Uphill charging

[nick2b]

My journey to work every day features several steep climbs (Hardknott and Wrynose Pass in the Lake District for those who know the area).
The PHEV is not the best climbing machine in the world - pressing the accelerator raises the revs with little increase in forward motion!!
Anyway, I wondered if I could take advantage of this by using the climbs to get the best effect of charge mode (given the fact the engine is over-revving anyway).

Anyone got any views on this?

 

[maby]

Something similar has been suggested and we have agreed to test it out when someone has the time - looks like that someone might be you! Getting it into parallel hybrid mode certainly should help, but it will not do this at speeds much less than 50mph - are you able to get it there?

 

[nick2b]

Sorry not sure if I understand. Are you asking me to get up to 50mph going up Hardknott?

 

[maby]

I don't know Hardknott - is 50mph not realistic? You will not get the engine directly coupled to the wheels at much less than 50mph and I don't think that anything else is going to reduce the revs.

 

[nick2b]

No, unfortunately not. Hardknott is the steepest road in the UK (1:3 hairpins).
My main question really, is would this climb be a good time to press the 'charge' button?

 

[maby]

No, unfortunately not. Hardknott is the steepest road in the UK (1:3 hairpins).
My main question really, is would this climb be a good time to press the 'charge' button?

I doubt it - the received wisdom is that the time to press the charge button for a route like that is half an hour before you reach the incline - you want as much battery as you can get.

 

[ian4x4]

The BMW i3 forums make good reading on this sort of subject, as that car is severely limited by the size of its internal combustion engine (37bhp), and therefore in continuous non battery power.

Basically your max electrical power available is 160bhp, and I suspect that your 119bhp IC engine will be nearly going flat out powering the 70kw (93bhp) generator to top up the batteries.

I cannot see where any spare generating power is going to come from, the car is doing its best to delay the batteries from running down, after which you will have a 93bhp 2 ton car on a 1 in 3 hill!

Thus the advice to use charge before you get to the incline, to get the batteries in the best condition to help.

 

[nick2b]

Great, different way of looking at things. So basically, rather than trying not to use the battery power on the hills, on the basis that it drains them rapidly, this is where I should actually be using it.

 

[maby]

Great, different way of looking at things. So basically, rather than trying not to use the battery power on the hills, on the basis that it drains them rapidly, this is where I should actually be using it.

Exactly - and use some combination of "save" and "charge" to make sure you begin the climb with a near-full battery

 

[nick2b]

I will try it tomorrow and let you know how I get on.

 

[jaapv]

No, unfortunately not. Hardknott is the steepest road in the UK (1:3 hairpins).
My main question really, is would this climb be a good time to press the 'charge' button?

Accepted wisdom is to keep charge pressed all the time in hilly country. My experience in the Alps is that it is a pretty good mountain vehicle, especially in snowy conditions.

 

[nick2b]

So I tried it differently today. I made sure that there was plenty of battery charge for the steep hills.
Tackled them much easier, with no 'over-revving'.
This however meant I needed to be in charge mode for the preceeding gentle sections which I normally get good EV range from.

So, from a comfort and performance point of view I can say it is better not to charge on the steep hills. However, I still don't know what is the best combination for the overall economy.

 

[maby]

Getting up a steep hill like that is going to use a lot of energy - no alternative, I'm afraid. On the plus side, you should be able to get a lot of it back via the regenerative brakes on the way back. Hybrids waste less energy than conventional cars, but they cannot break the laws of physics!

 

[alan]

So I tried it differently today. I made sure that there was plenty of battery charge for the steep hills.
Tackled them much easier, with no 'over-revving'.
This however meant I needed to be in charge mode for the preceeding gentle sections which I normally get good EV range from.

So, from a comfort and performance point of view I can say it is better not to charge on the steep hills. However, I still don't know what is the best combination for the overall economy.

You could try putting it in save mode with a full charge until you reached the hill.

Alan

 

[MadFrankie]

So I tried it differently today. I made sure that there was plenty of battery charge for the steep hills.
Tackled them much easier, with no 'over-revving'.
This however meant I needed to be in charge mode for the preceeding gentle sections which I normally get good EV range from.

So, from a comfort and performance point of view I can say it is better not to charge on the steep hills. However, I still don't know what is the best combination for the overall economy.

As said before, think of it that your car needs as much help as it can get going up hills like that. You wouldn't attempt to climb Mount Everest by tying your hands behind your back - however, think of the plus side - on the way home just slap it into B5 and see how much charge you can get into the battery. Love to see the results...wonder if you could get enough in it to drive the rest of the way home on EV.

 

[bretix]

Got here by googling Wrynose (going into Hardknott) and phev after experiencing that pass today and discovered fear beyond fear

Carried on unassumingly via Google maps (word of warning.... Don't trust sat nav especially in the lakes!), assuming 4x4 phev should be fine.

Already had used up electric reserve on smaller climbs etc and chuffed with how well car had been handling especially in wet/flooded conditions, so confidence growing.

So everything fine in petrol only mode, yeah a few heavy revs needed going uphill especially on the turns, but overall seemed to be handling ok....ish.
Some steepish uphills so also put into 4x4 mode.

Kept in B5 for regeneration all the way downhill (never had to flip the paddles so much!), and journey overall fun for me, the passenger, the 2 kids and an asleep dog.

Then the weather turned and going downhill this machine can be a beast to handle, hail had made the road slippery and the narrow steep roads hellish even driving slowly, carefully.

Never struggled so much trying to control a 2 tonner in light snowy/hail conditions going downhill, otherwise handled superb on hairpins up and down in dry and wet.
However after today would be quite happy not to return in the phev and those conditions and wonder how a LR would handle it better. Also lack of charging points in the lakes is a massive disappointment, especially for a national park.

Otherwise usually would drive alternating between save and normal to achieve 50 mpg ( left in normal discovered only get about 36 mpg) and when in hilly areas on save only to use battery uphill- yet to try the charge mode and not sure if this would benefit?