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Thread: Electric Element in Heater

  1. #21
    Administrator Daox's Avatar
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    I would imagine so.

    25A * 3 = 75A. That is a lot of amps.

    75A * 13.1V = 982W

    982 W = 1.3 hp

    Alternators are around 50% efficient, so those heaters on full blast suck up around 2.6 horsepower. That is significant. Cruising at 50 mph probably only takes 10hp.


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  2. #22
    Just A Mirage!
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    Just to chime in, my '17 GT with climate has two relays as well.

    Quote Originally Posted by Tyrelirwin View Post
    But the real question is: can I pull out a fuse/relay and improve my winter economy?
    Most likely. If Premeir620 was seeing 22-31 amps being drawn, that's a decent chunk of power that could be saved (at least until the coolant is up to temp).

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  3. #23
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    Quote Originally Posted by Tyrelirwin View Post
    But the real question is: can I pull out a fuse/relay and improve my winter economy?
    I went back & read post #7 (Daox sharing what 3dplane's thoughts on all this). I am not a mechanic, nor did I engineer the Mirage. These are just my initial opinions, & I will claim some ignorance on this topic.

    It cost Mitsubishi something to add a PTC heater to the Mirage, & they must have felt it was worthwhile enough to add this feature. Thus, I have to believe it serves a worthwhile purpose. I don't see a company adding a lot of unnecessary items to an economy car. What would be gained by doing that? If this feature cuts into the economy of the car without a worthwhile benefit, why add it?

    Several forum members go on & on about getting the engine temperature up to a certain level asap. Blocking off the radiator, using engine block heaters, & such are popular topics on this forum. If someone decides to disconnect their PTC heater, this goes against all that logic. I have to believe these PTC heaters not only contribute to warming of the interior quicker but also the engine's operating temperature. Unless someone really knows how these heaters are working, I wouldn't speculate that these added heaters are useless or even costly to operate.

    The forecast for my area is -4 degrees Fahrenheit tomorrow morning. If I decide to go somewhere, I am going to appreciate having those PTC heaters. The former small car that I compare my Mirage to the most is my former 1990 Ford Festiva. On extremely cold days, the Festiva really didn't hold its own. If you needed to travel a long distance in the cold, you would have considered putting your long underwear on. It was that bad! From my experience, these Mirages handle the extreme cold much better. My guess is the Festiva did not have any supplemental heater, & that car struggled with colder temperatures. It ran fine, but never really heated up inside. Side windows had to be scraped with an ice scraper not wiped off on the inside.

    Since the newer Mirages seem to have only two relays instead of 3, they may have discovered 2 was enough or designed the entire system better? Unless we talk to the engineers/designers of these cars, we are just speculating somewhat. I have to believe the PTC heater are useful. Otherwise, Mitsubishi wouldn't have bothered with them.
    Last edited by Mark; 01-19-2019 at 11:44 PM.

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    A-Aron (01-20-2019)

  5. #24
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    I pulled the glove box down tonight before I took the Pumpkin outside & had a look @ the heater Box. It's a 18 GT & I saw 600w @ 12 V on the side of the heater box. 600W is pretty good to help us heat the inside of our little cars as they warm up in the AM.. Do any of you know of any other car that has a pre heat in front of the heater???

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    Daox (01-20-2019)

  7. #25
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    Quote Originally Posted by Mark View Post
    I have to believe these PTC heaters not only contribute to warming of the interior quicker but also the engine's operating temperature. Unless someone really knows how these heaters are working, I wouldn't speculate that these added heaters are useless or even costly to operate.
    I was about to question why you'd think it did something for warming up the engine, but I re-read that same post as well. Completely missed that it was positioned before the heater core...

    Ideally, even if they were costly to operate, they should only be on for 10-15 minutes at most so I doubt there's a huge gain to be had. At least I don't have to think about it for another 11 months, we're done with the cold weather already

    Quote Originally Posted by klroger View Post
    Do any of you know of any other car that has a pre heat in front of the heater???
    I know for a while Ford used electric heaters in the Power Stroke-equipped SuperDutys (Duties?) to fill in until it was up to temp, but I'm not sure if it's pre-heater core.

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    I found two well written documents that explain the logic behind PTC heaters.

    http://webbut.unitbv.ro/BU2009/BULET...sat%20R_09.pdf

    https://www.researchgate.net/publica...e_HVAC_Systems

    If you don't take the time to look up these two articles, a couple facts strike me as interesting. The first quote explains the need for these systems. When researching this topic, I get a sense that the development of hybrid vehicles may be driving some of the need for this added automotive technology.

    "Since vehicles are getting more efficient, they free less heat for the heating system; thus, by including auxiliary devices consuming electric energy, the heating time will be improved and the engine efficiency increased. The electric energy is taken from the engine through the generator/battery system, which reduces the overall efficiency of the vehicle. Consequently, an adequate energy balance and management should be accomplished."

    This quote sort of addresses the question - Are these PTC heaters found in other cars?

    "After the significant increase in the fuel prices in 2006, much automotive research has shown renewed interest in fuel-efficient vehicles. In gasoline-fuelled vehicles, about 40% of fuel energy is wasted in exhaust heat, while 30% of energy is trans-ferred through the engine coolant. Because of that, these engines produce little heat excess, especially in winter time, in city traffic and traffic jams, and they are unable to warm quickly the passenger compartment to a comfortable level [12]. Various vehicle models from leading manufacturers around the world are now equipped with PTC auxiliary heaters. In 2007, 65% of all diesel vehicles in Europe were equipped with an auxiliary heater and this is expected to rise to 90% by 2010. It is obvious that PTC heaters will not be limited to diesel vehicles but will be also used in gasoline-powered ones as well [13]."

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    inuvik (01-20-2019)

  10. #27
    Administrator Daox's Avatar
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    The PTC heater does use a lot of power, and it will reduce fuel economy. In trade, you get heat faster. If you're willing to take the trade off, I see no reason why disconnecting it would be bad. How much it will improve your fuel economy is totally dependent on how you use your car. If you only ever take 10 minute trips, it could be substantial. My previous commute was only 15 minutes and it would have had a large effect on it. Now, with my newer commute at 25 minutes, it wouldn't have as large of a penalty. However, I still try to wait until my coolant temp is higher before kicking on the heat because I do know that heater is kicking on. A nice on/off switch would be nice so you could control it at will. Sometimes I really want it, other times I could definitely do with out it.

    Also, I do know the 2nd gen Prius had a PTC heater added to it at some point. I have a 2004 which doesn't have it. My in laws have a 2007, and it does have it. Apparently it works really well (and probably sucks even more power than ours).


    Custom Mirage products: Cruise control kit, Glove box light, MAF sensor housing, Rear sway bar, Upper grill block

    Current project: DIY Nitrous oxide setup for ~$100

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage DE 1.2 manual: 45.4 mpg (US) ... 19.3 km/L ... 5.2 L/100 km ... 54.6 mpg (Imp)


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