Climate Control Solution - Gain Control of your Heater!

[DaveEV]

I've had my A/C set to 78 degrees in the summer (it was about 100F outside at the time, and I did not want to waste energy cooling too far down) and when the interior of the car dropped below 78 the heater came on!!! very frustrating. I did not feel the heat immediately because it took a few minutes at 5000 watts just to heat the water in the system. By the time I noticed I'd burned a lot of range heating my car in the summer.

Yeah, any time temperatures get close to your set point and if there's any humidity the car will run a bit of heat and AC. You'll know this is happening when if you drop the temperature a degree and see HVAC power use drop from 500W or so to a couple hundred watts. Counter intuitive but sometimes more AC = less power consumption!

Phil's mod will keep power consumption low in these situations, though 500W of extra energy draw isn't usually a big deal unless you're stretching range limits.

 

[Ingineer]

Yeah, there is a number of things about this climate control implementation that just are unbelievable! It's as is the designers didn't even realize they were making something for an electric vehicle and assumed that heat was free as in other ICE cars.

The upgrade returns full control to you, so you can keep the heat off unless YOU want it on!

-Phil

 

[Ingineer]

I will try to bring a few units to this Saturday's BayLEAFs meeting. This will save from having to make a deposit, and as a bonus I can assist with the installation so you drive home with the upgrade fully operational. (for those in the Bay Area)

Either bring cash (easier) or I can invoice you at the meeting.

-Phil

 

[dgpcolorado]

The modified CC unit was waiting for me when I got home an hour and a half ago, installed it using the video in Ingineer's Post 133. No problems and it works fine. Nice to have fan, vents, defog with no unwanted heater use, at last! Thanks Phil!


Too late to ship the old unit back today so I'll have to wait until Monday.

 

[rawhog]

When did you order? I live 45 miles away from them. Paid Wednesday. So far Nada.

 

[Ingineer]

Hi Rawhog,

Sorry for the trouble, but when you ordered on Wednesday, there were 8 other orders in front of you, but now that's down to only 1. Since this upgrade service depends on us sending you an already upgraded unit, we depend on our previous customers returning the original units so we can upgrade them and send them on to the next customers waiting. To be fair to everyone, we fulfill orders in the order that we receive them. We sent a lot out this week, so we should have plenty coming back in next week, I suspect your order will ship on Monday.

If this is not acceptable, we will be happy to refund your order.

-Phil

 

[Yanquetino]

This morning I awoke to find that the weather was unseasonably cool and rainy. I decided to take advantage and try to reproduce the Climate Control problem with my Leaf. So this afternoon, I rolled down all the windows and drove around my subdivision for several miles so that the temperature on the interior would be the same as on the exterior. I then recorded this 4-minute MPEG (QuickTime) video of the experiment.

I am evidently doing something wrong! Here is what you'll see in the video:

• As the video starts, the temperature is 44°, and the GoM predicts 78 miles of range.
• I then turn on the Climate Control, and you can see that it is in Auto mode, set a 65°, i.e., 21° higher than the ambient temperature, and that the GoM now predicts 70 miles of range.
• As expected, the spiral on the climate control graph beings to climb.
• The spiral eventually levels off at about 2.0 kW (the heater firing up?).
• I then push the defogger button.
• And turn off the A/C.
• The spiral starts to climb higher, up to about 4.0 kW.
• Finally, I lower the temperature as far as it can go to 60°, i.e., still 16° higher than the ambient temperature.
• The spiral climbs even higher to 4.5 kW.
• But then, oddly, you'll see that the spiral starts to steadily go back down... down... down....
• It flutters between 0.5 and 1.0 kW for about 15 seconds.
• It drops to a mere 0.1 kW.
• And finally... it disappears completely (the heater has turned off?).
• I double check that the thermostat is at its lowest 60° setting.
• I double check that the spiral is no longer visible. The GoM now predicts 69 miles of range, i.e., one mile less than when I turned on the Climate Control.
• I double check the ambient temperature, which is still 44°.

WEIRD!

Could the heater have raised the interior temperature more than 16° in only a minute and a half? If so, it is more efficient and effective than I thought!

The only other explanation that occurs to me is that the interior temperature was still above 60°, despite having driven for several miles with the windows down. I can honestly state that it certainly didn't feel that way!

Either that, or... there's a glitch in my Climate Control that isn't allowing me to reproduce the problem. :? I would welcome advice and feedback!

 

[rawhog]

Thanks Phil. That will be fine. I just got concerned because of the confusion regarding the release form.

 

[Ingineer]

This morning I awoke to find that the weather was unseasonably cool and rainy. I decided to take advantage and try to reproduce the Climate Control problem with my Leaf. So this afternoon, I rolled down all the windows and drove around my subdivision for several miles so that the temperature on the interior would be the same as on the exterior. I then recorded this 4-minute MPEG (QuickTime) video of the experiment.

I am evidently doing something wrong! Here is what you'll see in the video:

• As the video starts, the temperature is 44°, and the GoM predicts 78 miles of range.
• I then turn on the Climate Control, and you can see that it is in Auto mode, set a 65°, i.e., 21° higher than the ambient temperature, and that the GoM now predicts 70 miles of range.
• As expected, the spiral on the climate control graph beings to climb.
• The spiral eventually levels off at about 2.0 kW (the heater firing up?).
• I then push the defogger button.
• And turn off the A/C.
• The spiral starts to climb higher, up to about 4.0 kW.
• Finally, I lower the temperature as far as it can go to 60°, i.e., still 16° higher than the ambient temperature.
• The spiral climbs even higher to 4.5 kW.
• But then, oddly, you'll see that the spiral starts to steadily go back down... down... down....
• It flutters between 0.5 and 1.0 kW for about 15 seconds.
• It drops to a mere 0.1 kW.
• And finally... it disappears completely (the heater has turned off?).
• I double check that the thermostat is at its lowest 60° setting.
• I double check that the spiral is no longer visible. The GoM now predicts 69 miles of range, i.e., one mile less than when I turned on the Climate Control.
• I double check the ambient temperature, which is still 44°.

WEIRD!
Could the heater have raised the interior temperature more than 16° in only a minute and a half? If so, it is more efficient and effective than I thought!

The only other explanation that occurs to me is that the interior temperature was still above 60°, despite having driven for several miles with the windows down. I can honestly state that it certainly didn't feel that way!

Either that, or... there's a glitch in my Climate Control that isn't allowing me to reproduce the problem. :? I would welcome advice and feedback!

Here's your rub: The PTC heater comes on to heat the COOLANT LOOP, so once that's up to temperature, it will back off. The target temperature is set by demand, which is some sort of (seekrit) math, probably involving the delta T between set temp and inside temp. So you heated your loop some, then backed off, so the delta T was lower, so the loop, now hot, didn't need to be any hotter.

Here's my experience:

Start with a preheat to warm the car while still plugged in, but wanting a long (50+ mile) trip. Have the temp set to 60 (as low as I can), but I want to keep the CC on so there is air circulation, some amount of defog, and the coolant pump keeps running.

After some miles, the car cools off, the coolant loop cools off, and the heater then begins drawing power. Enough that your range is majorly impacted. The only option I found was to shut off the CC completely, and thus suffer with humidity on the inside of my windshield.

It didn't take me too long to figure this out, just like it has been for hundreds (probably ore like thousands) of new Leaf owners. I took things into my own hands and figured out a way to disable the heater so I could keep some air circulating against my windshield. I "sat on" this for a long time, because we had a pending meeting with Nissan's engineering team December 3rd. Mark Perry indicated he was aware of the problem and said something like "Yeah, I hate that". I assumed the first chance Nissan could fix this obvious "bug", they would. Not so! They had everyone's car under the "knife" (Consult III+) for this latest service campaign, but decided not to address this issue after all. This is when I knew I was going to offer the solution I had for myself to everyone else. I waited to see if Nissan would address it, they apparently either work slower than that, or simply don't plan to fix it.

So for $138, I'll set you up with a permanent solution that returns control of the energy hungry heater to YOU! You will definitely notice the improvement in cold-weather range!

Now I preheat, leave the heater set to 75, and when I start driving, I make sure the CC is in auto, but turn off the A/C button. This disables power to the PTC heater then I keep the air in recirc as long as I can to preserve the heat. The coolant loop stays warm for a good while and the Leaf still "thinks" it's heating, so it keeps blowing warm air. If the windows fog, just hit defrost, but quickly override it's A/C button so the heater doesn't run. Just putting the warm air there seems to do the trick for me most of the time. If needed, you could let the A/C run for a few seconds, then kill it. The PTC Heater won't draw much in that time, and you'll still get the dehumidification function from the cold evaporator.

-Phil

 

[Yanquetino]

Now I preheat, leave the heater set to 75, and when I start driving, I make sure the CC is in auto, but turn off the A/C button. This disables power to the PTC heater then I keep the air in recirc as long as I can to preserve the heat. The coolant loop stays warm for a good while and the Leaf still "thinks" it's heating, so it keeps blowing warm air. If the windows fog, just hit defrost, but quickly override it's A/C button so the heater doesn't run. Just putting the warm air there seems to do the trick for me most of the time. If needed, you could let the A/C run for a few seconds, then kill it. The PTC Heater won't draw much in that time, and you'll still get the dehumidification function from the cold evaporator.

-Phil

Okay! I think I am starting to understand the problem --and your solution. The upgrade allows drivers to turn the PTC heater on and off by simply toggling the A/C button as needed. That would be much easier and more convenient than heating the coolant loop to 75°, then repeatedly pushing the temperature "down" button to its lowest 60° setting so that the heater cycles off, and then repeatedly pushing the "up" button back up to 75° again when needed. This latter solution would almost work as well as yours, at least for cool temperatures, but is much more tedious and irritating --and less efficient. 2 button pushes, off-and-on, is much better that 30 button pushes. Am I getting closer?

 

[Herm]

Yanquetino, this is quoted from the first message on this thread

"The system now will NOT turn on the heater unless you switch the climate control into "Auto" mode, or you enable the rear defroster. Any manual modes will not permit the heater to run, regardless of temperature setting, but you can always enable the rear defroster if you wish to use the heater while still in manual."

 

[Deleted member 3147]

Yanquetino, this is quoted from the first message on this thread

"The system now will NOT turn on the heater unless you switch the climate control into "Auto" mode, or you enable the rear defroster. Any manual modes will not permit the heater to run, regardless of temperature setting, but you can always enable the rear defroster if you wish to use the heater while still in manual."

Actually, I think that statement is a mistake. Later posts by Phil state that it is controlled by the A/C button (or a few other conditions) and, in fact, I asked Phil at the EAA/BayLeaf meeting this morning in San Jose and he confirmed this.

 

[linkim]

I had Phil install the modified CC yesterday at the EAA/BayLEAF meeting, but have not tested it in because the driving conditions were great here - weather was nice in the Bay Area yesterday with sunshine and mild temps in the afternoon. However, Phil showed me how it worked after installation, and I like it.

Here is a quote from Phil's post on this thread of Fri Apr 13, 2012 9:59 am:

"The final version of the upgrade differs a little from the prototype, you will now NOT have heater operation, regardless of set temperature / car temperature, unless at least one of these is true:

1. A/C button is illuminated.
2. Rear Defroster is on.
3. Climate Control timer engages."

 

[Yanquetino]

Here is a quote from Phil's post on this thread of Fri Apr 13, 2012 9:59 am:

"The final version of the upgrade differs a little from the prototype, you will now NOT have heater operation, regardless of set temperature / car temperature, unless at least one of these is true:

1. A/C button is illuminated.
2. Rear Defroster is on.
3. Climate Control timer engages."

Yes, I saw these features. Pretty cool! Pushing the A/C button makes sense. Since it turns on the air conditioning to cool the car when needed, might as well have it engage the heat when needed as well. We'll just have to re-interpret the initials to mean "ALL conditioning."

I am curious, however, about the rationale behind also using the Rear Defroster. I would guess that, if the back window is foggy, chances are that the windshield is also, so might as well defog both...? Just not sure why one couldn't simply press the A/C for the windshield. At least that way one could melt a bit of snow on the back window without turning on the PTC heater...?

 

[dgpcolorado]

Yes, I saw these features. Pretty cool! Pushing the A/C button makes sense. Since it turns on the air conditioning to cool the car when needed, might as well have it engage the heat when needed as well. We'll just have to re-interpret the initials to mean "ALL conditioning."

I am curious, however, about the rationale behind also using the Rear Defroster. I would guess that, if the back window is foggy, chances are that the windshield is also, so might as well defog both...? Just not sure why one couldn't simply press the A/C for the windshield. At least that way one could melt a bit of snow on the back window without turning on the PTC heater...?

Phil faced the problem of no unused buttons on the control module. His original fix, as described in the first post, was to link the heater to the rear defroster. But, as described in Post 133, he realized that linking heater function to the AC button was the "most intuitive" fix, with which I strongly agree. But he left the link to the rear defroster button in place so, yes, if you run the rear defroster the cabin heater loop will be enabled if the temperature set points are within range. But one doesn't usually run the rear defroster for more than a few minutes at a time IME. Not that big of a deal.

Unless you push the range of the LEAF in cool/cold weather and/or you just care about not wasting electricity, the heater mod isn't really necessary. Just set whatever temperature you like and let the CC system do whatever it wants. But for those of us who do push the range in cold weather and don't want to waste electricity anyway, Phil's mod fixes an annoying problem. It's up to you whether you want to take advantage of it. Perhaps by next Autumn Nissan will have a software fix in place and the question will be moot.

I appreciate Phil's work in coming up with a fix for the problem. And it works fine.

 

[Yanquetino]

Phil faced the problem of no unused buttons on the control module. His original fix, as described in the first post, was to link the heater to the rear defroster. But, as described in Post 133, he realized that linking heater function to the AC button was the "most intuitive" fix, with which I strongly agree. But he left the link to the rear defroster button in place so, yes, if you run the rear defroster the cabin heater loop will be enabled if the temperature set points are within range. But one doesn't usually run the rear defroster for more than a few minutes at a time IME. Not that big of a deal.

Unless you push the range of the LEAF in cool/cold weather and/or you just care about not wasting electricity, the heater mod isn't really necessary. Just set whatever temperature you like and let the CC system do whatever it wants. But for those of us who do push the range in cold weather and don't want to waste electricity anyway, Phil's mod fixes an annoying problem. It's up to you whether you want to take advantage of it. Perhaps by next Autumn Nissan will have a software fix in place and the question will be moot.

I appreciate Phil's work in coming up with a fix for the problem. And it works fine.

It sure sounds like a convenient fix! I will most probably order this upgrade, but perhaps wait until after our summer scorchers in this desert start to cool down. I really have to hand it to Phil: he does great work, and obviously has both the necessary skill and common sense to tackle such improvements. I can honestly say that I am immensely pleased with the his upgrade to my cordset, and would recommend his services to anyone without hesitation.

 

[Ingineer]

Okay! I think I am starting to understand the problem --and your solution. The upgrade allows drivers to turn the PTC heater on and off by simply toggling the A/C button as needed. That would be much easier and more convenient than heating the coolant loop to 75°, then repeatedly pushing the temperature "down" button to its lowest 60° setting so that the heater cycles off, and then repeatedly pushing the "up" button back up to 75° again when needed. This latter solution would almost work as well as yours, at least for cool temperatures, but is much more tedious and irritating --and less efficient. 2 button pushes, off-and-on, is much better that 30 button pushes. Am I getting closer?

Close, you are forgetting that heating the coolant loop still takes power, so even with your technique, you'll still lose range.

-Phil

 

[Yanquetino]

Close, you are forgetting that heating the coolant loop still takes power, so even with your technique, you'll still lose range.

-Phil

Right! That's why I said almost work as well. Turning the thermostat all the way down would temporarily reduce the power drain to heat the coolant, but not shut it off completely —like your upgrade does, with one easy push of a button.

 

[Reddy]

I would be fine if they just included:
1) another mode that blows air on the window without hitting the feet
2) the ability to turn on the fan without CC

I think that's what Phil's mod does.

Reddy

1) Hmmm. Doesn't the defrost button do that? I'll have to experiment with it, I guess.

2) But... I can turn on the fan without CC --well, without A/C-- as long as the designated setting is lower than the actual temperature. I just have to push the A/C button off. If, however, the designated setting is higher than the actual temperature... the heater fires up, with no way to turn it off (unlike with the A/C button).

Or am I missing something here? Wouldn't be the first time!

Sorry to respond so slowly, but THANKS (!!!!) for pointing this out. It's been so cold for the last 6-8 months I've only been heating and not cooling with the CC. This weekend the ambient temps got into the 60's with sunshine so the car interior got much hotter. I tried out your description and, lo' it worked like a champ. It made the drive much more pleasant. Thanks.

Reddy

 

[rawhog]

My car has all of the latest firmware updates. What I found is that if I turn CC off. Then hit mode button to face air. It opens the outside air damper and allows fresh air in without running the fan. So zero on the enegry readout for CC. This is with the setpoint at 60 degrees. With that said. I am watching for the UPS guy to show up with my Phil's upgrade