Practical solutions for extending cold weather range

[sandange]

Agreed -most heat loss is through windows - usually an R Factor -1
Ceilings are next likely place of heat loss - R factors depend on material used.
Door seal, weather stripping - they either seal or leak air and need replacing

The I Miev door panels & ceiling insulation in our case is a retro fit and space only allows limited type of product to be use .
The bubble foil itself may have a factor of R 1 but the vapor barrier & reflective characteristics are of more benefit.
If you can suggest another product that performs better for this application please do share it with us.

Although our homes have windows and endure the same heat loss, we still insulate our walls and ceilings to try and minimize it.
The sun is powerful & we have designed passive solar gain into our home .
The I Miev is mobile and can be strategically placed to either take advantage of the solar gain or take shelter from it.

 

[MLucas]

The reflective barrier insulation according to the HomeDepot web site has a minimum R value of 3. I do see this as a benefit to keeping the heat or cool inside the car, because there isn't much between the plastic door panels and the metal door skins. Basically, transporting the outside temp directly inside the cabin. The rear doors are worse with the huge triangular speaker hole and the open speaker grill. The windows are a factor and there is not much we can do, but I feel the plastic window tint helps a little bit in that it doesn't transfer heat or cold as easilly as glass does - its not much but some. And that is what we are looking for in this car, is any increase in heat/cool retention.

Reflective barrier insulation is used in all kinds of products besides insulation, like soft thermal lunch bags. Houses have used reflective barrier insulation for decades - the silver foil stuff with yellow fiberglass batting on the back. The foil doesn't have to be directly in front of the heat source to work, this stuff is used behind the walls of houses.

I drove the car again today on my commute and definitely felt a benefit to the insulation. I'm not going to take the time to find another i MiEV to compare inside temperatures or use an infrared camera to prove this works or not. It just matters to me that it does something, if you don't feel it does anything at all - then it doesn't do anything at all. I don't have the science you are looking for.

I do plan on pulling the headliner and insulating the roof as well.

 

[dominion]

Hi,

This is a view that can help you to realize the modification :


:mrgreen:

 

[NeilBlanchard]

The people can wear electric vests to stay warm -- this is much more efficient than any cabin heater.

 

[dominion]

Of course, but electric vest can't help us to avoid steam in your cars ...

 

[mievsolar]

I love the idea of putting a 12V "blanket" on the ceiling and running it off the Auxiliary battery bank. That is one of the best things I have heard in a long time! AFter all that is a form of radiant heat and radiant heat heats "objects" instead of just space. Therefore one feels much warmer than they would with just heating the space in the car.

I am considering adding a flexible PV panel to the top of the car (lots of room there) and then adding another auxiliary battery in the front as it appears to have plenty of room for a second battery. But I think I will change the auxiliary battery to a LiOH for two reasons. The LiON battery has much more storage for much less space and they perform much better in colder weather. Win Wn.

I also plan to insulate the hood with NANOGEL insulation (R 8 valve per inch of any insulation used in space applications) . That would help insulate that unheated compartment.

There is so much more that can be done with EV to say the least. With todays technology we certainly can improve on what is a great start.

 

[Don]

LOWRACER made up a 12 volt 48 AH Lithium Auxilliary battery using about $400 worth of Headway cells and he replaced the stock 32 AH auxilliary battery with that

The limit of what you can add to the 12 volt system in the car doesn't have anything to do with the AH rating of the battery though - You can't exceed the amp draw rating of the DC to DC converter which is 1 KW (85 amps @ 12 volts) or you'll still run the battery down . . . . the DC to DC converter won't like running flat out all the time either, so you'd first need to add up everything it's currently powering to see how much (if any ) of that 1 KW is left over . . . . I would bet there won't be enough left to generate any meaningful amount of heat

It powers all the lights, the climate control fan, the drivers seat heater, the power steering, the brake vacuum pump, the wiper motor, all of the cars electronics (there are a slew of computer controlled functions, all of which run on 12 volts) and the stereo, etc, and then there must be some left over to maintain the auxilliary battery. I *think* the 12 volt accessory outlet is rated for 10 amps (120 watts) so there's at least that much 'room' left over, but I'll bet you can't safely add much more to the 12 volt load than that. If your loads were more than 1KW total, the auxilliary battery would begin to discharge because the DC to DC converter could no longer keep it charged - It is where all the car's 12 volt power comes from

If you need power for any meaningful amount of heat, it would make lots more sense to get it directly from the 330 volt traction pack, since that's where all the 12 volt power actually comes from anyway - Getting it there eliminates the losses caused by the inefficiency of the DC to DC converter. That's the way the factory did it with the A/C and heater loads - They are all directly powered by 330 volts

Don

 

[sandange]

dominion

Thanks for posting the parts diagram for the heating system , makes things easier to understand.
I went ahead and did the heater & Pipe insulation - detailed posting on my install is here for those interested

http://myimiev.com/forum/viewtopic.php?f=9&t=694&start=20


Considering the title of this post - Focus on "Practical" & Extending Cold Weather Range.

I am curious as to how Practical & how much more Range this will result in. Definitely will add to passenger comfort & save some power.


Heater Draw to Remaining Range meter Effect

I charged the car up overnight and this morning there was 113 km (70 Miles) on the RR meter showing.

I then turn the heater on to full red scale and fan on full - the Remaining Range meter dropped to 76 km ( 47 miles).

next I pushed the Max Boost Button on and the RR meter dropped to 65 km (40.4 miles)


The loss activating the heater on max - = 37 km ( 23 miles)....... or 32.7%

The loss activating the heater on max with boost = 48 km (30 miles) ..... 42.5%

The Big question---

How much power will this save us or how many more KM or Miles will this Modification give us?

 

[Don]

I think you're going to find that the heater affects range about the same way using the A/C does - On the order of 15 or 20%

The A/C draws 4.5 Kw when set to max with the boost - But you don't actually use it that way, at least not for very long. With the A/C, keeping the car 'comfortable' on a 95 degree day we set the top temp dial at mid-range (mid way between off and the coldest setting) and the blower speed to midway and the A/C cycles off and on as needed - If you time the compressor runs, I would guess it's running 50% of the time or maybe a little more. Using the A/C full time on hot days, we routinely get RR's in the 50 to 65 mile range

The heater is 5 KW and when set to max with boost, it should run you out of the car after just a few minutes. The household 120 volt 12 amp heaters put out a little over 5,000 Btu's from 1500 watts of power. The cars heater is the equivalent of three of those and I would suspect those 15,000 Btu's should heat the car up very quickly - After that, all you need is enough heat generated to cover the heat loss in the vehicle . . . . maybe 1/3rd of that or so

It will be interesting to hear what some of you northern guys experience when it gets truly cold, and I doubt it's going to be as bad as it now seems. It's going to reduce range a bit, no question, but like the A/C, I suspect the reduction isn't going to be as bad as we think

Don

 

[MLucas]

Sandage - looks like you made Jiffy Pop.

I did the thermal wrap this weekend, what a PITA! Fortunately, my hands are very slim and I can reach in tight spaces but still...that was tight! I didn't do as thorough of a job of wrapping my heater module but managed to get some insulation around the unit.

I also built a box around the resevoir using the reflective barrier insulation that I used on the doors and made a small window so I could see the fluid level.

The thing I noticed this morning at 9C, is that I can keep comfortable with the heat at just one step above the green dot. As it gets colder I'm sure I'll need a bit more but hopefully I can keep it down.

Next up, insulate the roof - hopefully I can make it before the weather sets in. Quite sketchy this weekend with the rain.

 

[Don]

Next up, insulate the roof - hopefully I can make it before the weather sets in. Quite sketchy this weekend with the rain.

I'm not sure there's enough to be gained there to make it worth all the work

The headliner is a pretty solid, not porous piece and it's very well fitted to the car. Between it and the metal roof is a pretty nice dead air space which doesn't look like it'll leak much air - Dead air is a pretty darned good insulator. I don't see you gaining much by replacing that dead air space with foam so far as R values goes . . . . just my opinion

Don

 

[sandange]

Sandage - looks like you made Jiffy Pop.

I was thinking more like Baked potato, LOL

 

[tonymil]

I did the modification on Monday, what a job. I was pressed for time when I finished otherwise I would've taken pics. So last night I ran the heater on the way to pick up some food. Fifteen minutes later when I got back in the car and turned on the heater, the air coming out of it was still warm. Maybe a tangible benefit of the mod.

 

[MLucas]

Next up, insulate the roof - hopefully I can make it before the weather sets in. Quite sketchy this weekend with the rain.

I'm not sure there's enough to be gained there to make it worth all the work

The headliner is a pretty solid, not porous piece and it's very well fitted to the car. Between it and the metal roof is a pretty nice dead air space which doesn't look like it'll leak much air - Dead air is a pretty darned good insulator. I don't see you gaining much by replacing that dead air space with foam so far as R values goes . . . . just my opinion

Don

Alright, Don. I'll take your advice and pass on this one. Although the roof does need some sound deadening, its kind of loud during a rain storm.

 

[MLucas]

I did the modification on Monday, what a job. I was pressed for time when I finished otherwise I would've taken pics. So last night I ran the heater on the way to pick up some food. Fifteen minutes later when I got back in the car and turned on the heater, the air coming out of it was still warm. Maybe a tangible benefit of the mod.

I agree, it was a tough job. Did anyone else have a problem with the pop-snaps? I broke two of them and only had one remaining to put back. Didn't know about the bolt holding the RF screen in to ground behind the plastic cover. Luckilly, I didn't break it. Then it started to rain just as I was putting it back together, ugh. Glad that is over.

 

[sandange]

We left the bolt holding the RF Screen on and swiveled the cover out of the way while on the lift, he did break a pop snap but replaced it with some thing on re assembly.
Must of been difficult without a lift.

 

[Don]

Alright, Don. I'll take your advice and pass on this one. Although the roof does need some sound deadening, its kind of loud during a rain storm.

By all means, take it down and insulate it if you think it's worth the trouble, especially if you need it to be quieter in a rainstorm. I just have my doubts whether half an inch of insulation is going to make the car much warmer inside than the half an inch of dead air space does

Don

 

[psyflyjohn]

Wow ! Most of you people have no business living in such inhospitable climates.
Then expecting a poor little semiexperimental car to do well is just asking too much. :roll:

From S. Cal.

 

[MLucas]

Wow ! Most of you people have no business living in such inhospitable climates.
Then expecting a poor little semiexperimental car to do well is just asking too much. :roll:
From S. Cal.

I lived in So. Cal. for many years and had enough. I won't go into all the details. Its a bit cold here and we'll all make the EV livable during the cold time. Most of us have the Cold Weather package in this area, in Canada its standard - in the US, hope you ensured your car has it. For me, its all part of the experience. I rode motorcycles for five years in all kinds of weather (freezing cold, driving rain and sometimes combinations of both), I know many people wondered why I did that - it just was all part of the experience.

I gave up my motorcycle in March this year after my partner and I adopted a little boy. My new adventure is raising Jacob and driving my EV around. Things change and things come and go.

 

[tonymil]

Is there any interest in monitoring the car heater usage and its effect on range? Today I heated up the car while plugged in before leaving home, I drove my 7 miles to work with the heater temp up two notches from green and the fan speed up one notch. When I got to work and turned off the heater, my range remaining had gone from 75 miles to 71 miles, my range didn't suffer at all. But this is only the first test on a day that wasn't very cold. So what do you think, would it be useful to see what impact operating the heater has on range on different temperature/fan speed settings and over different distances?