What about Freight Hybrids, like a MACK truck? - Page 5 - GreenHybrid

ken1784 · #41 (**permalink**) 09-27-2006, 08:13 PM

Quote:

Originally Posted by nitramjr

I'm with Tim, I don't think the Escape uses electric heat and I doubt the Prius does either. A pure resistance load would drain a battery in no time. It probably uses scavenged heat from the cooling system. I've been wrong before though.

The 2004 or later Prius has two PTC heaters, 800W total.

Ken@Japan

nitramjr · #42 (**permalink**) 09-28-2006, 05:30 AM

Quote:

Originally Posted by ken1784

The 2004 or later Prius has two PTC heaters, 800W total.

Not the first time I guessed wrong.

I read in one of the links that was in an earlier post that the heater uses electricity when on HIGH only if I read that correctly. Does it use the more conventional heater core based system when not on high?

800 watts plus the fan is the equivalent of more than a 1 hp motor. I wouldn't be running the heat much.

SoopahMan · #43 (**permalink**) 09-28-2006, 03:26 PM

Quote:

Originally Posted by nitramjr

800 watts plus the fan is the equivalent of more than a 1 hp motor.

Did you mean 100hp? A lot of things require more energy than a 1hp motor... .

The fan shouldn't be a huge amount of power - typically those run at 12V and 10 Watts for a powerful fan, so that's 100 Watts on the Prius's 120V. If we assume an OK energy converter, that's 150Watts put in. Combined with the 800Watt heaters that comes in right around the 1000Watt numbers I ran earlier.

curtissac · #44 (**permalink**) 09-28-2006, 07:27 PM

Quote:

Originally Posted by SoopahMan

Did you mean 100hp? A lot of things require more energy than a 1hp motor... .

The fan shouldn't be a huge amount of power - typically those run at 12V and 10 Watts for a powerful fan, so that's 100 Watts on the Prius's 120V. If we assume an OK energy converter, that's 150Watts put in. Combined with the 800Watt heaters that comes in right around the 1000Watt numbers I ran earlier.

Not sure I am following your math. How does 12v and 10 watts equate to 100 watts on a 120v system?

Looks like you meant 10 amps on your 12v side. A 10 watt fan would not be very powerful at all. That would equate to 1/75 hp. Hardly enough to blow out a candle.

10 amps at 12v is 120 watts
1 amp at 120v is 120 watts.

SoopahMan · #45 (**permalink**) 10-02-2006, 11:51 PM

I'm not sure I am either - I checked that math with an Engineer ironically. I thought something didn't work out. However with your correction the fan only takes less power, not more.

A 10 Watt fan running at just 12Volts is an example I used because I've interacted with just such a fan: it's what I use to cool PCs I build. Those things are plenty powerful. You don't need a lot of horsepower to blow air at someone.

Tim K · #46 (**permalink**) 10-03-2006, 01:18 PM

Quote:

Originally Posted by nitramjr

Not the first time I guessed wrong.

I read in one of the links that was in an earlier post that the heater uses electricity when on HIGH only if I read that correctly. Does it use the more conventional heater core based system when not on high?

800 watts plus the fan is the equivalent of more than a 1 hp motor. I wouldn't be running the heat much.

From what I could find online, the "PTC" (Positive Temperature Coefficient) heater in the Prius is used as a temporary source of cabin heat until the engine comes up to temperature. If this is the case, I doubt the unit is designed to be used long-term nor would I expect it to be very efficient. In other words, its OK to use while you are waiting for your engine to warm up on a cold morning, but it won't provide much heat and it would use a great deal of electricity from your battery if the engine isn't on. I couldn't find much info on these heaters so I don't know what the real numbers are as far as wattage etc. Perhaps a Prius II owner can chime in with some real world heater experience....how long the engine stays hot enough to provide warm air....how quickly the electric heater drains battery power....etc.