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You should be able to charge a Bolt EV using a gasoline generator provided you use the correct type of generator. I would presume you would want to do a level 2 charge system; level 1 just takes far too long and level 3 is very expensive—the charge system and the required 50kW generator would cost almost as much as a Bolt and be almost as large and heavy.

A level 2 charge system provides 7.5kW or put another way, 32A at 240V. This is equivalent to a household clothes dryer outlet or what is often called an “RV Power Outlet”. With this power, you gain about 32 miles per hour of charge so to completely charge an almost empty Bolt battery requires about 7 hours. So this defines the size of gasoline generator you need to use. I would use a generator rated at 8000 Watts continuous. That’s a large generator, perhaps $1000, 250 pounds and the size of a small mini-dorm refrigerator. If you use something smaller, like a 3000 Watt generator, your charge time will go longer proportionally. Also, you need to look at fuel usage. Many generators will specify they can run for 6 or 8 hours on a tank when delivering 50% load. So if you use an 8000 Watt generator at full load (to fully charge the battery in 7 hours) you will have to refill the fuel tank once or twice during the charge cycle. Also, be sure the generator is rated to run continuously at full load for that long a time and won’t overheat.

Generators put out a “sine wave” which is the same kind of waveform you get from an electric utility (which also is produced by a generator—a very large one). Conversely, an “inverter” delivers a square wave or perhaps a “stepped square wave”. This may also be referred to as a “dirty” signal and can cause problems with many loads. The charging system inside the Bolt expects a “pure” sine wave and may have problems with power that is not a sinewave, such as an inverter delivers. I would certainly not use a generator that did not deliver a clean sinewave. How clean or pure the waveform is, that is how close to a perfect sinewave is specified by how much “Total Harmonic Distortion” is present. 0% is perfect and you won’t find nor do you need that clean. 5% THD is clean enough and good generators will have a number like that.

So to summarize, you need a 8000 Watt gasoline or propane generator (not an inverter-type), a level 2 charge station, and the proper AC connector or adapter to connect the two. The most common type of AC connector is an NEMA 14-50 but there are adapters to the other NEMA connectors used for a 240V 30, 40, or 50 Amp circuit.
FWIW, an inverter generator can put out a good pure sine wave with minimal distortion, it's just that inverters that do so are more expensive. It seems to be the case that most inverter generators actually do have high-quality inverters.

The issue with non-inverter generators is that they're much louder.

The Honda EU7000is and Yamaha EF6300iSDE generators are big fairly quiet 240V inverter generators. They can deliver 5500 W continuous, which is 23 amps. That's easily enough for an overnight charge, but huge and possibly overkill, since it costs almost $4000.

It would be be cool for someone to work out the cheapest route for getting meaningful power into a Bolt for the least money but with least risk of whatever the manual is warning against when it cautions not to use a generator.
 

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Can you tell us a bit more about this test. What does it look like when the Bolt's DC-to-DC converter “can't keep up” (i.e., how could you tell?)

When the DC-DC *could* keep up, the aux battery voltage would cycle from about 13.6V down to about 12.5V, when the DC to DC would kick in and bring it back up to 13.6V. It would do this on an ~30s cycle, with the 900W (at the inverter) load, IIRC. At too high a load (1200W), the DC-DC would *try* to bring it back up to 13.6V, but couldn't keep up and the aux battery voltage would continue to drop over time. I could see the voltage drop *rate* slow down when the DC-DC kicked in, but it was insufficient to stop the drop entirely. I only let it get to about 12V, when I removed the load to protect the battery. The DC-DC is rated at 1600W, but with inefficiencies in the inverter and cable losses, I'm guessing that translated to something less than 1200W on the inverter load side. This wasn't a very scientific study, and I didn't write anything down. I was just looking at the aux battery terminals with a DVM to make sure behaviors were as I expected. They seemed to be.


Memory is a funny thing. YMMV.
 

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Generators put out a “sine wave” which is the same kind of waveform you get from an electric utility (which also is produced by a generator—a very large one). Conversely, an “inverter” delivers a square wave or perhaps a “stepped square wave”. This may also be referred to as a “dirty” signal and can cause problems with many loads. The charging system inside the Bolt expects a “pure” sine wave and may have problems with power that is not a sinewave, such as an inverter delivers. I would certainly not use a generator that did not deliver a clean sinewave. How clean or pure the waveform is, that is how close to a perfect sinewave is specified by how much “Total Harmonic Distortion” is present. 0% is perfect and you won’t find nor do you need that clean. 5% THD is clean enough and good generators will have a number like that.
Aren't the "inverter generators" generally the more high end ones? I would hope that a generator that filters it's output through an inverter would output a pretty clean modified sine wave at a minimum. I guess you could have a situation where you have a cheap generator with a cheap inverter that only has the inverter so they can check a box on a spec sheet and pretend they are comparable with the good ones.

One of the common loads for an emergency/backup generator is a refrigerator or freezer and refrigeration compressors generally don't like square wave power as I recall.

On an unrelated (to generators) note, I've been thinking of picking up this inverter, advertises itself as "pure sine wave" but I can't find specs for THD. Would be mostly using it as an emergency backup power running off the Bolt's DC-DC system in the event of a power outage.
 

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... On an unrelated (to generators) note, I've been thinking of picking up this inverter, advertises itself as "pure sine wave" but I can't find specs for THD. Would be mostly using it as an emergency backup power running off the Bolt's DC-DC system in the event of a power outage.
A 12V DC- 120V AC converter certainly can be done. They've discussed this many times over the gm-volt forum. I think the gen 2 APM had a lower ampacity than the gen 1 volt, and not sure what the rating is for the BOLT APM. Don't forget to account from some base amount of the capacity being used by the BOLT itself, even in "idle" condition.

On the other hand, as one of the EEs pointed outed during the VOLT discussions, it is much more efficient (someday if and when EV mfgrs allow access) to go directly from the HV battery (as evidenced by the relatively small size of the orange HV wires, esp the orange wires feeding HV to the APM).

So, once you determine how many amps can be safely taken off the 12V DC bus, add a suitable fuse, or breaker, and cables (very large sizes as you go to 50A+), and connectors, is it worth it?

Something to consider instead is to buy a small inverter generator (with a high quality output) and running completely free of any risk to the BOLT or it's APM. The gold standard has been the Yamaha and HONDA small 2kW generators, however there are many other options now.
 

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... you need a 8000 Watt gasoline or propane generator (not an inverter-type) ...
It is correct that a conventional rotary generator will output a sinewave, however I doubt that is the only issue. For example, a relatively high power generator has a relatively low source impedance, so if things go wrong (e.g. modest priced portable home and contractor units), such as voltage fluctuation, it is possible that is what GM is worried about potentially damaging the BOLT charger box (likely (?) by overvoltage, or possibly very fast changes in voltage).

The el cheapo inverters are problematic because of the squarish waveforms, however, the high end inverter generators are very well regulated and may be (?) safer as less likely to overvoltage. But, of course to get enough power capability in a high end 240 VAC inverter generator, as was noted before, is probably $4k to $10k if the higher capacities even exist.

OTOH, by the original argument, some high end building back up generators, are probably okay too. Otherwise, how could a hospital run all kinds of high end electronics systems without risk of damage.

Did some googling, here is a Tesla thread on charging from generators, scroll down (Rocky_H | February 28, 2017) and there is a list of similar threads: https://forums.tesla.com/forum/forums/charging-generator-0 Lot's on Leaf too, most seem to have success with 2kW inverter generators (high quality sine wave), possibly after resolving the grounding issue, e.g. tying "neutral" to ground, or possibly two 10k power resistors, one from hot, one from neutral if the genny doesn't like the direct ground connection.
 

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Something to consider instead is to buy a small inverter generator (with a high quality output) and running completely free of any risk to the BOLT or it's APM. The gold standard has been the Yamaha and HONDA small 2kW generators, however there are many other options now.
I have thought about that, one issue is if you have a generator for backup/emergency power you need to store gasoline and you need to periodically use up and replace that gasoline so it doesn't turn stale. Potentially could need 5+ gallons of gas just to run a Honda generator at a moderate load for 24 hours.

I generally don't ever draw the Bolt's battery much below 40% so I should be able to use an inverter at 1000W for almost that long as a worst case scenario.
 

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I have thought about that, one issue is if you have a generator for backup/emergency power you need to store gasoline and you need to periodically use up and replace that gasoline so it doesn't turn stale.o
ALL of the lake houses up at my summer home run their emergency generators off natural gas. You already have NG to run hot water, furnaces, clothes dryers, cook stoves, so it’s a very simple, (& cheap) to run a line to the gen set.
It never goes stale, supply is unlimited, & it is dirt cheap.
 

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I have thought about that, one issue is if you have a generator for backup/emergency power you need to store gasoline and you need to periodically use up and replace that gasoline so it doesn't turn stale. Potentially could need 5+ gallons of gas just to run a Honda generator at a moderate load for 24 hours.
Some of the 2K Watt inverter gens are dual fuel type and will run off std 20lb bbq propane tanks too- so no need to keep gas in them.
I put "Star Tron Enzyme Fuel Treatment Concentrate" in my generator gas- I always have it on hand anyway for the boat. It keeps the gas good for up to two years (in theory) and at 1oz/8gal gas it doesn't take much to keep the generator gas fresh.
 

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ALL of the lake houses up at my summer home run their emergency generators off natural gas. You already have NG to run hot water, furnaces, clothes dryers, cook stoves, so it’s a very simple, (& cheap) to run a line to the gen set.
It never goes stale, supply is unlimited, & it is dirt cheap.
Where I live the most likely event that would require running a generator for more than a few hours would be an earthquake. Natural Gas would be down as well and would take longer to restore than electricity.
 

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Aren't the "inverter generators" generally the more high end ones? I would hope that a generator that filters it's output through an inverter would output a pretty clean modified sine wave at a minimum. I guess you could have a situation where you have a cheap generator with a cheap inverter that only has the inverter so they can check a box on a spec sheet and pretend they are comparable with the good ones.

One of the common loads for an emergency/backup generator is a refrigerator or freezer and refrigeration compressors generally don't like square wave power as I recall.

On an unrelated (to generators) note, I've been thinking of picking up this inverter, advertises itself as "pure sine wave" but I can't find specs for THD. Would be mostly using it as an emergency backup power running off the Bolt's DC-DC system in the event of a power outage.

I bought this one: [ame]https://www.amazon.com/gp/product/B00AYH686E/ref=oh_aui_search_detailpage?ie=UTF8&psc=1[/ame]


It's pricey, but is *very* well-regarded, both on Amazon, and elsewhere.


There's a thread about this already, where I showed my solution, complete with photos and parts list.


https://www.chevybolt.org/forum/82-charging-batteries/14986-using-bolt-battery-home-emergency-backup.html
 

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Where I live the most likely event that would require running a generator for more than a few hours would be an earthquake. Natural Gas would be down as well and would take longer to restore than electricity.
There are some advantages to having the APM - inverter combo, such having AC power on the go in the car, or at a remote location.

If you have not yet bought the inverter yet, something to consider, I went with the Xantrex ProPower some years back for the VOLT: http://www.xantrex.com/power-products/power-inverters/prowatt-sw.aspx . It takes some care not to put too much load on the APM.

Many years back now, I ran a little morningstar 300W suresine inverter in the Subaru to power a Spectrum Analyzer and digitizer for some field work studying FM broadcast signal strength in my regional area. There was power to spare, even with the last of the Agilent analyzers with CRT, just before they all went LCD display. https://www.morningstarcorp.com/products/suresine/

Also, if you get into relatively heavy gauge wires ("cables"), use care with some of the car audio fuse holders. I had one where the wire kept coming loose. And, don't size your wire ampacity for 90c heat rise! Finally, sizing the fuse or breaker can take some effort, because, for example, the fuse blow curves for many type of auto fuses take a very long time to open at rated current.

The Anderson high current connectors are really nice and robust. Some have heavy rubber covers to use on both sides when not in use. They need a giant crimper (e.g. Greenlee), or some pro car audio installers can do the crimps for you.

Tell us how it goes, include pictures!
 

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Sorry, I completely missed GregBrew parts lists, and another option for the inverter, see post #50, page 5 of this thread and the link there too. There is an example of the Anderson connector. They come in many sizes to match the size wire you use (and colors). Also, for the larger ones, you can add a pull handle on both sides.

Also, I just noticed Greg's post that 900W was as high as you can go with the inverter he was using, before the APM could no longer keep up with charging the 12 V battery (i.e. somewhere above 900W AC inverter load, the 12V battery voltage starts to fall off). So is 900W enough for your application? Especially, where the little Honda generator can supply something like 1,800W continuous.

The VOLT was much easier to work with for 12V inverters, because the both the 12V battery and APM are in the back behind the passenger seat.

In the Subaru Outback, I had a pro-audio company run wires back to the rear area behind the rear seat. They did a nice job, from a fuse at the battery up front, down somehow through the lower door jambs under the side doors, and out into and from a little side cubby in the back area. So, I had an Anderson with a rubber cover back there which could be coiledup and stored in the side cubby when not in use.

Maybe the only easy BOLT option is the short pig tail and you open the hood when needed? This subwoofer post https://www.chevybolt.org/forum/26-electronics-audio-lighting/22113-sub-amp-install-done-noob.html shows one possible path through the firewall, I didn't follow the entire route to the rear of the car.
 

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An even better load to gauge waveform quality would be an inductive load such as a motor or fluorescent lighting.
Is charging a Bolt an inductive load? I can see that running an electric motor would be, but I'm not sure what operting the Bolt's charging system would be. I'm not familiar with the intricacies of the charging system, but what would cause it to act like an inductive load?
 

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Is charging a Bolt an inductive load? I can see that running an electric motor would be, but I'm not sure what operting the Bolt's charging system would be. I'm not familiar with the intricacies of the charging system, but what would cause it to act like an inductive load?
The comment was suggesting that an inductive load would be a good way to evaluate the quality of the waveform produced, not that charging an EV is an inductive load. Generally, AC-DC conversion tries to reduce reactive (inductive or capacitive) load in order to improve efficiency, so it should appear close to a resistive load. Meanwhile, the converter operates optimally under a clean waveform. It does have filters and such to clear out noises and irregularities, but bad waveforms probably won't do any good. It's also possible that Bolt would reject charging from a bad power source in order to protect the circuitry.
 

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FWIW:

Source power has many attributes that (as some has alluded to above) more than Volts and Amps:
You have to worry about

1. Volts and amps, sure but
2. Harmonic distortion of the wave (as show above)
3. Source impedance
4. a WHOLE host of parameters such as Surge, sag, brownout, over voltage, spike (actually all technical power terminology).
5. Source Power factor tolerance.
6. Grounding/bonding
7. (and a bane of portable generators) frequency tolerance

So the 'easy button' for Chevy is essentially saying: 'source power from a well regulated, well maintained and ROBUST Source'. otherwise the manual would look like a very technical engineering specification...

And as an EE, I know what they look like :)

A 'generator' could meet these needs, but the manual would look like MILSPEC of requirements.
 

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FWIW:

Source power has many attributes that (as some has alluded to above) more than Volts and Amps:
You have to worry about

1. Volts and amps, sure but
2. Harmonic distortion of the wave (as show above)
3. Source impedance
4. a WHOLE host of parameters such as Surge, sag, brownout, over voltage, spike (actually all technical power terminology).
5. Source Power factor tolerance.
6. Grounding/bonding
7. (and a bane of portable generators) frequency tolerance

So the 'easy button' for Chevy is essentially saying: 'source power from a well regulated, well maintained and ROBUST Source'. otherwise the manual would look like a very technical engineering specification...

And as an EE, I know what they look like :)

A 'generator' could meet these needs, but the manual would look like MILSPEC of requirements.
None of those are show-stoppers for a quality generator of appropriate size. Where quality generators tend to have problems is with rapidly changing loads or when overloaded. EV charging is a relatively steady-state, and the problems with overloading can be solved by sizing the generator appropriately and/or turning down the Bolt's charge rate.

I'm curious what sort of power factor the Bolt presents as a load. I would assume they would attempt to design it to be as close to 1 as possible.
 

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I have a Generac Guardian 22kW setup for whole house transfer. It's their low end series, air cooled. Generac used to sell a model called the Synergy which was air cooled, but boasted super clean power for 'sensitive electronics.' As of a quick check tonight, it's still not listed for sale though they reference it's past existence. I don't have a good meter, in fact I have the opposite but for comparison purposes it has 'some' value for the test I just performed a couple minutes ago. The meter is the Luimy LM2001. I checked the waveform on utility and then on generator. There are two pics of each, different scale, same time frames.

Utility, zoomed in:
20190909_022610_resized.jpg

Generator, zoomed in:
20190909_023526_resized.jpg

Utility, zoomed out:
20190909_022526_resized.jpg

Generator, zoomed out:
20190909_023507_resized.jpg

My system will shed the EVSE if the generator overloads, followed by the 5 ton AC. However, I am not able to overload the generator in all my reasonable tests. I have installed a soft start on the 5 ton AC, so that will pretty much never overload anything on startup. Prior to the soft start it had a hard start capacitor and the lights would dim slightly when the AC kicked on, now not only does it not dim but the generator doesn't even sound like it's working any differently (harder). My utility company is currently transitioning off of a natural gas program called Rely-A-Bill so it has given me the luxury of doing some long endurance gen tests. The JuiceBox 40 seems to be ok, the car still drives, I've done half a dozen charging cycles on gen power.
 

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Great thread, and timing:
I'm considering a Generac XT8000 EFI.
Other models with the same 'Truepower' Tech as this one claim to have <5%THD, but I don't see specifics on this model.
I have a CC EVSE connected to a NEMA 14-50 connected to a 60A breaker (with a short run of 6 gauge wire in conduit), but I would most likely use this connection to backfeed the power into the house, so I'd most likely plug my bolt into a 120/20A.
https://www.generac.com/all-products/generators/portable-generators/xt-series/xt8000efi
I don't see a reason why this model wouldnt do the job, however I dont want to be the one to test it; at least not without more information.
The main use of this generator would be to power an AC, but even with a hardstart kit I dont know if this would be enough. But that question is probably best asked in a different placed.
 

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Some additional information. (Disclosure: We regularly charge a BOLT and a TESLA from a whole house Generac generator during ice storms and other Northeast power outages. This happens without hiccups and led to asking why.)

All onboard EV charging equipment presents a power factor of ~1. That means a fully resistive load with minimum impact to the generator.

Manufacturers of 'world' vehicles need to have their (OBC) onboard chargers comply with EN61000-3-2, a standard to avoid loads sending damaging harmonics back into the utility supply. How the OBC does this is via a circuit on a chip that only draws load in synchronous with the input AC waveform. If you have a pure sine wave, the circuit draws power in sync with the pure sine wave. Have a wonky, 5% distorted sine wave? The circuit draws in sync with that. The intent is not to disturb the utility or generator. Texas Instruments has a good explanation here: https://training.ti.com/sites/default/files/docs/analog_ac_dc_and_isolated_dc_dc_solutions_for_automotive_hev_ev_applications_det_tech_day_9_10_18_mo_b_0.pdf

Generators have different specifications and capabilities based on price points. More cost buys you principally better frequency control.


Current technology means a multi-pole AC generator head with internal AVC (Automatic Voltage Control). The generator components will be CNC machined and wound for minimum THD (Total Harmonic Distortion), even from offshore suppliers. If the generator armature goes around at constant speed, you get a sine wave. Most of the THD will occur from gasoline engine 'pulsations' that can be controlled by flywheel and mechanical design. Notably, most Generac engines operate at 3600 RPM or 60 RPS. Most 'pulsations' will be at 60Hz or lower and not generate higher harmonics.

Where you begin to see a difference in cost is speed regulation. A base model will have 'droop' speed regulation and list this as a tolerance on 60Hz. Droop means that the fuel engine will 'droop' to speed at about 50% load. Above this, frequency will increase within a band. (Those manufacturers who do specify tolerance may show 63-57Hz, or something like this.) For an EV on board charger, it should be tolerable.

A whole-house model in the Generac Protector series will have isosynchronous speed regulation. Isosynchronous means that the generator has an internal frequency reference and adjusts speed to meet the load. Generac lists +/- 0.25% as their tolerance with isosynchronous control. Great control, but you cost is now over $7000 for a 20kW whole-house generator.

A good overview is here: https://www.svri.nl/en/isochronous-vs-droop-control-for-generators/

Backfeeding your generator into your home wiring is the best way to meet the police, understand our criminal and civil justice systems, max out your liability insurance, and generally delay repairs for everyone.

Everyone wants to keep the AC and fridge on, and have watched hundreds of YouTube videos on how to 'backfeed safely'. Their neighbor may have shown their technical prowess by making a double-male extension cord. Besides potentially making 2000V appear at your local transformer, backfeeding is illegal. Doing it 'right' according to a YouTube video does not give you the same evidence that a legal transfer switch, properly installed, does. Thought experiment: Claim you did it according to a YouTube video in court, or show a fail-safe UL listed transfer switch as evidence--your choice.

You can obtain a manual transfer switch for about $300 that feeds power to critical circuits (https://www.generac.com/all-products/transfer-switches/manual-transfer-switches#?cat=133)

If you have been through Florida hurricanes or Northeaster ice storms, at the first sound of a generator utility workers will canvas a neighborhood to make sure there are no backfeeds. If they cannot verify, they will disconnect homes before proceeding with repairs. It slows up everyone.
 
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