heater does not get hot

<div class='quotetop'>QUOTE(DaveinOlyWA\";p=\"61096)</div>

Dave:

Right, so why are folks so afraid of this? Stick the electric heater next to the regular heater core in the plenum box and be done with it.

That's way safer than having a 115 VAC interior warmer plugged in. Folks usually perch those things on the seat or next to the carpet on the floor and cause an exciting fire by morning.

Much like the EMF post, I'm under the impression that a lot of folks regard our Prius as rolling Tesla Coils.

 

<div class='quotetop'>QUOTE(tomdeimos\";p=\"60797)</div>

I have a 2004 and I guess I wasn't careful reading this part of the manual. I too did not realize MAX heat and foot or foot/def AND blower not off were required. I just assumed (yeah I know) that Auto A/C would run the heaters for awhile when the car starts up until the engine is warm.

I'll be testing the defrost on foot/def and Max heat next time we get cold (should take about 1 day). I'm loath to run the car 5 minutes or so to warm it up so the defroster actually does something to the fog created as soon as I take the snow/ice windshield cover off and start driving.

Calling Coastal Dave!! Must be some way to kill the coolant temp and Max hot requirements.

I like it!!

 

<div class='quotetop'>QUOTE(jayman\";p=\"60633)</div>

Hi Daniel:

Well, if worse came to worse, I could wear the thermal underwear. But jeez, what a PITA to have to change at work and again before I leave![/b][/quote]

I chose a middle ground. As with Jayman, I couldn't wear thermals at work and I didn't want to change in the restroom. I got a pair of heavy material sidezip wind/ski pants. You can get them insulated too I think.

'Changing' involves running the zippers down the outside of the pant legs and taking them off in a front half/back half fashion, or unzipping from the bottom far enough to get them off easily with your shoes still on.

 

ok got my first taste of "cold" weather this morning. it was 26º F this morning... absolutely frigid by my standards.

had to warm up the car about 5 minutes because i dont have an ice scraper (i used a plastic egg flipper with limited success)

but after getting in the car, it did not warm up much before reaching my destination (gym 1.2 miles away) so cant really judge its effectiveness.

but will say that the defrost did work very very quickly and yes there is defrost coils on the lower rear window. (ok that was another thread)

 

Thanks Bruce!

Hadn't thought of ski pants. I was seriously considering a snowmobile suit, but those can be a royal PITA to take off in a car once things do warm up.

 

How about one of those $30-$40 12volt heated massage thingys that you put ontop of your car seat? But, then to be effective you would probably have to be in your underwear to feel the heat! Also, you would freeze to death from the cold air.
I don't know why I even posted this. :mrgreen:

 

While you shiver don't feel too bad. Looks like lots of cars are having heater
problems along with the Prius.

And it may take a lot of car companies time to figure out how to do it right.

http://www.beru.com/english/aktuelles/pres...se/20020204.php

 

<div class='quotetop'>QUOTE(DaveinOlyWA\";p=\"61146)</div>

When I first moved to VT and went through orientation at work (in Aug) they said "Do NOT use your employee badge as an ice scraper".

Well don't you know what came to mind the first time we had a light frost and I had no ice scraper. Those laminated badges work GREAT! :lol: One of the labs I worked in made similar badges for the operators with bar codes on them. They sometimes made blank one to use a ice scrapers. They aren't effective for a long time, but for emergencies, pretty good.

Next time, in a pinch, use a credit card or other narrow hard plastic thing. Probably best to keep the magnetic strip away from the glass. I don't suppose a little ice would hurt it, but who knows.

 

To test your electric heaters you could

1 add led's to show when they are on
2 monitor comverter current to see when it is high
or

3 You can barely feel the heat just enough to tell.

I started out this morning and started up in my driveway. Set heat on to normal with
med to slow fan speed and recircualte. Air to floor.

But I get some air to the left dash vent leaking through too. So I felt the air at my feet
and at the dash vent. Felt a tiny bit of heat from the thermos water, but the floor and
the dash vent were clearly at the same temp.

Then I set heat control to max hot and I could then feel the floor was a little bit warmer
than the dash air temp.

So clearly they do work. And if Toyota just gave us about 8 of them instead of just 2
there might be enough heat!

But they made a more serious goof. To keep heating at highest power they would
have to be placed on the intake side of the water heater core. I think that is why
they just let them shut off once the water warms a bit!

They may start out at 300 watts each but they probably run at less than 50 watts once
going and the car starts to warm its coolant.

 

<div class='quotetop'>QUOTE(tomdeimos\";p=\"61317)</div>

Nope, they are either on or off.

 

<div class='quotetop'>QUOTE(tomdeimos\";p=\"61311)</div>

In the case of the VW Golf with Direct Injection diesel, that's an entirely different situation. Diesel motors are, on average, much more cold-blooded than gasoline motors in cold climates. So I would naturally expect a diesel motor to run cold in a cold climate. Unless you work them, they stay cold, which is also bad for the motor too.

The key similarity is that with much higher efficiency, you produce less waste heat, since you're using much less fuel. The thing is, in a climate as frigid as this one is, you sure appreciate that waste heat: -34 C this morning, with windchill -44 C.

Given that the Prius already uses much higher voltages, that excess energy could be put to good use: keeping me toasty! At these temps, my SOC is always 1 bar away from the top.

Maybe the next generation Prius will have a high-voltage electric plenum heater.

 

<div class='quotetop'>QUOTE(DanMan32\";p=\"61321)</div>

Nope, they are either on or off.[/b][/quote]


No Dan you are wrong .even if it was a regular heater. Take even a standard house water heater. 4 kw element does not draw close to 4 KW, except when powered up and it is
still cold.

I may be off on the watts but the PTC Prius heaters are not putting out anywhere near 600 watts of heat. Their power goes down even more than a regular heater. That is
why they are used. Just like today's electric blankets that can never get warm enough.
Much safer, but less effective.

 

Well they are driven exclusevly off of a 15A fuse each, so they are no bigger than 300W total, but I doubt they would be much less either.

 

<div class='quotetop'>QUOTE(DanMan32\";p=\"61446)</div>

Where do you see a 15 amp fuse? Sure you're not looking at the power
for the relays? My manual shows each one on it's own 30 amp fuse.
Page 66 in the 2004 wiring book.

I admit I haven't measured the draw on them yet, but my point was if it
really is a "PTC" heater as advertised, it should draw considerably less power when heated than when cold, by definition. It is supposed to make them safer so they limit output if say the fan jams or something.

I also don't believe they could be using 600 watts because my 120 VAC
ceramic heater on low at around 700 watts warms my car up so I can
take off my coat in a few minutes and these don't even come close!

If they really changed them to half the power that also would help
explain their poor performance.

 

You are right, 30A each. I think I got it crossed with the power outlet fuses.

As for a water heater, you have to remember, the water will keep the element a lot cooler than say a home resistive heater in air. That would minimize the increase resistance due to heat, and thus minimize lowering of current draw.

 

Just resurrecting this thread, after a bit of searching. It appears this thread came to the conclusion that the PTC heaters only activate if MAX HOT is set. But I think this may be due to a misunderstanding of the manual. htmlspinner, in this thread, one year earlier, says that from his tests, MAX HOT doesn't make a difference, and they can activate at 75°F.

Could it be that the service manual's list of conditions is merely sufficient rather than necessary? I think they may be telling the service engineer a set of conditions that will definitely cause the heaters to activate, so they can test operation. I don't think it should be read as saying that the heaters only activate in those conditions.

If htmlspinnr's reading - how were you inspecting PTC operation? Did any of the people who believe MAX HOT is necessary determine that experimentally?

 

Of course, the reason my own fiddling was inconclusive may have been that there are no "PTC HTR" fuses in my fuse-box.

It appears the UK isn't cold enough to merit electric interior or mirror heaters... The coldest I've seen since getting the car is -1°C (30°F), so they may sort of have a point.

 

Well, it has cooled off a bit. Snow is falling quite heavily and is really being whipped around by the wind. Tomorrow morning should be *fun*

Over the past week it warmed to around +8 C, and in those temps the heater works just fine. You can just leave it at say 24 C and it quickly heats up.

Approaching -15 C, you need to manually select Max Hot and even then it's very slow.

At -30 C and colder, even if I sit in the heated underground parking for a few minutes to get hot air, after a couple of blocks the motor and the car will cool right down.

In the city driving I normally do - no faster than 70 km/h - the motor just cannot warm up at -20 C or colder. As I've commented before, it would be nice if Toyota had thought of running supplemental electric heat directly off the main battery.

 

It's a good thing we can even drive at those temps. Here in Europe, where diesels are very popular, low temperatures (-25C or lower) make national news every time due to all those expensive diesel cars (Mercedes, Audi etc.) that can't even start or get stuck due to fuel in-filterability. Here diesel fuel is only rated -15C (how unfortunate).

I, for once, am happy to be able to start and drive a Prius at -25C, hot, warm or cold air in the cabin. I do admit that in cases like these I do prefer highways over national "dirt" roads. They also plow highways more often than regulars.

So the problem (insufficient heat) iterates itself only in one case:
-it is darn cold outside (-20 C or colder)
-max. driving speed does not exceed 70 km/h
-you are doing city stop-n-go driving where the engine does shut off

One could argue that putting the gear stick in 'B' could cause the engine to run more thus generate more heat, but that's just an unfounded thought. Or you could drive more aggressively putting a bit of extra work on the gas engine although for me, driving at -30 C means extreme caution as a spit freezes before it lands on the floor!

Regards,
Boris

 

Giday BorisSlo

I am thankful that we NEVER have those cold temperatures. The worst winter's day this year got down to -3C and everyone thought their throats had been cut.

It is still reasonably warm here (33C yesterday) but given all your comments, I am relaxed as we begin to head into the southern hemisphere winter knowing the my Prius will take everything thrown at it.