What's the purpose of EV+ ?

[METROMAN]

So what's it for exactly? Seems to me it would be better to turn it off & save the battery for the next morning.

[LizM]

I actually kind of agree with you...I am experimenting by doing this myself to see if there is a difference.

[Adair]

It may eke out another .1 of a mile. In the winter, I think it hurts you because of exactly what you said.......you need the battery for the morning. But in the summer, maybe it helps a little. Also, it depends on how much battery you have left when it kicks in. This afternoon I was down at the bottom on my way home when EV woke up. It immediately gave me 2 full bars (which I didn't need, since it was flat and close to home), but still, I got another .1 in the mpg column.

[StoBro2]

When the engine is cold after sitting all day or overnight it will run after start up just to get it to the proper temperature for the catalytic converter and all of the various emission controls. Since the engine has to run anyway, it might as well do some good and charge up the HV battery as it warms up. Having EV+ squeeze every last bit of juice out of the battery before shutting the car down means that it can better take advantage of the "free" recharge later on.

[SnitGTS]

I tend to agree with the OP, a couple times now I've come home and the battery was almost depleted by EV+ which caused the car to start the ICE as soon as I turned it on the next morning.  This would be fine if I was immediately on the road, but I have to back out of my garage, get out of my car and shut the garage door, then get back in the car and get going.  Normally this doesn't take too long, but the first time this happened I thought it was so funny that the car was running I sat there and listened to it for a few seconds, by the time I got in the car my trip mpg dropped by a full mpg!  It took weeks to get that mpg back!

 

When I have more battery in the morning I can get out onto the road before the ICE starts, so I'm also accelerating while the car is warming up.  I still lose a tenths of a mpg or two, but not the full mpg that I lost when the car was sitting in my parking lot!

 

I haven't turned it off yet, but I have thought about it.

Edited June 22, 2013 by SnitGTS

[Noah Harbinger]

When the engine is cold after sitting all day or overnight it will run after start up just to get it to the proper temperature for the catalytic converter and all of the various emission controls. Since the engine has to run anyway, it might as well do some good and charge up the HV battery as it warms up. Having EV+ squeeze every last bit of juice out of the battery before shutting the car down means that it can better take advantage of the "free" recharge later on.

 

This is my interpretation as well. Especially when you consider that shortly after a cold-start should be the only time the engine will be running when you are at a complete stop. 

[salsaguy]

I'd like to hear from our 2 mpg experts Jus and Recump for their take to decide if it's better to keep it on our off.

[METROMAN]

Thinking about turning it off today

[salsaguy]

if you do please try it for a while off to compare with it on and post results/comments.

i wonder if you need to clear out the ev+ locations for it to really make a diff or just turning it off will be good enough.

[SnitGTS]

I've commented on this in other posts, but my EV+ seems to turn on a lot sooner than others.  If I'm coming home from work, I'm coming down a road that is almost parallel to my road, the roads connect in a V.  EV+ kicks in at one end of the V and my apartment is at the other end, the total distance is 0.7 miles that way.  When I come home the other way, it turns on about 0.4 miles from my apartment but this route is all uphill.  

 

I prefer the V route because there is a downhill component at the end and I end up with more battery left, it's when I come home the other way that the battery can be almost fully depleted.  If I had to guess, I would say I need at least 1/4 to 1/3 battery charge to make it to the road before the ICE kicks on.

 

When it starts warming up in the parking lot I lose significantly higher mpg than if I'm on the road when it's warming up.

[ScubaDadMiami]

EV+ works pretty well for me.  However, I live in flat territory.

 

When I come home, I make the last two blocks in EV+.  When I get out of my C-MAX at that time, there will be a very low battery.  However, as someone else mentioned in another post, if you have enough experience with many battery devices, you will find that the SOC will move up a bit while the vehicle sits.

 

The next morning, when I get back in to drive away, I have enough juice to move from my spot in the parking garage to the exit gate, so long as I maintain idle speed.  I travel perhaps 50 yards in EV.

 

It adds up over time.

[plus 3 golfer]

When the engine is cold after sitting all day or overnight it will run after start up just to get it to the proper temperature for the catalytic converter and all of the various emission controls. Since the engine has to run anyway, it might as well do some good and charge up the HV battery as it warms up. Having EV+ squeeze every last bit of juice out of the battery before shutting the car down means that it can better take advantage of the "free" recharge later on.

 

 

This is my interpretation as well. Especially when you consider that shortly after a cold-start should be the only time the engine will be running when you are at a complete stop. 

I agree.  I can't think of a reason to not deplete the battery using EV+.  

 

The goal on cold start would be to warm up ICE quickly to reach closed loop operation.  Charging the battery helps by adding load.  Also, generally a higher load will allow the PCM to operate ICE in a more efficient part of the Brake Specific Fuel Consumption curve.  IMO, this is likely the reason for EV+ as it should improve FE (on the Energi, it also makes sense to deplete the HV battery since replacement energy would be cheaper from the grid than from ICE). 

 

On a hot start, it really should not make a significant difference whether one used EV+ or not.

[KAL Cmax]

I have yet to use EV+ and seem to get great mpg.

 

Personal opinion, it seems to be a carry over from the Energi. I could see it being more useful if you are able to plug in and charge a fully depleted battery.

[plus 3 golfer]

I have yet to use EV+ and seem to get great mpg.

 

Personal opinion, it seems to be a carry over from the Energi. I could see it being more useful if you are able to plug in and charge a fully depleted battery.

Obviously, you haven't driven in the winter yet. :)  ;)

 

You'll want to get ICE up to operating temperature as quick as possible. As Stobro2 says - "When the engine is cold after sitting all day or overnight it will run after start up just to get it to the proper temperature for the catalytic converter and all of the various emission controls. Since the engine has to run anyway, it might as well do some good and charge up the HV battery as it warms up."  The quicker you reach operating temperature, the better your FE will be.

[SnitGTS]

I can understand wanting to get the car warmed up quickly, but when the car is sitting in my parking lot no matter how efficiently the engine is charging the battery I'm not moving and therefore mpg for the tank dives faster than if the engine is less efficiently charging the battery and I'm moving.  That's just my observation from a month and a half of owning the car.

 

Something similar happened to me the other day when I was driving home from work and I 'managed' to get 33.6 mpg on my commute (normally around 45 mpg).  It was raining hard and there was a section of my commute where the traffic was so bad that I never moved more than a car length or two at a time, the battery was low to start with and eventually it drained to the point that it ran the ICE a couple times for a few minutes to charge it / keep the car warm.  I was sitting there watching my mpg drop and there was nothing I could do.  It never drops that much when the ICE is running when I'm moving.

 

I think for the most part EV+ is a worthwhile idea, but for me and my driving conditions it *sometimes* drains the battery too much for its own good.  (this has happened twice to me in 6 weeks)

Edited June 22, 2013 by SnitGTS

[StoBro2]

Another factor that may come into play is the self discharge rate of lithium-ion batteries at various states of charge. From what I've read, a fully charged battery will lose about 5% of its charge in the first 24 hours of storage, then the self discharge rate tapers off after that. If the battery is stored with a partial charge (40% - 60%) the initial self discharge rate is much lower. Energy lost from the battery due to self discharge is energy wasted.

 

http://batteryuniversity.com/learn/article/elevating_self_discharge/

[salsaguy]

snig, did you use the heater/fan to keep you warm? some suggest using the seat heaters instead of the AC heater  so you don't kill your mpgs.

[SnitGTS]

I've not once turned on the heat in my car, never needed it as its been mostly warm here.  The few days that it was a little chilly in the morning I used the heated seats.  That's exactly why I got the winter package with the heated seats, so I don't have to use the climate controls to warm me up and save some gas.  I figure in the winter I will warm the car up to 50 then use the heated seats to keep me warm, I prefer it to be a little cool anyway.

 

If you thought I meant to keep the car's cabin warm in my previous post, I didn't mean that.  The day I 'managed' 33.6 mpg, between the cool temperature, the rain, and the fact I didn't move much for 30 minutes (and not using the ICE at all) that the car's temperature might have dropped below where it needs to be and that it might have run the engine both to charge the battery and to keep the car itself warm.

[Bill-N]

WFIW, it's my understanding the the HV battery needs to be warmed-up for it to operate and that the engine is run for that purpose also.

[nsteblay]

I always thought it was for the teenage children so that they don't wake their parents when they come home late.

[Jus-A-CMax]

I'd like to hear from our 2 mpg experts Jus and Recump for their take to decide if it's better to keep it on our off.

My answer is it all depends.  For me, I have hills to climb and the way my fe driving pans out I am half battery (or just a tad below) and my last leg is only doable (without gas) with the lower threshold from EV+ otherwise ICE kicks in and there goes more gas.  I now have ev+ before my work location and I luv cruising in. The subsequent cold restart, ICE is always gonna kick in any way (inevitable) so I am going to get my charge no matter what and away I go...

 

So yes, for me is to keep it on. 17,000 miles on & I keep my ev+ on. I see this as more gain than anything else due to my final destinations. 

 

Ps after the 3.5.1 update, I lost my ev+ and sure enuf, ICE kicked in right as I got to the start of my street. P*ssed me orf.

Edited June 28, 2013 by Jus-A-CMax

[Noah Harbinger]

WFIW, it's my understanding the the HV battery needs to be warmed-up for it to operate and that the engine is run for that purpose also.

 

I've noticed when running in split-power view that even though the engine will start to warm itself up, it will run at very minimal power for as long as it can, and the propulsion will come almost entirely from the electrical motors. 

 

Which, come to think of it, would generate heat in the battery and warm it up. HMMM….

[Bill-N]

I've noticed when running in split-power view that even though the engine will start to warm itself up, it will run at very minimal power for as long as it can, and the propulsion will come almost entirely from the electrical motors. 

 

Which, come to think of it, would generate heat in the battery and warm it up. HMMM….

 

Per the shop manual (emphasis mine):

 

Series Mode

The system operates in this mode when the engine is running and the vehicle is not moving. This is the preferred mode whenever the high voltage traction battery is charging, passenger compartment temperature control, high voltage traction battery temperature control or catalyst warm up is necessary.