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Discussion Starter #1 (Edited)
IMG_20170108_141933.jpg

I was just curious if this would look like the expected gas usage in the winter months due to ERDTT coming on. On short trips lately, ERDTT has been engaging and using a fair bit of fuel for very short trips.

Don't mind the dust in the photo!
 

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Here in Wisconsin I have seen as low as 9mpg on short trips.

When it gets cold I put in a Somms resistor in place of the ambient temp sensor
 

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Discussion Starter #3
Here in Wisconsin I have seen as low as 9mpg on short trips.

When it gets cold I put in a Somms resistor in place of the ambient temp sensor
Thanks. Well, this is probably normal then.

I was actually reading about doing that. Any good tutorials for doing so on Generation 2 Volts?
 

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Yes that appears to be fairly normal.

One thing you can do is set the climate to Max and set the fan speed low. The electric heater will boost things and get the coolant temperature up faster and it will help maintain coolant temperature to reduce ERDTT. Note climate temperature set point needs to be set well above cabin temperature.

On my commute ERDTT runs only once in the morning (Even at -15C). Uses only 0.38L of gas and stays off the rest of the 22km trip. My EV efficiency drops but I use less gas. And still stay reasonably warm.

 

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If you haven't already, change your setting under the Config menu for "Engine Assisted Heating" to "Deferred" ... Instead of ERDTT coming on at 35F, it will come on only under 15F.

That can save you some gas, assuming you're taking trips that don't typically exceed the range of the battery anyway.
 

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One thing some Volt drivers do not consider with ERDTT is that even on short trips, you use less battery charge due to electricity generated during ERDTT. After you get home and plug in, it will take less home current to fill the battery back up.
 

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It has been my experience that if you know you are going to travel further than the battery can carry you, or if you know that ERDTT is going to be running, it is considerably more efficient to just start out in HOLD mode for the first 5-9 miles and have the REX/ICE run steadily and get nice and warm and use that to heat soak the cabin as well because once the engine metal/fluids/oil, et-al is warmed up the whole thing runs a lot better.

See this thread (especially post #8) for details.
 

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One thing some Volt drivers do not consider with ERDTT is that even on short trips, you use less battery charge due to electricity generated during ERDTT. After you get home and plug in, it will take less home current to fill the battery back up.
A small amount maybe. Using the generator to make electricity is not very efficient. That's why people with short commutes complain bitterly about ERDTT.

For me, my commute is over the AER even in summer. I use hold so the engine is not running for a short time in winter. In summer (10 months here in Texas), I let the genset fire at the end of the commute.

I used to play with hold all the time within the high-speed portion of my commute, but, the car is smarter than me about efficiency. I mostly just let her do her thing now.
 

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Yes that appears to be fairly normal.

One thing you can do is set the climate to Max and set the fan speed low. The electric heater will boost things and get the coolant temperature up faster and it will help maintain coolant temperature to reduce ERDTT. Note climate temperature set point needs to be set well above cabin temperature.

On my commute ERDTT runs only once in the morning (Even at -15C). Uses only 0.38L of gas and stays off the rest of the 22km trip. My EV efficiency drops but I use less gas. And still stay reasonably warm.

Can anyone verify this?
 

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Can anyone verify this?
Is my picture clearly showing my climate settings and outside temperature not verification enough? Do you think I used Photoshop on it?

It's easy enough to verify. Go ahead and try it yourself. It works somewhat on a Gen I Volt as well. The idea came from a question posed to a GM engineer a few years ago on techniques to limit ERDTT. It works even better on the Gen II Volt.
 

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I verified this today. If the engine comes on due to ERDTT, turning the fan speed down while on Max will make it come on a lot less. Thanks for this tip. However I decided to just keep the engine off altogether by setting Engine Assist Heat to Deferred. My local temperature has not gone below 15 °F when driving yet, so this setting keeps me in battery only mode.
 
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