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Discussion Starter #1 (Edited)
Hello,
I have a JuiceBox 75Amp charger and noticed the Bolt is charging at 30 MPH on the charger, which is fine. I charge during Edison TOU settings and start at 10:00 PM and the car is ready at 05:00 AM when I leave for work the next day. I use a little over a half charge each day (maybe a bar or two into the third bank of batts). I was curious about my settings and checked with JuiceBox. Here is their reply:

"Taking a look at your charge session, it looks like the Bolt is charging at about 25.6 amps. The Bolt is capable of 31 amps while charging, and you may have the car or circuit limited?

In any case, the Bolt will only charge at it's max charge rate based on it's onboard charger, in this case 30-32 amps, or 7.4kW rate.

The Juicebox will only give the car what it asks for, and limits only come from the JuiceBox if you have it dialed down either via the app (which from what I can see you do not) or the trimpot on the board inside."


Does anyone know where to max out the charge capabilities on the car? I see a setting on the dash that says either 8 or 12 Amp but that's about it.
Thanks
DAVE
 

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The Bolt should pull 32 amps on 240 volt single phase power. But if you are using a 3phase 208 volt supply, it would be limited to roughly 29-30 amps, due to the lower voltage.
 

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The Bolt should pull 32 amps on 240 volt single phase power. But if you are using a 3phase 208 volt supply, it would be limited to roughly 29-30 amps, due to the lower voltage.
The Bolt will pull 32A if that is what the JuiceBox EVSE is programmed to advertise to the Bolt, regardless of voltage. 208V @ 32A will supply 6.65 kW, which is the equivalent of pulling ~28A @ 240V. Voltage isn't the limiting factor, it's the amperage.

The 8A/12A setting only applies to using the 120V portable EVSE that the vehicles comes with. For 240V L2 charging, the car pulls what ever the EVSE advertises, up to the maximum of 32A.
 

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There are also other factors. The Bolt will draw up to 32A from the EVSE if the EVSE will allow the Bolt to draw 32A. However, the Bolt may not draw this much, or may not use all of what it draws to charging the battery.

If the temperature of (some of) the cells is too hot or to cold, it will not supply a 32A charging current. It will attempt to cool or heat the cells to get them within a temperature range where they can be supplied with 32A. This temperature adjustment will use some of the 32A (or less if the EVSE can't supply 32A) supplied by the EVSE.

As the state of charge rises, the Bolt will limit the current supplied to the batteries to something less than 32A (if the EVSEcan supply 32A). The closer it gets to "full," the more the Bolt's battery management system (BMS) will limit the current and slow the charging rate.

Ed
 

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You are probably charging at max rate of the bolt given charge tapering closer to full and roughly 10% charging loss inheirent in all existing EV charging systems.

Also full charge to 100% every day isn't the best for the battery - so I would use hill top reserve unless you need it fully charged every day.
 

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Juicebox has settings and you can adjust the amp settings. You have 6, 12, 16, 24, 32, 40....... is yours set at 32?
 

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Discussion Starter #7
Thanks everyone for the info. I think I have the JuiceBox set to maybe 50 amps. Since the car won't take that much I guess I'll lower it to keep everything happy.


I think you guys are right, I'm not completely depleting the battery so perhaps at half charge, it's only using 25 amps to bring it up to full again. Not being electrically minded- what you're saying makes sense to me...
Thanks again
DAVE
 

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there is no harm in plugging the Bolt into a charger that can provide more power/watts/amps than the volt can take - the J-1772 standard is a negotiation - the Car "asks" what the EVSE can provide, and then will pull only what it can handle - if the EVSE says "24 AMPS" the car will pull 24 amps, if the eVSE says 60 AMPs the Bolt will only pull 32 AMPS
 

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The JuiceBox should be set to what the circuit it is on can safely provide using the 80% rule. This means that if the circuit it is connected to is on a 40A breaker, then the JuiceBox should be set to 32A. If it's a 50A breaker, then the JuiceBox should be set to 40A. 30A breaker, set it to 24A.
 

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I agree - the EVSE should be set to what ever properly installed circuit it's on - but there is no harm using a bolt with an EVSE that is properly installed/configured to provide more amps - because the Bolt will not pull more than it can handle, but yes follow building codes and wiring and circuit break specifications.
 

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8A/12A settings

The 8A/12A setting only applies to using the 120V portable EVSE that the vehicles comes with. For 240V L2 charging, the car pulls what ever the EVSE advertises, up to the maximum of 32A.
Thanks for writing this. My first two "non-home" charges at L2 and DC stations haven't given me the charge I was expecting. I was wondering if it was my 8A/12A settings and have been trying to figure out how to turn them both off (which is not a choice). I've going to have to figure out why i'm not getting as much as expected. Hilltop reserve is off. The DC/EVGo station today added 50+/- miles in 30 minutes and I was expecting more.

I'm on a road trip btw.
 

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The DC/EVGo station today added 50+/- miles in 30 minutes and I was expecting more.
This is actually a major bummer for charging at charging stations like EVgo that charges by the minute. The only time you really get the max of 50 kW/hr is if you are near 0% of your battery. There is a recent article on Green Car Report that went into more details about this.

Between 0 and 50% you may get closer to the 50 kW/hr that the EVgo station can deliver (maybe 48 kW/hr realistically). Between 50-70%, your charge rate slows down pretty significantly, maybe down to a little less than 30 kW/hr. Between 70-85% you drop down to 20 kW/hr and above 85% you are getting less than 10 kW/hr.

Based on my own personal experience, I got 14.92 kW in a 30 minute period when I was at 52% of my battery.
At 78%, I charged at ~10 kW in 30 mins.
At 92%, I charged at ~4 kW in 30 mins.

Since EVgo charges by the minute it is really only economical to use EVgo when you are near empty.
My rough calculation indicates that if you are at ~8% or less of battery, (about 5 kW left in your battery) you can get the best rate of charging and thereby the best cents/kW cost.
 

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Yeap. You got 44.28 kW/hr with the starting point of 21%. My guess is when you crossed over 50% full, your rate slowed down from what was probably close to 50 kW/hr at less that 50% giving you the average rate of 44 kW/hr. If you had tried charging again for another 30 minutes, you would have had an even slower rate.

I am not knocking the Bolt by any means. Just want to help people get the best possible cost when they charge.

"the Bolt EV starts to taper its charging rate fairly early in the curve, as we experienced two weeks ago.

That means that when you plug in a Bolt EV with 50 percent of capacity or more remaining in its battery, the fast charging rate may not be even 50 kw.

While charging rates taper off over the last 20 percent of battery capacity in virtually every electric car, the Bolt EV appears to start the taper much earlier and gently ramp down charging far earlier than the 80-percent level."

http://www.greencarreports.com/news/1109714_more-details-on-fast-charging-rate-in-2017-chevy-bolt-ev-electric-car
 

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Discussion Starter #15
Hello Everyone,
Thanks for all the great information you're giving me (and USayingBolt- have a nice road trip). I noticed something strange the other night when charging on my L2 JuiceBox.


My Edison Time Of Use (TOU) the cheapest cost to charge is technically from 10:00 PM to 08:00 AM. I normally leave for work at 05:00 AM so I was using that as my cut off time. I noticed it would fully top off the car when batts were at maybe a quarter charge left.


I changed the charger to the correct TOU the other day to end at 08:00 AM and when the car was at a quarter batt charge left, it did not fully charge the car when I shut it off to leave at 05:00 AM. It's like the car said- "Hey, I can sleep in 'til 08:00 AM so I'll just sip on this charging outlet a few more hours- why worry?" Is that possible? If I stretched out the TOU, the car would charge at a slower rate than if I needed it to be ready by 05:00 AM? Does that make sense?
DAVE
 

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Hello Everyone,
Thanks for all the great information you're giving me (and USayingBolt- have a nice road trip). I noticed something strange the other night when charging on my L2 JuiceBox.


My Edison Time Of Use (TOU) the cheapest cost to charge is technically from 10:00 PM to 08:00 AM. I normally leave for work at 05:00 AM so I was using that as my cut off time. I noticed it would fully top off the car when batts were at maybe a quarter charge left.


I changed the charger to the correct TOU the other day to end at 08:00 AM and when the car was at a quarter batt charge left, it did not fully charge the car when I shut it off to leave at 05:00 AM. It's like the car said- "Hey, I can sleep in 'til 08:00 AM so I'll just sip on this charging outlet a few more hours- why worry?" Is that possible? If I stretched out the TOU, the car would charge at a slower rate than if I needed it to be ready by 05:00 AM? Does that make sense?
DAVE
Not sure about the Bolt (yet), but the Volt has an options screen letting you choose what you want. You can set it to charge based on time of use rates, or time of use rates and departure time, or charge immediately. There was also a departure schedule that needed to be set in addition to the TOU rates. Maybe there is just one more option that you need to select.

I suppose you could have also been interrupted due to power outage, etc? This might be a bit too obvious though...
 

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I have my Bolt set to charge by departure time, plugged into a JuiceBox 40 Pro. In my experience, it will sit plugged in but pulling no juice until it decides that it needs to start charging to be ready for departure time, then it will pull the max current it can (depending on battery charge state) until it's full, and go back to no draw after scheduled departure time. While still plugged in if I then ask it to precondition the cabin I can see it pulling 32A again while it warms up.

While I haven't stayed up until 4:00am to monitor it's charge rate when the battery is at 50%, I can say that when in immediate charge mode it does pull the full 32A and assume it does the same at night as well. Looking at the EV JuiceNet logs for the last charge I see that it did 30.5kWh in 4.5hrs = average rate of 6.7kW. Sounds about right for starting heavy and tapering off at as it reached max charge of 88% (hill start mode).

Long story short, in departure time setting it begins charging at the last possible minute and goes full tilt, no sipping on the juice.
 

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I have a monitor for my usage - Bolt pulls full power from time it starts charing until it's done then drops to zero…

this little device lets you monitor your whole house - once it's only you can watch your house's power draw from phone/table/web - need a smartmeter, but once it paired with the meter you can get realtime and historical data about your power draw vs. time of day.

https://smile.amazon.com/Rainforest-Energy-Monitor-ZigBee-Gateway/dp/B00AII248U/ref=sr_1_1?ie=UTF8&qid=1491432627&sr=8-1&keywords=rainforest+power+monitor
 

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Hello Everyone,
Thanks for all the great information you're giving me (and USayingBolt- have a nice road trip). I noticed something strange the other night when charging on my L2 JuiceBox.


My Edison Time Of Use (TOU) the cheapest cost to charge is technically from 10:00 PM to 08:00 AM. I normally leave for work at 05:00 AM so I was using that as my cut off time. I noticed it would fully top off the car when batts were at maybe a quarter charge left.


I changed the charger to the correct TOU the other day to end at 08:00 AM and when the car was at a quarter batt charge left, it did not fully charge the car when I shut it off to leave at 05:00 AM. It's like the car said- "Hey, I can sleep in 'til 08:00 AM so I'll just sip on this charging outlet a few more hours- why worry?" Is that possible? If I stretched out the TOU, the car would charge at a slower rate than if I needed it to be ready by 05:00 AM? Does that make sense?
DAVE
As the battery gets full, the Bolt has to taper (reduce) the current going in. If you charge to 100% everyday, and you are starting out with a battery that is at 25%, 7 hours (10pm to 5am) may not enough time to complete the charge.

Have you set a departure time in addition to the rate schedule?
 

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Yeap. You got 44.28 kW/hr with the starting point of 21%. My guess is when you crossed over 50% full, your rate slowed down from what was probably close to 50 kW/hr at less that 50% giving you the average rate of 44 kW/hr. If you had tried charging again for another 30 minutes, you would have had an even slower rate.

I am not knocking the Bolt by any means. Just want to help people get the best possible cost when they charge.

"the Bolt EV starts to taper its charging rate fairly early in the curve, as we experienced two weeks ago.

That means that when you plug in a Bolt EV with 50 percent of capacity or more remaining in its battery, the fast charging rate may not be even 50 kw.

While charging rates taper off over the last 20 percent of battery capacity in virtually every electric car, the Bolt EV appears to start the taper much earlier and gently ramp down charging far earlier than the 80-percent level."

http://www.greencarreports.com/news/1109714_more-details-on-fast-charging-rate-in-2017-chevy-bolt-ev-electric-car
FTL: "Chevy's advertised "90 miles in 30 minutes" will only likely occur if the battery starts between 0 and 50 percent capacity."

This was totally my experience. I was on the road and maybe slightly above 50%, stopped at an EVGO for 30 minutes and only received (at most) 50 miles. Not a huge problem but it definitely lingered thru the trip. I returned home 2 hours ago and only have 40 miles available. My screen went orange (i think it was orange) just as I was pulling onto my street.

Four day stay at a Resort in Aptos. I had called prior and was reassured they had a working Level 2 charger. When I attached it I received a message on my dash that it was not fully connected and couldn't charge. ALSO, I didn't bring my trickle cord - which I will in the future. So... the EVGO DC station lack of a full charge was indeed an issue.
 
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