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Maximum Level 2 Charge Rate

Posted: Fri Jul 06, 2018 10:53 pm
by rcedwards
Greetings

Long time Nissan LEAF driver. Taking a hard look at the Chevy Bolt.

I've often seen the charging specifications for the Bolt listed as 32A/240V, 7.2KW.

It seems to me that 32A X 240V is 7.7 KW, not 7.2KW. I realize that this is rather small, but it does add up for a 60KWH vehicle.

Any clarification from Bolt owners?

Thanks

Re: Maximum Level 2 Charge Rate

Posted: Sat Jul 07, 2018 5:23 am
by DucRider
From the application GM submitted to the EPA:
Electric Drive Unit
One 3-phase AC Permanent Magnet electric motor
150 kW 10 second peak Power
360 Nm peak torque
Battery
Lithium Ion battery pack
60 kWh pack energy capacity
7.6 kW On-Board; 50 kW Off-Board charge power


https://iaspub.epa.gov/otaqpub/display_file.jsp?docid=38567&flag=1

Re: Maximum Level 2 Charge Rate

Posted: Sat Jul 07, 2018 1:23 pm
by paulgipe
rcedwards wrote:Greetings

Long time Nissan LEAF driver. Taking a hard look at the Chevy Bolt.

I've often seen the charging specifications for the Bolt listed as 32A/240V, 7.2KW.

It seems to me that 32A X 240V is 7.7 KW, not 7.2KW. I realize that this is rather small, but it does add up for a 60KWH vehicle.

Any clarification from Bolt owners?

Thanks


I am using the same HSC 40 that I used with the Leaf. I haven't observed the Bolt drawing more than ~6.6 kW from this circuit. The car says "7" kW but that could mean 6.6, 7, 7.2, etc. My meter measures total household draw so I have to interpolate from other loads.

It hasn't been an issue. I typically charge overnight and from a low SOC to 100% or to Hill Top Reserve, an overnight charge is sufficient.

Could be my instruments. I haven't looked into it further.

Paul

Re: Maximum Level 2 Charge Rate

Posted: Sat Jul 07, 2018 7:01 pm
by Zoomit
It'll do 7.7kW. Examples in archives on various forums

Re: Maximum Level 2 Charge Rate

Posted: Wed Jul 18, 2018 12:55 pm
by BillHowland
rcedwards wrote:Greetings

Long time Nissan LEAF driver. Taking a hard look at the Chevy Bolt.

I've often seen the charging specifications for the Bolt listed as 32A/240V, 7.2KW.

It seems to me that 32A X 240V is 7.7 KW, not 7.2KW. I realize that this is rather small, but it does add up for a 60KWH vehicle.

Any clarification from Bolt owners?

Thanks


Hi - Yeah I've had this question myself as the BOLT ev was listed in the advertising literature as 32 amperes, 7.2 kw. The GEN 1 VOLT and ELR were limited to 15 amperes, and apparently a hard 3.3 kw, since if you came in with more than 220 volts (e.g.: 240) the current would throttle down from 15. The time I rented a GEN 2 volt I confirmed the 16 amperes at lower voltages, but absent mindedly, forgot to check it during the time of day was much greater than 225. (The juice in my neighborhood is horrible during the summertime due to 5 separate issues of incompetence by the utility - National Grid - which I won't bore you with here).

But The BOLT ev seems different as if you come in with a high enough voltage, the current is limited to 32 amperes but the power level goes at least to 7.7 kw - the highest voltage (240) I could easily muster. (That horribly obtuse dashboard display occasionally flashes '8 kw').

Hope that answers your question.

Re: Maximum Level 2 Charge Rate

Posted: Mon Sep 09, 2019 5:56 am
by Rwolf01
There is typically a hard current limit of 32 Amps. (but depending on the EVSE, the supply may assert a lower limit, which the car must obey)

But it will take whatever voltage it gets. You have little direct control over that. 240V is optimistic. That assumes limited upstream losses. At current, 230V is more typical. In an industrial location 208V is common (one branch of a 3-phase supply) which gets loaded dow to ~205V.

240V => 7.68kW
230V => 7.36kw
220V => 7.04kw
205V => 6.56kw

So I think they pick 7.2kw as a 'typical' input power.

Another possible explaination is that 7.2kw is the power delivered to the battery, after accounting for ~6% conversion losses in the on board charger.

Worry about the current, not the power. The car can take up to 32 Amps, so for fastest Level 2 charging make sure you are using a 40 Amp or larger breaker to feed a 32Amp or larger EVSE.

At home, you should look at the voltage losses in your home wiringing. The voltage at the EVSE will always be a little lower than at the power meter. A small drop is unavoidable, but if the voltage drop flucturates, or is higher on one leg of the 240V circuit than the other, you potentially have a wiring problem. At best, the voltage drop is costing you money because you are paying to heat your walls. At worst, that heat is concentrated at a bad connection somewhere and could start a fire)