Bought a 2017 Bolt EV
 

As some of you know from posts in other threads - I bought a 2017 Chevy Bolt EV back in November. Paid $24K out the door for a fully loaded Bolt with 32K miles. Not a bad price in the current market but 2 years ago I could have got a new Bolt for that.

This will be a thread for any modifications, general observations, and dealing with the battery recall.

So far I've really liked the Bolt. It is a bigger and quicker version of my old Spark EV with better tech.

Modifications:
To date just snow wheels and tires + scrounging a spare tire. The Bolt is based the Gamma II platform so the GM parts bin is pretty deep.

Snow Tires / Wheels:
I bought 15" aluminum wheels off a 2013 Chevy Sonic. I mounted my old Blizzak 15" snow tires from my old Prius. (I sold them to a co-worker after I sold the Prius, he never mounted them, I bought them back for $100)

Spare Tire:
The Bolt doesn't come with a spare. It has room for a spare under the floor in the hatch but GM was too cheap to provide one on a $43,000 car. I sourced a compact spare from a Cruze, bought a 19mm deep socket online, and a cheap breaker bar from Harbor Freight. For a jack I just put my compact Craftsman floor jack in the back for now. I may get a bottle jack sometime but I had the floor jack already.


Battery Recall:
As most people know - Chevy is replacing the battery in every Bolt made due to a manufacturing defect in the LG cells. (LG is footing the bill) Until the replacement is complete GM recommends charging outside and only using from 30% SOC to 90% SOC. Then in December they released a software update that they claimed would allow normal use, charging inside, and just cap charging at 80%. I got that recall at the end of December and it took 2 hours.

I WOULD NOT recommend anyone get the recall. Prior to the software update I was getting 200 miles of range per charge. After the recall the range dropped to 130 miles and has slowly crept up to 160 miles. There is no way 80% of the battery is still available after the recall. With my current miles / kWh I should be getting about 175 miles per charge if 80% of the battery is available. What's done is done, all I can do now is is get the battery replaced to lift the 80% cap.

Last week I got a notification that my car is eligible for a battery replacement. I called my local dealer that works on EVs (not all Chevy dealers do) and they said they would order the battery. Once it was in shipment to their dealership they would call me to set up an appointment. Their estimate was that it would be 4 to 6 weeks from now. When I was in for the software update they had 9 batteries stacked up so they are doing a bunch of recalls.

Charging:
As with the Spark, I can charge for free at work although I don't go into the office every day anymore. However, with the much larger battery I can go longer without charging so there is no real need to charge at home if I don't want to. I could have just used the 120V EVSE that came with the Bolt but I bought a Wallbox Pulsar Plus Level 2 charger with the car for $500. It is pretty nice, easy to install, and allows charging from 1 amp to 40 amps. Sends notifications and charging stats to my phone via Wifi or Bluetooth.

I did some experiments last week and found charge efficiency varies wildly based on state of discharge. All charging sessions were done at 45F and charged to the 80% limit.

1. When I charged after using 31.4 kWh charging to 80% required 33.4 kWh at the charger. 6% charging loss
2. When charging after using 13.9 kWh charging to 80% required 15 kWh at the charger. 7% charging loss
3. When charging after using only 2.4 kWh charging back to 80% required 3.4 kWh at the charger. That is a HUGE 29% charging loss.

I decided to run the Bolt down to near 0% SOC to see how much battery capacity is left after the software recall. It is most definitely not 80% as claimed by Chevy in the recall notice. I suspected they may have capped the top level at 80% but also took some capacity from the bottom. Testing confirmed my suspicion.

This week I topped off to 80% and then started driving for a couple days to drain it to near 0% SOC.

Observations:
At 10% SOC the battery level gauge went orange, I got a warning that power was reduced, and I should charge. I laughed because I still had almost 30 miles of range left which was about 1/3 of the total rated range in my Spark EV.

At about 5% the car stopped showing estimated miles remaining and just said LOW. I found this REALLY annoying because the time you really want to know your remaining range is when the battery is almost dead. (The MyChevy app still showed estimated range and even added tenths of a miles)

Capacity:
In the end I drained the battery from 80% SOC to 4% SOC. The app showed 8.7 miles remaining. I drove 160.1 miles, used 40.1 kWh of electricity, and efficiency showed 4.0 mi/kWh. So that math checks out.

The capacity doesn't check out though. According to the SOC meter I used 76% of the battery capacity. However, 40.1 kWh = 67% of the rated usable capacity. So Chevy is holding back 9% SOC at the bottom - or my battery has massive capacity loss in only 35k miles of driving.

Looking at it in miles: 80% of the battery is 48 kWh. At my 4.0 mi / kWh I should be able to go 192 miles on a charge. So Chevy is holding back 23 miles of driving range.

I'm not a happy customer - but I have no recourse besides getting my battery replaced. (Which is likely Chevy's plan all along)


Charging Efficiency:
My charger showed it took 42.7 kWh to charge back to 80% so that is 6.5% charging losses.

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Good info...:thumbup:


>

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The question could be asked: exactly how far can you go if you can ignore the ever increasing alarms? Also what would be pack voltage there? I have pushed my volt pack to 19 KWH by abusing the cells but I have no way of knowing if that damaged them. Being everything stayed typical, I don't believe I did.

From reading on the Bolt Forum - 0 miles. When the Battery Meter hits zero SOC and range hits 0 miles the car stops and says to shift into park. The battery isn't really at 0% SOC - it is at 5% - but GM has that last 5% locked away to protect the battery.

Cell voltage was was 2.8 to 3.0V for most cells but the total range was 0.4V

This is all before the recall software updates.

Hmm so the low cells trigger the bms and you have a wider range of voltage mismatch. Wonder if they are cutting corners on the assemblies. If you turn it off, let it rest, does the SOC recover much?

any given day the maximum difference in my pack is only .2 volt between cells, pretty much the same cell locations charged or discharged. I tried a top balance, and a bottom balance and it didn't make any change worth noticing.

That isn't my data it is from ChevyBolt Forum member gallen. His post is the only on I've found were someone has actually driven their Bolt until it stops moving. Unfortunately he did not start this test with a full battery so he didn't have data on starting cell voltage or total kWh used by the vehicle on the run.

When his car stopped moving his readings were:
0% SOC from the app
0.4% User SOC (PID 228334)
4.9% Raw SOC (PID 22432f])

As to cell values he said:
Cell volts spread gets larger as %SOC gets low - up to 0.4 volts range. All cells were +/- 0.01 V when charged, but one cell was much lower than all the others as SOC approached 0, starting at a few % user SOC.


For another look at the Bolt battery there is:
(https://allev.info/2019/02/bolt-battery-buffer/)

He says RAW SOC isn't actually battery SOC and claims there is no buffer in the Bolt battery and GM allows 0% to be used. I don't really follow his logic - it is from a based on a graph from a paper on a different battery - but keys things from the article to me:

He is showing fully charged cell voltage at 4.165 and dead at 2.7 Volts.
When fully charged the Raw SOC is 96.5% when the app shows 100% SOC

Assuming Raw SoC is actual SoC GM is holding back 8.5% of the battery capacity - which what most of the industry was doing 5 years ago.

That is also very close to the 9% I found to be missing on my test. So it looks like the software recall might be holding back another 20% of the battery capacity in addition to the 8.5% that was originally held in reserve.

Continuing my charging experiments - last night I charged on the 110V EVSE that came with the car at 8 amps. My wife used 11.9 kWh driving 53 miles to work and back. Per the Kill-a-Watt I checked out from the library the EVSE consumed 14.55 kWh for a charging loss of 18%. This wasn't directly relatable to the charge on the 220V wallbox because the charge took so long (15 hours) the temperature dropped from 60F at start to 30F at the end.


Here is my spare tire set-up
https://ecomodder.com/forum/attachme...9&d=1644684306

More experiments with charging:

Last night I charged on the 110V EVSE that came with the car at 12 amps. We used 12.4 kWh driving 53.8 miles to a fantastic brewery (Wolves and Peaple). Per the Kill-a-Watt the EVSE consumed 15.35 kWh for a charging loss of 19%. Charging took 10 hours (per the car's estimate) and temperature dropped from 60F at start to 46F at the end.

So changing the charge setting from 8 amp to 12 amp doesn't seem to have any effect on efficiency and the stock EVSE is MUCH less efficient than the Wallbox I purchased.

I also downloaded the Bolt PIDs and loaded them into Torque Pro so I'll be able to see some more parameters.

Any possibility you have PIDS for battery temps? I am curious about the charge rate below 40f since I know it gets reduced below 60 by my chemistry.

The Bolt will target something like 70 degrees for the battery while charging, so if it has to burn some electricity to warm it up, it will.

There are something like 35 different PIDs for battery temp.

I'm charging on the Level 2 at work right now.

Air Temp - 46.4F
Battery Coolant Temp - 80.6F
Battery Temp - Avg - 55.4F

So right now as I charge the car is heating the battery coolant and circulating it through the battery attempting to raise the module temperatures.

I can't get a good idea on charge current right now because I'm above 70% SOC and the rate is tapering but I can look at that in the future if our ambient temperates drop below 40F again.

If your pack is anything like my pack, every module has two thermocouples every couple sets of cells, and a couple in the cooling string at exit and entrance. Not suprised they report that many PID since you have that many Bms modules.

you don't charge until you get to 70 degrees so my question is moot.

It also looks like they are using poorer quality cells since your voltage differences are what mine are when it's time to replace

There are PIDs for every module, average, min, max, ALT average, ALT min, ALT max. These are duplicated (C or F)

100% of my charging so far has been below 70 degrees. You asked for data charging below 40F. There are no temperatures below 40F in the 10 day forecast.

I haven't measured cell voltage yet.

You're system is configured such that heaters come on below 70 degrees which did answer one implied question, but not whether your cells would actually charge at colder temps. The Volt pack I have will charge down to 32 but the process elongates horribly from 4 hours to 12

Yesterday the dealership called and said my battery has arrived and I needed to schedule an appointment today or tomorrow. So today at 8 I'm getting a new battery. They say the car will be ready by 5 pm. That is MUCH faster than the 5-6 weeks they said it would take to get the battery - more like 5-6 days.

With this in mind I decided to do a last battery experiment and take my battery down to 0% SOC. I drove to less than 5% SOC and then parked in the driveway and turned the heat and A/C to max. Some early observations

A. The electric resistance heater maxes out at 7500 watts on high and the A/C adds about another 1500 watts.
B. At 5% the last orange bar on the SOC gauge blinks
C. At about 3% the last bar disappears
D. At 0% SOC (0.376%) the RAW number was 5% higher so it looks like GM has a 5% buffer at the bottom.
E. At 0% SOC (5% RAW) my cell voltages were at at 3.2V +/- a bit. I haven't compiled the data from each and done an average or min / max yet

The MyChevy app doesn't work to pull data when a OBDII dongle is installed so I don't have range estimates at low SOC.


Some charging data for Piotrsko.
The Bolt does not slow charging - at least not at temperatures in the 40s.

When I plugged in the Level 2 charger at 0% SOC and 49 degrees it jumped right to 5.78 kW charge rate which is the max for my charge (limited by home wiring not the charger) I charged for a couple hours and then turned it off. This morning at 27% SOC / 43F it jumped right back to charging at 5.78 kW.

Thanks for the experiment. Any idea what the battery temps were while charging? Interesting that it will let you drive the SOC to "0" with the hvac

At those SOC, the battery should absorb every amp you can give it

Other than the obscene quantity of attaching hardware, should only take an hour of labor to swap the pack. Please report the level of charge when they gave it back to you

Last night the battery temperature was 60.8F. This morning I would expect them to be at ambient as the charger was turn off but I didn't connect and check.

Book time is 4.5 hours to 5.5 hours. I dropped off the car at 8:15 am and they called at 11:45 am to say it was done. They charged it on their DC fast charger to 100%

The guess-o-meter is ALL over the place. Started at 200 mile range and then dropped to 135 after driving 25 miles. Average mi / kWh dropped from 4 to 1 and then has been slowly increasing since. The Service Rep said it would take 2-3 full discharge / charge cycles to learn the new capacity.

It is most definitely a new battery pack. The old pack had a flat bottom from sill to sill. The new one isn't so fancy.

https://ecomodder.com/forum/attachme...3&d=1645154600


When I dropped off the car they had 17 batteries stacked up. When I picked up the car they had 22 batteries. Service Rep said they replace 4 batteries a day

https://ecomodder.com/forum/attachme...4&d=1645154680

Personally I'd have waited another 5 years, then got the new pack.

Jason's in the business and probably more sensitive to those jerk moves.

If I planned to have this car in 5 years I would have seriously considered it. Since I don't plan on keeping the car long term I didn't see any reason to delay getting the new pack with more range.

This morning I came outside, turned on the car, and was surprised to find out that the car magically found 25 miles of range while sitting overnight even though the temperature dropped 20F.

I drove the 25 miles to work and ended up with a project range the same as when I turned off the car last night. It will be interesting to see if the car found some more range while sitting in the office parking lot.

(This is exactly what threads on the Bolt Forum describe when the battery is learning its new capacity.)

new pack
 

You just earned about $10,000, tax-free!:D

How do you figure that?

how?
 

Actually, AeroStealth questimated it from contemporary costs for a Kilowatt of Lithium Ion battery.
He got a call the other day from his dealer, and will be getting the 66-kWh for his BOLT.
He and his wife just did an 800+ mile trip with the defective pack, and will be cleared for trip to San Diego, CA, from New Mexico.
Regardless of the actual cost, you scored big-time!:thumbup:

I understand 10 large to be the price for a black market factory new bolt pack, slid under your door, so to speak. Wink, wink, nod nod

Just a wee cosmetic damage from falling off the lift gate.

so to speak
 

'Nod's as good as a wink'?
'I cut down trees, I wear high heels
Suspendies and a bra
I wish I'd been a girlie, just like my dear papa'

You are mixing your comedians up. However nice catch on the obscure quote.

Comedians? or Faces?
This appears to be identitarian anti-logger safety propaganda. Should be in The Lounge.

Know what I mean, Vern?

should be
 

Monty Python, Benny Hill Show, and Mel Brooks humor would probably all be a fail today.

Lenny Bruce, Mort Sahl, George Carlin....

Comedy itself is being 'canceled'.

The problem with that calculation is that I didn't get 66 kWh of Li-Ion batteries. It isn't like I got to keep the old 60 kWh battery to use as home storage or in my campervan. The old battery went back to GM and a new one with 6 more kWh replaced it.

I did gain 6 kWh of battery. Yes, that extra capacity adds 20ish miles of range although 90% or more of my trips are 50 miles or less. A handful of trips I'll be able to go a bit farther between charges and might save a few minutes. Minor score there.

Yes, I got a new battery to replace a 4 year old battery so the vehicle should go longer before an replacement battery is needed but I had no plans to own this vehicle outside of the original battery warranty so - again - nothing gained.

The only way this would be real gain to me is if the future buyer is willing to pay more for my Bolt because it has a newer battery. Time will tell if that overrides the fact that the Chevy Bolt has a reputation for catching on fire.


Now for losses. The old battery had a flat aerodynamic bottom that sealed the underside of the car. Better for aerodynamics, efficiency AND better for long term life of the car because there were no places for road grim, mud, and salt to collect and corrode the unibody. The new battery leaves the huge areas exposed to collect grim and rust out the car. Not much of an issue here in Oregon were salt use is very limited but for people in the rust belt they can expect their car to rust out faster. (Likely before the battery gives out)

There is also the time lost between the two recalls.

Preliminary data from the first couple of days of driving with the new battery.

21.6 kWh used to travel 83.4 miles. That is 32.7% of the battery capacity so using 100% I should have a range of about 255 miles. Of course that is range at 50F, range in the spring and summer should be better.

I'm on my 3rd battery charge with the new battery. The dealer tech and everything I've read online said to discharge down below 25% to help car learn the new battery capacity faster.

1st Charge
When I picked up the car from the dealer the range read 200 miles
SoC (Display) = 100%
SoC (RAW) = 100%

I drove it 191.2 miles and used 49.5 kWh of juice.
94% driving / 5% HVAC / 1% Battery Conditioning
Remaining range = low
SoC (display) = 9.4%
SoC (Raw) = 13.4%


2nd Charge
Charged it up and the range read 218 miles
SoC (display) said 100%
SoC (Raw) said 96%


I drove 190.8 miles and used 46.8 kWh of juice
91% driving / 7% HVAC / 2% Battery Conditioning
Remaining Range = 46 miles
SoC (Display) = 22.7%
SoC (Raw) = 27.2%


3rd Charge - In Process

It will be interesting to see what the range meter says tomorrow with a full charge. The car does seem to be learning the battery has more capacity.

On the 1st charge the car thought 49.5 kWh was 90.6% of the usable capacity. That calculates to 54.6 kWh usable capacity

On the 2nd charge the car thought 46.8 kWh was 72.3% of the usable capacity. That calculates to 64.7 kWh usable capacity.

A little update:

The range has been slowly growing but I was curious how much I was throwing off the car by running undersized tires. Does the car pull speed from the speedometer, GPS, or both? I assume the speedometer.

My winter tires are Bridgestone Blizzak sized 185/65R15 with a diameter of 24.5 inches and 852 RPM. Stock tires for the Bolt are Michelin Energy Saver A/S sized 215/50R17 with a diameter of 25.5 and RPM of 815. So the tires are 4% smaller and the car thinks it is going 4% farther than it actually is.

I have no answer on this yet - the car will take some time to adapt.

What I did notice right away is that the stock wheel / tire combo is HEAVY. I could easily tell the difference when swapping wheels. The stock wheel / tire weights 44 lbs even with the tread worn down almost to the wear bars. The 15" wheels / winter tires weigh 34.9 lbs. So 9 lbs lighter - likely 10 lbs lighter with full tread.

WHY do automakers put such heavy and oversize wheels on their vehicles? I know the answer - big is in style but the penalty for that style is less efficiency, poor ride, and expensive tires when it is time to replace them.

Part of that weight is Chevy deciding to remove the spare from the Bolt and instead having Michelin put a layer of tar on the inside of the tires to self seal small punctures. That adds a pound per tire vs the regular version. Just the tire is 23 lbs while the Blizzak weighs 18 lbs.

I'll be shopping for replacement summer tires. I won't be buying another set of stock tires. They are crap with a BB rating for performance and temperature. Feel on the road matches that poor rating.


Since everyone has been talking about fuel prices lately: My wife has been driving the Bolt for her 50 mile commute since I've been travelling. To date we have spent $28.67 on electricity. It is pretty crazy that we bought here a car to replace the TDI on April 4th and she didn't drive it until yesterday.

Ride harshness is a somewhat common complaint on the Bolt forum, and some have gone with lighter weight wheels/tires to mitigate the issue.

I don't know how much impact rotational weight plays in efficiency, but at least on the Bolt it will recover the majority of that energy with regen. It may play some role in why Chevy decided to go with such heavy tires/wheels. Perhaps they simply wanted stronger wheels since you can't repair a tacoed rim with fix-a-flat.

Curious to hear feedback from your wife with regards to ride comfort.

Yes, you get some of the energy expended accelerating heavy wheels back through regen but only some of it. Studies I've read put it at 70% max

The "winter" wheels are stock aluminum wheels from a Chevy Spark / Sonic / Cruze / Trax so they are plenty strong - just smaller.

My wife likes the Bolt. She likes the quiet, the acceleration, and handling. She likes having CarPlay. Comfort is fine although our longest trip has been about an hour. It will be interesting if I get it back or if I'll end up driving the new to us Acura.

First charge after going back to stock wheel / tires = 263 miles range. That is about 20 miles more than I ever saw with the under size winter tires.

This pretty much confirms that the Chevy dealer did not do the complete recall and reprogram the car to show the new battery capacity.

263 / 4.5 mi/kWh = 58 kWh battery capacity. That is the usable capacity of the old battery not the new 65 kWh battery.

I'm curious if there's a PID that would show actual SOC, or if that depends on the car having been programmed correctly?

SOC is based on average cell voltage so it should be reading correctly. Chevy holds back 4% SOC on the top end and 5% SOC on the bottom end.

I take back the statement from my last post - before the battery replacement the PID showed Battery Capacity at 52.9 kWh. That would seem to be usable capacity not total capacity as the original battery was advertised 60 kWh and GM held back 9% of the capacity for a usable capacity of 54.6.

So 58 kWh is more than the old battery. Now is that just from the car learning through repeated charges or did the dealer reprogram the car like they said? No way to know.

One thing that did drop a lot with the new wheels is the calculated efficiency. With the old wheels I was showing about 5.0 mi/kWh. On the half charge after the wheel swap I'm down to 4.5 mi/kWh. That would make sense as with the undersize wheels the car would think it was going farther than it actually was.

I haven't plugged in my OBDII scanner and used Torque Pro to check the PIDs for almost 2 months so I'll need to do that.

It has been a couple of weeks since swapping back to the summer tires / stock wheel sizes and the estimated battery range is growing. After a week of driving in moderate temperatures without needing HVAC I was up to an estimated 289 miles of range with a full charge. After a week of my wife driving and running the heater and it was back down to 240. I suspect summer range will be 300 miles or higher.

So far I’ve really liked the Bolt. My biggest complaint is the HVAC. It has a dial for temperature and a manual and auto mode. In my mind manual should just be just be a rheostat. Turn it up and the air through the vent gets warmer, turn it down and it gets cooler. If the display says 50F it should be blowing air that is 50F. If it is set to 70F the vent temp should be 70F. That is not how it works. In both manual and auto modes the computer varies vent temperature all the time. Looking at PIDs through Torque Pro the heater wattage is all over the place.