[somms]

So what about putting a resistor in parallel or series (it's early) with the original sensor to offset ambient temp up 10° or 20°?
This offset would be easy to figure if you want to know what the real outside air temp is from the display.
10° would work for me. Canucks would need more.

If you wanted to keep the original ambient air temp sensor in circuit, the addition of a fixed resistor in parallel would be the only option since put in series the fixed resistor would then offset the center console temp reading in a more negative direction (more resistance=colder readback value) defeating the purpose...

 

[Norton]

Of course parallel !!

Now, what would that value be for a 10° positive offset? Or a 20° offset?
But please,,, let it not be that cold this winter that I need a 20° offset to keep that smelly gas burner from starting up!!!! Please !!

 

[somms]

Of course parallel !!

Now, what would that value be for a 10° positive offset? Or a 20° offset?
But please,,, let it not be that cold this winter that I need a 20° offset to keep that smelly gas burner from starting up!!!! Please !!

Unfortunately, you couldn't just add 1 fixed resistor in parallel to the ambient air temp sensor and have an accurate but offset new outside temp reading: http://diyaudioprojects.com/Technical/Electronics/parallel-resistor-calculator.htm

If the Ambient Air Temperature Sensor Resistance chart were correct (which it isn't), lets say you wanted to have the ambient air sensor(R1) at 14F=27Kohm resistance instead read 34F (offset of +20F) by adding a fixed resistor in parallel(R2)=39Kohm. Using the above linked calculator total resistance is now 16Kohm or offset by +20F.

Now, lets go to the other end of the scale and say the outside temp is now 104F and the Ambient Air Temperature Sensor (R1) is now only reading 2.6Kohm. Throwing the R1=2.6Kohm value into the calculator with the same fixed resistor in parallel(R2)=39Kohm shows the new total resistance value of 2.4Kohm which is now maybe only offset by+5F. It would no longer be accurate linear offset you were looking at...

 

[Natemeins]

But at that point would it really matter? I mean we're talking about avoiding ERDTT in cold climes. The added resistor in parallel would help offset the temp during the cold times so as to avoid the ERDTT, But once the temps move back up for summer we're no longer concerned about ERDTT so other than for the sake of having an easily calculated offset to an inaccurate temp display it'd work just fine. It's true, due to being a parallel resistor the change would not be linear (thanks Ohm's Law ha!), but if we're not concerned with the accuracy of the displayed temp we've solved the problem. Quite frankly if one is looking for a more permanent fix I like the idea of a simple switch which would add or remove the permanently installed resistor during the cold climes. We wouldn't need access to it often, so a simple switch rigged somewhere in the engine compartment that's easily accessible would be a simple, effective, and clean setup.

 

[Steverino]

Lots of details on resistor values and results over here as well as differences between 2011/2012 and 2013/2014 requirements: http://roulezelectrique.com/recalibration-du-senseur-de-mesure-de-temperature-exterieure-de-la-volt/

Use Chrome for auto translation.

 

[frankydude]

A class lawsuit against GM just got lauched in Quebec. The subject of the lawsuit is the Volt.
The basis of the lawsuit is because GM did a false representation, when it claimed you can get 40 milles of all electric range in winter and with your battery full.
The claim is false because of the ERDTT. Especially in Quebec's very cold winter weather.
link: http://cnw.ca/YzADo

They ask for a refund of the gas expenses ($400 per year) that are inavoidable in cold weather, plus moral damages.

I really think that GM should rethink/redesign the ERDTT thing all over.

Francois
B2653

 

[Norton]

The lawsuit sounds silly, especially when ERDDT is spelled out in the Owner's Manual.

However, GM could shutup us cry babies that hate ERDDT with an an Optional SW load to allow disabling it, or adjusting the set point lower than 15° F.

Will it ever happen? No way..... They're way too busy to make existing owners happy with a new optional SW load.

 

[ari_c]

so a simple switch rigged somewhere in the engine compartment that's easily accessible would be a simple, effective, and clean setup.

That's exactly what I have. Works perfectly. I've brought my Volt in twice and they never noticed the switch I had hidden in the engine compartment. I really would not like to be going in and swapping it out twice a year. It was painful enough to get to the sensor the first time. Hopefully, I will never need to swap out the modified temperature sensor I have installed.

 

[Steverino]

That's exactly what I have. Works perfectly. I've brought my Volt in twice and they never noticed the switch I had hidden in the engine compartment.

Did you buy the hacked ambient air sensor with switch from Joel on ebay? By the way, hacking the sensor with a resistor to prevent or limit ERDTT was the idea of Frank J Weber, the leader of the team that transformed the Chevrolet Volt from a concept to a production vehicle. Weber was the global chief engineer for electric vehicles at General Motors during his time in the U.S.

This is a link to his post: http://roulezelectrique.com/recalibration-du-senseur-de-mesure-de-temperature-exterieure-de-la-volt/

Use Chrome for auto translation.

 

[ari_c]

Did you buy the hacked ambient air sensor with switch from Joel on ebay? By the way, hacking the sensor with a resistor to prevent or limit ERDTT was the idea of Frank J Weber, the leader of the team that transformed the Chevrolet Volt from a concept to a production vehicle. Weber was the global chief engineer for electric vehicles at General Motors during his time in the U.S.

This is a link to his post: http://roulezelectrique.com/recalibr...re-de-la-volt/

Use Chrome for auto translation.

Yes I did buy the switch from Joe. He's a member here as well. I have that French site bookmarked and have read through it a number of times.

Nice thing about having the resister in parallel is it just offsets the temperature, so after a while I was able to guess pretty closely what the actual temperature was. I wanted to find an actual chart of the GM OAT sensor, but never found one with actual values. If anyone has it, I would love to create a complete table with original and offset values for next winter.

Here's what the sensor I have installed looks like. Recently he went with a different switch and raised the price a bit as well.

 

[Steverino]

Yes I did buy the switch from Joe. He's a member here as well. I have that French site bookmarked and have read through it a number of times.

Nice thing about having the resister in parallel is it just offsets the temperature, so after a while I was able to guess pretty closely what the actual temperature was. I wanted to find an actual chart of the GM OAT sensor, but never found one with actual values. If anyone has it, I would love to create a complete table with original and offset values for next winter.

Is yours using the original or the newer 47k Ohm version, ari-c? At what (actual) temp did ERDTT turn on for you?
For those interested, Joel has a new improved switch here: http://www.ebay.ca/itm/Sonde-tempera.../281246258931?

 

[ari_c]

Is yours using the original or the newer 47k Ohm version, ari-c? At what (actual) temp did ERDTT turn on for you?
For those interested, Joel has a new improved switch here: http://www.ebay.ca/itm/Sonde-tempera.../281246258931?

I assume I have the original 47k Ohm version. Mine was made in Nov 2013. I believe my ERDTT ran at 26F. I only had that happen twice and the last time was Jan 2012, so whether it was 25F or 26F I do not remember!

 

[doudis2]

A class lawsuit against GM just got lauched in Quebec. The subject of the lawsuit is the Volt.
The basis of the lawsuit is because GM did a false representation, when it claimed you can get 40 milles of all electric range in winter and with your battery full.
The claim is false because of the ERDTT. Especially in Quebec's very cold winter weather.
link: http://cnw.ca/YzADo

They ask for a refund of the gas expenses ($400 per year) that are inavoidable in cold weather, plus moral damages.

I really think that GM should rethink/redesign the ERDTT thing all over.

Francois
B2653

Just to clarify, the article when translated by Chrome, said 40-80 km, not 40 miles.

As far as I know GM targeted 40 miles AER, but never claimed the car could do that. They claimed an average of 35 mi in 2011 -2012, then it was raised to 38 mi for 2013 - 2014.

They will lose because this is an average over the entire year and there is TONS of data showing that the car does EXCEED these values for the vast majority of owners.

By the way ALL cars lose efficiency (MPG) in Quebec in the winter.

 

[Norton]

Gents,
I got to remind you that it is late spring, closing in on summer !!!

I'll talk to you about this later, hopefully next January.

Have a good Summer !!

 

[saghost]

Just to clarify, the article when translated by Chrome, said 40-80 km, not 40 miles.

As far as I know GM targeted 40 miles AER, but never claimed the car could do that. They claimed an average of 35 mi in 2011 -2012, then it was raised to 38 mi for 2013 - 2014.

They will lose because this is an average over the entire year and there is TONS of data showing that the car does EXCEED these values for the vast majority of owners.

By the way ALL cars lose efficiency (MPG) in Quebec in the winter.

Those 35 and 38 numbers for the two halves of the first generation aren't averages - they are EPA test results (the only number GM is allowed to advertise - and not something you can sue a manufacturer for not meeting unless you can demonstrate flawed/falsified testing by the manufacturer.)

Because of the way the EPA tests, they do fall somewhere between typical summer and winter performance; if I had to guess a unweighted annual average, I'd put it on the high side of the EPA number (but it'd be a guess, and YMMV of course.)

GM did say 40 miles - back in the prototype days before they had real Volts. Since they started production, the official line has been "25-50 miles" - which is 40-80 km. (This number didn't change with the increased battery for whatever reason - possibly because it is nice round numbers.)

 

[ari_c]

Gents,
I got to remind you that it is late spring, closing in on summer !!!

Thank goodness for the reminder, I totally forgot . No wonder I'm the only one still wearing fleece in DC.

 

[Steverino]

Gents,
I got to remind you that it is late spring, closing in on summer !!!
I'll talk to you about this later, hopefully next January.

Sure, but when is a better time to crawl around under the car and grapple with something behind the bumper, June or January?

 

[ari_c]

Sure, but when is a better time to crawl around under the car and grapple with something behind the bumper, June or January?

Well, I did it in December when it was around 20F in my garage and that was not much fun. I wanted to do it in November, but the first sensor did not work forcing me to repeat the process. Nothing like laying on the cold garage floor trying to pop that sensor back into that hole. Probably the most difficult part of the whole procedure.

I could have waited for a warmer day, but driving with my ICE turning on was out of the question for me!

 

[Dyohn]

I can offer a sure-fire absolutely certain method for minimizing the amount of time the engine runs due to winter, without trying to force the car to operate any way other than the way it was designed. Move to Arizona. It really works.

 

[ari_c]

I can offer a sure-fire absolutely certain method for minimizing the amount of time the engine runs due to winter, without trying to force the car to operate any way other than the way it was designed. Move to Arizona. It really works.

But then Winter is no longer your problem. Potentially traded for a much bigger problem......Summer.