bretti_kivi
Member
Hi,
I'm coming at this from the absolutely pragmatic "I need heat in here ASAP" that comes with living in an area where -10 is a daily occurence for two-three months of the year and we used to hit -30 at least once per winter.
That there is a finite amount of heat coming from the engine is true, I'd missed that. However, I'd be very surprised if you can tell the difference between leaving the heat off (which will mist the windscreen, which, at least here, tends to freeze then) so for me it's a theoretical point. May make a difference, I'm not prepared to prove it either way. Just leaving it at "21" is also not an option when you actually need to demist the screen; start the car, HI, 3 bars, up, get out, brush snow, by the time you get back in it's probably above zero. The air flow is so slow if you leave it on auto that there's no way it would clear the screen. Yes, ice on the inside.
I have a theory on the real reason the climate buttons wear? Hand cream. Females with handcream use melt it off.... mine are fine and I change the temp all the time in the winter.
That the heater puts more load on is clear. But you have a 120A alternator regulator on a 75, possibly a 140. At that, with cold temperatures, I'd be really worried about emptying the battery extremely quickly, load or no. Especially short journeys would just kill it. The fan motor is also not exactly a small one.
The logic Steaman and Spike posted is pretty clear: for the PTC to be turned on, ALL of the following need to be true; ECON off, <70C coolant temp, <6C outside, >600rpm, and less than 60% alternator load. Since that will essentially never be true (after a start, the alternator is not going to be only 60% loaded!) then I wouldn't be surprised if it's essentially never on. I suspect the alternator load is to avoid it deep-discharging the battery.
Re-reading, the test procedure seems to be to make sure something actually happens, whereas in real life the "HI" or no is not relevant. That would fit with the understanding that the PTC is a straight replacement for the Webasto, which could keep running permanently if necessary.
- Bret
I'm coming at this from the absolutely pragmatic "I need heat in here ASAP" that comes with living in an area where -10 is a daily occurence for two-three months of the year and we used to hit -30 at least once per winter.
That there is a finite amount of heat coming from the engine is true, I'd missed that. However, I'd be very surprised if you can tell the difference between leaving the heat off (which will mist the windscreen, which, at least here, tends to freeze then) so for me it's a theoretical point. May make a difference, I'm not prepared to prove it either way. Just leaving it at "21" is also not an option when you actually need to demist the screen; start the car, HI, 3 bars, up, get out, brush snow, by the time you get back in it's probably above zero. The air flow is so slow if you leave it on auto that there's no way it would clear the screen. Yes, ice on the inside.
I have a theory on the real reason the climate buttons wear? Hand cream. Females with handcream use melt it off.... mine are fine and I change the temp all the time in the winter.
That the heater puts more load on is clear. But you have a 120A alternator regulator on a 75, possibly a 140. At that, with cold temperatures, I'd be really worried about emptying the battery extremely quickly, load or no. Especially short journeys would just kill it. The fan motor is also not exactly a small one.
The logic Steaman and Spike posted is pretty clear: for the PTC to be turned on, ALL of the following need to be true; ECON off, <70C coolant temp, <6C outside, >600rpm, and less than 60% alternator load. Since that will essentially never be true (after a start, the alternator is not going to be only 60% loaded!) then I wouldn't be surprised if it's essentially never on. I suspect the alternator load is to avoid it deep-discharging the battery.
Re-reading, the test procedure seems to be to make sure something actually happens, whereas in real life the "HI" or no is not relevant. That would fit with the understanding that the PTC is a straight replacement for the Webasto, which could keep running permanently if necessary.
- Bret