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Discussion Starter · #1 ·
I have a 2019 Bolt and I find that when I use the provided battery charger that i only get about 3 miles of range per hour of charge rather than the 4 I was told that I would get. I do live in Phoenix Arizona, so it is hot, but i haven't seen anything that says that this will reduce the rate of charging. Does anyone have any ideas on whether I may have a problem with my charger or if this is "normal"?
Any ideas are appreciated.
 

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username LT
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Use the 12 amp setting and you can set your "home" to know that it can do 12 amps.
But no it can take up to a couple days to fully charge even then.
There are some uncertified workarounds to use the charger (EVSE) at 240V where you would halve that.
 

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I have a 2019 Bolt and I find that when I use the provided battery charger that i only get about 3 miles of range per hour of charge rather than the 4 I was told that I would get. I do live in Phoenix Arizona, so it is hot, but i haven't seen anything that says that this will reduce the rate of charging. Does anyone have any ideas on whether I may have a problem with my charger or if this is "normal"?
Any ideas are appreciated.

You need to plug the unit into a 240v outlet, using the appropriate mating connector.






 

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As @Bolt2019 said, it's most likely that you've not set the charging rate to 12 amps. It defaults to 8 amps in case the house wiring is old/scary, and will sometimes forget and auto-reset back to 8 amps even if you've set it previously.

At 12 amps, at best you'll get 120V * 12A = 1.44 kW per hour, which at 89% charging efficiency translates to 1.28 kW added to the battery, assuming the car isn't using any energy for anything else, like cooling. That would be about 5.1 miles added per hour if you averaged 4 miles/kWh and only 4.5 miles if you only averaged 3.5 miles/kWh. Cooling would eat into that. If it is really hot (necessitating cooling during charging) and your general driving efficiency is low, and your house supply is closer to 110V than 120V, it's conceivable that you might be getting closer to 3 miles/hour of charging even at 12A.

@RichCapeCod is wrong to say that you're supposed to plug the provided adapter into 240 volts. This is a trick the community has discovered to double the charging rate from the stock adapter (and determined is safe from disassembling the charger and looking at the components used). You can totally do it (and I have), but it's not something sanctioned by Chevy nor is it needed to get charging at 4 miles/hour for most owners. But if you have a 240V outlet, like a dryer outlet, it's certainly the cheapest way to get a boost in charging speed.
 

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Discussion Starter · #5 ·
Thanks for the replies - I really appreciate the information. I found that the car had defaulted to 8 amps. I've changed it to 12 amps - I'll see how it does now. I will also look into the 240 volt solution. Thanks again.
 

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If you don't set a home location then it will always drop back down to 8.
The 240V with the included charger will always only ever take 12A. So all you really need is a 240V 15A receptacle and breaker.
 

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.... @RichCapeCod is wrong to say that you're supposed to plug the provided adapter into 240 volts. ....

Uh, never used the word "supposed." Said, "You need to plug the unit into a 240v outlet, using the appropriate mating connector." As in, if you want to increase the amount of juice going into the car.


Rich
 

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Uh, never used the word "supposed." Said, "You need to plug the unit into a 240v outlet, using the appropriate mating connector." As in, if you want to increase the amount of juice going into the car.
But you were mistaken. The only thing @jimbrodie needed to do to get the advertised charging speed was set the max current to 12 amps (and turn on location-based charging so that it remembers the setting).
@jimbrodie's question was 鈥淚'm not getting the advertised charging rate, what's up?鈥. By saying that @jimbrodie needed to plug it in to 240V, it certainly gives the impression that this is the normal and standard solution to get the advertised charging rate. You can say that wasn't your intent, but that's how I read your message.
 

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鈥淚'm not getting the advertised charging rate, what's up?鈥. By saying that @jimbrodie needed to plug it in to 240V, it certainly gives the impression that this is the normal and standard solution to get the advertised charging rate. You can say that wasn't your intent, but that's how I read your message.
title was to slow char the Bolt...
 

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At 12 amps, at best you'll get 120V * 12A = 1.44 kW per hour, which at 89% charging efficiency translates to 1.28 kW added to the battery
L1 is about 75%, not 89%. That's because 120V requires twice the current of 240V to step up to battery voltage (about 360V). Chargers typically use the same components for 120V and 240V, which fixes the resistance. That leaves twice the current resulting in twice the loss. So. 1.44*0.75 is about 1 kW.

Also, L2AC 240V is about 85% efficient not much beyond that. Step up is much loss due to higher currents involved. But DCFC can get above 90% due to step down from 480V AC.
 

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My house has a good 20amp breaker on the 110v outlets in the garage so I set mine for 12amps, which based on very casual observations I'm seeing about 7 miles/hr charge rate there (which seems high based on the math).

**edit, I am using the OEM charger, and my home voltage is typically on the high side (~120-122v)
 

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Also, L2AC 240V is about 85% efficient not much beyond that. Step up is much loss due to higher currents involved. But DCFC can get above 90% due to step down from 480V AC.
Nope, you're mistaken.

On a recent trip, I drove 55 miles and used 14.3 kWh from the Bolt's metering. When my JuiceBox Pro refilled the battery, it added 15.39 kWh. That's 92.9% efficiency. We could worry that the discharge-from and charge-back-to points weren't quite the same, so let's instead do the cumulative total from several days of use and charging. The Bolt said I used 57.6 kWh, whereas the JuiceBox metered 63.86 kWh, which is 90.1% efficiency (with lots of short charges which are typically less efficient).

You can tell me that my JuiceBox's metering is wrong (and my electricity meter too!), but that won't be very persuasive.
 
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