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Discussion Starter #1
Hello All,

Very new to the EV World. Had some questions.

1. How do i tell what Amperage the vehicle is charging at? Currently i am plugged into 240v with an EVSE that can go to 32 Amps. but on the screen it bounces between 6kw to 7kw on the Instrument cluster. Is that right?

2. MyChevy Bolt app seems to not be updating and telling me when its charging. Is there a reason for that? It sometimes work and sometimes doesnt.

Thanks!
 

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1. How do i tell what Amperage the vehicle is charging at? Currently i am plugged into 240v with an EVSE that can go to 32 Amps. but on the screen it bounces between 6kw to 7kw on the Instrument cluster. Is that right?
You have the car on and using power, what you are seeing is the varying car usage. Best way to tell total is from your EVSE if it supports it, highest I've seen is 7.6kW or 7.8kW total, of course with losses the net to the battery will be somewhat less.

2. MyChevy Bolt app seems to not be updating and telling me when its charging. Is there a reason for that? It sometimes work and sometimes doesnt.
That app can be a little flaky, ignore it.
 

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also the actual amount may vary based on voltage

watts = volts * amps

208 volts * 32 amps = 6,400 watts
220 volts * 32 amps = 7,040 watts
240 volts * 32 amps = 7,680 watts
250 volts * 32 amps = 8,000 watts

so depending on time of day and the actual volts your service provider is giving you a 32 amp charge rate can vary from 6,400 watts to 7,680 watts

also voltage drops as a function of distance of the wire you're using - so while you may be 242 volts at your main electrical box, if your garage is far away from the main box the wire distance may drop the voltage to say 232 volts…

if you're in the 6,000 - 7,000 watt range you're charging at 32 amps :)

the basic AMPs I've seen from chargers fit into neat/tidy categories - see even though it is possible for an EV to charge at 17 amps - typically you will seeing the following EVSE setups

8 amps EVSE L1 charging (15 amp circuit) - 960 watts
12 amps EVSE L1 charging (15 amp circuit) - 1,440 watts

12 amps EVSE charging (16 amp circuit) 2,880 watts
16 amps EVSE charging (20 amp circuit) 3,840 watts
24 amps EVSE charging (30 amp circuit) 5,760 watts
30 amps @ 208 volts - Commercial/Public J-1772 chargers (typical charge point for example) - 6,240 watts
32 amps EVSE charging (40 amp circuit) 7,680 watts
40 amps EVSE charging (50 amp circuit) 9,600 watts - not for Bolt - Bolt is limited to 32 amps - Boll will charge, but only at 32 amps
48 amps EVSE charging (60 amp circuit) 11,520 watts - not for Bolt - Bolt is limited to 32 amps - Boll will charge, but only at 32 amps

the following forum postings have most of the information you're looking for

http://www.chevybolt.org/forum/82-charging-batteries/16738-charging-table.html
http://www.chevybolt.org/forum/82-charging-batteries/7186-charger-math-skip-post-if-you-know-already.html#post76418
 

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Discussion Starter #4
Thanks for the quick reply guys!

So my understanding is i can not see actual charging amperage or kw on screen somewhere? Or where can i find that?
 

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^ As David posted above... there's charging loss, so the dash indicator only shows what's going in to the battery- not what's going in to the charge port.
The Dash indicator may show 6-7kW but the car is drawing 7.5kW (32amps at 240VAC).
 

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Level 2 charging keeps its voltage relatively stable throughout charging (and actually the amperage, too). Calculating amperage (rather than "measuring" it) is fine. Having kW indicated is all you really need.

When you Level 3 charge, the amperage may start at 100 amps (40 kW @ 400 volts), but tails off to <5 amps when approaching fully charged. This is why you may get range increases of 90 miles for the first 30 minutes, but only 70 miles, 50, 30, & 10 miles for the ensuing 30 minute increments. When travelling, charging only to 80% (192 miles) is the "time-effective" method. Get on up the road and charge again when down to 10% SoC. I once had the luxury of free Level 3 charging during an overnight stay. I fully filled (100%) from my initial SoC in 2 hours and 7 minutes. I would never do that if I had that next 200 miles to go the same day. There is a reason Level 2 EVSE are termed "destination chargers" while Level 3 EVSE are "travel (or "touring") chargers". If staying overnight, 25 miles per charging hour is fine, but it AIN'T if you are going 450 miles in one day of driving!
 

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When you Level 3 charge, the amperage may start at 100 amps (40 kW @ 400 volts), but tails off to <5 amps when approaching fully charged. This is why you may get range increases of 90 miles for the first 30 minutes, but only 70 miles, 50, 30, & 10 miles for the ensuing 30 minute increments.
I have never seen 90 miles in 30 minutes. The maximum I have seen is 72 miles in 30 minutes. However, I have never charged from a low of 10 miles using a fast-charger. I usually charge from about 50-60 miles of range left, and then charge to about 210 miles of range left which is 80% with my driving of the Bolt EV. For this type of charging it has taken about 60 minutes at a average of 2.4 miles per minute.
 

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I have never seen 90 miles in 30 minutes. The maximum I have seen is 72 miles in 30 minutes. However, I have never charged from a low of 10 miles using a fast-charger. I usually charge from about 50-60 miles of range left, and then charge to about 210 miles of range left which is 80% with my driving of the Bolt EV. For this type of charging it has taken about 60 minutes at a average of 2.4 miles per minute.
And I was emphasizing the decreasing step rate over time, not the exact numbers. I have charged from less than 10%. I fully charged because it was free, I had the time (was actually staying overnight and they had no Level 2 “destination” charger), and wanted to learn how it went. More commonly seen range increases over 30 minute increments may be 80, 65, 50, 35, and who cares! All of these are greater than 24 range miles per charging hour!
 

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Thanks for the quick reply guys!

So my understanding is i can not see actual charging amperage or kw on screen somewhere? Or where can i find that?
I wanted the exact numbers, so I ended up getting an ODB2 dongle to read them, per http://www.chevybolt.org/forum/10-technical-discussion/10010-onboard-diagnostic-obd-port-tools-5.html#post229194

You pretty much just have to use the bolt PIDs and you can get the AC/DC Voltage/Amperage. It's possible to approximate from the charging power on the dashboard, but that can vary due to battery conditioning, lights, radio, etc.
 

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Just as an aside, I own the ClipperCreek HCS-50 EVSE, i use the Juiceplug from eMotorwerks that I had before to read the data. I get the Current, Voltage, Power, Temp and Line Frequency. It also logs this online and to my app. Works good, and you can add to any "dumb" EVSE you may have. It's a little pricey but I do like the ability to swap it around the chargers I may be using that don't have network ability. Just another option if you want to see what the battery is doing.
 

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Here is a graph of high voltage and current for my level 2 charger. I posted this before, so the conditions are elsewhere on this site. Note that the current from the wall is 32 amps at 240 volts, although my voltage can pull down to as low as 228 volts during charging.
 

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My Bolt keeps defaulting to an 8KW charge unless you manually override to 12KW before charging. Is there a way to set the default to 12KW? Very annoying.
 

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My Bolt keeps defaulting to an 8KW charge unless you manually override to 12KW before charging. Is there a way to set the default to 12KW? Very annoying.
FYI, you probably mean 12A, not 12kW. On a standard house hold outlet, your 12A charging current would yield 120V x 12A = 1440 W = 1.44 kW. Our Bolts max out at 7.68kW.
 
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