Cooling in Roadster 2.x vs. 1.5 for Hot Climates

[Cattledog]

I am kicking around the idea of getting a roadster and am wondering if people can weigh in on how much better the cooling system is for the 2.xs (I understand there was a cooling system upgrade from 1.5 to 2.0). I live in San Antonio and the days from June through September are over 95 degrees 95% of the time and over 100 degrees for 10-50 days a year. I'd mostly use this as an around town car, so likely never a roadtrip.

Trying to gauge how important limiting my search to a 2.x is.

Thx.

 

[DeedWest]

Hi! Glad to hear you're interested in a Roadster.

I live in Dallas, and our temperatures are very hot most of the time as well. I would recommend searching for a 2.0 or 2.5 due to the cooling threshold alone.

The 1.5 will force cooling of the battery (ESS) once it reaches a temp of 35C, whereas the 2.0 / 2.5 will force cooling when it reaches 41C. The force cooling will divert your air conditioning to the ESS and leave you without A/C for a short period of time.

In the 1.5, it'll force cool the ESS down to about 32C before returning your A/C. In the 2.0 / 2.5, it will "steal" A/C until it drops to about 38C.

These temperatures can be viewed in the car's display screen for live reference. In my experience driving a 1.5 in the Texas heat, I found it to be very debilitating that it was constantly diverting my A/C. In higher ambient temps, it's obviously tougher to keep the car below 35C than it is to keep it below 41C, respectively.

When the car charges, it will use A/C to cool the battery, and will usually bring you down to 31C or lower based on charging time & amperage. I've found that this gives me a solid 1-2 hours of consistent driving with ice cold A/C (which seems to be far more excellent in the 2.0 / 2.5 models). With these temperature references, you can essentially gauge your time with A/C in hot climates when you enter the car.

I should also note: to view live temps in Celsius, you must be in "Debug Mode" which can be activated from the service menu, but you won't need to worry about doing that until you get a Roadster.

Hope this helps!

 

[Cattledog]

DeedWest - Thank you, that's very helpful and the input I was seeking. It sounds like the the cooling improvements to the 2.x cars creates a much more manageable buffer in hot areas like Texas.

 

[DeedWest]

DeedWest - Thank you, that's very helpful and the input I was seeking. It sounds like the the cooling improvements to the 2.x cars creates a much more manageable buffer in hot areas like Texas.

No problem - and I absolutely agree. Granted, I drive my Roadster 2.0 without its roof for probably 7-8 months out of the year in Dallas, so a 1.5 would be a fantastic car for most of the year. Those other four months above 85 degrees? The increased A/C timing is VERY important.

Lucky for you, 2.0 cars seem to be the most common when it comes to cars on the market. If you'd like me to assist you in choosing the right one, shoot me a PM & I'd be thrilled to help! Nothing makes me happier than adding another enthusiast to our very small but passionate family.

 

[redan]

If you'd like me to assist you in choosing the right one, shoot me a PM & I'd be thrilled to help! Nothing makes me happier than adding another enthusiast to our very small but passionate family.

@Cattledog definitely take @DeedWest up on this offer. He will be more helpful than you can ever imagine. I wouldn't buy a(nother) Roadster without first obtaining the @DeedWest seal of approval! He is a brilliant and cherished resource on this site (at least by me! ). You'll see the Roadster owners (and former owners) and enthusiasts (@TEG and @bonnie among too many to count/name) on this forum are among the friendliest, most welcoming and most knowledgeable of all Tesla owners anywhere.

I'm also pleased to assist with my limited (but growing) Roadster knowledge base.

Good luck!

 

[supersnoop]

I'm in the Austin area and have owned a 1.5 for three and a half years. The heat has made me uncomfortable in the car once. And I drive it almost every day.

I haven't seen the threshold that DeedWest mentions before, and I don't believe they're accurate for my car.

 

[DeedWest]

I haven't seen the threshold that DeedWest mentions before, and I don't believe they're accurate for my car.

I gathered this data using the Vitals screen in the diagnostic menu (as the 1.5 does not show degrees in Celsius when in Debug Mode). I tested it four times on a warm day, and each time, the A/C would be routed to the ESS at 35C and stop when it lowered to 32C.

Now, could it be possible that your Roadster 334 has different cooling threshold than my experience in the Signature 100 I regularly drive? Totally!

Which makes this even more enticing to research.

Could you possibly test this in your 1.5 and report back with information? I'd love to hear other 1.5 owners' input on this claim, too!

 

[supersnoop]

I gathered this data using the Vitals screen in the diagnostic menu (as the 1.5 does not show degrees in Celsius when in Debug Mode). I tested it four times on a warm day, and each time, the A/C would be routed to the ESS at 35C and stop when it lowered to 32C.

Now, could it be possible that your Roadster 334 has different cooling threshold than my experience in the Signature 100 I regularly drive? Totally!

Which makes this even more enticing to research.

Could you possibly test this in your 1.5 and report back with information? I'd love to hear other 1.5 owners' input on this claim, too!

I hit 36c today with the a/c going and it didn't switch to the battery. I may run out again this even and see if I can heat it up again.

 

[DeedWest]

Was the car in Performance or Range Mode by chance?

****I should probably note that I only tested those 1.5 thresholds in Standard Mode.

 

[wiztecy]

From what I know about the battery cooling threshold, those are the same for the 1.5 / 2.x's. However what is different is the PEM cooling thresholds. The upgrades the OP discussed are with the blower upgrade on the 2.x's, the upgrade gave them a dual blower/fan with a single motor. This drastically cooled down the PEM when temps would rise and makes a huge difference. So if you're looking for a Roadster that can handle hotter temps I'd search for a 2.x with that upgrade or find a 2.x that doesn't and then have Tesla upgrade it.

Another upgrade is the fan shroud that covers the front HVAC condensor, That improves cooling of the fans, this was available as an upgrade for all versions of Roadsters.

No cooling upgrades were ever done for the battery or motor. However the 2.x blower/fan upgrade may have helped with the motor cooling but I haven't heard anyone saying if it helped or not.

 

[S-2000 Roadster]

I remember reading that there was a firmware upgrade to alter the A/C performance. Originally, all A/C cooling was used for the battery when needed, leaving nothing for the passenger cabin. If I recall correctly, the firmware upgrade allows a percentage of the A/C cooling power to be used in the cabin. I don't have any details on whether this firmware change was limited to certain models or if it was part of all. Take these comments with a grain of salt, of course, because I haven't done a forum search to confirm.

Additional data would be useful: if DeedWest could tell us whether his Signature 100 has the latest Roadster 1.5 firmware upgrade. Also, maybe supersnoop could let us know his firmware version. If everyone is on the latest firmware, then we know we're comparing apples to apples.

 

[ecarfan]

My 1.5 has the latest firmware, as it has the 3.0 battery. A few weeks ago driving from Willits CA to San Mateo CA I spent about 2 hours in 104+ temperatures while driving. I noticed that my AC cycled on an off. I can't provide quantitative data on the cycle time, but guess it was about 15 minutes intervals. I thought it was overloaded due to the heat, but now I realize it was probably alternating between cooling the battery and cooling me.

I never had to slow down from my 65mph speed due to battery or PEM overheating.

 

[supersnoop]

Not in range or performance mode.

I've been assured that I'm on the latest firmware, but it's difficult to be sure. There seemed to be a new release with the 3.0 upgrade, but I don't think anyone knows if it's applicable to cars without the upgrade.

Tonight, my OVMS showed the battery above 35c again, but it was a beautiful evening, so I had the windows down and the a/c off. It never spun up to cool the battery.

 

[Rotarypower]

Questions about battery cooling.....

See this post for the only definitive info I have been able to find on the design and temperature set points for the ESS battery cooling system design. However, this was taken from a Tesla training seminar in 2012, so it is unclear on applicability to 1.5 vs 2.0 vs 2.5 cars.

 

[hcsharp]

The upgrades the OP discussed are with the blower upgrade on the 2.x's,

The OP is talking about the HVAC* system. It had a significant upgrade in the 2.x models and it was one of Tesla's talking points for things they improved in v 2.0. It's not just the AC. The heater is also stronger. Not that you need that in TX! In fact it's a rare day that I use the heater to its maximum capacity even in ice-cold Vermont.

*HVAC: Heating, Ventilation, Air Conditioning