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Discussion Starter · #1 ·
New EV owner here...

My understanding is that if you are charging on a 120 volt outlet you set it to 8amps. If I'm charging at a Level 2 Charge Point Station can I set it to 12amps for a faster charge? I do have the DC Fast Charger on my Bolt however we don't have a DC Charging station in the area. We do plan to get a home charging unit installed soon.

Can someone steer me in the right direction on when to use the 8 vs. 12amp setting? Many thanks!
 

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JSheehan: Both these settings are for Level 1 (supplied EVSE/cable) charging. In older houses, some circuit's wires cannot handle 12 amps. In any house, someone may have added a new outlet in the garage (or elsewhere) for a specific "low watt" need, not from its own circuit breaker, and using small (18 gauge) wire. In these cases, you may need to charge at only 8 amps to keep the wire from overheating. (The Bolt even gives you this warning.) 8 amps gives you only ~ 4 mpch (miles per charging hour).

MOST of the time, any home circuit can handle 12 amps. This past weekend, I charged (to full) at my sister's house at 12 amps (7-8 mpch), using a 120 volt plug in the garage. When she plugged in the steam iron (in the family room) not knowing it was on the same circuit, the extra 14 amps tripped the breaker. I unplugged my Bolt, reset the breaker, and she finished ironing. Then, I finished charging (@ 12 amps).

When you charge at 240 volts [Level 2] (at home or at an outside EVSE station) you do NOT set the 8/12 option as all these EVSEs are at 16 amps or above (usually 30, 32, or 40 amps). I installed my Siemens VersiCharge, 240 volt, 30 amp EVSE only 3 feet from the service box [40 amp breaker] and safely used 12 gauge wire.

Hope this helps.
 

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When you charge at 240 volts [Level 2] (at home or at an outside EVSE station) you do NOT set the 8/12 option
You can set it if you want, but the setting is ignored as it only applies to 120 V charging.
 

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I still think Chevy need to provide control over the amp's used by the car's charger for both 120 & 240 volt charge sessions. I find this feature very useful in my other EV's…

charging at 28 amps right now (even thought he EVSE advertises 30 amps) because I know this charger at work is more reliable at 28 amps than 30 amps - if you charge at 30 amps it pop's on/off all day - where as at 28 amps it charges all day with no problems - this particular charger is a known problem child at my employeer and to date they haven't had the ability to fix it - something to do with tearing up the parking lot to "fix" the wire…

just easier to lower the charge rate slightly and it then works flawlessly.
 

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JSheehan: Both these settings are for Level 1 (supplied EVSE/cable) charging. In older houses, some circuit's wires cannot handle 12 amps. In any house, someone may have added a new outlet in the garage (or elsewhere) for a specific "low watt" need, not from its own circuit breaker, and using small (18 gauge) wire. In these cases, you may need to charge at only 8 amps to keep the wire from overheating. (The Bolt even gives you this warning.) 8 amps gives you only ~ 4 mpch (miles per charging hour).

16 gauge wire can handle 12 amps up to a 6 foot run. 14 gauge is needed for a 6-12 foot run, 12 gauge for a 12' run, 10 gauge for a 14' run and 8 gauge kicks in for a 20 foot run.

MOST of the time, any home circuit can handle 12 amps. This past weekend, I charged (to full) at my sister's house at 12 amps (7-8 mpch), using a 120 volt plug in the garage. When she plugged in the steam iron (in the family room) not knowing it was on the same circuit, the extra 14 amps tripped the breaker. I unplugged my Bolt, reset the breaker, and she finished ironing. Then, I finished charging (@ 12 amps).

When you charge at 240 volts [Level 2] (at home or at an outside EVSE station) you do NOT set the 8/12 option as all these EVSEs are at 16 amps or above (usually 30, 32, or 40 amps). I installed my Siemens VersiCharge, 240 volt, 30 amp EVSE only 3 feet from the service box [40 amp breaker] and safely used 12 gauge wire.

Hope this helps.
There are some areas of the US where (from the 60s to the mid 70s) aluminum wiring was used. The numbers above are for copper. In addition, if improperly installed (the wrong sockets used for example - look for a CU-AL designation on the connectors), aluminum can suffer from "creep", due to it's high coefficient of heat expansion. This can cause poor connections between the wiring and the device, and under significant currents, heating to the point of causing fires.

So, if you have aluminum wiring from this era, be extra careful. If you don't, count your blessings.
 

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Discussion Starter · #7 ·
So helpful...thank you! When I took ownership of the car a Chevy rep pointed out the settings. From what I can see the Bolt has to be set to one of the other so if I'm reading correctly it doesn't matter which since at a charging station since it will override any setting. Or is there a way to opt for neither?

Yesterday I was at a Charge Point level 2 charing station and the Bolt was set at 12 amps. It charged for about 30-45 minutes and when I returned to the car it had stopped charging despite not being at a full charge. I only received 4.5 kWh for the charge. Is this common, a user error or a Charge Point issue?
 

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So helpful...thank you! When I took ownership of the car a Chevy rep pointed out the settings. From what I can see the Bolt has to be set to one of the other so if I'm reading correctly it doesn't matter which since at a charging station since it will override any setting. Or is there a way to opt for neither?

Yesterday I was at a Charge Point level 2 charing station and the Bolt was set at 12 amps. It charged for about 30-45 minutes and when I returned to the car it had stopped charging despite not being at a full charge. I only received 4.5 kWh for the charge. Is this common, a user error or a Charge Point issue?
There are a few settings in the car that *might* cause this. If you have "hilltop" mode set without specifying the location, this would stop the charge at around 87%. There are Time of Use (TOU) setting that might cause the car to stop charging as well. Have you looked these items over? Charge mode can be set as "Immediate", "Departure" , or "Departure and Rate". How is yours set?

I have experienced public chargers that are poorly maintained, and the handle loses contact over time (especially with big temperature swings), causing the charger to stop charging.
 

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Discussion Starter · #9 ·
There are a few settings in the car that *might* cause this. If you have "hilltop" mode set without specifying the location, this would stop the charge at around 87%. There are Time of Use (TOU) setting that might cause the car to stop charging as well. Have you looked these items over? Charge mode can be set as "Immediate", "Departure" , or "Departure and Rate". How is yours set?
"Hilltop Reserve" is off as is "Location Based". I'm also in Immediate charge mode. Couldn't find anything about "Time of Use" other than in the Departure or Departure and Rate which is not enabled.

So perhaps it's a charging station issue...
 

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Yesterday I was at a Charge Point level 2 charing station and the Bolt was set at 12 amps. It charged for about 30-45 minutes and when I returned to the car it had stopped charging despite not being at a full charge. I only received 4.5 kWh for the charge. Is this common, a user error or a Charge Point issue?
The Bolt charger (built in the car) is 7.2 kW
That means in one hour, you would get 7.2 kWh into the battery (less a little as charging is not 100% efficient).
30 minutes @ 7.2 kW = 3.6 kWh
40 minutes = 4.8 kWh
45 minutes = 5.4 kWh

Sounds like everything worked just as designed. Are you sure that charging had stopped when you returned?
 

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Discussion Starter · #11 ·
Sounds like everything worked just as designed. Are you sure that charging had stopped when you returned?
Thank you! While I'm relieved that all is working as designed, yes when I returned it was no longer charging and the station was asking me to swipe my card to begin. I'll be returning tonight as it's where we play tennis and will give it another go!
 

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JSheehan:

16 gauge wire can handle 12 amps up to a 6 foot run. 14 gauge is needed for a 6-12 foot run, 12 gauge for a 12' run, 10 gauge for a 14' run and 8 gauge kicks in for a 20 foot run.


Hope this helps.

please edit or remove this portion of your answer. That is absolutely incorrect information about wire gauge & distance.
Consult an electrician, your also incorrect about 30A service wire.

here is a web tool where you can enter your AMPs and distance, to calculate voltage drop. For EV chargers you have to be very careful & specific due to the fact EVs draw huge currents for hours and hours.

you don’t adjust wire gauge for +/- 10ft. The type of wire tho is a big factor, as can be the conduit free space, so direct burial wire will have different heat dissipation than SO cable or individual strands in SCH40 conduit
 

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I always used 12 amps with the 120v charger. It shaved a little time off. But now use a 16 amp L2 charger.
 

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please edit or remove this portion of your answer. That is absolutely incorrect information about wire gauge & distance.
Consult an electrician, your also incorrect about 30A service wire.
That's an almost 4 year old post you're trying to correct.

Also, your link is missing, so it's not actually clear what you're claiming is the right value.
 

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Isn't it true, that there isn't much difference time to charge between 8 and 12 amps, when using a Level 1 charger? :unsure:

If so, why risk over-heating the outlet/wiring?
 

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Isn't it true, that there isn't much difference time to charge between 8 and 12 amps, when using a Level 1 charger? :unsure:

If so, why risk over-heating the outlet/wiring?
120V * 8A = .96kw
2017-earlier 2019 60kwh / .96 * 1.1 (10% loss) = ~68.75 hours

120 * 12 = 1.44kw
60 / 1.44 * 1.1 = 45.8 hours

I'd say just about a whole other day is a substantial difference.
If you're over-heating an outlet/wiring while running something equivalent to an electric heater at full blast the entire time...you've got electrical problems.
It would be best to not plug in said heater or vacuum or hair dryer in the same circuit as that L1 EVSE otherwise you might trip the breaker.
 

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8A actually exists because it is the lowest common denominator in US wiring. There are a few obscure codes out there that allow for sockets on 10A circuits.

It is also useful when you are charging the car on circuits which may have other loads on them.

(Apparently, in the UK you are limited to 8A continuous off their 13A socket and it has to have its own fuse... Crazy.)
 

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I didn’t post it to be inconsiderate, just that folks using search here or via Google could be really confused by the otherwise accurate post. They had a lot of correct information, but wildly wrong information about AMP’s vs wire gauge & distance. Not sure why my URL didn’t work, but Google “amp wire gauge “ will pull up useful charts and there are online calculators that let you figure this out.

That's an almost 4 year old post you're trying to correct.

Also, your link is missing, so it's not actually clear what you're claiming is the right value.
 

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120V * 8A = .96kw
2017-earlier 2019 60kwh / .96 * 1.1 (10% loss) = ~68.75 hours

120 * 12 = 1.44kw
60 / 1.44 * 1.1 = 45.8 hours

I'd say just about a whole other day is a substantial difference.
If you're over-heating an outlet/wiring while running something equivalent to an electric heater at full blast the entire time...you've got electrical problems.
It would be best to not plug in said heater or vacuum or hair dryer in the same circuit as that L1 EVSE otherwise you might trip the breaker.
With the 66 kW batteries (0 to full charge in about 55 hours) in the 2020 Bolt (not sure of the '18, or '19), I would hope that anyone who uses a Level 1 Charger, wouldn't allow their vehicle to get too low, let alone, depleting the battery.

For sure, a battery that needs a lot of juice, 12 Amps would be much better. But, when it comes to the as required "Topping Off", it probably wouldn't make much difference to the person charging.

But, I did have the electrician out here to see about putting in a 120 Outlet by my Parking Pad ($210.00; but since I probably won't be here for longer than a year, or so, I don't think I'll do it), and he said the 12 Amps shouldn't be a problem. So, I'll try that on my next charge day.
 
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