Turning On The Fan (without running the heater)?

So it's a little hard to be sure, but it looks like I'm seeing a pretty big drop in efficiency with the colder whether. Just a month ago or so I was seeing 4.6 MPkW and within the last few weeks it has dropped to 3.8. I've been reading threads that suggest others are seeing quite a drop to, then it hit me to pay attention to the energy info and I noticed that climate control was eating up quite a bit of juice all of a sudden. During the summer I was mostly using the fan only, by turning off the AC and keeping the temp down to 60, using neither AC nor the resistive heater most of the time. Now that it's going below 60 outside and in the cabin, it appears that the heater is coming on and chewing up juice with no way to stop it without shutting off the fan. From what I've read and from a few failed attempts on my own, it appears that there is no way to run the fan without the heater kicking in if the temperature is below 60. It appears that someone at Nissan has overlooked how one might want air movement without any climate control. Please correct me if I'm wrong, I hope I am, but this is no small deal. there will certainly be circumstances where I am willing to "bundle up" to get the extra distance during the winter. The loss of range due to the effect of cold on the battery is a matter of chemistry and I can accept that but adding insult to injury and forcing the use of the heater on me is unthinkable. Maybe I'm borrowing trouble from the future and this will turn into another paper tiger, but I can imagine getting low on juice and having to turn off climate control only to have the windows fog so badly I can't drive... a bit of air circulation can make this managable but none could turn this into choosing between being able to see and a dead battery. It does not make sense to me that we are given ways to control so many things but not the one thing that can deteriorate range the most, the heater!

Are other experiencing this frustration?

Maybe Nissan can easily allow the temperature selector to go below 60 with a new firmware update or something. As I've read in other threads, a simple on/off switch for the heater would be very nice.

Yes, this is an absolute travesty. A simple fix would be to prevent the heater from running if the A/C is not selected, thus turning the A/C button into an "eco" mode of sorts.

I looked into a mod, but it's a little more complicated than just a jumper, as the HVAC ECU sends commands to the heater over a dedicated LIN (Local Interconnect Network) connection. The only fix I can see is reverse-engineering the firmware and patching it, or the addition of a small microcontroller with LIN function to intercept and alter the heat commands.

It baffles me why Nissan didn't install a heat pump system in the LEAF. Toyota has it in the Plug-in Prius, it would be much more efficient than electric resistance heating. Maybe in the next generation LEAF.

-Phil

Ingineer said:

It baffles me why Nissan didn't install a heat pump system in the LEAF. Toyota has it in the Plug-in Prius...

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Are you positive on that?.. It seems like an easy task to install a bypass switch on the Leaf's heater.. unless it throws up some sort of code.

Heater is 400v 12.5 amp "chopped" DC, so select a suitable switch.

Maybe mount a Relay right at the heater connection?

First, try to disconnect the HV heater connection (is that it under
the hood, center, very back ???) and see if any Errors occur.

I have already looked at this. You definitely will get codes, and I cannot stress enough; DO NOT SPLICE INTO 400VDC WIRING! Switching 400VDC is very difficult to do safely!

The best way to inhibit the heater I can come up with right now is to intercept the LIN connection and manipulate the frames. This way you should get no codes, and the goal is achieved without even popping the hood. This would only entail cutting one wire.

Though I'm looking into other options as well.

-Phil

Why not just crack the windows a bit? That is what I do. If it is so absolutely cold outside that you don't want outside air coming in, then I can't imagine why you'd be wanting air circulation.

The entire climate control on my Leaf stays off 99% of the time. Only when my wife or other people are riding in the car do I bother to turn it on. But that has been true in most cars I've owned, even gas cars.

adric22 said:

Why not just crack the windows a bit? That is what I do. If it is so absolutely cold outside that you don't want outside air coming in, then I can't imagine why you'd be wanting air circulation.

The entire climate control on my Leaf stays off 99% of the time. Only when my wife or other people are riding in the car do I bother to turn it on. But that has been true in most cars I've owned, even gas cars.

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I like to have the fan going pretty much constantly in the summer to cut down on the AC use. As for the winter, maybe I breathe heavily or something but the windshield is on the verge of fogging much of the time lately. The issue I'm grumpy about is specific to cold weather, like this morning it was 37 outside, too cold to roll down the window. being able to use air circulation/defrost without the heater kicking in is an important option to me since the heater combined with the decline in range due to cold is apparently eating 20% of my range, that is if the MPkW calculator in the car is correct, I have not checked it against actual miles. Truth be told, I could live with a lot less range most days, but in terms of understanding what the car's new limitations are for longer trips in cold temps and how hard I'll need to work to maximize mileage if need be, I'd prefer to have ultimate control over the heater.

I did try preconditioning the cab, which required me to start charging again as the car was already finished it's 80%. It did not take long before the heater kicked in even with preconditioning.

I'm not sure at all how much of the loss in MPkW is attributable to the heater, I'm of course hoping it's a lot because if this much range has been lost to cold before real cold whether hits, it makes me cringe to think what's going to happen in say January/February.

Best option right now is to leaf the HVAC off and turn on/off the defrost as needed. In my experience defrost works quickly so you can turn it off after not too long.

If we cannot turn the Heater Off except by having all CC off,
maybe we can turn the 12v Fan ON while CC is Off?

Remember the little dash board fans before heaters became standard equipment? (Yes, I'm older than dirt)

Harbor Freight markets a little plug in unit that draws right at 10 Amps when heat is turned on, much less with fan alone. I carry one in the trunk just in case of a situation that Gasless pointed out occurs - low on battery and can't see out the windows.

http://www.harborfreight.com/12-volt-rubberized-heater-with-fan-96144.html" onclick="window.open(this.href);return false;

I got my car late enough that I only fooled with A/C a wee bit. Now that I am experiencing the need for a bit of heat and window defogging, I am really frustrated and unhappy with the design. Just ain't right!

Bill

GaslessInSeattle said:

As for the winter, maybe I breathe heavily or something but the windshield is on the verge of fogging much of the time lately. The issue I'm grumpy about is specific to cold weather, like this morning it was 37 outside, too cold to roll down the window. being able to use air circulation/defrost without the heater kicking in is an important option to me since the heater combined with the decline in range due to cold is apparently eating 20% of my range, that is if the MPkW calculator in the car is correct, I have not checked it against actual miles.

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Best you can do is switch defrost on & off. You can also keep the temperature as low as possible. In the past few days it has been fogging up a lot because of humid weather - I don't remember it being so bad last winter. With a bit of freeway driving I got 4.1 m/kwh - instead of usual above 5.

Just make sure defrog is switched off a quickly as possible - otherwise it draws over 3.5 kw of power.

evnow said:

GaslessInSeattle said:

As for the winter, maybe I breathe heavily or something but the windshield is on the verge of fogging much of the time lately. The issue I'm grumpy about is specific to cold weather, like this morning it was 37 outside, too cold to roll down the window. being able to use air circulation/defrost without the heater kicking in is an important option to me since the heater combined with the decline in range due to cold is apparently eating 20% of my range, that is if the MPkW calculator in the car is correct, I have not checked it against actual miles.

Click to expand...

Best you can do is switch defrost on & off. You can also keep the temperature as low as possible. In the past few days it has been fogging up a lot because of humid weather - I don't remember it being so bad last winter. With a bit of freeway driving I got 4.1 m/kwh - instead of usual above 5.

Just make sure defrog is switched off a quickly as possible - otherwise it draws over 3.5 kw of power.

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I'll give that a try. I do wonder if a simple fix might be for Nissan to give a colder setting for the climate control. maybe allowing it to go down to say 30 or even lower, essentially giving the driver a way to keep the fan on while not using the heater without having to do any major redesign of climate control... not sure how set the 60-90 range is, hopefully software determined, I can hope... the EV project is going to get a call from me. I'll get over it I'm sure, it's just the first major outright design flaw I've come across and it's just sadly ironic that it compounds the cold weather decline in range. It's going to be an interesting winter!

GaslessInSeattle said:

... I do wonder if a simple fix might be for Nissan to give a colder setting for the climate control. maybe allowing it to go down to say 30 or even lower, essentially giving the driver a way to keep the fan on while not using the heater without having to do any major redesign of climate control... not sure how set the 60-90 range is, hopefully software determined, I can hope...

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My old Honda simply had one more step after 60 which was "max cold" which simply guaranteed no heat, and constant AC (if the AC button was on).

davewill said:

GaslessInSeattle said:

... I do wonder if a simple fix might be for Nissan to give a colder setting for the climate control. maybe allowing it to go down to say 30 or even lower, essentially giving the driver a way to keep the fan on while not using the heater without having to do any major redesign of climate control... not sure how set the 60-90 range is, hopefully software determined, I can hope...

Click to expand...

My old Honda simply had one more step after 60 which was "max cold" which simply guaranteed no heat, and constant AC (if the AC button was on).

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That would do it, if a "max cold" option could be added easily it would satisfy my concern. I'll bring that up with the EV project. Chime in if you would like "max cold" added... they're listening!

GaslessInSeattle said:

Are other experiencing this frustration?

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The simple solution: Heated seat cushions...they are very inexpensive and use an inconsequential amount of power compared to the LEAF heater. I plan on using the pre-heating and then the heated seat cushions. Remember, the pre-heating/cooling is ONLY meant to have the cabin cool when you get in, NOT to cool the car down to a certain temp, which means you would only need 5-10 minutes for pre-conditioning depending on the ambient temp. It's just a waste of energy to pre-condition any longer than 10 mins. because it doesn't keep it cool or heated.
I know this doesn't solve the problem of 'fan only' without the heater being on.

LEAFfan said:

The simple solution: Heated seat cushions...

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Seat heaters may keep you warm, but as your breath (and body heat) heats up the car, the windows will fog up. You're gonna have to use the windshield defroster sooner or later....The question becomes is it better to:

1. Use it for a long time to get the windshield warm which eliminates the cause of the fog or
2. Use short bursts which will clear the windshield, but keep the windshield cold meaning fog will quickly re-accumulate.

I'm thinking #1 will be the most efficient. I've got the CWP in my LEAF, in a few months I'll have a chance to test staying warm and what happens to the windshield in a cold damp climate.

LEAFfan said:

GaslessInSeattle said:

Are other experiencing this frustration?

Click to expand...

The simple solution: Heated seat cushions...they are very inexpensive and use an inconsequential amount of power compared to the LEAF heater. I plan on using the pre-heating and then the heated seat cushions. Remember, the pre-heating/cooling is ONLY meant to have the cabin cool when you get in, NOT to cool the car down to a certain temp, which means you would only need 5-10 minutes for pre-conditioning depending on the ambient temp. It's just a waste of energy to pre-condition any longer than 10 mins. because it doesn't keep it cool or heated.
I know this doesn't solve the problem of 'fan only' without the heater being on.

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Yeah, I think you missed the point a little. Max cold would simply allow us to use the fan without using the heater during winter months. Bottom line, air circulation is often adequate to keep the windows clear/defogged in the winter. Mainly I'm trying to adjust the baseline for range in the winter months, being forced to use the heater is going to produce a rather grim number for maximum range... like maybe as bad as 60 miles. I think Nissan would rather find a nice easy solution to this than have me and others join the camp that has freaked out about the range. my guess is that based on the numbers some were getting in the summer, stated as low as 60, those same folks may very well be chiming in soon belly aching about the mid 40's. It's not going to look pretty even for us more conservative drivers if there is in fact no way to make the fan work without the heater in colder weather. If I have to use the heater because of foging, then that's on me, if I don't have the choice, that's on Nissan.

I haven't been trying this measure very long, and it very well may not work. But one day last Summer, I was picking up a perscription and noticed a floor display of on-sale bags (5#, I think) of Epsom Salts, where the chemical formula for the substance was printed in bold on the bag: "MgSO4 * 7H20" . The "seven water molecules per molecule of salt" kind of grabbed my eye, because I'd long nursed a zany idea of trying to get a rechargeable dessicator for my car, which (as all cars I've ever owned have) gets moss-ranching wet inside in wintertime. A little Googling showed that the material is used by DIY food-drying folks for dehydrating stuff like mushrooms and fruit, so I bought the bag of salts for a couple bucks, poured half of it in a spare bread pan, and baked it in the oven at about 400deg. F. In short order, the top of the salts formed a crust, beneath which was a puddle of at least (just estimating) over half their original volume in liquid water. With enough stirring and crunching of the stuff, and ventilating the oven, I baked the water out, and then pulverized the solid lump of anhydrous salt with a sledge. It's kind of a bother, but given that I've not been able to solve the humidity problem any other way, I was thinking that I could stick the pan of dehydrated salts in the car each evening in hopes of soaking up the water vapor inside.

So far, the Leaf's defroster has been more effective than my old car's, but there are signs that its rear window's still going to become opaque as the weather worsens. As I think of it, I'm going to try soaking up the vapor with my bread-pan of salts, and see if it helps.

Too crazy?

Levenkay said:

I haven't been trying this measure very long, and it very well may not work. But one day last Summer, I was picking up a perscription and noticed a floor display of on-sale bags (5#, I think) of Epsom Salts, where the chemical formula for the substance was printed in bold on the bag: "MgSO4 * 7H20" . The "seven water molecules per molecule of salt" kind of grabbed my eye, because I'd long nursed a zany idea of trying to get a rechargeable dessicator for my car, which (as all cars I've ever owned have) gets moss-ranching wet inside in wintertime. A little Googling showed that the material is used by DIY food-drying folks for dehydrating stuff like mushrooms and fruit, so I bought the bag of salts for a couple bucks, poured half of it in a spare bread pan, and baked it in the oven at about 400deg. F. In short order, the top of the salts formed a crust, beneath which was a puddle of at least (just estimating) over half their original volume in liquid water. With enough stirring and crunching of the stuff, and ventilating the oven, I baked the water out, and then pulverized the solid lump of anhydrous salt with a sledge. It's kind of a bother, but given that I've not been able to solve the humidity problem any other way, I was thinking that I could stick the pan of dehydrated salts in the car each evening in hopes of soaking up the water vapor inside.

So far, the Leaf's defroster has been more effective than my old car's, but there are signs that its rear window's still going to become opaque as the weather worsens. As I think of it, I'm going to try soaking up the vapor with my bread-pan of salts, and see if it helps.

Too crazy?

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Sounds like a real PITA to me. :roll: :roll: :roll: :roll: :roll:

Search "Desiccant Car Dehumidifier" and you'll find many chemical products advertised for cars.

I used to use them to keep poorly sealed cars I parked outdoors all winter, dry, and they worked ok, in keeping the interior less wet...

Might be worth a try, to reduce fogging.