Practical solutions for extending cold weather range

[MLucas]

Follow up on infrared lamp heating :

First experiment yesterday. Installed a ceramic socket under the dashboard and 50W lamp. T° in the car was 35°F. Car not moving. Came back 20 minutes later and T° was 65°F on the floor under the accelerator.

Seems good so far. Next step will be to drive in cold conditions (yesterday was more like warm 40°F), and try 75w or 100w. The energy comes from 400w inverter in 12v power socket.

Very easy to install. Lots of room under the dash and many places to attach. We don't even see the fixture, just the nice red light flowing to our feet.

Pictures please?

 

[Pier]

Sorry Mlucas, no pictures. Reasons ? I don't have what is needed at the moment, there is not a lot to see except a red light on the feet, the socket is more inside the lower dash, difficult to take pictures, it is a temporary installation for experiments. Just look under the dash and you will find an easy way to fix the socket there. Later, next summer, when I will know the best combination, I will make a nice permanent installation , like an aluminum heat sink as a support for the ceramic sockets and permanent wiring.

This afternoon I went on a 40 km leg to test the setup, in 4°C air T°. First time seat heater on... too hot... had to turn it off. 50w infrared bulb on... right foot too warm after a while and the left foot was cold. The best will be two bulbs for both feet or a setup in the middle. I am waiting for very cold weather to test 75w and 100w bulbs.

Moreover, contrary of what I said yesterday, it doesn't take 20 minutes to heat up. It is instant heat, but it may take some time to warm the boots or the carpet.

 

[Don]

Four 50W bulbs should keep your tootsies warm. Add a switch so you can turn off the two on the passenger side when no one is sitting there. 200 watts of red light shining down on the floorboards may reflect back on the windshield though and make it hard to see when driving at night

My experience with the seat heater is the same as yours - Turn it on for 2 or 3 minutes and it's way too warm, so I turn it off and forget about it. I wish it had a user adjustable thermostat . . . . it would probably use 1/2 as much energy if you could regulate it down to a comfortable temp

Don

 

[JoeS]

...When I turn the dial to full defrost I manually turn off the AC - I already have ice on the window and need heat to remove it.
Cracking the window helps as cold air is dry ....

Sandange, thank you for clarifying the settings you use.

Focusing on maximum defrosting (and for the time being ignoring energy consumption), here's where I'm confused: the iMiEV automatically kicks in the aircon when the Mode selector switch is turned to Defrost even though heating is selected. I thought turning on the aircon does not lower the temperature of the air blowing out of the system, but instead its purpose is to extract moisture from that air prior to it running through the heater. Thus, would it not be better to leave the aircon ON (like the iMiEV tries to do for us) when maximizing defrosting?

Summarizing (and probably maximizing energy usage), here are the settings that I thought were required for maximum windshield defrost:
• Mode switch select the final upper setting (full defrost)
• Temp setting at maximum
• Fan setting at maximum
• Aircon ON
• Recirculation OFF

Sorry for being a little bit off-topic, as the purpose of this thread is to minimize non-motive energy use.

 

[peterdambier]

There is 2 things: Defogging inside and Defrosting outside.

Defogging, no heat needed but A/C.

Defrosting, no A/C needed but heat.

Unfortunately defogging will result in a frozen windscreen.

If we could help dehydrating the air - e.g. rice or silicagel, we could save the energy for defogging and reduce the energy needed for deicing.

If we could termoisolate the windscreen we would save energy for heating the inside and reduce condensation and fogging but deicing might become a problem again.

 

[emissionimpossible]

I've wondered about switching out regular LEDs for infrared LEDs on a flashlight or some form of portable LED type light. Battery powered or even better to find one that plugs into the lighter socket.

 

[tonymil]

Focusing on maximum defrosting (and for the time being ignoring energy consumption), here's where I'm confused: the iMiEV automatically kicks in the aircon when the Mode selector switch is turned to Defrost even though heating is selected. I thought turning on the aircon does not lower the temperature of the air blowing out of the system, but instead its purpose is to extract moisture from that air prior to it running through the heater. Thus, would it not be better to leave the aircon ON (like the iMiEV tries to do for us) when maximizing defrosting?

I agree with you JoeS, keeping the temp on hot while running the a/c results in warm air coming out while the a/c dehumidifies the air. It's the quickest way to defog the windows. As soon as the windows are clear I turn off the a/c and just run the heat. The defogging seems to last longer this way.

 

[jaraczs]

I have also noticed that my feet get cold before the rest of the body. After inspecting the under-dash, I though there is not enough of firewall insulation, no side wall insulation and the metal frame components are functioning as a heat dissipators so, perhaps insulation of the under-dash could help somewhat.

My local Home Depot did not have a flexible insulation (other that fiberglass which is not suitable for interior) so I selected 1.5" thick polystyrene foam (R=7.5), cut it to match the under-dash opening, detached the underdash cover and inserted the styrofoam in. It took several adjustments and cuttings to obtain a good fit. It is really important for safety to cut the foam around the pedals to allow for free pedal motion.
After a few days, I have removed the panel to further cut it around the steering column because it was making squeeking noise every time I moved with the steering wheel. It is back in place and no squeeks anymore.

If I were to do it again, I would use 1" thick panel because 1.5" seems too thick.
Unfortunately, I have no idea how much I am benefiting in terms of energy saving but my feet feel less cold with the insulation panel (subjective).

I would not do the same insulation for the passenger side as the recirculation inlet has to remain unobstructed.

 

[jaraczs]

For this winter I have decided to replace the rigid styrofoam with flexible foam (padding protection foam), 1.25" thick. I hope it will have R4 insulating index. The installation was much easier because of the material flexibility. No taping/clipping was required except of one spot on the left (see pic). There is no limitation in pedal and foot motions.

 

[MLucas]

Looks great, where did you get it?

 

[jaraczs]

Looks great, where did you get it?

I did not purchase it. It was used as a padding in an instrument that was shipped to our company. It would go to the garbage, I saved it. I wish I can direct you to Home Depot or any other specific store ...

 

[Llecentaur]

Just a thought, I have been trying the following:

Only turn on the heating when in regen. Of course this is only possible when you have long stretches, but it seems that it benefits from the regen rather than depleting the battery. Might be an option Mitsu could add as an Eco mode heating.

 

[jray3]

Just a thought, I have been trying the following:
Only turn on the heating when in regen. Of course this is only possible when you have long stretches, but it seems that it benefits from the regen rather than depleting the battery. Might be an option Mitsu could add as an Eco mode heating.

It's definitely more efficient to burn up regen Watts as heat rather than to put it into the battery and then pull it out a minute later as heat! I'd wager a good 20% better, and should be easily implemented with software... at the factory.

I've been thinking on what it would take to add a Prius-style coolant thermos to store more pre-heating. The Prius uses some valves that we wouldn't need if it were pumbed in series with the heater core, but there's some appeal to using quick hydraulic connectors to delete (or drain) that heat tank during summer, and drop the weight. I also thought about using some heat sink other than coolant, but there's pretty much no material that's solid or liquid at room temperature with greater specific heat than water.
http://www.engineeringtoolbox.com/specific-heat-capacity-d_391.html

At approx 4182 J/kg/degree C, and lets say we extract useful heat from water between 90 degrees C and 30 degrees, then 60 degrees * 4182 could give up 250,920 Joules per Kg.

Our batteries are rated at 80 Watt-hours per Kg, which equals 288,000 J per Kg.

With no losses, a kilo of battery makes more heat than a kilo of hot water. Figuring 10% loss from battery to hot air, and we're at 259,200 J/Kg- just barely better than hot water. Figure in 20% loss from regen to battery to hot air, and a hot water bottle is more valuable than maximized regen.

SO, a hot water bottle could be worth it's weight in battery, especially for you arctic i-MiEVers!
:idea:
This calls for a device I'll dub the Mountain MiEV Mug. Place one insulated box (ice chest or "Igloo cooler" to Americans) full of water in the cargo area, with a small pump and a water heater element inside, a water coil and fan mounted on top, and a drain valve at the bottom. Heat the water to near-boiling overnight, and run the pump and fan while driving, until all useable heat is gone. Then drain the box (off the pavement, unless being chased by bad guys) and continue on your way with a minimized weight penalty. For summer usage, simply fill the box at the top a mountain and use the added weight for enhanced regen all the way down, but dump the water (while underway if possible) before climbing the next mountain!
:mrgreen:
:roll:

 

[Llecentaur]

Here is a thought that might deserve its own thread.

Instead of installing a webasto which is an effective solution for heating, Why not source a DC - DC converter capable of delivering close to 500-1000W per hour at adequate voltage to the car to recharge batteries or in our case feed the heater. Ideally small enough to fit near engine below trunk, then we learn how to make our own custom Li battery by practically makings a flat battery to the shape of the trunk, maybe only 10 cm high.

This way the heating would have less of a drain on the battery and even when parked the converter would continue recharging the main pack...

During summer, it would also add range...

Question is can we have a 4 KW battery and converter for the price of a Webasto installation (~2000)?

4 KW being the equivalent of one hour of heating...

 

[jray3]

The only DC-DC options I know of in that range are the Enginer el cheapo version, and a Manzanita Micro PFC charger, which needs 72+ V to pull from in dc-dc mode rather than the 48V Enginer. Of course, a cheap square wave inverter feeding off of 12V should be able to feed the OEM charger. The challenge is transferring power while under way without confusing the BMS into causing damage. :? The Manzanita bypassing the OEM charger would actually require less hacking, I think, as sia47 has done.

 

[Llecentaur]

I found one on the web only 100w. There must be some build constraints I ignore.

 

[Don]

If 4KW is the equivalent of one hour of heating, a 100 watt inverter will do . . . . next to nothing

Charging the car while it's in motion is pretty complicated

If you're looking for a simple way to add heat and extend the car's range in the winter and you want to do it electrically, why not keep it simple . . . . really simple?

Buy 40 of the Headway 38120S 10 amp screw tab LiFePo4 cells (about $17.50 each) connect them in series for a 128 volt auxiliary battery pack (1.28KW) and then use them to run a standard household ceramic 10 amp 120 volt heater? If you replaced the fan motor in the heater with a DC motor, you wouldn't even need an inverter. Attach a voltmeter to monitor the pack and shut off the heater when the voltage drops to 90V (2.25 volts per cell) so you don't harm your battery pack

. . . . or, go with something like this to keep your water warm http://www.ebay.com/itm/EV-Solar-Inline-Heater-Single-Element-120v-144v-Volt-5-500-BTU-ECO-/171076678072?pt=Electric_Vehicle_Parts&hash=item27d4f6f1b8

Should last you 45 minutes or so and if you preheated before leaving, the little household heater should replace most of the ambient heat lost . . . . especially if you've insulated the car

Don

 

[RobbW]

How does that inline water heater work, Don?

 

[Don]

For us, I think you just cut the existing water hose leading to the car's heater core and insert the new heater inline, the same as you would for a Webasto. If you added a switch (or relay) in the high voltage line to the car's heating element (so you could turn it off when the dash switch has it turned on) then the car's water pump and heat controls on the dash should work normally

Don

 

[DonDakin]

I have been thinking about the webasto solution but I'm wondering where the heater could be mounted.

Having a look at the car where would you put the heater ? It pretty tight in there. Anyone have any ideas ? I believe the unit is 11x5x9 inches.


Also I am thinking of adding a small 250 watt electric heater for the rear feet area. I want to bring in 12 volts directly from the 12 volt battery. What is the best area to do this in terms of passing wires thru the firewall ? I took a look and I can't find any area to pass the wires thru that already exist. Has anyone done anything like this already ? I don't mind drilling thru. Did anyone find an easy way to do it ?

Don.......