I'm done with Quick Charging and Road Trips...

[saywatt]

I don't think what happened at the top of this string is any reason NOT to have gotten the QC port option or not use QC for that matter. Even for limited use, the QC infratructure is going to save time especially when something unexpected pops up during the course of ones day. I consider my time valuable and if I can save time during the unexpected, that is important to me. I am glad I got the QC port and it will make a fine selling point should I ever sell the car.

I totally agree with the thread title, which is why I didn't buy the QC port anyway. I'll repeat what's (basically) already been said: the Leaf is an EXCELLENT local/commuter car and if we need to take a road trip, we'll take my wife's ICE car.

 

[GaslessInSeattle]

well put! I would add that for occasional long trips if temperature is the issue, that it's not hard to manage the temp by moderating driving habits. I'm sure we will know a lot more after Tony is done QCing his way up the WCGH from the CA/OR border to Canada... he's got the Leafscan and is a data hawk. We'll have one maybe two Leafs in caravan when I run Tony's car along the Seattle/Portland portion of it's return home this weekend. I'll report back on the temps that we see.

I don't think what happened at the top of this string is any reason NOT to have gotten the QC port option or not use QC for that matter. Even for limited use, the QC infratructure is going to save time especially when something unexpected pops up during the course of ones day. I consider my time valuable and if I can save time during the unexpected, that is important to me. I am glad I got the QC port and it will make a fine selling point should I ever sell the car.

I totally agree with the thread title, which is why I didn't buy the QC port anyway. I'll repeat what's (basically) already been said: the Leaf is an EXCELLENT local/commuter car and if we need to take a road trip, we'll take my wife's ICE car.

 

[tbleakne]

>>> From what I can tell so far, It's not the number of QC's that necessarily leads to a hot battery, it's the combination of continuous fast highway driving, which is only possible because of the QC's, and QCing. I found early on that if I drove 70-80 mph between QC's (which I have to admit is a lot of fun!) that the battery would start out a bit warmer from the QC but then not cool off in between, gradually accumulating heat with successive charging and driving. My conclusion is that if you are going to QC multiple times, you must manage power use and battery temp and adjust accordingly. If the battery is warmer than you'd like, slow down. this both increases the time between QC's and reduces heating from driving fast. Driving 55 to 65 may turn out to be more important on long road trips when you are QC'ing frequently with little idle time.

I agree, but with the caveat that what counts for battery heating while driving is the power it is delivering, not just your speed. 60 mph on a smooth level highway without wind uses less power than a gentle uphill grade at 50 mph, where I often see 30 kW output.

Using the gid meter's DC voltage display, I have measured the power lost in the battery due to power discharge at about 1% per 10 kW. This loss is quadratic: .1kW loss at 10kW output but about 1 kW loss (3%) at 30 kW output. Power lost in the inverter and the motor is not reflected in the DC voltage, so this lost power is all going into battery heat except for the heat being removed by the passive cooling system. At low powers the passive cooling system probably keeps up, with only modest temperature rise.

My suggestion when you know your battery temperature is rising is to slow down on uphill grades. The trucks are usually slowing down as well, so slower speeds are safe.

 

[tbleakne]

An interesting report on Li battery temperature during charge and discharge, with the usual caveats that our LiMn chemistry might be somewhat different, but the general trends should be similar:

http://www.micro-power.com/userfiles/file/mp_tempcharge-1250026530.pdf

Note the slightly endothermic chemistry at the beginning of charge, overwhelmed by resistive losses, but the dramatic increase in heat loss at the end of discharge.

QC rates of 36 kW corresponds to a charge rate of 1.5C for our 24kWh battery. I am not quite sure what are the units of "Time per hour" on the abscissa of the plot.

 

[GRA]

What I take from the above is that at least with LiMnO chemistry, if you want to use QC regularly and cruise at freeway speeds, you'd better buy a BEV with an active TMS. Of course, there aren't any yet that have that combo (possibly excepting the i? Not sure of its battery chemistry).

The Tesla Model S 60kWh and 85kWh support QC and has active TMS. The chemistry is however not LiMnO.

If you can afford a Tesla you don't have to worry about pack degradation - you just buy a new one (or a new car) every year or two. And with the extra range, you have less need to do multiple QCs in any case.

 

[Rat]

I have only had one QC, one I didn't need, but I was curious. It didn't give me much extra mileage in the 15 minutes it took; I found it disappointing. Upgrading from the SV to the SL-e at Nissan's suggestion in order to get the QC and be in the EV project has cost me almost $3000 even with the free QC port and the "free" Blink EVSE. It certainly hasn't been worth it yet and I doubt it ever will. After hearing Tony Williams talk about his BC2BC trip up the coast I despair of EVs ever being practical for distance driving. My Leaf is perfect for the use I anticipated, which is my retired lifestyle of driving <50 mi. a day, mostly <10 mi. a day. I still think EVs are a great thing and will replace many ICE cars, but unless there is a major battery breakthrough (a real one, not the dozens of touted ones I've read about in AutoblogGreen or elsewhere that still aren't on the market) EV's are going to be suitable only for local driving. I keep an ICE car for longer trips and encourage everyone else to do so. I think driving EVs in obvious hypermiling ways, like going 10 mph on the highway in a heavy fog at night as Tony Williams did, only serve to draw attention to their limitations and prevent wide acceptance. If QC stations become more available I'm sure I will find a few occasions to use them, but probably only for specialty trips intended only to show that it can be done.

 

[DaveEV]

After hearing Tony Williams talk about his BC2BC trip up the coast I despair of EVs ever being practical for distance driving.

Tony drove 375 miles today. With probably 10 stops for short QC sessions or about 3 hours worth of QC. Yeah - that stinks. But that's not an EV limitation - that's a LEAF limitation.

There is an EV being released to the public in 3 days - this Friday - which can do that same drive with a single 45 minute stop for charging. Yes - it will cost you a minimum of $77.4k or about twice as much as a LEAF SL. But will be practical. And the future is closer than you think.

Tesla Model S

Does it make sense for someone who normally drives between <50 miles/day? Absolutely not! You're better off renting a car for long trips. Or perhaps a plug-in hybrid. The Volt isn't far from 50 miles EV range...

 

[mrradon]

until battery technology changes, quick charging stations will just cause your car's battery to fail sooner. Drive a VW TDI for highway cruising... Leaf for commuting, doing 80% charges.

I'd cut my arm off before doing one quick charge.

 

[DaveEV]

until battery technology changes, quick charging stations will just cause your car's battery to fail sooner. Drive a VW TDI for highway cruising... Leaf for commuting, doing 80% charges.

I'd cut my arm off before doing one quick charge.

Occasional QCs to enable road-trips is not going to significantly affect your car's battery life with today's technology. Regular use will, but in reality the charge rates being pushed for today's QC rates of 1-2C does not stress the battery much.

Toshiba SCiB or A123 batteries also available today can handle significantly faster charge rates than the LEAF's AESC high energy batteries. The LEAF could handle QC much better if it had any sort of active cooling - especially the multi-QC in a day scenarios.

Tesla is confident enough in their laptop cells that they are providing an 8-year unlimited mileage warranty on their 85 kWh pack.

Today's batteries can handle today's QC rates just fine.

 

[FairwoodRed]

The missing charger was supposed to be near Longview, WA and it not being there means that the distance between chargers is 70 miles - most of that way under a 70 mph speed limit.

What is "way under 70 mph"? It has been my experience, traveling up steep grades, that there is a huge difference between 50 mph and 55 to 60 mph - as in 2 - 3 power bubbles.—not that I want to drive 50 in a 70 again any time soon either! :shock: Also, I have not driven over 60 for any length of time

I didn't mean "way under 70". I meant "most of that way(trip), in a 70 mph zone". I prefer not to travel below the speed limit.

 

[TomT]

The speed I drive in my Leaf is pretty simply: It is the lesser of 5 over the speed limit or what I need for my range on a given day and trip... If I have a lot of battery and not much need for range, I'll fly.

I didn't mean "way under 70". I meant "most of that way(trip), in a 70 mph zone. I prefer not to travel below the speed limit.

 

[GaslessInSeattle]

thanks for your useful posts!

An interesting report on Li battery temperature during charge and discharge, with the usual caveats that our LiMn chemistry might be somewhat different, but the general trends should be similar:

http://www.micro-power.com/userfiles/file/mp_tempcharge-1250026530.pdf

Note the slightly endothermic chemistry at the beginning of charge, overwhelmed by resistive losses, but the dramatic increase in heat loss at the end of discharge.

QC rates of 36 kW corresponds to a charge rate of 1.5C for our 24kWh battery. I am not quite sure what are the units of "Time per hour" on the abscissa of the plot.

 

[davewill]

... I'd cut my arm off before doing one quick charge.

Not sure how cutting off your arm is supposed to substitute for a quick charge, but to each his own, I guess. :lol:

Seriously, there's been absolutely nothing reported to suggest that a QC every now and then will have any measurable impact on your battery's long term health. I wouldn't hesitate to use one QC each way to facilitate an occasional trip to the next city. I also wouldn't hesitate to use one in the unusual case where one charge can't get me through a whole day's driving. My biggest problem with QCs is availability. I agree that the LEAF is not a road car, but QCs definitely have their place.

 

[Stoaty]

... I'd cut my arm off before doing one quick charge.

Not sure how cutting off your arm is supposed to substitute for a quick charge, but to each his own, I guess. :lol:

I think you misunderstood--he said he would cut his arm off BEFORE doing the quick charge, not as a substitution. Of course, that would only allow two quick charges over his lifetime, unless he has a team of very skilled surgeons.

 

[GRA]

... I'd cut my arm off before doing one quick charge.

Not sure how cutting off your arm is supposed to substitute for a quick charge, but to each his own, I guess. :lol:

I think you misunderstood--he said he would cut his arm off BEFORE doing the quick charge, not as a substitution. Of course, that would only allow two quick charges over his lifetime, unless he has a team of very skilled surgeons.

But for the price of a single re-attachment he could buy several Leafs, so I don't see how this works out in TCO. :lol:

 

[ztanos]

What is the rate of charge given by the regenerative braking in eco? Is it close to QC? Will he stop using his brakes too?

 

[mrradon]

I work in the heavy duty trucking industry and we have a class 7 hybrid truck using the same batteries as the Leaf's. That hybrid system has an EPTO mode where the engine quickly charges the batteries then shuts off (like in a crane application) Even though the batteries get charged at 1.5C they degrade 75% faster than the non-EPTO chassis battery packs.
We looked into the issue, and Li Ion 1) don't like heat, 2) don't like rapid charge/discharges.

I guess I see QC as a liability, just like those people who do jack rabbit starts. It's a cumulative thing. i'd rather pamper the batteries than hammer away at them with QC's, when I sleep 8 hours every night the car has plenty of time to charge.

If I want to drive to Portland, I pull out the Z06...

 

[LEAFfan]

What is the rate of charge given by the regenerative braking in eco? Is it close to QC? Will he stop using his brakes too?

Even though the car's energy meter only shows up to 30kW of regen, using brake regen can be as high as 50kW which is more than a QC. I believe the LEAF limits a QC to about 43kW and that's only at the start.

 

[JeremyW]

I work in the heavy duty trucking industry and we have a class 7 hybrid truck using the same batteries as the Leaf's

Do you know what sort of thermal management system they have, if any?

Jeremy

 

[planet4ever]

... I'd cut my arm off before doing one quick charge.

Not sure how cutting off your arm is supposed to substitute for a quick charge, but to each his own, I guess. :lol:

I think you misunderstood--he said he would cut his arm off BEFORE doing the quick charge, not as a substitution. Of course, that would only allow two quick charges over his lifetime, unless he has a team of very skilled surgeons.

Sorry, I can't resist:

DOROTHY: Oh, goodness! How did you ever get like this?
TINMAN: Well, when I was flesh and blood like you, I fell in love with a Munchkin maiden whose mother hated me. So to stop me from marrying her daughter she hired the Wicked Witch of the West to put an evil spell on my axe. When I tried to chop down a tree it chopped off my leg instead.
SCARECROW: It chopped your leg off?
DOROTHY: That's terrible.
TINMAN: But by good fortune I knew of a wonderful tinsmith and he made me a new leg almost as good as the old one. So back I went to work and you know what happened?
DOROTHY: Something terrible I bet.
TINMAN: I swung my axe again and dang me if it didn't take off the other leg.
SCARECROW: You shoulda got a new axe.
TINMAN: I guess you're right. But I got me a new leg instead. And back I went to work.
SCARECROW: You sure were persistent.
TINMAN: This time I chopped off both my arms.
DOROTHY: Oh my.
SCARECROW: I can see how you coulda chopped off one arm but how did you manage to chop off the other one?
TINMAN: I told you. The axe was enchanted.
SCARECROW: Of course. See Dorothy, if I had a brain I coulda worked that out for myself.

From "The Wizard of Oz", naturally.

Ray