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ERDTT add-on module option

  • Dont need ERDTT modification stock setting are perfect for my needs

    Votes: 26 29.5%
  • Want to control it from inside the car

    Votes: 37 42.0%
  • Want a option for enabling ERDTT at any temperature on demand

    Votes: 20 22.7%
  • Want only enable or disable ERDTT option from inside hood hidden switch

    Votes: 3 3.4%
  • Permanent resistor disabling modification

    Votes: 2 2.3%
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Discussion Starter #1
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Alot of people ask me for a controllable from inside the car ERDTT disabling add-on module or a tri-mode option for enabling ERDTT at any temperature for long trip what do you think of it ?
 

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I'd like to be able to disable it on weekends where I would like to use full electric around town. My commute, on the other hand, is a different story. I'd love to have full functionality of ERDTT.

First of all it's a 100 mile round trip commute, add in colder Western Illinois winters and I'm bound to use some gas. But I try to use it to my advantage. I usually start in Hold mode to warm up the interior. Placing it back into Normal mode, it doesn't take too long to notice the difference in heat source. Lately I've been bouncing back and forth between the two modes to maintain a comfortable cabin temperature by viewing the amount of energy being used for the heat. The commute takes me an hour and it's my feet and knees that get cold when I get too conservative. It doesn't help that I'm wearing running style shoes but I've learned to focus most of the heat to the floor and have always used the heated seats.

Bouncing back and forth between modes manually as I am depresses that button quite a few times in a day. I hate any wear and tear that may be causing.
 

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I sometimes use Hold mode when the temps are in the 40s, when what I really want is ERDTT just to keep me warm. My round trip commute is right at the limit for full EV in the winter unless I play games with the heat. I would enjoy being able to activate it manually from inside the car without a restart.
 

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What Henry_Fl said.

I would like to set it to 45F since I use gas most days in winter. Hold does a similar thing, so, it's not a huge concern. Besides, DFW average temp in Jan is north of 50F.
 

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I wonder how much gas would be consumed if one could just have the ICE idle for added charging and heat management purposes? Essentially a low generator setting with the use of it's heat. I think that would be ideal for my winter commute.
That's pretty close to what you're getting with ERDTT in a 2013 or later Volt. While it stays at a fixed 1400 RPM I've noticed that it does couple to the wheels somewhat once you're above 36 mph or so.
There's a lot written about how inefficient ERDTT is compared to Hold mode but for my 38 mile roundtrip commute it works very well. I find that Hold mode is noisy overkill, even in small doses.

That being said, when temperatures are below freezing I'm finding that I'm splitting settings: I avoid ERDTT in the mornings with the Very Cold setting after pre-conditioning in my garage. With no charging at work my battery's cold for the first part of the return trip and it's somewhat uphill so I opt for Cold ERDTT for some or all of the drive home. With this strategy I manage about a 0.10 gallon burn on a typical day with the comfort of heat both directions.
Obviously this requires some gymnastics with Config menus and an on-off cycle at a traffic light sometimes on the way home. A cabin-controlled override might make this easier.

Would the car have to be power cycled to adapt to a change in setting?
 

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Idk if I'd make the jump to replace the OAT sensor, but I'd definitely want an in-cabin switch like this if I were to do it.

For one thing, I like having an accurate temperature displayed 99.9% of the time.

The option to engage ERDTT manually even when the outdoor air temperature is above the set threshold would be a nice-to-have. I could see myself potentially using it on occasion, but I'm not certain of that.
 

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I'd like to control it from from inside the car. For short trips, I'd like to disable ERDTT so it doesn't fire up the engine as I exit the garage, amd about to park, or am pulling into the garage. On a long trip, I'd like to disable it as I exit the garage, and as I am approaching my destination.

It bugs me that my warm, garage-sheltered car will start the engine as I pull out of the garage, or that it will start-up as I enter the garage, or just as I am parking. I'm not interested in getting rid of ERDTT altogether, just making it's use smarter, and conveniently controlling it from inside the car.

I understand that the sensor wires go to a box under the driver's seat. Theoretically, ERDTT could be controlled from there rather than the sensor in the bumper.
 

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If it can be forced on at any time, could that be a "HOLD" mode for 2011 and 2012?
 

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I too would like to disable ERDTT for my daily 4 mile commute and use it when I take longer trips. I drove the car as I typically would for my commute last winter and ended up with milky oil and rusted cams (car was brand new). This year I take it out on hold for 20 minutes or so every other week....fingers crossed. I'll probably do something about it post warrantee
 

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The current ERDTT resistor switch mod certainly works, but requires you to either have it on all the time, or to open the hood, engage the switch, close the hood, then turn on the car. Reverse the process when you want to change the switch. This is inconvenient to the point of being impractical for people who have mixed driving distances and want ERDTT for some, but not all trips.
 

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Discussion Starter #15
Usually i turn it ON went i install my winter tyres en turn it off went installing summer tyres. i use hold or montain mode for engine use, running idle for long period when very cold are very bad for ICE and catalitic converter are inefficient in ERDTT mode. there no need to turn of the car to engage or disengage ERDTT switch but reading can be very long to be done sometimes more than 10 minute.
 

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After successfully 'correcting' my ERDTT outstanding issue on my Volt 2yrs ago now, chose to just leave the modified OAT sensor in all year round since the non-linear resistance temp offset is much smaller during the hot summer months than during the winter. Also, installing the above w/Velcro wireless outdoor/indoor backlit Acurite Thermometer that records hi/lo temps has proved useful!;)
 

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If it can be forced on at any time, could that be a "HOLD" mode for 2011 and 2012?
Sort of. Except the engine will turn off once the coolant reaches a certain temperature. So you would still be drawing down the battery, just not as quickly.
 

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Sort of. Except the engine will turn off once the coolant reaches a certain temperature. So you would still be drawing down the battery, just not as quickly.
Maybe it was just me but it certainly seemed that ERDTT ran a lot more aggressively for the short time I had the OAT sensor removed (creates an open which is read as -40F/C on the toushscreen) a couple years back. I didn't leave the sensor out of the circuit long enough to verify the ICE cycling off/on in this mode though.:(
 

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Thanks to Somms, I've been running the resistor mod all winter. What has been most remarkable is how little benefit ERDTT had for range. I expected my electric range to drop dramatically due to using the electric heater exclusively, but it didn't. I was previously using a third gallon of gas every day on my 20 mile commute, and had about 30 miles of "electric" range. After the mod, that seems to be about 28 miles under similar conditions. The heat is also quite adequate. The only downsides are that the temperature display is wrong and the automatic temperature control is a little off. For example, the heated seats don't turn on automatically until the real temperature is down around 0f. All in all though, I'm very happy with the mod.
 

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Thanks to Somms from me too. I have been running a parallel resistor mod this winter. My observation is on the defroster. I have not had any problem with the defroster not clearing fog quickly from my windshield in temperatures below 14F. The government test must be pretty brutal if ERDTT was required to pass it. I'm curious if any modders out there have noticed a defrosting issue. As for heat, I stay toasty warm. No issue there either.
 
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