Charging with Portable Generator

[slimothyjames]

In case anyone was wondering about putting a 2200W portable generator into their vehicles as backups IRL ?

Remember you're supposed to use an inverter type generator for a clean sine wave of power output. It is not recommended to plug into cheaper cycloconverter generators due to inconsistent output.

I'm just doing some Spring cleaning - had to burn off the remaining fuel (2 year old stabilized fuel) in my generator so I plugged in my mobile charger to put load on it.

So you're looking at about 1kW per hour. Indicated 5km of range added in the hour.

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[superdave80]

It is not recommended to plug into cheaper cycloconverter generators due to inconsistent output.

Why would an 'inconsistent output' be bad for the AC/DC converter in the vehicle?

 

[Mach-Lee]

Why would an 'inconsistent output' be bad for the AC/DC converter in the vehicle?

It will stop charging if the power from the generator is too dirty or the wrong frequency. It was designed for 60 Hz AC without big voltage spikes.

 

[HuntingPudel]

It will stop charging if the power from the generator is too dirty or the wrong frequency. It was designed for 60 Hz AC without big voltage spikes.

Yep, I have seen 240V capable power supplies freak out because they were not engineered properly for 50Hz power overseas and some overseas 240V stuff that won’t work on 60Hz. ??

 

[the golden eel]

So how many miles per gallon (or KM/liter) did you get??

 

[RickMachE]

1kW per hour is the rate one would expect from 120v.

 

[slimothyjames]

So how many miles per gallon (or KM/liter) did you get??

Really rough calculations, but:

• Generator 4.5L tank - runs just over 7 hours (5 hours was running my fridge/freezer & TV, last 2 was charging my EV).
• 2 hour mark, my app showed 12km added
• Assuming 6km/h charge rate
• 7 hours for 4.5L of gas - 42km
• Works to be about 10.7L/100km/about 22MPG +/- other factors

 

[generaltso]

So you're looking at about 1kW per hour.

1kW per hour is the rate one would expect from 120v.

I'm not usually this pedantic (or maybe I am), but there's no such thing as "kW per hour". A charging rate of 1kW will give you 1kWh per hour. That's where a kilowatt-hour got its name.

 

[slimothyjames]

@the golden eel

I just filled up my generator at the pump directly and it was actually only 3.9L as it overlfowed haha.

Using that on a basic calculation it's closer to 9.3L/100km or 25.3MPG

 

[machetrackingmachine]

@the golden eel

I just filled up my generator at the pump directly and it was actually only 3.9L as it overlfowed haha.

Using that on a basic calculation it's closer to 9.3L/100km or 25.3MPG

oh whoa, thats surprisingly good MPG. Question, since your generator is capable of output 2.2kw, and you're consuming 1.1kwh, does the extra energy just lost or is your generator automatically adjust and lower the gas consumption? At this 25MPG, equivalently 10kw takes about $4.8 if you charge from EA fast charging. Gas per gallon is lower than $4.8 in many cases and seems like it's not a bad cost options to just charge with generator, especially while in remote camping area. but noise is another thing.

Thx for this interesting datapoint. I am sure the mpg will depend on your generator efficiency, temperature, power output etc too.

 

[Mach-Lee]

Ran the numbers for a Honda EU2200i 120V generator:

1440W/1800W rated = 80% load
0.24 gal/hr fuel consumption
1.1 kW to the pack after charging losses
80 hours (3.3 days) required to fully charge 0 to 100%
19 gallons of gas required, $69 @ $3.65/gal
20-25 refills required, once every 3 hours
11 miles of range added per refill (3.4 MPH)
Aprox 14 MPG, $0.76/kWh delivered

Sounds like a horrible camping experience babysitting a noisy generator for 3+ days and having to refill it every 3 hours to get 11 miles at a pop. Plus all the space used up for 20 gallons of gas plus the generator. Adjust as necessary, but it's still going to a whole day without rest to charge back even 30%.

 

[Logal727]

This is like one of those anti-EV Facebook memes that people think are some kind of gotcha

 

[slimothyjames]

oh whoa, thats surprisingly good MPG. Question, since your generator is capable of output 2.2kw, and you're consuming 1.1kwh, does the extra energy just lost or is your generator automatically adjust and lower the gas consumption? At this 25MPG, equivalently 10kw takes about $4.8 if you charge from EA fast charging. Gas per gallon is lower than $4.8 in many cases and seems like it's not a bad cost options to just charge with generator, especially while in remote camping area. but noise is another thing.

Thx for this interesting datapoint. I am sure the mpg will depend on your generator efficiency, temperature, power output etc too.

Most modern inverter generators will adjust throttle depending on load. I have a switch on mine called Eco-Throttle which just provides enough power for whatever is plugged in.

Like you said there are many factors - I was only using rough data I had since I didn't want to run a full tank of fuel through the generator to see how many kW/range added to my MME.

 

[slimothyjames]

Ran the numbers for a Honda EU2200i 120V generator:

1440W/1800W rated = 80% load
0.24 gal/hr fuel consumption
1.1 kW to the pack after charging losses
80 hours (3.3 days) required to fully charge 0 to 100%
19 gallons of gas required, $69 @ $3.65/gal
20-25 refills required, once every 3 hours
11 miles of range added per refill (3.4 MPH)
Aprox 14 MPG, $0.76/kWh delivered

Sounds like a horrible camping experience babysitting a noisy generator for 3+ days and having to refill it every 3 hours to get 11 miles at a pop. Plus all the space used up for 20 gallons of gas plus the generator. Adjust as necessary, but it's still going to a whole day without rest to charge back even 30%.

I understand where you're getting the numbers from (spec sheet from website) but I wouldn't trust the run times/ratings - they're not very accurate for so many different applications. It's a general statement and it is understated to prevent legal issues.

There are a lot of factors to try to calculate it - for me to be accurate I would have to run my generator charging my car with a full tank of fuel until it cuts out, then fill it up to see how much fuel was used. Mine was rated at 4.5L but I could barely fit 3.9L into it and it ran until it wouldn't run anymore.

Your 0.24 gal/hr fuel consumption is from 0.95 gal fuel tank divided by rated 3.2 hr @ rated load of 1800W, then 80% of it.

But if you use the 8.1 hr at 1/4 load (25% of 2200W = 550W), 0.1117 gal/hr / 550W, 0.0002 gal/W x 0.29 gal/hr.

You would think you would use less fuel under a lower load.

 

[RickMachE]

Talking about cost benefit. We put in a whole house generator back in September, after enduring 15+ years of regular outages. I computed the cost per 24 hours at 1/2 and full load in analyzing the purchase.

We were out of town during a nearly 2 day outage, heat set to 50 degrees. The generator ran for 46 hours. Using roughly $40 in natural gas. Our electrical usage on those days would have been about $1.50. Had we been home, we would have used more with the heat on 70, but I would have manually turned the generator off for hours at time to save on the natural gas bill.

Doesn't take much analysis to realize that a power company can generate electricity cheaper than you can, so any generator you use to power an EV is wasting a lot of money.

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