Charge Mode/Button

[Shamusj]

Has anyone on this forum measured exactly how much petrol it takes to charge the PHEV battery from 0% to 80% using the "Charge" button when the car is stationary? It's just that I live in a communal garage with no access to an overnight charge (yet) so am curious as to how efficient it is to just use petrol to charge the battery during stationary periods (e.g traffic lights, car parks). This EV power would be for inner city driving obviously.

 

[Grigou]

Yes someone has measured but I don't remember the number of litres.

Anyway, it isn't a good idea to charge when the car is stopped.
Instead of that you should try to charge when driving in parallel mode, when the engine is more efficient

 

[Shamusj]

I've seen in the technical forum someone mentioned 2 to 3 litres but I didn't know how much of a guess that was.

When you say it's more efficient in parallel mode, this would imply that it's for when we're going over 70mph, is that correct?

 

[jaapv]

No, there is nothing left for charging over 70 mph.

 

[anko]

When you say it's more efficient in parallel mode, this would imply that it's for when we're going over 70mph, is that correct?

I guess we need to make a distinction between parallel mode (which is more or less 70 mph and above) and parallel hybrid mode, which is roughly 40 - 70 mph. The latter applies to this topic.

 

[HHL]

When you say it's more efficient in parallel mode, this would imply that it's for when we're going over 70mph, is that correct?

I guess we need to make a distinction between parallel mode (which is more or less 70 mph and above) and parallel hybrid mode, which is roughly 40 - 70 mph. The latter applies to this topic.

It is 70km/h... actually, 65km/h when parallel mode can engage. And it is more efficient fuel use than serial mode, nothing to do with charging.

 

[Shamusj]

This does not tally with the official FAQ:

In Parallel Hybrid mode the engine drives the wheels directly, which activates when the battery is empty or the car is driven above 74mph.

 

[anko]

When you say it's more efficient in parallel mode, this would imply that it's for when we're going over 70mph, is that correct?

I guess we need to make a distinction between parallel mode (which is more or less 70 mph and above) and parallel hybrid mode, which is roughly 40 - 70 mph. The latter applies to this topic.

It is 70km/h... actually, 65km/h when parallel mode can engage. And it is more efficient fuel use than serial mode, nothing to do with charging.

So, if your engine must run during part of the trip to generate electricity for the other part of your trip, it would be best to let the engine run while driving fast enough to engage parallel hybrid mode ....

 

[anko]

This does not tally with the official FAQ:

In Parallel Hybrid mode the engine drives the wheels directly, which activates when the battery is empty or the car is driven above 74mph.

Above 74 mph (approx. 125 km/h), or when the battery is empty, or when the Charge or Save button is pressed. But only when speed is 40 mph (65 km/h) or more. At lower speeds, serial hybrid mode is engaged when the battery is empty or when Charge or Save is pressed.

Parallel mode above 74 mp/h (125 km/h) can hardly be called hybrid mode, as it will hardly allow you to gain SOC for future EV driving.

 

[jaapv]

To add, between 65 km/h and 125 km/h the car can decide to go from parallel hybrid -if engaged- into series hybrid when power demand makes it necessary. (also below 65 from EV of course)

 

[Grigou]

When you say it's more efficient in parallel mode, this would imply that it's for when we're going over 70mph, is that correct?

I guess we need to make a distinction between parallel mode (which is more or less 70 mph and above) and parallel hybrid mode, which is roughly 40 - 70 mph. The latter applies to this topic.

It is 70km/h... actually, 65km/h when parallel mode can engage. And it is more efficient fuel use than serial mode, nothing to do with charging.

Of course there is something to do with charging : the engine's "sweet spot" is between 65 kph and 120 kph
So this is the best range of speed if you want to charge the battery at a lower cost as possible.

A contrario, charging with a stopped car is not a good idea for fuel saving

 

[SSJ3]

Hi, just in case and since i don't have enough battery to return home i use charge on downhills (along with regen) or when stopped for large (5m or more) periods of time, this gives me extra % to drive some Kms on queues when road in plain or uphills.

 

[anko]

Of course there is something to do with charging : the engine's "sweet spot" is between 65 kph and 120 kph
So this is the best range of speed if you want to charge the battery at a lower cost as possible.

A contrario, charging with a stopped car is not a good idea for fuel saving

The sweetspot is related to RPM en relative load. Only indirectly to vehicle speed. Even in serial mode, the engine can operate right in the sweetspot. In theory even more so then in parallel mode, as in parallel mode RPM is dictated by vehicle speed.

IMHO, the real advantage of running the engine (and thus charging) in parallelel mode rather than in serial mode is more related to the small losses associated with the driving itself compared to the losses in serial mode:

- In parallel mode, out of max 87 kW (@4500 RPM) of available engine power, 82.5 kW can make it to the front wheels. The 4.5 kW lost in the process include 2.8 kW consumed by the generator when it generates power needed to eliminate E-drag in the front motor. So, approx. 2% is lost in the transmission.

- In serial mode, out of max 82 kW (@4100 RPM) of available engine power, no more than 60 kW reaches the wheels.

This is in my opinion why serial mode should be avoided when possible, and thus charging should take place in parallel mode when possible.

I do agree that charging (or in general: letting the engine run) while parked or under any form of low load (hill descends, coasting, etc.) is a bad idea, indeed because the limitation to the charge current means you can never reach the sweet spot of the engine and fuel is burned inefficiently.

 

[anko]

Hi, just in case and since i don't have enough battery to return home i use charge on downhills (along with regen) or when stopped for large (5m or more) periods of time, this gives me extra % to drive some Kms on queues when road in plain or uphills.

Please see the remark in my previous post on running the engine under low load. Especially regenning i.c.w. Charge mode must be very inefficient: The amount of charge the battery is willing to accept is limited and probably fulfilled by regenning alone (the battery will accept more power from regenning than it will ever accept fro the generator). This means the engine cannot add any additional charge and the engine is just burning a little fuel in order to prevent it from slowing down the car.

 

[Grigou]

Thank you anko, you've developed my toughs quite perfectly, in the same way than I could have done in my French language :lol:

 

[jaapv]

Hi, just in case and since i don't have enough battery to return home i use charge on downhills (along with regen) or when stopped for large (5m or more) periods of time, this gives me extra % to drive some Kms on queues when road in plain or uphills.

Please see the remark in my previous post on running the engine under low load. Especially regenning i.c.w. Charge mode must be very inefficient: The amount of charge the battery is willing to accept is limited and probably fulfilled by regenning alone (the battery will accept more power from regenning than it will ever accept fro the generator). This means the engine cannot add any additional charge and the engine is just burning a little fuel in order to prevent it from slowing down the car.

Yes, but on a downhill stretch the amount of fuel burnt by the engine must be very low to the extent of not making a discernible impact..

 

[anko]

Yes, but on a downhill stretch the amount of fuel burnt by the engine must be very low to the extent of not making a discernible impact..

Maybe to you. Maybe not to others Regardless, not using Charge on a downhill stretch he would have burned even less fuel, namely 0. If SS3J turns on Charge mode purposely on downhill stretches (as he suggests he does) and it turnes out it has no positive effect on SOC, he would definitely be better off if he did not do that.

BTW: While coasting in parallel mode at 100 km/h, the amount of fuel burned is already more than 2 liters per hour, so more than 2 l/100 km. This is already more than the (unrealistic, but yet ...) advocated plug-in hybrid fuel consumption number.

 

[jaapv]

No argument that turning on charge driving downhill might be counterproductive. However the inconvenience of pushing charge uphill and switching it off downhill all the time can been seen differently.

 

[SSJ3]

Thanks all for your feedback but numbers don't lie and that facts are, after 2 weeks for driving my daily commute, if don't use charge on downhill’s and on some few slow queues (downhill as well) along with SAVE on Motorways (100Km/h or plus) i spend more 3 to 4L once i arrive home.

My daily commute is made of 45Km with several uphill’s and downhills (10 i would say) with more the 10% inclination on a couple of them and I've been trying all possible combinations (1- Let the car manage the battery by himself 2- Use CHARGE only on Motorways 3- Use SAVE only on Motorways 4- Use Charge on downhill’s and queues and SAVE on Motorway) and I've being get better fuel consumption's, from 9-10L to 6-7 now, which along the 1,5-2L that i get on my way to work it makes me more happy then before (4-6L way in and 9-10L returning back).

Still, I’m looking forward to get more fuel efficient tips.

 

[jaapv]

I would say that is because that enables you to use EV in fuel-inefficient driving situations.