Generator requirement to charge the Leaf @240 in 7 hours

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vulcan33

Member
Joined
Aug 16, 2010
Messages
5
We have a rustic cabin in Southern Ohio without power.
How big would a 240 Volt generator need to be to complete a 7 hour charge?
 
If the charge rate is 3.3 KW, assuming you wouldn't want to push it with a sustained load beyond about 80%, I'd think you'd want a minimum of 4 KW. As a practical matter you'll find a lot of 5-6KW models on the market and that's probably where the better deals are.

If you think you're going to use it a lot you'll probably thank yourself to invest in a better quality unit like a Honda. Be sure to run the gas out and/or drain the carb if you're going to be letting it sit unused for extended periods between usages.
 
With the charger built into the LEAF, a "full" charging might take 8 hours or more.

However, since you would rarely start the charging truly empty, many times the charging would finish in less than 8 hours.

Assuming your generator can produce more continuous power than the LEAF can use (15, maybe 16 amps), a more powerful generator will not make the charging go any faster. However, it might be easier on the generator if it does not need to run "flat out" (at max. output) for a long time.

CAUTION: Often, a generator's "continuous" rating is substantially less than its "peak" rating.
 
Since the LEAF charger is 3300w I would suggest a minimum of 5000va rated continuous power.
(don't look at surge rating)
Many uncorrected chargers have a power factor of ~.7 so 3300/.7 = 4714 required available power.

Correction... if the 3300 is output there will be a higher input requirement of 10 to 20%.

If someone knows that the charger is power factor corrected you might get by on 3500-4000 rating but that will not save much.
 
How often, and at what time of the day, do you need to charge at the cabin?

Maybe solar panels, a few batteries, and an inveter would both power the cabin and provide a partial charge each day?
 
Good points ... "how often ..." and "partial charge" (using solar).

But think carefully "how often" you'll be doing this. You might end up with a LEAF that gets 4 mpe, but also only 20 mpg :shock: It might be worth using the (cough!) gas car !

If you end up with solar ... and the utility has good rates ... when you're not at the cabin (if you can get the grid connected) you can MAKE money selling to the utility ...
 
This is a perfect use of the "Honeywell" panels that come with the Microinverters, you can add them 1 at a time, 240Watts each. of course they need AC power to "startup", but that could be done with a 12V battery and a very small inverter, just enough to get the microinverters going. As long as the load is pretty well matched, it would work fine...

http://honeywellsolarsystems.com/solar-products/solar-power-smartgrids.asp

http://honeywellsolarsystems.com/honeywell-retail-solar-center-locations.asp

http://honeywellsolarsystems.com/solar-products/ac-solar-modules_z.asp

Edit: Never mind, probably won't work, without a way to store the power, you will only be able to charge during the day, and you may not have 7 hours of "peak" production (most places don't). A PV System with battery storage and an inverters is what you will need...
 
vulcan33 said:
We have a rustic cabin in Southern Ohio without power.
How big would a 240 Volt generator need to be to complete a 7 hour charge?
I actually researched this a few months ago. I found a tri-fuel generator which could run on propane, gasoline, or natural gas. My plan was to run it on propane. I found a large propane tank which enabled the generator to run for 18 hours. I found propane was available at most U-haul stores. I was going to charge the car from the generators 110v 20a circuit. Here's my biggest issue and I never received a satisfactory response. Does the Leaf require grid quality pure sine wave power? If so, does the generator actually produce grid quality pure sine wave power (rather than modified sine wave)? If anyone has any insights in that regard please share.
 
Generators are generally sine wave. Poor power factor devices tend to disrupt the sinewave but chargers don't usually care too much.
An inverter/generator such as Honda 3000 will hold the sinewave better than standard contractor generators.
 
smkettner said:
Generators are generally sine wave. Poor power factor devices tend to disrupt the sinewave but chargers don't usually care too much.
An inverter/generator such as Honda 3000 will hold the sinewave better than standard contractor generators.
Right, and that's the issue. Nissan couldn't tell me if the Leaf charging required grid quality power. I remember I had a cordless drill once that came with a warning to not connect its charger to a modified sine ware inverter or any generator which could produce grid quality pure sine wave power.
 
LTLFTcomposite said:
If the charge rate is 3.3 KW, assuming you wouldn't want to push it with a sustained load beyond about 80%, I'd think you'd want a minimum of 4 KW.
. . . . . . . . . . . . . . . snip
Be sure to run the gas out and/or drain the carb if you're going to be letting it sit unused for extended periods between usages.

we converted our 7k generator to run on LPG. No need to worry about fuel going bad that way. the only down side is we loose about 15% of the 100% duty cycle rating, as LPG has less energy than gasoline. the other up side is we don't have a ton of foul exhaust.

.
 
We have not heard about the input AC requirements of the LEAF's charger. The only safe assumption for now, is NOT the "modified" sine wave (really a two-tier square wave), but use a "real" sine wave for Level 1 (120v) and Level 2 (240v) charging.

Charging on 110/120 volts (at 12 amps, not 240v at 15 amps) will take a LOT longer than 8 hours ... closer to 20.

But, perhaps charging for 5 hours each day would be sufficient, depending upon your usage.

A typical 100 amp-hour 12 volt lead-acid battery would store 1.2 kWh, of which ... maybe 50% would be "usable". So, charging 25% of the LEAF's 24 kWh battery (6kWh) would take only 10 "car" batteries, and a 90-140v DC to 120v (or 240v) inverter (AC out) to "feed" the EVSE.

Also, the 6kWh might be enough to power the cabin overnight.

With enough PV panels, you might be able to charge the EV AND the 12v batteries during the day.

Or, ... charge the LEAF's batteries from the PV, and use a reverse "Quick-Charge" type connection to power the cabin from the LEAF's batteries during the night!
 
garygid said:
We have not heard about the input AC requirements of the LEAF's charger. The only safe assumption for now, is NOT the "modified" sine wave (really a two-tier square wave), but use a "real" sine wave for Level 1 (120v) and Level 2 (240v) charging.
Nissan have sated the following," It will charge on a regular 110/120V 20-Amp dedicated outlet. This is considered a "trickle charge," which means it would charge at a slower rate. For home charging, we recommend a home charging dock on a dedicated 220/240V, 40A circuit."

This is why I was looking at generators which had a 120V 20-Amp connector. Also, for my application, I didn't need a full charge, I just wanted to keep it topped off. It would only require a few hours on the 120V connector.

Related question, should we be concerned about plugging the Leaf in on a 120V circuit (at a friends home for example) because the circuit may not be 20-Amp nor dedicated?
 
The 120v charging does not "require" a 20-amp circuit (or socket), since the EVSE is designed to be used on "any" (unloaded) 120v circuit, even the commonly-found 15-amp circuits, where the common household "parallel-prong, 15-amp" socket is usually found.

We suspect that the L1 EVSE is "set" to tell the EV to use only 12 amps maximum.
 
garygid said:
The 120v charging does not "require" a 20-amp circuit (or socket), since the EVSE is designed to be used on "any" (unloaded) 120v circuit, even the commonly-found 15-amp circuits, where the common household "parallel-prong, 15-amp" socket is usually found.

We suspect that the L1 EVSE is "set" to tell the EV to use only 12 amps maximum.
If that's the case, why didn't Nissan specify it that way rather than stating 120V 20-Amp dedicated circuit?
 
garygid said:
Where did you see Nissan's statement of "20-amp dedicated"?
It's described in question #19 in the charging FAQ.

Q. Will it plug into a regular household outlet?
A. It will charge on a regular 110/120V 20-Amp dedicated outlet. This is considered a "trickle charge," which means it would charge at a slower rate. For home charging, we recommend a home charging dock on a dedicated 220/240V, 40A circuit.

Where did you get your information?
 
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