When to use 'battery save' button

Hi All,

When is the best time to use the battery save button?

Part of my journey to work is about 4-5 miles on the motorway but noticed on my demo that the battery runs down very quickly when driving at 60mph. Would it actually work more efficient to enable battery save and use the petrol engine for the motorway part of my journey?

It depends on your overall commute. If you are reaching your charging point with no charge left, then yes use save mode when you are doing 50mph plus as this is when the EV is at its least efficient. But it is still preferable to use electricity rather than petrol if you do not run out of charge before you can recharge.

Thanks,

My overall commute is about 25 miles, although I was unable to make it on battery alone - probably because of the motorway reducing the battery. It sounds like saving battery on the motorway portion of the journey will be the best option.

I usually get about 25 miles from a full battery, but I tend not to do many motorway miles. But with practise I think you could probably do it without 'save'!

I'm surprised you're not making the full journey on EV as what you describe ought to be within the range, albeit not with much, if anything, to spare. Unless perhaps that 4-5 miles motorway is uphill when the charge drops much faster.

Presumably you've tried turning AC off, switched eco mode on and using B0 to coast, B1-5 whenever you can?

maddogsetc said:

I'm surprised you're not making the full journey on EV as what you describe ought to be within the range, albeit not with much, if anything, to spare. Unless perhaps that 4-5 miles motorway is uphill when the charge drops much faster.

Presumably you've tried turning AC off, switched eco mode on and using B0 to coast, B1-5 whenever you can?

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Steady on maddogs, I don't think he's got the car yet....

:!: :roll:

When you do get the car, I would try using save just to get up to motorway speed and if you can cruise at 60 ish and, as maddogsetc says, use b0 wherever possible (or appropriate b if downhill) then you might just do it, but will depend on hills. It is all part of the fun - working out the best tactics for your out of range routes! As you do it every day, you'll get plenty of chance to try different strategies!
H

Hypermiler said:

When you do get the car, I would try using save just to get up to motorway speed and if you can cruise at 60 ish

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Don't forget that when you first hit battery save with the engine cold it will only produce a little power until it warms up which might take 2-3 minutes. So accelerating upto motorways speeds in this way will use battery rather than ICE. Obviously, if the engine is already warm, then this would be a good way to extend the battery range by using the ICE for higher power use.
Since the amount of miles on the motorway is quite small my suggestion would be to travel as slowly as you can safely manage, without being a nuisance, in order to enhance the EV range.
Kind regards,
Mark

avensys said:

...Don't forget that when you first hit battery save with the engine cold it will only produce a little power until it warms up which might take 2-3 minutes....

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Is this really true? The manual says nothing about this as far as I can find. I've only seen high performing sports cars adopt this as a means of engine protection and even then, the limitation is a lower maximum RPM rather than limiting power output.

Kev.

The ICE doesn't come on as soon as you hit save, which can be a bit irritating (hadn't really thought about why that is)- I try to put it on half a mile before I need it and/or put my foot down a bit to force it on. An alternative would be to use charge as that forces the engine on straightaway (altho costly in terms of petrol). Sometimes you can lose a few miles of ev range on a hill waiting for the ICE to kick in when in save mode.
H

Isn't there a danger of overdoing this? Four miles is going to use a pint of petrol - just use the car and enjoy it!

avensys wrote:

...Don't forget that when you first hit battery save with the engine cold it will only produce a little power until it warms up which might take 2-3 minutes....

Click to expand...

Is this really true? The manual says nothing about this as far as I can find. I've only seen high performing sports cars adopt this as a means of engine protection and even then, the limitation is a lower maximum RPM rather than limiting power output.

Click to expand...

It's certainly fits with my experience, which is that for the first minute or two after switching Save on the car still operates in series mode, even at 60mph.

BeerHunter said:

avensys said:

...Don't forget that when you first hit battery save with the engine cold it will only produce a little power until it warms up which might take 2-3 minutes....

Click to expand...

Is this really true? The manual says nothing about this as far as I can find. I've only seen high performing sports cars adopt this as a means of engine protection and even then, the limitation is a lower maximum RPM rather than limiting power output.

Click to expand...

Hi,
It doesn't mantion it anywhere but it is true. I had a Gen 2 Prius and then a Plug-in Prius and it is both documented and easily observable behaviour for those so I was already expecting it with the PHEV.

Anyone with the slightest interest in cars knows not to work the engine hard while it is cold as that is *bad* for the engine. In normal use an ICE has a chance to warm up somewhat while driving slowly getting out of your drive, housing estate, whatever before getting to a motorway. With a PHEV you could be driving at 70mph, even climbing a motorway gradient, with a stone cold engine when the battery depletes and the ICE starts. If it took the full load straightaway, before warming up, then this would be bad for engine wear as well as emmissions since the CAT wouldn't be warm either.

I have verified this behavious with an OBD2 meter. It shows that when the engine starts from cold it runs as 1500rpm until warm enough to take the load. From an observational point the easiest way to verify it is to be cruising at anything over 45mph in EV mode with a cold engine, hit charge mode, then watch the power display. You will see that it stays in series hybrid mode for 2-4 minutes then switches to parrallel hybrid mode when warmed up. Repeat this again with a warm engine and you will see it is very quick (seconds) to select parrallel hybrid mode.

Caveats: Selecting charge mode when the battery capacity is above 70% may not start the engine. Selecting save mode when the battery capacity is over 90% may not start the engine.

I suspect that when people say they see the car in series hybrid mode at speeds above 45mph (apart from pretty much flooring it) it is because they are paying more attention to the power source when the engine first starts.

Kind regards,
Mark

Hypermiler said:

The ICE doesn't come on as soon as you hit save, which can be a bit irritating (hadn't really thought about why that is)- I try to put it on half a mile before I need it and/or put my foot down a bit to force it on. An alternative would be to use charge as that forces the engine on straightaway (altho costly in terms of petrol). Sometimes you can lose a few miles of ev range on a hill waiting for the ICE to kick in when in save mode.
H

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I think that when you think the engine hasn't come on with save mode, it actually has but is warming up. Selecting charge mode with a cold engine makes no difference to its bahviour. With a warm engine selecting save may not start the ICE so using charge then would be a great idea to run the engine to prepare for overtaking etc.
I would suggest you never to put your foot down to start the engine from cold. When you demand more power than the EV system can give it will run the ICE as hard as it needs to in order to give you the power you need even if this is bad for the engine.

Kind regards,
Mark

maby said:

Isn't there a danger of overdoing this? Four miles is going to use a pint of petrol - just use the car and enjoy it!

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Hi Maby,
It isn't about the cost of the petrol, it is about the pleasure of not using any if it can be avoided. Some of us would see doing a 25 mile commute purely in EV as a personal challenge

Kind regards,
Mark

avensys said:

Hypermiler said:

The ICE doesn't come on as soon as you hit save, which can be a bit irritating (hadn't really thought about why that is)- I try to put it on half a mile before I need it and/or put my foot down a bit to force it on. An alternative would be to use charge as that forces the engine on straightaway (altho costly in terms of petrol). Sometimes you can lose a few miles of ev range on a hill waiting for the ICE to kick in when in save mode.
H

Click to expand...

I think that when you think the engine hasn't come on with save mode, it actually has but is warming up. Selecting charge mode with a cold engine makes no difference to its bahviour. With a warm engine selecting save may not start the ICE so using charge then would be a great idea to run the engine to prepare for overtaking etc.
I would suggest you never to put your foot down to start the engine from cold. When you demand more power than the EV system can give it will run the ICE as hard as it needs to in order to give you the power you need even if this is bad for the engine.

Kind regards,
Mark

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You'll find in winter that the ICE will come in for the first few miles regardless - in series hybrid mode, in order to heat the interior and battery compartment. It runs at normal power. The only way to minimize this is to preheat the car with the electric stationary heating, but even then it will run for bit.
I do not think this will shorten engine life, modern lubricants have come a long way.

avensys said:

maby said:

Isn't there a danger of overdoing this? Four miles is going to use a pint of petrol - just use the car and enjoy it!

Click to expand...

Hi Maby,
It isn't about the cost of the petrol, it is about the pleasure of not using any if it can be avoided. Some of us would see doing a 25 mile commute purely in EV as a personal challenge

Kind regards,
Mark

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Hmmm, each to their own, I guess! I'm a sailor - perhaps I'll try bolting a mast on top and see if I can avoid using any fuel at all...