Chevrolet Bolt EV Coolant System Loops

TIMELINE:
0:00 Video introduction
0:22 Corrections from the previous video
4:12 Coolant system loop number one (Hybrid/EV Electronics Cooling)
5:36 See coolant hoses, connections, pump, and surge tank
11:26 Review of connections and coolant flow in loop one
12:00 Coolant service interval
12:26 See the radiator for coolant loop number one
14:11 See the cooling fan
14:34 See the active grille shutters
16:28 Coolant system loop number two (Hybrid/EV Battery Cooling)
17:20 See the 2.1 kW A/C compressor and hose/pipe connections
18:25 See the battery coolant chiller
20:21 See the double pipe A/C lines to the passenger compartment evaporator
21:52 See the electric water pump, surge tank, and coolant hoses
22:54 See the 2 kW battery heater
23:12 See the A/C condenser (I mistakenly called it an evaporator)
24:45 Review of coolant loop number two
27:30 A/C Refrigerant oil warning
28:40 Coolant system loop number three (Passenger compartment 7.5kW heater)
30:09 Underhood components
31:08 Video review
ABOUT US:
Weber State University (WSU) - Department of Automotive Technology - Ardell Brown Technology Wing - Transmission Lab. 2017-2019 Chevrolet Bolt EV high voltage electrical system coolant system loops - A KZbin first! See the three different coolant system loops of the Chevrolet Bolt EV high voltage system. Learn how they are connected and how they function. This is the sixth in a series of videos on the 2017-2019 Chevrolet Bolt EV
W.S.U is a leader in Hybrid and Electric Vehicle education. This topic is taught as part of our 4-year bachelor's degree program. For information on joining the Weber Automotive program, visit: www.weber.edu/automotive
This video was created and edited by Professor John D. Kelly at WSU. For a full biography, see www.weber.edu/automotive/J_Kel...
ADDITIONAL TRAINING FOR YOU
Join us for hybrid and electric vehicle training with two online courses and in a 5-day on-campus boot camp with Professor John D. Kelly. See www.weber.edu/evtraining
DONATE TO OUR DEPARTMENT
Please consider a donation to the Department of Automotive Technology at Weber State University here: advancement.weber.edu/Automotive

[@stalbaum]

This is such fine public service, Weber State and your program deserve a lot of credit, Professor.

[@ai4px]

What is so very nice about these videos is that they are such a contrast to everything available today. So many videos simply show off some device but no one breaks it down to the component level or explains how it works. It was the value of Heath Kit or Ramsey Kits in electronics... they told you how it worked and why. Recently I watched a video on 5G to find out about it and all the info was about how fast (but never said exactly how fast) and wonderful it would be. Not a bit of techie detail. Even Popular Mechanics is a big ol' glossy useless advert for new products. Have a gander back into the 1930's and 1950's pop mechanics to see how good they used to be. Thank you Professor Kelly for going to the level of detail you do. It is a much appreciate drink of water is this drought of information.

[@WeberAuto]

My pleasure, thank you!

[@tracymathews4122]

I agree! There is little to no available knowledge base to pull from besides Professor Kelly's videos.

[@clif9710]

And what you are talking about is widespread. Sony, with it's U-Matic commercial/broadcast videotape machines, put out service manuals that went into detail on every circuit with waveforms, timing diagrams and extensive text not to mention fabulous circuit board graphics that showed both sides of every board. Those were the days (circa 1980). Now it is all board swapping and who knows what is going on.

[@Jasona1976]

As a Bolt EV owner I find this video, and all of your other Bolt videos, very helpful and extremely interesting.

[@WeberAuto]

Thank you! I am glad they are helpful.

[@tracymathews4122]

@@WeberAuto Me too! I also am a Bolt EV owner, and a licensed master electrician. I think you are doing an OUTSTANDING job on these video's, and I love the humanity you are quick to demonstrate when you make the inevitable mistake; you simply own it and move forward. Please keep these video's coming. Personally, I'd love to learn more about the software (such as the DC Fast Charging conversation that takes place through the Powerline Carrier Interface). At least, I THINK that's what they call it!

[@KTPurdy]

The amount of time and effort put in these videos is amazing.

[@cryptogolfer8888]

This video makes me appreciate my bolt even more! Thank you professor for the knowledge!

[@glenngoodale1709]

Just remember your efforts are very appreciated by a lot of us viewing online.

[@bnjoo]

Thank you, John. I really enjoy your lessons. These are excellent quality videos and I so enjoy your enthusiasm! You have several avid KZbin students out here and I am one.

[@wunderkind56]

As a new owner of a 2019 Bolt this is a fantastic way to understand what I am looking at when I pop the hood.

[@WeberAuto]

Thank you!

[@Tomgillchevy]

Thank you for sharing your wide ranging knowledge Professor. We all need to learn more about these automotive high voltage systems

[@WeberAuto]

Thank you very much!

[@guyhasd]

Nice to learn from a professional. Excellent video. Thank you.

[@mitchellbarnow1709]

Fantastic video! Thank you so much for taking the time to carefully explain each part of the cooling systems and for explaining why they don't use the a/c compressor as a heat pump, to warm the passenger cabin.

[@WeberAuto]

My pleasure, thank you!

[@boxedowl]

Your channel has always had good content but these hybrid/electric/alternative powertrain videos have been exceptional. Thank you for doing these!

[@WeberAuto]

Thank you very much!

[@reider_mcfeely]

These videos are incredibly helpful. I've been converting a car to electric and being able to see what manufacturers do has had a huge impact on my designs for my conversion. Thank you sir!

[@WeberAuto]

Glad it was helpful. Thanks for watching

[@Maltanx]

Extremely well explained as always. I'm very curious about the drive unit, been waiting since the (amazing) battery disassembly video!

[@WeberAuto]

Thank you, coming up next!

[@tesfasinclair1953]

You are one of the best teacher i see on youtube you are so detailed and simple thats very good thank you.

[@EV-Darryl]

Thank you. I’ve been wondering about the three separate coolant systems on my 2023 Bolt 1LT, now I know. I could not find anything on the GM pages. I’ve watched numerous videos of yours on the Bolt, and I must say, you have more knowledge of the Bolt and its systems than any GM engineer, no question!

[@alexisvan222]

Lucid and enlightened presentation. I had no idea it was so complex in there....

[@JlerchTampa]

20:37 I always thought that would be a good idea, glad to see I wasn't over-thinking an optimal solution! Thank you for all of this content, very neat!

[@WeberAuto]

Thank you very much! It is a "Cool" idea ;)

[@edmarkham2632]

I thank you for being very methodical in your explanation of the (3) cooling systems for the Bolt EV. They are all doing the same thing ( cooling or heating) in their respective areas. One could look at those systems and see where one could effect the other. The finding of that one and the replacement of it, could be quite expensive.

[@WeberAuto]

Thank you and thanks for your feedback! It could be expensive, but I believe they will be quite reliable.

[@jordaninmyeyes9520]

Hi MR John I'm Mohammad from Jordan i just want to thank you for all your video's and your simple and clearly way for explaining these systems and about your reward from KZbin I'm sure you deserve it and more

[@WeberAuto]

Thank you!

[@jordaninmyeyes9520]

You welcome and thank you again

[@1986215]

Really thank you for your honesty , great exlpanation and your time

[@WeberAuto]

Thank you!

[@v3ctormax]

Thanks again for such great information. Watching your explanation of the Voltec system on your Chevy Volt is one of the reasons I purchased a 2016 Volt Premier back in November. You make the complexity of these systems less "scary" for the lay person. I've always done my own oil changes, tune ups, etc. on my vehicles. I hope to go full electric in four years, around the time I retire, and no longer have the need to commute. Hopefully our choices in BEV's will be much larger. Who knows, maybe a few more Chevy's!

[@WeberAuto]

Thank you! The Volt is a GREAT car!

[@msmith3395]

As a person used to doing his own ICE car maintenance, this series of videos are very helpful for understanding my new (2023) Bolt (same drive train as in these videos I believe). According to the user manual the a/c desiccant is scheduled to be changed after 10 years or so (don't have the manual in front of me, pulling that number from memory). As far as having separate coolant loops and the lost opportunity to reuse reject heat across systems, I believe the Tesla "octovalve" does just that. Maybe that sort of system will become standard in the industry.

[@andrewk778]

I saw you received an award from TST Seminars for a vibration APP. Congratulations, professor.

[@WeberAuto]

Thank you very much!

[@hovlandbound]

I'm not the first to say this but my wife and I just bought a Bolt and I find these videos really interesting. It's like inventing the car for the second time! Looking at these videos I can't believe they can make a car like this and make it affordable. Thanks for the videos, really enjoy them.

[@WeberAuto]

Thank you, I am happy the videos are useful to you.

[@Rekomeister]

Absolute excellent series. Congratulations Professor !

[@WeberAuto]

Thanks you very much!

[@mikechiodetti6737]

Great Video Professor. You know with all these cooling systems, especially with component location and positioning, there will be problems. Corrosion will take it's toll on the modules and I suspect owners may or may not follow that 5 yr/150,000 mile service. If I owned one, I'd change the coolant every 2 to 3 years. Experience has taught me that, regarding GM's "orange" coolant. The pumps will cause problems also. BUT, it seems the motoring public wants these vehicles!

[@WeberAuto]

Thanks for your feedback. I agree, that coolant must be changed at the proper service interval with the exact coolant required or trouble will occur.

[@mohammadjuma4757]

Thank you professor, I enjoyed every single second of your videos :)

[@WeberAuto]

Thank you very much!

[@benjaminal-doory1817]

We just bought a 22 bolt euv. These videos are simply fantastic, I have been binge watching them anytime I have a minute. I can't stand owning and operating a machine without at least a fundamental understanding of how it works, so my appreciation of your work here cannot be overstated. Gear heads everywhere are forever indebted to you and folks like you who take the time to learn and share your knowledge. Much obliged. I may have missed it in the video, but I'm curious how much current the ac compressor uses? I know the heater uses 2kw, I imagine the ac would be in a similar range?

[@DvACtOid]

It's very easy to derive the amperage of the compressor, we know the high voltage battery uses 350V, you just divide Watts by Volt then you got the current. For the compressor, it would be likely around 6.5 kw at max. Which is draw in between 5A to 18A of power depend on the load.

[@applemachome]

Great video, just got a Bolt and love learning about it from your videos. Compared to hybrid this system is simple.

[@slam854]

Thank you Prof. Kelly, this vehicle has some very intelligent engineering. My impression is each aspect is fairly simple in operation. In concert they make a very functional unit. I finally got Android Auto & My Chevy link working together. I am looking forward to some road trips this year. A big one will be SLC to Flagstaff to see my nephew. Got to learn about DC fast chrg'ng.

[@WeberAuto]

Great car. Have a nice trip.

[@brianhind6149]

Thank you for another excellent presentation, especially without the annoying music with which most video makers insist upon assaulting your ears! Your videos are of the highest professional level, incorporating carefully articulated well chosen words, spoken at a pace that permits easy listening, & helps ensure correct interpretation of what was said. I had no idea that the support technology was so complicated, but am impressed by the quality of the Bolt's documentation & superb details such as alignment marks on hoses, & other essential data apparently stamped into the castings. Professor, I have remarked to several colleagues that the viewers remarks are nearly universally positive, with criticisms being essentially all positive, & the comments written in a style that suggests well educated correspondents, who understand the niceties of correct grammar, syntax, & spelling, 7& who eschew vulgarity or obscenities in their commentary. Many messages on other channels make me feel like a referee at a Sanskrit spelling bee ! Thank you again & I look forward to viewing any & all videos you choose to make.

[@WeberAuto]

Thank you very much! I have noticed the same thing about the comments.

[@liweiguo2986]

It's really fantastic! It's a such good explanation with real parts and really very easy for us to understand. Thanks a lot!

[@throttlebottle5906]

having a battery heater in very cold weather makes sense, due to battery compound/chemistry. I totally didn't catch that in previous video, either my ears missed it or I didn't think about it. nobody is perfect and nor will anyone ever be. it's a fact of life, all you can do is be as best as you can and always keep learning and help when you can with tips and tricks!

[@WeberAuto]

Thank you!

[@red1share962]

when experts make videos , it gives this kind of work . thank you .

[@8thman8]

Thank you so much for your superb instructional videos! You have greatly helped me understand the Bolt EV.

[@razergd]

I always wondered why my ioniq is doing refrigeration noises when plugged to rapid charger... I think that's answers this. Thanks! Great video.

[@juanthedad]

Great info ! Just got a used bolt and knowing what’s what and how it work is great info. Thank you.

[@eugeneleroux1842]

Another very informative and well presented video. Thank you for this.

[@romariorodrigues1698]

Perfect,is technology of the future!!beautiful!! I Love

[@raitchison]

26:30 Based on my testing there are a couple of factors that define when and how the battery is cooled. It matters if the car is "on" or "off" and it matters if the car is "plugged in" to an L2 (220V) charger (and possibly also an L1 (110V ) charger). First, there are two modes, what I call "weak mode" the car will attempt to cool the battery to about 31C. The second I call "aggressive mode" the car will try to cool the battery to about 27C. The only mode I've seen "weak mode" cooling active is when the car is both turned on and _not_ plugged in. Generally "aggressive mode" cooling is only active when the car is "plugged in" and the battery is not charging (either charge complete or charge not needed) I have seen the battery go as high as 37C with the car turned off and not plugged in and the car will not cool the battery. As soon as the car is turned "on" the car starts "weak mode" battery cooling. I have never tried to charge my car with the battery hotter than 31C so it's possible that "weak mode" cooling does occur while charging if the battery is above this temperature. You can "trick" the car into performing "aggressive mode" cooling while charging by charging with the car turned on. During both "weak mode" and "aggressive mode" cooling there is a difference in behavior depending on if the passenger compartment AC system is active. If you do not have the AC setting enabled the car will cycle the AC compressor on and off several times per minute but if the passenger AC is turned on the AC compressor runs continuously. Also at least when "weak mode" cooling (probably also with "aggressive mode") the battery coolant temp is chilled to a much colder temperature (about 10C colder) if the passenger AC is turned on. I have a lot of raw data I've collected from OBD if you are interested.

[@gregoryjward]

Good information! I posted a question above about whether or not the battery loop evaporator operates when the temperature is low but the cabin A/C is on (for defroster or whatever). Did you test that condition? I didn't see any electrical control on the battery loop chiller block that could override operation, but it's possible there is a temperature-limit built into it. Otherwise, they would need to run the battery loop heater to compensate for A/C operation.

[@Miata822]

@@gregoryjward The Perfesser mentioned in a reply to me that the battery cooling loop pump is modulated. If coolant isn't flowing the refrigerant in the coolant heat exchanger will reach the same temperature as the cabin evaporator and cool no further. This could cause an issue only if the battery needed heating but the cabin needed cooling, a Very unlikely scenario.

[@adamcampbell8794]

I cannot say how great these videos are.

[@wayne1559]

thank you very much, just bought my first ev..chevy bolt euv. very helpful idea

[@emantsal1643]

JOHN!! I AM YOUR BIGGEST FAN!!! Thank you so much for educating us. This is fantastic.

[@WeberAuto]

Thank you very much!

[@ghall05]

Those coolant hose clamps on a lot of gm vehicles lock in the fully open position which makes removing/installing much easier

[@gauchejim]

Excellent as usual John.

[@laird2k2]

Excellent in depth series. So great to have actual details of operation and how everything is connected. Are you planning the same for other Electric vehicles. It would be interesting to contrast the different designs. I'm specifically interested in how the Leaf's cooling/heating is laid out as it has a heatpump for cabin heat and loses much less range in the winter.

[@WeberAuto]

Thank you. Yes, I am planning on the leaf in the near future.

[@Miata822]

Fascinating review of the cooling system and you've finally stumbled onto "my turf." A properly designed refrigerant system with a properly functioning TXV won't return liquid to the compressor. The tube-in-tube heat exchanger's primary function in to reduce the temperature of the liquid refrigerant. Cooler high pressure liquid passing through an expansion device wastes less of its mass (called "flash gas" in the industry) cooling the refrigerant itself before it can begin absorbing heat from the cabin. While the efficiency improvement is significant the main reason automakers are doing this today (my opinion) is to reduce the R1234 refrigerant charge which is, as you state, very costly. Adding tube-in-tube heat exchangers does increase the superheat seen by the compressor so there are other design considerations to manage before just slapping one on. A quick note on POE oil- Ester based oils are used in high voltage automotive compressors because PAG (glycol based) oils dissolve the lacquer insulation on the windings inside the compressor, eventually leading to a 400V short inside the compressor. Cross-contamination with PAG can be a real issue with these systems on previous generation EVs that used R134a. And, yes, PAG and POE really do absorb that much water. Cool experiment- Get a cheap 4-place electronic scale from your local purveyor of drug paraphernalia. Pour out a sample of either oil into a small dish and record the weight. Allow it to sit for 2-3 days and weigh again to see how much it has gained. All the new weight is water absorbed from the air. As for the cabin coolant heater and not using battery or motor heat; existing cabin heater coils work best with coolant that is quite warm, 180F+. Lower temperature coolant can be used but it requires the use of very much larger heater coils. We are experimenting with PTC DC heating elements which heat the air directly. While more costly they are physically far less complicated. I imagine GM is using this system because the in dash components are likely shared with other vehicles, but that's just a guess. The motor will seldom generate enough heat to warm the cabin using a normal size heater coil and the battery never will.

[@WeberAuto]

Excellent feedback, thank you!

[@daveconna6271]

HI Bill, About ten minutes ago, I wrote a post with a lot of questions about whether the batteries or the electronics & motor cooling loop produces more heat when the cabin needs it (I figure it is the electronics/motor). I think that it would be a really simply thing to add a heat exchanger that allows transfer of heat from the electronics/motor cooling loop to the cabin heating loop so that during cold weather (especially on long distance drives), one isn't wasting precious battery kWh to turn into cabin heat (as a physicist, I cringe when I see high grade energy turned into heat when a relatively easy alternative is available). Do you have any comment on this idea? Thanks, Dave PS. if you can't find the post, I will copy and paste it to you

[@pedromeza2398]

Thank you for this excellent informative video on the Chevy Bolt EV, I am new to the Chevy 2023 EV Bolt and an Old School car mechanic. I am really interested in learning about the Chevy Bolt EV.

[@ob_gyn_inc]

Thanks for another great video, Prof. Kelly

[@WeberAuto]

Thank you

[@sushovanbasu]

Excellent video professor, as usual. Thank you! Do you mind sharing any documentation / mechanization that lays out the Battery heating / cooling loop. This seems to be complicated and want to follow when you explain it in words.

[@JustforFun-cb7bo]

Wonderful explanation, thank you Professor!

[@WeberAuto]

You are welcome

[@mohammedmuoffak4216]

Nice explanation, I hope you always provide the best

[@gregsmith7412]

Great video! The pumps on the cooling circuits, do you happen to know if they are "wet rotor" type (no shaft seals needed)? Like the ones that run non-stop in hot tubs, quietly, for years.

[@aatheus]

Great video. I feel informed after watching this.

[@Vilneful]

great and very helpful summary!

[@dandelay8639]

I like your honesty and retake of, by the way, I missed this in the last video! That's just the way things work sometimes in automotive repair and life, we may not catch it the first time but, before we're done, we will get it right! I look forward to your next video. You are a great teacher and congrats on your award!

[@WeberAuto]

Thank you very much!

[@fenixshogun]

Thank very much Professor Kelly

[@WeberAuto]

Thank you!

[@alixwhite4054]

Very interesting and I saw many chevy Bolts EV on 10 day drive thru Ohio

[@antonioaguiar2227]

Love your vídeos professor. Best regards from Portugal.

[@Derpy1969]

Professor,I love your channel and wish I lived closer. My friend and I tour the USA in his Tesla (and hopefully, some day, my own) and would love to visit you on one of our trips, take you do dinner, and just talk EVs. Would you be up to a visit some day from some fans?

[@ai4px]

I monitored the passenger cabin loop with a thermometer and when asking for a few degree increase in temperature, the coolant spiked up over 100F for a short period. I've also noticed that there must be an air diverter vane in the airbox under the dash that quickly selects between warmed air and airconditioned air paths. Turning off the heat/ac button but still manipulating the temperature knob demonstrates this behavior. Although I see Professor Kelly's point about wanting to heat the cabin w/o heating the battery, I'd be very happy using the waste heat from the SPIM to heat the cabin. If there's enough heat to need a radiator, there's got to be a better use for it on cold mornings.

[@WeberAuto]

Thank you for the information! Yes, there is an air-mix door to blend heat and cooling for optimum vent outlet temperature. On cold day there may not be enough heat from the SPIM to satisfy passenger heating requirements.

[@daveconna6271]

Wes - I am having a discussion with Bill Kerr about this very topic . If you are interested, my post was on Saturday Feb 2.

[@notafanboy250]

You are awesome for doing this. Thanks a lot!

[@samihasalhi6168]

Thank you very much, it's amazing video!

[@xiaomingouyang]

Extremely well explained as always.

[@WeberAuto]

Thank you very much!

[@xiaomingouyang]

Thank you, Professor, I am Chinese.

[@stevenhzoll7057]

I wonder if it was decided to use a conventional cabin HVAC system and if that had an influence on the drive train temperature management design. Thank you for this series and the rest of your videos.

[@WeberAuto]

All EVs that I am aware of use a conventional AC system. The heating systems can be different.

[@leonardoarandadeleon8563]

Excellent videos !!! Very good!!! My regards from Uruguay !!!

[@leonardoalmanzamiranda7229]

Gracias maestro..! 👏🏻😎

[@patrickgarant3643]

I really enjoy your videos, great knowledge and and a great sharing of enjoyment in auto evolution. Any thought or hopes of checking out a Hyundai Kona Electric?

[@WeberAuto]

Thank you! That would be fun

[@idolhanz9842]

On behalf of all 40,000 + Bolt EV owners, than you. Would love to see instruction video on minor maintenance like headlamp , brake tail light or wiper blade replacement.

[@WeberAuto]

Thank you for your feedback!

[@hasawalmeh]

THANK YOU VERY MUCH , YOU ARE DOING ALOT FO US .

[@hoodahandasa6371]

Thank fou for your great and helpful video

[@WitchDoctor87]

Extremely helpful thanks alot! I personally am making a EV and wonder if this will work if my motor was a Tesla S? Do you think it will be enough cooling and be compatible? Is there a place where I can buy this while unit? Also the unit separate for batteries

[@harley62t]

BTW, excellent video - superb presentation!

[@WeberAuto]

Thank you!

[@bradfordjhart]

The way I understand it if the air conditioning system breaks you must service the vehicle immediately, essentially the battering cooling system is not functioning as well. Also can you explain how air conditioning refrigerant is split between the cabin and the battery cooling. I had a Chevrolet volt, I believe it had a similar system, I could feel the air conditioning on even when the cabin air conditioning was off, I believe it was cooling the battery even on mild days.

[@aephelps99]

Wonderful explanations! Question: If cabin heat is just an electric heating element, heating coolant that's pumped through the heater core to transfer the heat to the cabin air, why couldn't they simply have put the electric heating element in the air stream instead, and not needed the coolant and pump and surge tank?

[@emantsal1643]

I want to come help you put the Bolt back together!!! :)

[@stevelloyd3692]

Love to watch your interesting educational videos .I was wondering will there be a video on how to test the air conditioning systems on electric /hybrid vehicles ?

[@WeberAuto]

That is on my list of future videos

[@stevelloyd3239]

Great. Look forward to it. Thanks for the reply

[@svtwrc]

Looks similar to my Spark EV system, I was checking the reservoirs for leaks and following the lines. Looking for a coolant flush how to, just draining the radiator seems like it would not flush all three systems. Looking for the Chevy service manual for the Spark EV

[@WeberAuto]

Yes, very similar. Visit www.acdelcotds.com/acdelco/action/subscribehome for access to online manual subscription (3 days for $20 USD) Best wishes

[@MsPokey1234]

Love to see "WALMART" be the first to have about 6+ charge stations @ EVERY STORE in USA near front or side of store to buy say a 1 hour Charge! Walmart knows the Customer will have an hour+ to shop during the charge & we will know that if you go to Walmart to shop there here will be charge stations too!

[@royamberg9177]

Being a refrigeration repair tech. I see they have fairly complex simple a/c System. From how that is designed it's a charge critical System. There isn't much room for error on the charge. The tech working on it better have things in order when he's working on it

[@WeberAuto]

Thank you for your feedback!

[@sergiogg2371]

Hi, wonderful videos! Do you have anything on how to prime (bleed) the cooling radiator and hoses for the HighVoltage Charging system on a 2013 Chevy Volt? It appears to be a very common problem (to get the Service HighVoltage Charging System) I used a Vacuum filler and I don't think I was able to pull any air out of the lines. I also tried to use the SnapOn scanner to do the Priming Test to no avail. I would love to do it without any computers involved if at all possible. Thanks

[@benssolarandbattery]

Hi John, thanks for such a detailed analysis of these systems! I've recently started driving my 2020 Bolt on the track and have been seeing some brief "propulsion reduced" messages that last for around 5-10 seconds. These typically occur after a long straight with heavy acceleration, breaking followed by acceleration again. I've purchased an OBD2 reader to figure out what's overheating. After watching this video, I've identified a couple points of interest. If the front louvers stay closed for a majority of the 20 minute run, the cooling system may not be able to keep up with the increased demand, causing it to limit power. I also wonder if keeping the air conditioner running while driving would potentially keep the battery at a lower temperature throughout the runs. The alternative there is it could hinder the drive train cooling system because the AC radiator is in front of the drive train radiator. I should be receiving the OBD2 reader soon and will report back with my findings. Thanks! Ben

[@estebanamador7601]

Hi, what did you discover? thanks

[@imho7250]

I like the simplicity of the cabin heater loop. It would add a lot of cost and complexity to scavenge heat from the motor/inverter. At some point it was probably just easier to use that money to put a bigger battery in it. Sort of like the concept of putting solar on a car. The cost of adding 200 watts solar is enough to add 1 kWh of battery, which can be used even at night.

[@WeberAuto]

Thank you for your feedback

[@daveconna6271]

IMHO - I think I disagree with you: As a physicist, turning valuable battery storage energy into heat is a sin - and increasing battery storage is a MUCH more expensive way to deal with it than a few more controls and a little bit of piping and valving. I suspect that GM simply didn't figure it out and will add it to in the next few years.

[@imho7250]

Dave Conna, GM has been building EVs since the 60s. Even Tesla doesn’t use a heat pump. Is Elon too stupid to figure out what Jaguar, Leaf, Zoe knows about heat pumps?

[@daveconna6271]

@@imho7250 I'm not following your reply - I wasn't suggesting a heat pump. That having been said, the Nissan Leaf does (or at least DID) use a heat pump for cabin heating: www.quora.com/Which-types-of-electric-cars-use-heat-pumps-as-a-cabin-heater That having been stated, there are problems with this approach: a heat pump delivers much lower temperature air and thus would not work for defrosting or quick heating of the cabin during cold starts. But for long distance travel, it should work, even in colder (but not too cold) climates. At any rate, the initial question was about how to scavenge the waste heat to heat the cabin, which I still think is possible and will happen in the future.

[@imho7250]

Dave Conna, I PACE reportedly scavenges heat from the drive unit/inverter, but it can only be done with a heat pump, and it requires more valves and hoses. If you look at the Tesla cooling system it’s already got plenty of failure points, but it allows them to redirect coolant where needed. It doesn’t scavenge that heat, it more likely allows the heat from the motor/inverter to heat the battery. With cheap cars comes some loss of efficiency, but I’d rather have a $25k EV that goes 200 miles on a 60 kWh battery than a $35k car that goes 200 miles on a 50 kWh battery. I’ll spend $1-$2 more per 200 miles.

[@bobcumbers2842]

great video - does anyone know what polymers or elastomers these coolant hoses are made from, and/or if it has multiple layers of different elastomers?

[@Fountain380]

Thank you for this vidéo :-)

[@stevenlipps1176]

Looking at purchasing 2022 Bolt Ev and viewed with interest thus video on the cooling system. One of my concerns is that I live in the Phoenix area and intend to park and charge the battery in my garage. Temps can easily reach 120+ degrees in the garage. First, does the battery cooling loop only run when the battery is charging or would it also run when plugged in and not in charging mode. I am wondering if there is not a likelihood of premature failure of the battery cooling pump and other components due to almost constant running in the high temp environment. Thank you.

[@DonMillerNC]

Professor Kelly another informative and useful video. Several of the (longer) hoses appear to have two clamps side by side near the middle of the hose. Are the longer hoses actually two shorter hoses couple together?

[@WeberAuto]

Thank you. Yes they are

[@compu85]

Professor Kelly, thanks for striving for accuracy in your presentations. Is the APM active while the high voltage battery is charging? It seems like it is on my ELR, I have an issue causing a 12v battery drain. I can see 100-250 watts of draw on my 240v charging station, even after the high voltage battery is done charging. If I clip on an external 12v battery charger the draw on the charging station will go down, so it seems the car is able to charge the 12v battery while not charging the high voltage battery.

[@WeberAuto]

Yes, the APM is active while charging. It needs to provide power to run the cooling fan(s), water pumps, and the computers involved in monitoring and controlling the battery temperature. It also keeps the 12V battery charged while plugged in. It is normal to see additional current draw from your charger after the battery is charged. The battery temperature will still be hot from charging; the cooling system will continue running as long as is needed until you unplug your charger. My 2014 Volt will see a pulse in power usage every few hours when parked in my hot garage at home in the summertime just to keep the battery cool. The Nissan leaf does not do this and it is killing their batteries from overheating.

[@newscoulomb3705]

Thanks for the video! Quick question: Does the CCS system communicate with the BMS through its own cable or that secondary power cable you presented in this video? Also, regarding 26:33 Based on my observations, the battery chiller will start cycling the AC somewhere between 92 F and 94 F. With the cabin fan on, you will start to feel chilled air even when the cabin climate control is not activated.

[@WeberAuto]

Thank you. There are CAN lines between the OBCM and the EBCM. The CCM is hard wired to the OBCM.

[@iansanderson]

Another great video! I am guessing that tieing into the electronics cooling system would make little sense. It would provide only minimal cabin heat at low ambient temps, would need a dual-circuit heater core (do these exist?), an electronically controlled valve, more hoses, more coolant, programming. We’ve now increased cost, weight, and complexity, still need the other heater, and saved 2 miles of range

[@WeberAuto]

Thank you, I have not heard of a dual circuit heater core.

[@laird2k2]

Or perhaps a heat exchanger that takes heat from the drive cooling system just before the radiator and puts it into the cabin heating system before the heater element.

[@daveconna6271]

Ian - I will bet that for those who use their EVs to take longer trips, scavenging heat rather than producing it via electric resistance WOULD make sense in the long run. you would certainly need the electric heat during start up and until the heat coming off the motor and electronics was sufficient -but at that point, you would be able to run the fan at a lower speed and perhaps the lower temperature coolant would be adequate. Before we can answer this question definitely, we need to know HOW much heat is removed from the various parts of the car and what the coolant TEMPERATURE is. Without that info, we are only guessing at what makes sense...

[@TheVdfv]

Great video! Thank you Professor! I saw in my carscanner Brake Motor Driver Temp with 60 degrees Celsius while others motor parts 21 degC after car spent night in garage. Do You know what is brake motor driver? Why it so hot? Or it can be some carscanner mistake? Thanks!

[@molihuaaa]

Great video professor, thank you for your explanation please allow me to ask: 23:31 "so let's look at the evaporator next this....", 23:33 "this is the evaporator assembly". The part that you have mentioned should be a condenser right instead of an evaporator? because the evaporator has been mentioned before in 18:30 as a mini evaporator. Or am I confused?

[@toomanyuserids]

Thank God modern EPDM hoses last a very long time. See you in March.

[@garygraycar5751]

Thank you Professor for helping this 2020 Bolt owner understand. My question is since the passenger side is heated via a separate system that draws heat off the high voltage battery, might there be a way to isolate that heating so you don't experience a huge drain trying to heat the whole car via electric heat?

[@WeberAuto]

The passenger compartment heat is not tied to the battery cooling system; it is separate. it is powered by the high voltage battery. If you want heat, it will start using battery power. Thanks for watching

[@simonreeves2017]

Very interesting. I don't own a GM Volt, but I assume many of the principles apply to my BMW i3. Do these systems use the same type of coolant as a combustion engine? I assume the coolant itself is not as stressed as in a combustion engine, because it will not be operating at such high temperatures?

[@paftaf]

Radiators are passive cooling. Used when the temperature delta is high, for example ICE. The battery need to stay at a lower temperature, sometimes even lower than ambiant, that’s why a radiator wouldn’t work. Need an heat exchanger, and active cooling with compressor.

[@WeberAuto]

Thanks for your feedback

[@Sam_Haddad]

wonderful !!!

[@huge_balls]

Does anyone know if the battery thermal management operates when the Bolt is parked but not plugged in? For example if you are parked with no charger in a temperature extreme like below freezing or very hot.

[@harleyv1969]

Thanks!

[@WeberAuto]

Thank you very much!