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Member Since 15 May 2012
Offline Last Active Nov 27 2013 05:27 PM

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In Topic: Retrofitting Ptc Heater To Mk2

26 September 2013 - 11:55 AM

it depends - if you have deatc (automatic aircon), then it is smartly controlled

but with manual aircon, then PTC control is binary: on or off - only certain manual aircon panels can control (=have additional microswitch) PTC




it's hard to call Focus2 (10 years old design, counting from first C-Maxs from 2003) a modern car ;)


You are right about calling Focus 2 a modern car..  :)
Below is a direct copy from PTC operation description in Etis:
When the passenger compartment temperature is set to HI at the climate control assembly or the heater control is set the highest level, the Electronic Automatic Temperature Control (EATC) transmits an “electric booster heater ON” request signal to the Generic Electronic Module (GEM) via the MS CAN bus. If a manual air conditioning system is installed, the signal is transmitted via a conventional cable connection.
The GEM switches on the electric booster heater depending on the following parameters:
Engine coolant temperature is below 60 °C.
Ambient air temperature is below 10 °C.
Sufficient generator capacity is available.
The electric booster heater consists of three individual heating elements, which are incorporated into a single housing.
The electronics of the electric booster heater controls three output stages dependent upon a pulse width modulation signal (PWM), which is generated by the GEM. The output stages switch the three heating elements of the electric booster heater ON or OFF individually, whereby the heating periods of the individual elements can overlap. Due to the variable switch-on duration, continuously variable temperature control is possible. The overall heating power of the three heating elements is linearly proportional to the PWM signal. If the PWM signal is below 10% or above 95%, the electric booster heater is not activated.
The electric booster heater is switched off when an engine coolant temperature of 70°C or an ambient air temperature of 20°C is exceeded.

In Topic: Retrofitting Ptc Heater To Mk2

26 September 2013 - 11:21 AM

petrol Focus never had PTC but it's possible to retrofit, see here: http://ffclub.ru/topic/288750/ 

You should consider installing more powerful alternator (105A -> 120A  then modify VIDblock in PCM) and during 4km trip your battery won't charge much, so recharge at home


Actually GEM uses PTC only if there is enough reserve power in alternator. It won't affect battery charging at any level, voltage is kept over 14 at all times. I have 120A alternator and PTC is ran with only about 20-30% power (at idle) until glow plugs are turned off. Modern cars are very intelligent when it comes to battery charging, you can't use more power than the alternator can supply. Unless car has some DIY circuits which are not controlled by GEM..

In Topic: Retrofitting Ptc Heater To Mk2

22 September 2013 - 12:26 PM

My car is used regularly for short trips (home to work is only 4 KM). Most times the heater remains cold during these trips. Because of this I am planning to install an additional electric or Petrol powered heater to warm up the interior more quickly in winter time.


Actually I have both now.. 5,2kW diesel powered heater AND PTC heater.. Diesel heaters con is that it's quite slow after all. It takes few minutes to start and few more minutes to get to full power. It also transfers heat through coolant so it won't give much heat until the engine is also warm. It's great for preheating if you remember to take care of battery, it gets easily drained if trips are short all the time.



cant see the point of it on a petrol as it warms up within minutes even during the winter warm air is available quickly



It maybe that we are speaking a little different kind of winters, for example 2012 here was -38c. it would be nice to see a petrol Focus which "warms up in minutes" at -38c :)