[jcramer]

The 2015 Volt Owner's Manual states "240 volt/40 amp circuits provide flexibility for future vehicle charging needs."
However, it doesn't say that 40 Amps is the maximum current. JuiceBox makes a 75 Amp charger for EVs that costs about $899. It might be difficult to connect to a home breaker box, but it exists. Could a Volt be charged with 240 volts at 75 amps?

 

[SharkVolt]

Max amps on gen 1 Volts is 15 amps.
Max amps on gen 2 Volts is 16 amps.
These require a 20 amp circuit.

Max amps on Bolt EV is 32 amps.
This requires a 40 amp circuit.

All with level 2 240 volt chargers.

All higher amp chargers will drop down to what the car requests, so they will work.

 

[bentbiker]

Could a Volt be charged with 240 volts at 75 amps?

No Volt that has been produced thus far. The Gen1 is limited to ~13.75 A as I recall, and ~15 A for the Gen2. The key words in the quote you reference is "for future vehicle charging." And "future" modifies "vehicle", not "charging."

 

[llninja]

Save your money and buy what you minimally need today. I spent double of what I could have 4 years ago and have yet to use the higher current in the EVSE. Plus, my next car could have a 100 amp or a Mr. Fusion on board requiring different hardware altogether. I don't have a crystal ball.

 

[Mister Dave]

All higher amp chargers will drop down to what the car requests, so they will work.

The EVSE connector (J-1772) has a signaling protocol that reports the EVSE's capabilities to the charger in the car. The car will draw the number of amps that the EVSE tells the car it can pass.

To be very clear, an EVSE is not a charger. In this photo the charger is the silver box below the headlight:

 

[bjrosen]

Save your money and buy what you minimally need today. I spent double of what I could have 4 years ago and have yet to use the higher current in the EVSE. Plus, my next car could have a 100 amp or a Mr. Fusion on board requiring different hardware altogether. I don't have a crystal ball.

The difference in price between a 16A and a 32A is only a couple of hundred dollars, the price of a good dinner, so there is no reason not to buy a 32A EVSE even though the Volt only needs a 16A EVSE. A ClipperCreek or other quality EVSE should last a decade or more so you will be using it for your next car as well as this one. A 32A EVSE will be able to provide 100KWh in 14 hours which is good enough because even if you do buy some future 120KWh BEV (the biggest Tesla battery is only 100KWh) you will hardly ever need to do a full charge. If you assume that your daily use is likely to be 100 miles or less, and assume 3.5 miles/KWh, that's 28KWh which can be charged in less than 4 hours (the Volt takes 4.5 hours to fully charge). A day trip of 300 miles would use 86KWh which would take 12 hours with an 32A EVSE which is the typical time that your car would be plugged in overnight. Unless you are running a taxi service there is no scenario where you would ever need a 100A Level 3 EVSE at home.

 

[2VoltFamily]

The 2015 Volt Owner's Manual states "240 volt/40 amp circuits provide flexibility for future vehicle charging needs."
However, it doesn't say that 40 Amps is the maximum current. JuiceBox makes a 75 Amp charger for EVs that costs about $899. It might be difficult to connect to a home breaker box, but it exists. Could a Volt be charged with 240 volts at 75 amps?

Save your money. Unless you plan to get a Bolt or Tesla in the next five years buying an EVSE with a higher amp rating is a waste. The 2015 can only accept up to 14 amps MAX.

Also, double check the forum, some 2015s come with an EVSE that can do both L1 and L2 (120/240). It would require an adapter. It is important to verify the model of the EVSE before attempting to use an adapter.

 

[2VoltFamily]

Max amps on gen 1 Volts is 15 amps.
Max amps on gen 2 Volts is 16 amps.
These require a 20 amp circuit.

Not to split hairs but I think the max on the Volts are:
Max amps on gen 1 Volts is 14 amps = 3.3 kW = (240V x 14A)
Max amps on gen 2 Volts is 15 amps = 3.6 kW = (240V x 15A)

But it doesn't change the point you make that anything above a 16A L2 EVSE does nothing for speeding up a charge on any Volt, Gen1 or 2.

 

[Qinsp]

The fastest way to charge a Volt will probably be if you have access to a 265vac power supply.
The amps are fixed, but the voltage can range from 200vac to 265vac per spec.

I have considered doing this at work since all I have 208 and 277vac nominal. I have yet to test whether 277 will work like it can with a Tesla charger. I would need an expensive step down transformer with high kW rating.

 

[PH2]

The fastest way to charge a Volt will probably be if you have access to a 265vac power supply.
The amps are fixed, but the voltage can range from 200vac to 265vac per spec.

I have considered doing this at work since all I have 208 and 277vac nominal. I have yet to test whether 277 will work like it can with a Tesla charger. I would need an expensive step down transformer with high kW rating.

Neither amperes nor voltage are fixed on the Volt during charging on the AC side. Many, many threads discuss this... The cap is the kW rating of the charger so long as the voltage is greater than ~240 VAC. If you put in >240 VAC, it draws fewer amperes. If you put in <240 VAC (i.e. 208 VAC commercial), it draws more amperes up to the cap of 15 or 16 amperes.

 

[Loboc]

To future proof or not. That is the question.

Personally, I re-purposed a 50-amp range circuit (and replaced the range with gas) and then installed a 40-amp GE EVSE. I purposefully buy equipment that is over-sized for any application. In this case, I figure that the contacts rated for higher amperage would last forever charging my Volt/ELR. Has for 4+ years so far. Although, I have not heard of a 20-amp CC ever failing outside of warranty.

The corollary to that is: do you need over 50miles of range replenished daily? Pretty much any EVSE 20-amps or over can recharge 50-miles of range in any EV (even a Tesla) within an overnight charge. Even fitting in TOU windows.

 

[2VoltFamily]

It depends on line voltage. It usually varies between 220 and 240 volts in residential lines.

Not sure what you mean by line voltage. For example,

-The maximum amps on Gen1 is 14A. It will never exceed that.
-It also has a maximum charge rate of 3.3 kW. It will never exceed that.

So if the line voltage is 240V or below, the amps will remain at 14A. If the voltage drops from its maximum (240V x 14A = 3.3kW) to say 220V as you suggest you will no longer get a maximum charge rate because the onboard charger will not exceed 14A. Your charge rate would be 220V x 14A = 3.1kW.

However, if the voltage increases to say 250V the amps will drop below 14A. In this case it would charge at 250V x 13.2A = 3.3kW. The onboard charger reduces the amps draw to maintain 3.3kW rate.

 

[2VoltFamily]

The fastest way to charge a Volt will probably be if you have access to a 265vac power supply.
The amps are fixed, but the voltage can range from 200vac to 265vac per spec.

I have considered doing this at work since all I have 208 and 277vac nominal. I have yet to test whether 277 will work like it can with a Tesla charger. I would need an expensive step down transformer with high kW rating.

Anything above 240V will not increase the speed at which the onboard charger will charge the Volt.

 

[Sheldon]

The way I like to think about it is the minimum 16 amp L2 charger will probably meet your needs.
gen1: charging at 10miles/hour, @13.5 amps
gen2: charging at 12miles/hour, @15.0 amps
Bolt: charging at 13miles/hour, @16.0 amps full charge takes ~19 hours
Tesla S: charging at 12miles/hour, @16.0 amps

A Tesla at 40amps could charge at 30 miles per hour. But at home, maybe 12 miles per hour is enough, as long as you don't drive 200 miles a day two days in a row.

 

[jcramer]

The fastest way to charge a Volt will probably be if you have access to a 265vac power supply.
The amps are fixed, but the voltage can range from 200vac to 265vac per spec.

That's interesting. There appears to be a market opportunity for someone to produce an EVSE that can take a 220-240 volt input and deliver 265 volts @ 15 amps to the charging cord. That might need an expensive high-current step-up transformer, but perhaps there is some electronic trickery that produce the same result cheaper.

 

[mr_raider]

Go with a 32A charger on a 40A breaker. These are reasonable priced and top out at 7.2kW which covers pretty much anything non Tesla. Even a Tesla will charge pretty fast. The only reason I would go with a cheaper 20A unit is if your electrical panel was not up to the task.

 

[Mister Dave]

The way I like to think about it is the minimum 16 amp L2 charger will probably meet your needs.

Continuous load can only be 80% of the supply rating. A 16 amp continuous load requires a 20 amp supply.

 

[jcramer]

OK, the consensus seems to be that for Gen 1 the charging current is limited to 14 A, the charging power is limited to 3.3 kW, and the charging system never exceeds either one.

But why did GM choose to set the charging power limit at 3.3 kW and the charging current limit at 14 A? Both seem arbitrarily low. Power and current limits set by the Volt's internal wiring have been suggested as the reason. However, regenerative braking clearly sends charging power and current levels many times larger to the HV battery, and this happens every time you drive your Volt.

Does anyone understand this GM decision?

 

[llninja]

OK, the consensus seems to be that for Gen 1 the charging current is limited to 14 A, the charging power is limited to 3.3 kW, and the charging system never exceeds either one.

But why did GM choose to set the charging power limit at 3.3 kW and the charging current limit at 14 A? Both seem arbitrarily low. Power and current limits set by the Volt's internal wiring have been suggested as the reason. However, regenerative braking clearly sends charging power and current levels many times larger to the HV battery, and this happens every time you drive your Volt.

Does anyone understand this GM decision?

Heavy regen happens in spurts, not continuously for 4+ hours. It's temperature management and battery life protection all at play here. If they made it charge twice as fast, expect much fewer charging cycles and loss of battery bars. Folks who push Leafs and Teslas to the extreme are seeing range loss and battery degradation. If you supercharge too much or use the mode that maximizes your range every day (or in a leaf use level 3 charging daily) expect battery degradation at an unprecedented pace.

 

[Sheldon]

... But why did GM choose to set the charging power limit at 3.3 kW and the charging current limit at 14 A? Both seem arbitrarily low..... Does anyone understand this GM decision?

Nope. Nor do I understand why GM only bumped it up to 3.6kw/16amps for the gen2. The limitation primarily effects public charging; charging at home is usually not an issue. 32amps makes more sense, which is what the Bolt supports, and is also what nearly all public chargers support. If the Volt supported faster charging, I would be slightly more likely to consider paid public charging, but truth is paid public charging is always more expensive then my gas tank, and most of the time, I'm hitting the six week mark to turn on engine maintenance since I only use the ICE for trips out of town. So mostly, I would like to charge faster when I'm out of town since 53 miles of EV range and my L2 at home already meets all of my local needs.