maybe the Leaf's charger ramps up faster than a normal generator can and that for some reason stops the charging process immediately. I really don't know why it doesn't work.

But the day I see someone on here go get a construction grade generator and charge their Leaf off of it just fine I'd be getting one myself right away. But until then I'm keeping my eyes out for a good used pure sine wave generator.
 
I believe the stock EVSE has a pretty tight range for allowable variances, just guessing here, but maybe 59 to 61 hz and 115 to 125 vac? Maybe someone has already found the range?

It amazes me that when the car starts charging it is a sudden "hit", it could so easily ramp up the draw and then most gensets wouldn't have a problem, but when you drop an inductive load of 1300 watts all at once, all but the largest gensets will bog a bit, thus dropping out of range for a split second on the EVSE.

With the stock EVSE I personally have used a Hondau EU2000i and it works fine, once charging you can switch in to "eco" mode to slow the genset a bit, but you can't be in eco mode to start. I have also used the stock EVSE with a xantrex prowatt 2000 and it works from that as well. I have tried a "well used" generic 2500w genset and the EVSE would just never start, kept going in to fault when it tried to start charging.
 
BrockWI said:
With the stock EVSE I personally have used a Hondau EU2000i and it works fine, once charging you can switch in to "eco" mode to slow the genset a bit, but you can't be in eco mode to start. I have also used the stock EVSE with a xantrex prowatt 2000 and it works from that as well. I have tried a "well used" generic 2500w genset and the EVSE would just never start, kept going in to fault when it tried to start charging.
That sounds typical. Both the Honda EU2000i and the Xantrex Prowatt are high quality true/pure sine wave inverters. Frequency, voltage and wave form won't hardly change on those (unless it's in eco mode). And the wave form is not a modified sine wave on either.

Personally I've been contemplating either getting a Honda or Yamaha sine wave inverter generator or install a stand alone sine wave inverter and then running a 12, 24 or 48V DC generator.

The latter option would allow me to expand to using solar energy to charge the Leaf some time in the future. It would also allow me to possibly build a larger +6kW generator that would be lighter for a small hitch basket (perhaps as light as 100lbs vs +200lbs for a 240V inverter generator set.) since the weight of the inverter would be placed somewhere on the Leaf itself. Also if I didn't go that powerful I could make it run off of a 12V system and then charge my Leaf off of another ICE car in an emergency.
 
Cheap generators are nothing but pure sign wave
Where they fail is in unsteady HZ and startup voltage.

Cheap inverters are not pure sign wave.
 
rmay635703 said:
Cheap generators are nothing but pure sign wave
Where they fail is in unsteady HZ and startup voltage.

Cheap inverters are not pure sign wave.

Interesting. I'm guessing that the pure sine wave is because they use rotating coil/stator setups? I've been reluctant to use electronics with my Champion (Honda) clone, but it's never caused a problem when I have.
 
rmay635703 said:
Cheap generators are nothing but pure sign wave
Where they fail is in unsteady HZ and startup voltage.

Cheap inverters are not pure sign wave.
True. Don't cheap/construction grade generators also have voltage spikes when loads are dropped?
 
I ordered this DuroMax 5500EH to charge my Leaf in case I got stranded when going on a adventurous trip that might take me somewhere there is not a charging station in range. I used it with my OpenEVSE it worked without being grounded or a special plug modification. I started out at 6A and gradually increased the load to a max of 14A and it ran for about 20 min. then suddenly quit charging. I had tried 16A and the generator surged and bogged down enough for the OpenEVSE to error out. Looks like max current should not be over 12A and probably 10A may be the max for longer charge period. I need to now find out what I damaged, the breaker did not trip. I haven't checked it out today yet to see what the problem is.

https://www.dropbox.com/s/mrfbn92w9g2lu63/20170602_194626.mp4?dl=0
 
Good News!! The DuroMax Lives!!. Must have been a thermal switch situation, as it now is charging quite happily at 12A. I ran it for approx. 30 min. no issues.

Here is a link to a video when I was running at 14A which caused it to suddenly quit charging after about 20 min.

https://www.dropbox.com/s/mrfbn92w9g2lu63/20170602_194626.mp4?dl=0
 
To get the most “bang for your buck” try your best to achieve the 10% of the bank’s AH rating. Obviously there will be times when this is not possible such as having too small of a generator or too small of a charger. You can charge at a lower current, it just won’t be as efficient.

If you charge with more than 10% of C20, you risk damaging the batteries due to over heating and over gassing.

Let’s try another example:

This time we have sixteen Trojan T105s (225 AH @ 6 volts) wired in series and parallel to make a 48 volt battery bank. There are two banks of eight batteries that are paralleled to make 450 amp hours (C20) at 48 volts.
 
The Harbor Freight 3500W unit was a waste of money. It does not recover fast enough and cycles over and over. My 120V inverter 2K unit works fine. I did have to connect the neutral and ground together in a shorting plug. Since it is used alone this is OK. Tied to a panel this is poor practice.
 
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