anko
Well-known member
Last week, I've been trying to find ways to hang on to as much SOC as possible while towing my caravan. Playing with ECO, Save, Charge and even 4WD Lock button. With the last one, I had an interesting experience.
I was driving about 94 km/h. Charge mode engaged. The energy flow diagram showed an energy flow only from the engine to the wheels, so there was no charging going on. After switching to 4WD Lock mode, the diagram displayed the red arrow from engine to wheels, a blue arrow from engine to battery and a blue arrow from battery to wheels. So, it appeared to be charging
But it wasn't. Far from
At 94 km/h the engine can and will produce up tot 36 kW, when more than 26 kW of power is needed for driving. Otherwise, it will produce about 26 kW. Any surplus will be used for charging. Consequently, when more than 26 kW is needed for driving, no charging is going on. (If the surplus power is more than 8 kW, output will be reduced to less then 26 kW, but that is not relevant here.)
Now imagine, due to a strong head wind, you need indeed 36 kW for driving. The engine works its ass off, but can manage without impacting SOC. Now you switch to 4WD Lock mode. First 18 kW is delivered via the front wheels, the next 18 kW via the rear wheels. The engine settles down from producing 36 kW to producing 26 kW. There is 8 kW surplus, which is used to generate electricity. Nice. But at the same time, the rear motor is taking 18 kW. So, effectively 10 kW is taken from the battery. All the time. You could actually see the battery indicator drop.
In theory, the engine could have continued to produce 36 kW and use 18 kW directly for the front wheels and send the other 18 kW to the battery / rear motor. It would still have been able to deal with the load without impacting SOC (Well, almost. Additional conversion losses might have tipped over the balance).
As I have explained in another post, again it seems the car has a strong preference of producing a predefined amount of power, only to exceed that when driving conditions dictate it, but not in order to maintain SOC. Not even in Charge mode.
Note: kW numbers given above were calculated based on instantaneous fuel consumption plus an estimated fuel efficiency (actually I've used the default setting from DashCmd). In reality, you would expect the max output to be about 40 - 42 kW or so at these speeds. But for the observation itself, the deviation between reported and actual kW is not really relevant.
I was driving about 94 km/h. Charge mode engaged. The energy flow diagram showed an energy flow only from the engine to the wheels, so there was no charging going on. After switching to 4WD Lock mode, the diagram displayed the red arrow from engine to wheels, a blue arrow from engine to battery and a blue arrow from battery to wheels. So, it appeared to be charging
But it wasn't. Far from At 94 km/h the engine can and will produce up tot 36 kW, when more than 26 kW of power is needed for driving. Otherwise, it will produce about 26 kW. Any surplus will be used for charging. Consequently, when more than 26 kW is needed for driving, no charging is going on. (If the surplus power is more than 8 kW, output will be reduced to less then 26 kW, but that is not relevant here.)
Now imagine, due to a strong head wind, you need indeed 36 kW for driving. The engine works its ass off, but can manage without impacting SOC. Now you switch to 4WD Lock mode. First 18 kW is delivered via the front wheels, the next 18 kW via the rear wheels. The engine settles down from producing 36 kW to producing 26 kW. There is 8 kW surplus, which is used to generate electricity. Nice. But at the same time, the rear motor is taking 18 kW. So, effectively 10 kW is taken from the battery. All the time. You could actually see the battery indicator drop.
In theory, the engine could have continued to produce 36 kW and use 18 kW directly for the front wheels and send the other 18 kW to the battery / rear motor. It would still have been able to deal with the load without impacting SOC (Well, almost. Additional conversion losses might have tipped over the balance).
As I have explained in another post, again it seems the car has a strong preference of producing a predefined amount of power, only to exceed that when driving conditions dictate it, but not in order to maintain SOC. Not even in Charge mode.
Note: kW numbers given above were calculated based on instantaneous fuel consumption plus an estimated fuel efficiency (actually I've used the default setting from DashCmd). In reality, you would expect the max output to be about 40 - 42 kW or so at these speeds. But for the observation itself, the deviation between reported and actual kW is not really relevant.
