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240V Charging for 2013 Chevy Volt: only 13.2 Amps?

1846 Views 21 Replies 11 Participants Last post by  Billr580
Hello Folks,

I own a 2013 Chevy Volt Premier. Have owned it since 2015, and it only has abou 45,000 miles on the odometer.

Always used the 120V Level 1 charger that came along with the vehicle. But recently I installed 32 Amps Level 2 Charger in my garage and, as expected, it charges the Volt much faster than the one that came with the vehicle, but it seems to only feed up to 13.2Amps to the Volt. Is that a limitation of the Chevy Volt itself (that internally does the conversion from AC to DC) or is the new charger defective?
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2017 Chevy Volt Premier
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tk3000

That's why you charge an EV with an EVSE (electric vehicle service equipment) and a J1772 plug/cable. The EVSE is a device that for safety reasons negotiates a current and voltage that it has to offer, the the Volt asks "I need 16 amps at 240 volts" after negotiating and checking for ground faults (E.G plug under water) 32a EVSE then turns on the "juice". That's why you can't just plug an EV onboard charger into any old power source directly like a golf cart charger. The protocol used by the EVSE to talk to an EV car is the ISO 15118 Protocol explained in the link below.


The EVSE only asks the car what it needs and if it can do that it will provide the power limited up to it's maximum current (protocol negotiation advertisement) and used by the onboard EV charging system. So with a Volt and a 32 amp EVSE the Volt will only draw 16 amps after the Volt "told" EVSE what it's requesting (16a). 32 amps would still be available but only 16 amps will be drawn by the Volt. If an EV said "I need 40 amps at 240" lets say, the 32a EVSE would reply "I only can do 32 amps" and not turn on to prevent blowing fuses, burning it's wiring, etc. The EV would reply "OK I'll only draw 32 amps can you send power?" the EVSE would reply "yes, turning power on now" example EV would then limit its draw to only 32 amps while charging. I might have the semantics wrong, an engineer on this forum can correct me, but you get the point I hope. The 120v level one provided EVSE only maxes out at 12 amps, the Volt will only ask for 12 or 8 amps at 120 volts. GM and all EV manufacturers engineers follow the SAE J1772-2017 standard which defines the levels of charging supported:


Charge methodVoltage, AC (V)PhaseMax. current,
continuous (A)
Branch circuit
breaker rating (A)[a]
Max. power (kW)
Charge methodEVSE DC output voltage (V)Max. current (A)Max. power (kW)
AC Level 11201-phase12 or 1615 or 201.44 or 1.92
AC Level 2208 or 2401-phase24–8030–1005.0–19.2
AC Level 3https://en.m.wikipedia.org/wiki/SAE_J1772#cite_note-27




Stephen

Hello Folks,

I own a 2013 Chevy Volt Premier. Have owned it since 2015, and it only has about 45,000 miles on the odometer.

Always used the 120V Level 1 charger that came along with the vehicle. But recently I installed 32 Amps Level 2 Charger in my garage and, as expected, it charges the Volt much faster than the one that came with the vehicle, but it seems to only feed up to 13.2Amps to the Volt. Is that a limitation of the Chevy Volt itself (that internally does the conversion from AC to DC) or is the new charger defective?
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· Registered
2017 Chevy Volt Premier
Joined
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317 Posts
tk3000,

An EVSE is a safety device or a safety "on OFF" switch. It does not control amps or voltage, it only provides a "service" after the negotiation and safety parameters are met. Really its just a fancy outdoor "gate keeper" switch, a "relay with rules" so to speak. Only an expensive inverter/rectifier can make the regulated high voltage DC needed to charge an EV's traction battery.

Stephen

Stephen,

I never really did work on my chevy volt (great and reliable car, shave on GM for having killed it). But I am somewhat familiar with the can bus due to have used in the past when working on an electric motorscooter that I had -- the vectrix.

It my understanding that the saej1772 plug and port have some pins dedicated to the data bus. Still, the firmware would have to be programmed, configured and setup based on the limitation of the Volt's internal charging module I would assume (given that I would imagine that such a small light weight charger would not be able to convert AC into high voltage DC)
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