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Discussion Starter #1
So I am purchasing a used 2017 Chevy Bolt (off-lease, 55K miles) and want to get a quick assessment of battery health. I have been reading up on various discussions but want to be sure I have it right before finalizing the purchase. Here is what I know...

1. Using the Chevy App (android) I am checking the vehicle's charging status and efficiency. Charging status is 68% and 138 miles of range. Efficiency is 3.3 mi/kWh.
Therefore -> (60 kWh battery) * (68% charge) * (3.3 miles/kWh) = 134.6 miles
So since this matches the range indication it should mean that the battery has 60 kWh of capacity. Correct?

2. This is a 'Certified' vehicle so it underwent the usual checks before being sold. So I spoke to the service department and was told the following... As a matter of course when they receive a used Bolt for sale they fully charge it and then check the car for error codes that would indicate an issue with the batteries. If there are no issues then the battery capacity is OK. Seems a little indirect to me but I get the point.

So, given 1&2 above, are odds reasonably good that the battery in this vehicle is in good condition? As quick background I am currently a Leaf owner and so I have a few years experience with EVs.

Thanks
 

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odds reasonably good that the battery in this vehicle is in good condition?
odds for a Bolt are pretty good. this isn't like your Leaf as the Bolt has active thermal management of the battery.
Welcome to the forum and good luck with your purchase.
 

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Discussion Starter #3
Yes exactly I do not know why Nissan is sticking with passive cooling other than meeting a price point.
 

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So, given 1&2 above, are odds reasonably good that the battery in this vehicle is in good condition.
It appears you got one of the real 60 kWh batteries. I am intensely jealous. Our 2017 had ~58 kWh when we drove it off the lot three years ago. We are sitting at ~55 kWh at 33K miles.

I strongly suggest you get an OBD II adapter, Torque Pro, and Telek's PIDs to real get to know your Bolt.

 

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Discussion Starter #5
I hope so on the 60 kWh battery. But I would be happy with 57 as well.

I have Torque Pro, and the PIDs, just need to move my OBDII adapter over from the Leaf so I am almost there.
 

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Discussion Starter #6
OK so I ran a test... Starting from a L2 full charge that had all night to balance the battery (after reaching 100%) I drove in a loop through the area and ran the battery down to 4%. Distance traveled according to the Bolt was 184.4 miles with an efficiency of 3.3 mi/kWh. My driving was a mix of interstate and back roads, and a bit on the spirited side.

So, here are the results:
  • Started fully charged
  • Drove down to 4% SOC as reported by the MyChevy app
  • Energy Detail screen shows 52.9 kWh used
  • Therefore 52.9/(1-.04) = 55.1 kWh (8.2% loss)
  • Calculating from efficiency and distance it works out to 184.4/3.3 = 55.9 kWh (7.1% loss).
So that may actually be alright since it is about 7.1% - 8.2% capacity loss. Being an Engineer I have to consider sources of error...
  • I have read that some believe that during a past update Chevy reduced the depth of discharge and/or the full capacity and as a result it may no longer be the full 60 kWh. In that case the degradation could be less than 7%.
  • One significant digit is not much of a measurement. Let's say the remaining charge is actually 4.9% and was rounded down to 4%. Therefore 52.9/(1-.049) = 55.6 kWh (7.2% loss) which agrees more with the second method of calculation (distance/efficiency)
There are a lot of implicit assumptions being made here of course but now I at least have an estimate.
 

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One significant digit is not much of a measurement. Let's say the remaining charge is actually 4.9% and was rounded down to 4%
The app rounds up, not down. I just checked our Bolt. The dash board (DIC) shows a GOM center reading of 183 miles. The app shows 183 miles, and 89%. The mychevrolet.com website shows it as 182 miles, and 88%. Torque Pro shows 88.6% DIC
 

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This is a 'Certified' vehicle so it underwent the usual checks before being sold.
As for your "certified" Bolt. I would be surprised if they have checked for, and performed, the two battery management software updates, the several infotainment center software updates, and several other updates which you only get if you complain. I would want verification these were done..
 

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Discussion Starter #10
The DIC efficiency number is also rounded. Go with the miles and kWh used from the center screen. In your case 184.4/52.9 = 3.48
So would that have an impact on the calculated capacity, or is the reported efficiency just incorrect?
 

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As for your "certified" Bolt. I would be surprised if they have checked for, and performed, the two battery management software updates, the several infotainment center software updates, and several other updates which you only get if you complain. I would want verification these were done..
Would those show up in the myChevy app if they had not been completed? Right now it is saying there are no recalls for this vehicle.
 

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So would that have an impact on the calculated capacity, or is the reported efficiency just incorrect?
No, doesn't effect the capacity calculation. The efficiency may not be incorrect. It is still reflecting the car's longer driving history.
 

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Would those show up in the myChevy app if they had not been completed? Right now it is saying there are no recalls for this vehicle.
I am not sure of that. I remember someone saying there was a deadline for some of them. If you didn't get them by a certain date, it was on you.
 

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Discussion Starter #15
Thanks all. I think the conclusion of this thread is this one is a keeper. Correct me if I am wrong.
 

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So I am purchasing a used 2017 Chevy Bolt (off-lease, 55K miles) and want to get a quick assessment of battery health. I have been reading up on various discussions but want to be sure I have it right before finalizing the purchase. Here is what I know...

1. Using the Chevy App (android) I am checking the vehicle's charging status and efficiency. Charging status is 68% and 138 miles of range. Efficiency is 3.3 mi/kWh.
Therefore -> (60 kWh battery) * (68% charge) * (3.3 miles/kWh) = 134.6 miles
So since this matches the range indication it should mean that the battery has 60 kWh of capacity. Correct?

2. This is a 'Certified' vehicle so it underwent the usual checks before being sold. So I spoke to the service department and was told the following... As a matter of course when they receive a used Bolt for sale they fully charge it and then check the car for error codes that would indicate an issue with the batteries. If there are no issues then the battery capacity is OK. Seems a little indirect to me but I get the point.

So, given 1&2 above, are odds reasonably good that the battery in this vehicle is in good condition? As quick background I am currently a Leaf owner and so I have a few years experience with EVs.

Thanks
my car doesn't have 55000 miles on it, but it does have 36,000 miles on it and I have no loss of range and still 58 kilowatts of usable energy. The battery packs in this vehicle are proven to last between 350000 to 500000 miles
 

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So I am purchasing a used 2017 Chevy Bolt (off-lease, 55K miles) and want to get a quick assessment of battery health. I have been reading up on various discussions but want to be sure I have it right before finalizing the purchase. Here is what I know...

1. Using the Chevy App (android) I am checking the vehicle's charging status and efficiency. Charging status is 68% and 138 miles of range. Efficiency is 3.3 mi/kWh.
Therefore -> (60 kWh battery) * (68% charge) * (3.3 miles/kWh) = 134.6 miles
So since this matches the range indication it should mean that the battery has 60 kWh of capacity. Correct?

2. This is a 'Certified' vehicle so it underwent the usual checks before being sold. So I spoke to the service department and was told the following... As a matter of course when they receive a used Bolt for sale they fully charge it and then check the car for error codes that would indicate an issue with the batteries. If there are no issues then the battery capacity is OK. Seems a little indirect to me but I get the point.

So, given 1&2 above, are odds reasonably good that the battery in this vehicle is in good condition? As quick background I am currently a Leaf owner and so I have a few years experience with EVs.

Thanks
Sounds like ya got a good one.
 
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