GM Volt Forum banner

1 - 20 of 32 Posts

·
Registered
Joined
·
420 Posts
Discussion Starter #1
Where I live we have a very moderate yearly temperature range - it only rarely gets above 30 degC in summer and also rarely drops below freezing in winter. As we purchased our 2017 Volt late last August we have not needed to use the air con until the last few days.

I have been noticing that at idle with no AC/heat the vehicle consumes about 0.5kW, in winter with the heater on about 5kW and now in summer with the air con on Auto, set to 22degC, Eco, recirculated air and an outside temperature of about 30 degC the system consumes between 0.5kW to a max of 2kW and usually sits at 1kW.

I find that to be quite efficient and the air con system quite rapidly cools the car nicely. Well done Chevrolet!

I wonder how those who say live in Arizona or much hotter climes find the air con system works when temperatures sit at around 40 deg C (104 deg F)??
 

·
Registered
Joined
·
2,488 Posts
I have to agree on the AC as I have noticed the same with our 2016 Volt. Winter heat is an entirely different story as you have noted...
 

·
Registered
Joined
·
514 Posts
I think the A/C system in most all EV's is pretty efficient. Where we live, we use it daily for at least 6 or 7 months per year and it doesn't have nearly the detrimental effect on the vehicles range that the heating system does. For us, it's right around 10%, whether we're driving the Volt or one of our Mitsubishi BEV's. We have at least 4 months where the average high is around 90 degrees or better

Don
 

·
Registered
Joined
·
277 Posts
It's the same on Gen 1. I've sat in the car with the car running at my kids soccer practice on a 90 degree day before for an hour with the AC on, and only used about .5kwh of battery. I figure it cost me 5 cents to be comfortable for that hour, since I charge for about 9.5 cents per kwh off peak. You certainly can't do that with an ICE.
 

·
Registered
Joined
·
485 Posts
I agree it's pretty efficient most of the time. However, when it got above 95 here a few weeks ago, I saw my MPGe tank from about 110 average down to 89, and it required pretty heavy constant fan usage.

Granted, that's only about a 20% reduction in efficiency, which would be the difference between 30 and 25 or so MPG in an ICE vehicle and most of us wouldn't really notice. It's just that the energy screens and the larger units exaggerate the difference.
 

·
Registered
Joined
·
1,266 Posts
While I haven't been able to measure it the same way as in the Gen 1, I do think the Gen 2 A/C is slightly more efficient. It seems to consume less power to get to a comfortable temperature. Although sometimes it can consume quite a bit initially cooling the cabin + running battery cooling if the car has been sitting on hot asphalt all day baking in the sun.
 

·
Registered
Joined
·
897 Posts
AC is awesome, and I love how it doesn't drag down the acceleration as AC typically does in a 4cyl. ICE car.

Electrical resistance heat in the winter is far less efficient.

Can anyone comment on how much better preheating while plugged in with Level 2 is vs Level 1? All we had last winter for our 2018, was Level 1 and we certainly lost some miles before even pulling out of the garage. I'm hoping for a much smaller loss this coming winter now that we have Level 2 charging @ 16 amps.

Sent from my SM-G930V using Tapatalk
 

·
Registered
Joined
·
4,821 Posts
AC is awesome, and I love how it doesn't drag down the acceleration as AC typically does in a 4cyl. ICE car.

Electrical resistance heat in the winter is far less efficient.

Can anyone comment on how much better preheating while plugged in with Level 2 is vs Level 1? All we had last winter for our 2018, was Level 1 and we certainly lost some miles before even pulling out of the garage. I'm hoping for a much smaller loss this coming winter now that we have Level 2 charging @ 16 amps.

Sent from my SM-G930V using Tapatalk
I usually precondition my 2017 Volt in winter using Level 2 (240V/16 amps). In the mid-Atlantic region what we experience as far as cold temperatures does not approach the frozen north. Generally the garage, because it is shares a wall with the house, stays 10 degrees warmer than the surrounding air temperature but not always. According to the thermometer in my garage the coldest temperature inside the garage last winter was 12F. It is unusual for the garage to ever get colder than ~20F.

I usually precondition 1x for 10 minutes while my Volt is parked inside my garage. Immediately following the 10 minute preconditioning period I observe a 0.6 - 0.8kW SOC deficit on what would otherwise be a fully charged battery. I have on occasion extended the preconditioning period for an extra 10 minutes. In those cases the deficit was a bit more but I do not recall how large. It takes a good 12 to 20 minutes for the battery to top off again after preconditioning, of course by then the Volt's cabin has started to cool down.

The 7.2kW on-board charger available on the 2019 Volt should outperform the current 3.8kW charger as far as preconditioning. I would expect the 2019 Volt's battery to remain fully charged throughout a 10 or 20 minute preconditioning cabin heating period.
 

·
Registered
Joined
·
1,230 Posts
Got to look at the difference in change you are asking of the system. While cooling is still more efficient we rarely get more than 20 to 25F difference for AC but when heating many of us compare it to freezing temperatures and we are raising that twice if not more than what we need to cool in summer.

Cooling from 100 to 70 is just 30 degrees, but 30 degrees to 70 is 40 and it just keeps getting worse if the winters are bad where you are.

does anyone know what the high temperature has to be before the scoring system rates it a negative value?
 

·
Registered
Joined
·
2,359 Posts
I agree that the Volt A/C is fantastic.
And it gets even better with some good quality window tinting!
 

·
Registered
Joined
·
897 Posts
I usually precondition my 2017 Volt in winter using Level 2 (240V/16 amps). In the mid-Atlantic region what we experience as far as cold temperatures does not approach the frozen north. Generally the garage, because it is shares a wall with the house, stays 10 degrees warmer than the surrounding air temperature but not always. According to the thermometer in my garage the coldest temperature inside the garage last winter was 12F. It is unusual for the garage to ever get colder than ~20F.

I usually precondition 1x for 10 minutes while my Volt is parked inside my garage. Immediately following the 10 minute preconditioning period I observe a 0.6 - 0.8kW SOC deficit on what would otherwise be a fully charged battery. I have on occasion extended the preconditioning period for an extra 10 minutes. In those cases the deficit was a bit more but I do not recall how large. It takes a good 12 to 20 minutes for the battery to top off again after preconditioning, of course by then the Volt's cabin has started to cool down.

The 7.2kW on-board charger available on the 2019 Volt should outperform the current 3.8kW charger as far as preconditioning. I would expect the 2019 Volt's battery to remain fully charged throughout a 10 or 20 minute preconditioning cabin heating period.
Thanks for the info. It will be an improvement for sure.

Yes I would take the 7.2 kwh just for that if nothing else ( plus the lower temp ERDTT), but we needed to replace my wife's aging Mazda 3 and she needed to stop driving a stick with her bad left knee so, no regrets. It often happens like this though or so it seems when buying something.

Sent from my SM-G930V using Tapatalk
 

·
Registered
Joined
·
514 Posts
Electrical resistance heat in the winter is far less efficient.

Can anyone comment on how much better preheating while plugged in with Level 2 is vs Level 1?
Well, a little ceramic household heater draws 1500 watts from a 120 volt outlet to make about 5,000 btu's of heat and they don't do too much to warm up an insulated room in a house

Level 1 at 8 amps is only 960 watts and the car is using a bit of that, so not all of it gets turned into heat. While the car is a 'small room' it's also mostly metal and glass with no insulation and if you're preheating it's probably pretty cold outside, so you can't expect very much from just 8 amps. 12 in a little better, but my winter experience with our BEV's has shown that unless you have 30 to 45 minutes to wait, preheating is best done at 240 volts

Don
 

·
Registered
Joined
·
4,821 Posts
Well, a little ceramic household heater draws 1500 watts from a 120 volt outlet to make about 5,000 btu's of heat and they don't do too much to warm up an insulated room in a house

Level 1 at 8 amps is only 960 watts and the car is using a bit of that, so not all of it gets turned into heat. While the car is a 'small room' it's also mostly metal and glass with no insulation and if you're preheating it's probably pretty cold outside, so you can't expect very much from just 8 amps. 12 in a little better, but my winter experience with our BEV's has shown that unless you have 30 to 45 minutes to wait, preheating is best done at 240 volts

Don
That's not the way preconditioning works in the Volt. The Volt's electric heat (air conditioning too) is powered by the high voltage traction battery drawing at a rate of as much as 9 kw (typically 6-8 kw) from the Volt's battery to heat the vehicle for the 10 or 20 minutes that the preconditioning cycle is set to run. The level 1 charger is just recharging the traction battery at the nominal 120V, 8 or 12 amp rate. Topping off using level 1 charging following preconditioning in winter is not efficient use of time or energy because by the time you have topped off the battery the cabin is cold again.
 

·
Registered
Joined
·
420 Posts
Discussion Starter #14
Can anyone comment on how much better preheating while plugged in with Level 2 is vs Level 1?
I did a couple of tests last winter. With the car fully charged up, outside temp 1-3 degC, one 10 minute preheating session the Level 1 charging tookl 45-50 minutes to fully recover 100% charge. Level 2 charging took less than 5 minutes to recover a full charge.
 

·
Registered
Joined
·
897 Posts
That's not the way preconditioning works in the Volt. The Volt's electric heat (air conditioning too) is powered by the high voltage traction battery drawing at a rate of as much as 9 kw (typically 6-8 kw) from the Volt's battery to heat the vehicle for the 10 or 20 minutes that the preconditioning cycle is set to run. The level 1 charger is just recharging the traction battery at the nominal 120V, 8 or 12 amp rate. Topping off using level 1 charging following preconditioning in winter is not efficient use of time or energy because by the time you have topped off the battery the cabin is cold again.
So this from the owners manual is a bit misleading. Obviously the engine may start portion can be turned off if desired. I'm just referring to the part about it using electricity from the outlet.

I was under the impression that electricity was only drawn from the traction battery as needed to supplement that drawn from the outlet for preheating. So with Level 2 @ 3.6kwh, less would have to be drawn from the traction battery vs Level 1. And with Level 2 @7.2kwh, perhaps none at all, so after 15 minutes of preheating a 100% charge would remain.



Sent from my SM-G930V using Tapatalk
 

·
Registered
Joined
·
420 Posts
Discussion Starter #16
Well I am sure they have done the math to show that irregardless of also consuming some battery to do the preheating it is still more efficient to get that at least some of that energy from the grid rather than the battery, thus extending your range. So its not that misleading. But yes, preheating comes at a cost, but significantly less so at 240VAC.
 

·
Registered
Joined
·
897 Posts
I did a couple of tests last winter. With the car fully charged up, outside temp 1-3 degC, one 10 minute preheating session the Level 1 charging tookl 45-50 minutes to fully recover 100% charge. Level 2 charging took less than 5 minutes to recover a full charge.
That's excellent and good enough for us. Even if we don't wait the 5 minutes or so, it's a trivial loss of range. Thank You!

Sent from my SM-G930V using Tapatalk
 

·
Registered
Joined
·
4,821 Posts
If you precondition in the winter while unplugged, as long as the Engine Assist Heat is set to Deferred and the temperature is above 15F, then only the traction battery is used to heat the cabin. If you do this then view the Energy screen it will show the kWh consumed (assuming the battery was fully charged when you started preconditioning). The next time you precondition do so while plugged in, then view the Energy screen to see and compare the net kWh used during the preconditioning.

I can see how the wording in the manual under Remote Start is misleading. The Volt's on-board electric heating element for the cabin heat exchanger operates at 300VDC and up to 9kW (30 amps),this is twice the maximum amperage that the Volt can draw while charging. Also, the EVSE is on the input side of the battery charging system, not connected to the Volt's high voltage equipment (drive motors, AC compressor and electric heating elements) on the output side of the high voltage system. There is a separate electric heating module for heating the battery coolant loop in cold weather, probably not more than 2kW for the battery coolant heating element. That heating module could theoretically be powered by a level 2 EVSE but the Volt will also heat the battery coolant as needed while driving so there would be no power from the EVSE while on the road.

If the ICE is running, in round numbers, 30% of the energy from burning fuel is used to propel the Volt and recharge the battery, up to 30% is used to heat the passenger cabin, the rest goes past the catalytic converter and out the tail pipe. The heat from the ICE is never used to heat the Volt's traction battery. The battery cooling/heating is on a separate loop from the engine coolant loop and cabin heat exchanger loops.
 

·
Registered
Joined
·
897 Posts
If you precondition in the winter while unplugged, as long as the Engine Assist Heat is set to Deferred and the temperature is above 15F, then only the traction battery is used to heat the cabin. If you do this then view the Energy screen it will show the kWh consumed (assuming the battery was fully charged when you started preconditioning). The next time you precondition do so while plugged in, then view the Energy screen to see and compare the net kWh used during the preconditioning.

I can see how the wording in the manual under Remote Start is misleading. The Volt's on-board electric heating element for the cabin heat exchanger operates at 300VDC and up to 9kW (30 amps),this is twice the maximum amperage that the Volt can draw while charging. Also, the EVSE is on the input side of the battery charging system, not connected to the Volt's high voltage equipment (drive motors, AC compressor and electric heating elements) on the output side of the high voltage system. There is a separate electric heating module for heating the battery coolant loop in cold weather, probably not more than 2kW for the battery coolant heating element. That heating module could theoretically be powered by a level 2 EVSE but the Volt will also heat the battery coolant as needed while driving so there would be no power from the EVSE while on the road.

If the ICE is running, in round numbers, 30% of the energy from burning fuel is used to propel the Volt and recharge the battery, up to 30% is used to heat the passenger cabin, the rest goes past the catalytic converter and out the tail pipe. The heat from the ICE is never used to heat the Volt's traction battery. The battery cooling/heating is on a separate loop from the engine coolant loop and cabin heat exchanger loops.
Your analysis makes sense. I imagine in the owners manual they wanted to keep it simple.

The effect is the same anyway if I understand it correctly. While the traction battery powers the precondition cycle, the plug simultaneously puts a charge into the battery pack. The higher the charging rate the more closely it can keep up with the rate of depletion.


Your knowledge about the Volt is amazing by the way! Thanks for sharing.

Sent from my SM-G930V using Tapatalk
 

·
Registered
Joined
·
21 Posts
there must be something wrong with my ac's efficiency because it seems like it's a lot less efficient than what everyone else is claiming theirs to be. mine will easily consume more than 10+ miles. I've seen my efficiency drop from 50+ mies without ac to around 28 miles with the ac on. the power meter reads around 2-5kw when the ac is on. is there something wrong with mine? it's a 2013 model.
IMG_0315.jpg
 
1 - 20 of 32 Posts
Top