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Discussion Starter · #1 ·
I bought the Volt in late June. Almost all my driving is on battery, so in Sept the car ran an EMM cycle. Now that it's colder here, the last couple weeks the car has run ERDTT on almost every time I use it. But today as I left home it again ran an EMM cycle.

Apparently the time the ICE runs in ERDTT does not register on the timer for EMM?

I suppose this is because the short ERDTT cycles are only sufficient to warm the coolant for cabin & battery heat, but not enough to thoroughly warm the engine oil to eliminate condensation, etc.

Also - it also appears that the engine is not doing much, if any, recharging during the EMM because my range guesstimate fell just like it normally does without the ICE running.
 

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Correct.

ERDTT does not get the system to proper operating temperature, so EMM is still necessary.

And also correct, EMM does not generate electricity.
The net result is electricity used.
The electric motor keeps the engine spinning (fuel use drops to basically zero) after the initial warmup period and carries it through to completion.
 

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As a fellow Minnesotan, welcome to the Volt forum I was initially annoyed when the ICE came on just to warm the cabin when outside temp was in the 20s, especially if I was only going a short distance. You can adjust settings so ERDTT will come on only when outside temp is below 14 deg.F if you want. There is also a device you can purchase to "trick" the temp sensor so ERDTT won't come on at all. I'm gong to try it this winter for really short trips when the ICE wouldn't heat the cabin anyway.
 

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Discussion Starter · #4 ·
As a fellow Minnesotan, welcome to the Volt forum I was initially annoyed when the ICE came on just to warm the cabin when outside temp was in the 20s, especially if I was only going a short distance. You can adjust settings so ERDTT will come on only when outside temp is below 14 deg.F if you want. There is also a device you can purchase to "trick" the temp sensor so ERDTT won't come on at all. I'm gong to try it this winter for really short trips when the ICE wouldn't heat the cabin anyway.
Jim: It's a toss-up between cabin heat via gas or electric. Spend a little for gas, or spend it for recharging. Electric probably is the cheaper way but at the cost of range. This is the first winter with a Volt, so I'll see what works out best for the way I use the car. I haven't run out of electric range for 3 months, so at least the ERDTT will use up the gas before it gets stale!

My biggest winter concern is ground clearance - this thing sits almost as low as a snowplow. Nice thing about retirement: I don't have to be somewhere when the snow is deep, I just wait until the roads are plowed!
 

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Jim: It's a toss-up between cabin heat via gas or electric. Spend a little for gas, or spend it for recharging. Electric probably is the cheaper way but at the cost of range.
I get BACK about 5-7 miles of range when the weather's consistently in ERDTT temperature ranges. And use up about .13 gallons draining a whole battery. So it really is about even, WHEN at about the crossing point. It seems cheaper to burn the gas if the range would otherwise keep going down as the temp drops.
 

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Jim: It's a toss-up between cabin heat via gas or electric. Spend a little for gas, or spend it for recharging. Electric probably is the cheaper way but at the cost of range. This is the first winter with a Volt, so I'll see what works out best for the way I use the car. I haven't run out of electric range for 3 months, so at least the ERDTT will use up the gas before it gets stale!

My biggest winter concern is ground clearance - this thing sits almost as low as a snowplow. Nice thing about retirement: I don't have to be somewhere when the snow is deep, I just wait until the roads are plowed!
It's not even about cost, but about usefulness.
On short trips (like my commute, and sounds like they're common for Jim as well) on very cold days, the engine doesn't warm up enough to actually provide heat to the cabin. The entire time you'd be heating with electricity anyway AND burning gas at a higher than normal rate due to cold start. All for next to nothing (you'll get a tiny bit of electricity generated in exchange for a larger than typical amount of gas).
If you're driving <10 mins and it's a fair amount below zero, I'd wager you're actually spending more by wasting that gas instead of just using electricity.

ERDTT shines when you're going to blow past the battery range anyway. When you're only using 10% of it, not so much.
 

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I agree. Frankly, if its not brutally cold and the trip is short, I just use the seat heaters and wear light gloves and don't bother heating the cabin at all. ERDTT is fine when you're going to need the ICE to run for part of the trip anyway.
 

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ERDTT shines when you're going to blow past the battery range anyway. When you're only using 10% of it, not so much.
Um, not really. Engine heat is free, electric heat decimates range. (Resistive heating wastes the high-entropy nature of stored electricity, but I digress). The best winter strategy when you're sure to exceed battery range is to first run the engine on "hold" and "fan only" which will heat the cabin without burning electricity. When you do switch to electric, there will be quite a bit of retained heat to continue warming the cabin for 15-25 minutes for "free". Then switch to "hold", rinse and repeat. Doing this in ~ 0 C weather, I can milk a ~30 mile battery range contribution to the total trip which is impossible if electric heating is used.
 

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I have an 11 mile trip to work and after 5 winters with Volt's I find if it's cold enough to trigger a ERDTT run during my trip I do the following:

1. Pre-heat cabin before leaving on shore power

2. Switch to HOLD mode almost immediately after departing and switch HVAC to FAN and HEAT to HI

3. Once the cabin is nice and warm and coolant temp is as high as it can be I switch back to NORMAL mode and set the HVAC to Eco and the temp between 74 and 78

Why, because my Volt's seem to SLOWLY read the OAT drop and seems to hang at whatever ERDTT set point I choose. On my 2017 ERDTT doesn't trigger until the digital readout reaches 33 degrees and it takes several minutes to go from 35 to 33, all the while I'd be using the battery to heat. My 2017 seems to need windshield defogging more often than my Gen I's.

Can't wait to retire and not care anymore.
 
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