HVAC - lower the power drain or disable the heater ?

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test0s

New member
Joined
Jan 21, 2016
Messages
2
First of all i just like to say hi to all from a new user, from Norway.
I've had my electric focus for almost 2 years now and i'm fairly happy with it. Have to say that the european focus manufactured in Germany lacks a lot of vital options that you guys have in the US - such as go times or being able to preheat the car via mfm, touch screen (heck there is no mfm in europe whatsoever). This winter is one of the coldest i have experienced in the last 8 years here and without the possibility to preheat the car you can guess that my range takes a very big hit. It's currently -26C (-14,8F) and the heater stays at 5+ KW a very long time even tho i set the temp at 18C / 64F.
Anyway back to the topic. While searching for options to improve the power drain of the heater i've came across some 1st gen (2011-2012) nissan leaf users that have succesfully modified the power drain with some fairly easy modding. Seen that they mention that the 2011 leaf has the same type of resistive heater as the focus has.

Here is the topic : http://www.mynissanleaf.com/viewtopic.php?t=11412#

They actually have 3 methods of resolving the issue tho i think nr 2 and 3 are best.
I know they are very different cars but maybe we can get method nr 2 to work on our cars?

There is also this thread where some users sell an upgraded Leaf climate control module. Think its just a regular module that they modify like in the other post. Anyway they mention :

With our upgrade, You will now NEVER have heater operation, regardless of set temperature / car temperature, unless at least one of these conditions is true:

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

I found that controlling the heater with the A/C button is the best and most intuitive. Also, anytime the system is in Auto, the A/C button is illuminated, so this new method is actually more flexible. You can now run any aspect of the system under manual control, and still choose to have heat (or not). You can also have front defrost with no heat or A/C, or just Heat. You also now don't need to run the rear defroster in most "manual" conditions where you still want heat, as during testing we discovered it's on a timer and doesn't stay on.

Here is the 2nd thread :

http://www.mynissanleaf.com/viewtopic.php?t=6751
 
You can use FORScan control on the computer to disable the heater. I generally just turn down the temp until it stop showing usage on the heater. You could install a switch but it would be a pain.

FORScan can also put the state of the heater at whatever % output you want. Since its resistive heater is a PTC heater, it won't be able to burn anything up. If you put the coolant pumps all at 0 and close all diverter valves, the coolant temp will not pass a certain temperature even if you tell the heater to output max. The resistance will increase and flow of electricity will slow down.
 
Interesting. So i can program the heater to work at 50% with forscan? This would be great if it was possible. I will get a OBDLink MX adapter and test this.
 
I wonder what else FORScan is able to modify. Really wish I could turn off "creep" mode, and change the throttle response a bit.

Wasn't happy about getting my doors blown off by a Leaf, of all things.
 
rsanders4 said:
Wasn't happy about getting my doors blown off by a Leaf, of all things.
FFE 0-60 is about 10 seconds.

But, I thought Leaf 0-60 was only about 9 seconds. So, better, but doesn't seem exactly "door blowing" compared to the FFE.

Maybe you were asleep. ;)
 
It was a shockingly quick off the line - I used to race 1/4 mile, so my rt isn't bad.

Not quite Tesla like, but enough to make me a little upset that a bland econobox like the LEAF left my Focus in the dust.

Still doesn't change the fact I'd love to tinker with the throttle response.
I've tried running with traction control off, and that doesn't seem to change a damn thing. :(

Then again, from everything I've learned about the Focus EV, Ford really went out of their way to not tax anything too hard (battery, motor, etc.)
 
rsanders4 said:
Still doesn't change the fact I'd love to tinker with the throttle response.
I've tried running with traction control off, and that doesn't seem to change a damn thing. :(
The only thing I can suggest trying is "priming" the accelerator while in neutral (N), then simply "flipping" into drive (D) when you want to "go". This way, power is applied in a more "switch-like" manner.

Some people say this technique makes no difference, but it "feels" slightly quicker to me. (But, I have not made any kind of measurement.)

Anyway, after you come to a stop (say at a red light) the procedure is as follows:

  • While holding the B pedal as normal, shift to N.
  • Switch to holding the B pedal with your LEFT foot (assuming you're normally a single-footed, right-footed driver).
  • Fully depress ("floor") the A pedal with your RIGHT foot.
  • When you want to "go", simultaneously release the B pedal and shift to D (while continuing to depress the A pedal of course).

Depending on the terrain (e.g., whether or not you might roll away) you may be able to release the B pedal somewhat before the last step (e.g., when you predict the light will soon be turning green) and take-off using "nothin' but shifter".
 
WattsUp said:
rsanders4 said:
Wasn't happy about getting my doors blown off by a Leaf, of all things.
FFE 0-60 is about 10 seconds.

But, I thought Leaf 0-60 was only about 9 seconds. So, better, but doesn't seem exactly "door blowing" compared to the FFE.
That would surprise me considering that the Focus has more available power than the Leaf...
rsanders4 said:
It was a shockingly quick off the line - I used to race 1/4 mile, so my rt isn't bad.

Not quite Tesla like, but enough to make me a little upset that a bland econobox like the LEAF left my Focus in the dust.

Still doesn't change the fact I'd love to tinker with the throttle response.
I've tried running with traction control off, and that doesn't seem to change a thing. :(

Then again, from everything I've learned about the Focus EV, Ford really went out of their way to not tax anything too hard (battery, motor, etc.)
My experience with the Focus is that if you're stopped and you floor it the acceleration isn't that great. If you get a rolling start & floor it then it takes off a lot faster. I should do some test runs & monitor HVB amps/volts via FORScan to see if there is a difference in total kW output by the HVB in those scenarios. The challenge is finding a road where I could do runs from 0-60 without risking a speeding ticket or causing issues for other motorists... I live too close to the center of the city so country roads are all far away.
 
So back on topic and reviving an old topic, I confirmed this morning that using the FORscan commands on a computer will force the heater to 0 even after disconnecting. I can now set my HVAC to 70°F and it doesn't burn the 5kw that it usually does when I turn it on in the mornings. It's 67 outside and even having it set to 70 with the AC off, it is using almost no power. Now I have to make sure I turn it back on before it gets cool out this fall, but I'll leave it off all summer! I'll make a new topic later with pictures and how-to. Thanks
 
Just back in the car after hitting the gym and when I turned on the car, it was pulling 5kw+ again. So it's not permanent, only for that drive cycle before turning the car off and back on. That's unfortunate.
 
There should be a high voltage fuse for the PTC heater. I wonder if anyone has experimented with removing it?

The FFE probably has a temp sensor like the one mentioned in the Leaf forum so I imagine methods 1 and 2 could be adapted if the appropriate wire/connector can be identified. Method 3 seems like it would require a lot more info to implement properly.

Wouldn't it be easy enough to just use manual control and switch the heat on or off periodically - keep the fan going in recirc (why does this car hate recirculation so much?!?!?) to suck every last bit of heat into the cabin. I often have to resort to a similar approach with the AC to prevent the F%$&*@! heater from coming on during the spring to fall in my hot, humid climate.
 
amped said:
There should be a high voltage fuse for the PTC heater. I wonder if anyone has experimented with removing it?
According to the wiring diagrams it's 40A and it appears to be in the TCM. If I can locate the fuse I'll remove it I'm guessing its under the cover of the TCM. Of course taking all HV precautions.

The other idea I had was simply unplugging the HV cable to the heater. However I'd have to get a junk cord to modify as I wouldn't want to leave the plug on the end of the wire or the socket on the heater exposed to the elements.

I was kind of hoping this would be simple like cutting a control wire and inserting a switch or using FORScan or FoCCCus to enable/disable in software...
 
Considering that post was made in 2017, I don't think they will be posting pictures anytime soon.
 
Based on how difficult it is to get into the TCM, you'd be best off splicing a switch into the heater or just disconnecting it entirely when not needed.
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You could also tap something like a CANDue into your CAN bus and have it resend your preferred heater command each time the car starts. Now that I have the Arduino in place for CHAdeMO, I've been thinking of having it modify a few things like this - watch for the recirc to turn off and turn it right back on.

I might add a new control for the seat heaters (I don't think they are controlled on CAN) so they don't turn on unless the temp is below a certain threshold or add a stand-alone interlock circuit that turns them on/off with a momentary contact switch - but defaults them to off when the car starts locally and on when it's started remote and plugged in.

Maybe something that would mute the stereo when it can't connect to my Bluetooth or when I disconnect from USB audio...
 
Yeah I gave up on this years ago. I just use "vent" mode when temps are in-between summer/winter. Temp set to "lo" and manual fan speed. AC off unless it's needed. I had thought about putting a diesel (kerosene) parking heater in place of the PTC heater to help with winter range but I never had the time to enginerd it.
 
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