WattsUp
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Joined: Mon Jan 07, 2013 2:58 am
Location: SF Bay Area, CA

Re: 2012 Drivers battery experience

Fri May 17, 2013 12:07 am

Not quite. You may be thinking about the fact that EV systems are programmed to discharge only about 80-90% of the total battery capacity. That is, while the batteries are indeed charged to their full capacity, they are never discharged past 10% charge remaining. This is because a complete discharge (to 0%) could cause damage.

The battery pack in the FFE has a total capacity of 23 kWh, of which the car will only ever make use of about 19.5 kWh (which is about 85% of the total). At the point where the FFE indicates that the battery is "empty", it still actually holds a charge of 3.5 kWh.
2013 FFE, Platinum White, Delivered January 2013
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Vach
Posts: 16
Joined: Tue May 07, 2013 10:24 pm

Re: 2012 Drivers battery experience

Fri May 17, 2013 12:52 am

Oooh... really? That makes more sense. I always thought the battery simply charged to "maximum" at 80%, IE: the computer tells the car that it is fully charged at 80% capacity. Therefore keeping it between 20% and 80% at all times.

Thanks for the info.

dmen
Posts: 218
Joined: Sun Dec 09, 2012 4:05 pm
Location: Illinois

Re: 2012 Drivers battery experience

Fri May 17, 2013 5:03 pm

WattsUp wrote:Not quite. You may be thinking about the fact that EV systems are programmed to discharge only about 80-90% of the total battery capacity. That is, while the batteries are indeed charged to their full capacity, they are never discharged past 10% charge remaining. This is because a complete discharge (to 0%) could cause damage.

The battery pack in the FFE has a total capacity of 23 kWh, of which the car will only ever make use of about 19.5 kWh (which is about 85% of the total). At the point where the FFE indicates that the battery is "empty", it still actually holds a charge of 3.5 kWh.
Do you know this for sure, about all the unavailable capacity being at "the bottom"? I haven't seen anything official from Ford, but I personally assume the FFE both saves a percentage at the bottom that is unavailable to the driver, and also saves a percentage at the top which cannot be filled. Since Ford has appeared to take a maximum battery life approach, and the FFE manual and Ford's web materials repeatedly recommend plugging in whenever possible, I wouldn't think it would be "allowed" to potentially sit long at a true 100% charge state since that's not ideal for battery life.
2013 Ice Storm FFE, Dec 2012

WattsUp
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Location: SF Bay Area, CA

Re: 2012 Drivers battery experience

Fri May 17, 2013 8:58 pm

dmen wrote:
WattsUp wrote:At the point where the FFE indicates that the battery is "empty", it still actually holds a charge of 3.5 kWh.
Do you know this for sure, about all the unavailable capacity being at "the bottom"?
I don't know for sure. You may be right... it is possible that the car doesn't fully charge the battery either, and the 19.5 kWh of usable charge actually occupies the "middle" of the battery's total capacity range. But, we do at least know that only 19.5 kWh of the total 23 kWh capacity is available for normal use... from a usability standpoint, it doesn't really matter whether it comes from within the battery, eh?

I guess what I should have said is that, when "0 miles" remaining is indicated, the battery has definitely been drained of 19.5 kWh worth of charge, while the remaining (potential) capacity of 3.5 kWh goes either undischarged (at the "bottom", as you put it) or simply unused (at the "top").
2013 FFE, Platinum White, Delivered January 2013
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Vach
Posts: 16
Joined: Tue May 07, 2013 10:24 pm

Re: 2012 Drivers battery experience

Fri May 17, 2013 10:09 pm

I'll ask around. I have a friend that works for Ford headquarters. I'm sure he can find out for me.

jeffand
Posts: 441
Joined: Thu Jan 31, 2013 3:26 pm
Location: WI

Re: 2012 Drivers battery experience

Sat May 18, 2013 1:59 pm

The battery capacity is rated at 23 kwh. Of that 23 kwh the car uses 19.5 kwh. So FFE uses about 85% of the battery capacity.
The fact is most people will not run the battery down to less than 15 miles of range on routine basis. In my case when I get down to around 30 miles range I will plug in. For most peolpe they are not pulling into the charging station with a low battery warning.

Lithium batteries don’t like hot conditions. 100 degree weather can age the batteries more quickly. Parking in the hot sun can also create a hot environment if the car is exposed to these conditions for a long period of time. Dark colors will accelerate the heating process.
What to do? Parking in the shade will help. Park on the lowest level of a parking structure will also help. Avoid parking in a large black top parking lot. I live in Wisconsin and seeing 90 degree heat or more is very rare.
2013 FFE, Ingot Silver
Delivered September 2012

blavenn
Posts: 10
Joined: Sun Jun 03, 2012 9:52 am

Re: 2012 Drivers battery experience

Sat May 18, 2013 10:56 pm

I have a 2012 model purchased in July last year and used to have 19.5kw of usable capacity and now its dropped to about 17.5kw all of a sudden the past few months after I hit about 12k miles or so. I'm wondering if the computer has something to do with it bringing the capacity down that much since there's been updates for the car's systems since late last year. took it to the dealer to get it updated but they failed to complete the task which is a whole other story.

Charged Up
Posts: 59
Joined: Wed Aug 10, 2011 7:13 pm
Location: Virginia

Re: 2012 Drivers battery experience

Sun May 19, 2013 5:12 am

blavenn wrote:I have a 2012 model purchased in July last year and used to have 19.5kw of usable capacity and now its dropped to about 17.5kw all of a sudden the past few months after I hit about 12k miles or so. I'm wondering if the computer has something to do with it bringing the capacity down that much since there's been updates for the car's systems since late last year. took it to the dealer to get it updated but they failed to complete the task which is a whole other story.

How do you know that usable capacity has dropped?

jeffand
Posts: 441
Joined: Thu Jan 31, 2013 3:26 pm
Location: WI

Re: 2012 Drivers battery experience

Sun May 19, 2013 5:58 am

Cold temperatures will temporally reduce battery capacity. Repeatedly running the battery down to very low levels could age the battery faster. Prolonged exposure 90 degree plus heat will age the battery faster. More extreme temperatures can result in faster aging. I don’t think FFE is immune to the affects of heat. I just think the Focus does a better job of managing battery temperatures than the Leaf does. :P

Or it could be the method being used to calculating the capacity of the battery.
2013 FFE, Ingot Silver
Delivered September 2012

blavenn
Posts: 10
Joined: Sun Jun 03, 2012 9:52 am

Re: 2012 Drivers battery experience

Sun May 19, 2013 7:31 am

my one way commute that I do once a week is about 78 miles so its a perfect test to run the ffe down to near zero when needing an accurate total energy used number. of course when there is traffic I still arrive with about 15 or so miles leftover but when I want to see the true capacity and energy being used I just drive faster.

funny thing is I was getting the 19.5kw of usable capacity during the hot summer months last year and about 17kw during the cold spell days when it would hit 50 degrees early this year. I'm down in Miami. But now that its heating up again down here I'm not getting that 19.5kw of usable capacity like I used to.

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