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Discussion Starter #1 (Edited)
I have searched but couldn’t find a answer that suited me.

I understand the option I understand it’s settings. But I noticed tonight the temperature finally dipped below 32° and I have it set to normal, the engine started, but the fuel range did not illuminate it was powering the vehicle and get the engine up to operating temperature about 147° use that to warm the car up. But then when the coolant with dip down to about 118 or 116° the engine would start back up again. I had my air-conditioning set on 78° and eco. It seems to charge the battery a little. I guess the question is how much gas is being used, and how much power is being directed into the battery, also is is the same when it is deferred?



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You know that you didn't actually ask any questions in there right?
 

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"Deferred" will lower the trigger temp to 15F instead of the default 32F.
The "Info" page of the Power Display will show how much gas is used.
 

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You know that you didn't actually ask any questions in there right?

The OP: "I guess the question is how much gas is being used, and how much power is being directed into the battery, also is is the same when it is deferred?"

Very little gas is being used when the car runs the ICE due to ERDTT. Under ERDTT, the engine is run only until the engine coolant gets heated to 160°F. Then the engine shuts off. It will kick on again when the coolant temp drops to 140°F. Rinse and repeat. So, maybe 12 ounces of gas per ERDTT event? (just a guess).

I think there is some power added back to the battery in 2016+ when the ICE runs under ERDTT. If so, not sure how much.
 

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The OP: "I guess the question is how much gas is being used, and how much power is being directed into the battery, also is is the same when it is deferred?"

Very little gas is being used when the car runs the ICE due to ERDTT. Under ERDTT, the engine is run only until the engine coolant gets heated to 160°F. Then the engine shuts off. It will kick on again when the coolant temp drops to 140°F. Rinse and repeat. So, maybe 12 ounces of gas per ERDTT event? (just a guess).

I think there is some power added back to the battery in 2016+ when the ICE runs under ERDTT. If so, not sure how much.
I've been observing that ERDTT shuts off at 147 degrees and kicks back on around 120 degrees.

A tip that seems to help avoid the engine coming back on after the initial ERDTT session was pointed out by someone on the Facebook page and it seems to be working- running the electric heat on Max with the fan on low seems to keep the coolant warm enough so the engine doesn't kick on again. Here is what I've tried:

I precondidtion the car while plugged into my L2
When I get in the car, I press the Max button, set the temp to 72 and drive
I've noticed that once the initial ERDTT session is done, keeping it on Max, low fan and 72 keeps the coolant between 125 and about 136-138 degrees.

I've only tried this so far on a 12 mile trip. ERDTT runs for the first 1.5 miles on this route. When I did it without doing the above, the engine came on every 5 minutes or so (maybe evven less...?). Doing the above, it did not come on at all after the initial ERDTT session.

...and it was 7 degrees Fahrenheit outside.

I don't know if this is more economical than ERDTT, but it does seem to help avoid the engine coming back on.

Putting it on Eco does not seem to do the trick. Not sure why.

Interested in other people's thoughts here.
 

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Well I got to experience ERDTT today, 11F will do that in Georgia. Was waiting for it, got about six miles into my drive before the car decided to run the gasoline motor. I did eventually set it to HOLD mode for part of my commute that is all four lane as I have been using a ten mile segment to burn off the dealer tank.

still so odd seeing the vapor/exhaust come from under the car, not sure I care for the exhaust opening's location
 

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I've been observing that ERDTT shuts off at 147 degrees and kicks back on around 120 degrees.

A tip that seems to help avoid the engine coming back on after the initial ERDTT session was pointed out by someone on the Facebook page and it seems to be working- running the electric heat on Max with the fan on low seems to keep the coolant warm enough so the engine doesn't kick on again. Here is what I've tried:

I precondidtion the car while plugged into my L2
When I get in the car, I press the Max button, set the temp to 72 and drive
I've noticed that once the initial ERDTT session is done, keeping it on Max, low fan and 72 keeps the coolant between 125 and about 136-138 degrees.

I've only tried this so far on a 12 mile trip. ERDTT runs for the first 1.5 miles on this route. When I did it without doing the above, the engine came on every 5 minutes or so (maybe evven less...?). Doing the above, it did not come on at all after the initial ERDTT session.

...and it was 7 degrees Fahrenheit outside.

I don't know if this is more economical than ERDTT, but it does seem to help avoid the engine coming back on.

Putting it on Eco does not seem to do the trick. Not sure why.

Interested in other people's thoughts here.
Did you get enough heat in the car this way to keep warm?
 

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Discussion Starter #9
Yes. I looked real quick when the car shut down and the info screen said I used .07 gallons for 2.4 miles, (if I remember right) but I will confirm it today.

I also noticed that while it was plugged it at work and fully charged there were some peaks.



The large peak at the end was preconditioning.


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Yes. I looked real quick when the car shut down and the info screen said I used .07 gallons for 2.4 miles,
So, about 9 ounces of gasoline. or about $0.19/ERDTT. In my short trips to the store I can see 4 to 6 ERDTT's equal to the cost of 50%-90% of my battery charge. Given that I have plenty of battery to arrive home on these trips, there is no need to waste the money on gas for heat.
 

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I can do it using the torque application and the PID download I got. I can dig it up if you can't find it. However, you have to be in range of the bluetooth or wifi OBD2 dongle. This dongle resides in the car as you get this information straight out of the OBD2 port.
 

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My Torque setup has a screen with a couple of ACTIVE/INACTIVE indicators for the HVAC pump, the battery heater, and the REX.
I'm pretty sure that those spikes are when the battery heater kicks in to bump the temps up again.

OHM-RIDE seems to like keeping the battery between 45-55F when it's super cold like this.
 

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Did you get enough heat in the car this way to keep warm?
Yes. Absolutely. Still had my coat on, but it wasn't bad at all.

Today, it was about 10 degrees when I left for my 30 mile commute. Doing the above the first 1.5 miles was on gas the rest was on electric.

Running on max the whole way for sure ate into the electric range, but it was still far better. Last time I did it with ERDTT running I was split 50-50 between gas and electric.
 

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I think there is some power added back to the battery in 2016+ when the ICE runs under ERDTT. If so, not sure how much.
Ah, I think this may answer the question I just came to the forum to ask. Yesterday it was 10 degrees F or so, and I had to take a 90 minute drive, averaging 30mph or so on pretty flat roads the whole time. ERDTT ran when I started the car, and I kept it in Normal as usual, and then didn't pay any attention until about an hour later the car bongs to let me know the gas is low. I look down, and to my surprise see that the battery is still totally full despite running on Normal the whole time. I assume ERDTT had been coming on intermittently the whole time I was driving, and in addition to powering the heater, provided enough power to the car and/or battery that the battery never actually ran down -- is that right?

As a possibly separate thing, the car wouldn't actually remote-start that morning (while plugged in, 240v), I don't know why -- does it refuse if it needs ERDTT or it's just too damn cold?
 

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Ah, I think this may answer the question I just came to the forum to ask. Yesterday it was 10 degrees F or so, and I had to take a 90 minute drive, averaging 30mph or so on pretty flat roads the whole time. ERDTT ran when I started the car, and I kept it in Normal as usual, and then didn't pay any attention until about an hour later the car bongs to let me know the gas is low. I look down, and to my surprise see that the battery is still totally full despite running on Normal the whole time. I assume ERDTT had been coming on intermittently the whole time I was driving, and in addition to powering the heater, provided enough power to the car and/or battery that the battery never actually ran down -- is that right?

As a possibly separate thing, the car wouldn't actually remote-start that morning (while plugged in, 240v), I don't know why -- does it refuse if it needs ERDTT or it's just too damn cold?
If the Volt is running low on fuel for the ICE then the remote start feature may be disabled. How much fuel do you normally keep the Volt's fuel tank?
 

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Let me offer an alternative idea I have in my head based on observations I have made.

First, after the engine warms up from ERDTT, when I set the HVAC to relatively low thermal demand (low fan speed), I notice my battery getting hit with typical ~7 kW electric heater load. The engine coolant will be pretty steady during this period and remain elevated. At the same temperature and same speed, I will then turn the fan up and notice the electric power hit drops off and the engine coolant temp also drops off much quicker.

When I make my trip above the ERDTT threshold and I use the electric heater, the block coolant temp goes up MAYBE 2 or 4 degrees from its starting point over the course of several miles. During this time, the air coming out of the HVAC goes from cold to warm in a minute or so.

I don't think the electric system is heating the block during the time of pure electric heat. I think it's heating a subset of the coolant loop that's isolated from the block via a valve. The heat from the electric element is only allowed to flow to the heater core in the passenger compartment. This would explain all of the observations I have made.

As for some of the experiences in this thread, I think at low thermal demand (warm air at low fan speeds), it simply meets the low demand with electrical heater because it doesn't need to do anything else. When someone cranks the heat, it then needs to dip into the already-warm engine's thermal well to get sufficient thermal energy into the passenger compartment heater core.

This is of course only conjecture. The way I would validate it is to get a set of the factory service manuals and look at the design of the thermal control system. It would need to have the electric heater and a small electric coolant pump on the heater core side of a valve that isolates the block.
 

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Each single-digit day, I burn about a pint of gasoline, a half-liter. I suppose that equals two gallons of fuel in a cold winter month. When I commuted with a Prius, I was burning two gallons per week.
 
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