Road Tripping The Electric Drive

[steveyfrac 73]

I'm going to attempt a long distance drive this coming weekend. 165 km. Definitely far enough to be uncomfortable. So my route will take me past a 70 amp charger both ways. Plan is to charge both directions to be comfortable.

I'll stop at the charger for only as long as I need, and read a book on my phone. Will charge up to 80 percent tops on the way down. Don't want to enter the top 20 percent which charges slower.

Will post pictures. Should be an adventure.

[RunSilent 15]

Good luck! Is this going to be mostly at highway speed?

[steveyfrac 73]

Almost entirely. I also will not be able to charge at my destination.

[RunSilent 15]

Well, that'll cure any remaining range anxiety for sure!! I tried the charger unit that comes with the car at my parents place, I was a bit dismayed to find how sensitive it is to electrical faults. It was detecting some sort of fault on the outlet and therefore refused to charge at all. Yet you can plug in a light and it works fine. Will go back and do some trouble shooting and check for ground faults. The moral is just because power is available, it doesn't mean it can be accessed.

[steveyfrac 73]

I had a similar issue at my parents house. Turned out to be a bad extension chord, and another extension chord worked fine.

[darren 192]

Don't they recommend plugging directly into the wall, with no extension cord?

I'm probably going to make my own heavy-duty 14- or 12-gauge cord and keep it in the car just to be safe.

[steveyfrac 73]

They do. But it's a safety thing. Your risk of getting shocked with an extension chord is much higher than if you plug into the socket. If you are in trouble, plug in the charger to the extension chord, then plug into the wall, and you should be OK. Note: I am not an electrician, take my advice at your own risk.

[steveyfrac 73]

Confirmed with the soul at the destination. I won't be able to charge at the destination. So i'll be stuck mostly charging at that 70 amp charger near Brantford. It's a shame we only have a 3.3 kW onboard charger. Even a 6.6 kW charger as a paid option would be a huge boon for this type of trip.

[darren 192]

Indeed. But it is really intended to be a "city" car, so we're really punching the boundaries of what the car was designed to do. An there's nothing wrong with that.

[steveyfrac 73]

I don't see why it has to be only a city car... You can get a 22 kW charger in Europe. If they had a 6 or 10 kW charger available, I'd be able charge much faster, and it'd be ready for the rest of the day that much sooner. It would also mean less use of public city charging infrastructure if I could charge more quickly, then leave. As it sits, my little car is going to monopolize this big charger, despite only using a fraction of it's output.

[RunSilent 15]

I tend to agree, it is a city car, and one designed for compact cities in Europe, not our sprawling suburban landscapes on this continent. I for one would not be keen to be using a 22kW charger too frequently, especially in the context of rapid charging at highway rest-stop and pushing the battery hard up to close to 100% in a hurry. Battery life is going to suffer as result. You can do long trips if you want too, a lady did a 1,000km tour around La Gaspésie over ten days in her iMiev, and some gent just did 2,000km on his electric motorcycle out of Québec City.

Besides, the sizes of cables for 100A is getting heavy, and in the cold of winter, good luck with that. You need three phase power for that output, which few of us have.

Maybe a 6kW charger might be a better option, but I just plugged my car in tonight after having gone 110km with 30% charge remaining, and the dash says it'll be good to go in only 4.5hrs. Since I have programmed the charge and depart for 0630 in the morning, it knows it has 9.5 hours to top up the battery and takes advantage of it, judging by the the homepage results. But with a 6kW charger I'd need a bigger electrical service to my garage, and might think twice about the economics of the whole thing. For me, the 3.3kW is a good compromise between convenience of overnight charging, battery life, and the size of the circuits and cord sets.

[steveyfrac 73]

Our battery is rated to perform 4000 ish cycles from 100% to 0% before it gets to 80% capacity, at 2C. That represents a full charge in 30 minutes, and a full discharge in 30 minutes.

You can see the specs for yourself here: http://www.energiemetropole-leipzig.de/tl_files/Energiemetropole/Expert09/vortraege/5_Vortrag_Schaefer_Li-Tec_Energie_Metropole%20Leipzig_Battery_Tim.pdf

Page 25 is the graph you're interested in.

By comparison, a charge in an hour is leisurely. We don't need to worry about that. It's really not going to hurt things. That's actually slower than the car charges itself during hard breaking. Furthermore, the battery management system is smart, and will rate limit the charge as it gets full, limiting the available current. The charger already has this ability, as if the batter is really cold, it can't be charged at full rate without damaging the cells. You'll also notice you don't get full regen if the battery is only drained a few percent. The 22 kWh charger plays by the same rules. Full steam ahead to 80% then it slows down greatly, controlled by the battery management system.

Just because you have a bigger charger, doesn't mean you need to use it. In the J1772 standard the charger signals to the car the available amperage, and the car only draws that much. It also allows the charge to suddenly drop the available current, and the car will honor that request. That's why you can draw 12 amp from the 110v charger that comes with the car (or 8), and 16 amp from a proper 240v charger. You'd be able to continue using the same charger, the same electrical connection, and the same chord, and charge at the same rate. The only downside of a bigger charger is the cost of putting it in the car. Which is why I suggest it being an optional extra.

But then, if you ever wanted to, you'd be able to charge really fast to go on a bit of an extended journey! Win-Win!

[darren 192]

I think Tesla has the right idea. Reasonably robust charging capability at home, but DC fast-charge capability when visiting dedicated Tesla SuperCharger stations. The upcoming Kia Soul EV also has DC fast charging capability, so i think that's likely the way things will be going in the future.

[steveyfrac 73]

I tend to agree. That's one of the reasons why I was only willing to sign a 3 year lease on my ED. In three years, I think the lay of the land will be vastly different. I think the SAE combo charger will be a big thing, and I think that commercial fast chargers will be springing to life in a big way. But we'll see in three years, and re-evaluate!

[darren 192]

Indeed! And with Tesla opening up all their patents, i'm hoping that change will start accelerating. I think the Model III is going to be a massive game-changer for the whole automotive industry.

[RunSilent 15]

Our battery is rated to perform 4000 ish cycles from 100% to 0% before it gets to 80% capacity, at 2C. That represents a full charge in 30 minutes, and a full discharge in 30 minutes.

You can see the specs for yourself here: http://www.energiemetropole-leipzig.de/tl_files/Energiemetropole/Expert09/vortraege/5_Vortrag_Schaefer_Li-Tec_Energie_Metropole%20Leipzig_Battery_Tim.pdf

Page 25 is the graph you're interested in.

Well, we can agree to disagree. There is not much in those graphs that has much bearing to the performance of the packs in our cars in the real world . Those are single tests performed at standard temperature and pressures, on ideal cells set up perfectly in the lab for just that test. It doesn't take into account the vagaries of mass production, the debilitating effects of (in my area at least) a 75 degC annual temperature swing, effects of partial charging at 3C rate when in high regen mode careening down a steep hill, discharging at even higher rates when zipping down the highway using the full 55kW discharge throttle switch, and when one or more of the individual cells starts to go bad. For these reasons, I think the 4,000 cycle to 80% is probably going to be somewhere closer to 2,500 or less depending on how often the small suggestion on page 113 of the owners manual about discharge and recharge levels is heeded.

[steveyfrac 73]

We can agree to disagree, for sure.

But I really thing you're being overly pessimistic.

It's true that it's a lab result, and not a real world test. But it's a really harsh lab test. 2C discharge rates are much higher than we see on average. That would mean driving around *everywhere* with the car floored, (but not in kickdown). And 2C charge rates effectively means every charge was an insanely fast quick charge! That's crazy! That's a horrible way to treat a battery. That borders upon abuse. That it *still* achieved 4000 cycles on this severe test means that in the real world, our packs should do BETTER, because we don't push our packs anywhere *NEAR* that hard. And that's 4000 cycles to 100% DoD. I don't know about you, but my average cycle is between 50 - 60% for my drive to and from work. And this will translate to 1000's more cycles available in the real world. The Depth of Discharge alone will extend the life of packs immensely. Sure there are vaugeries. They might have cherry picked the cells, etc. But I don't that to cut the result in half

Even at 3C charge and discharge, our cells manage a respectable 3000 cycles to 80%. And that's just evil to a battery. (previous page, same document). That's a 20 minute discharge, 25 minute full charge. And it still beats your 2500 estimate. At 1C average charge, and 1C discharge, what would the lab result be.. 6000 cycles? more? About about when we only cycle to 50%? 10000? At a 2% DoD the pack did 3.5 million cycles.... (at 50% SoC and at 6C)

Heat is dealt with by air-conditioning the pack. Cold is dealt with using battery pack heaters, so your pack should remain more or less comfy through a wide range of temperatures. That's why there is a complicated, expensive, and heavy thermal management system.

I fully expect that our packs are capable of 4000 average DoD cycles, in the real world. If not more.

[steveyfrac 73]

In any case, this thread is not to argue about bigger chargers that will never happen, or how long our batteries will last. It's about my road trip this Saturday. The plan is to leave very early, stop at the big charger, and charge all the way up. If I play my cards right, I might not need to charge on the way home... I've done a few runs lately and gotten 60 km on 40% battery. I need to do about 50% on 70. And I plan on charging half way through anyways....

[SmartElectric 31]

I recently did 128km on a single charge with 5% SOC remaining.

64km using 40% of battery with some hypermiling techniques (following dump truck at 10 feet off bumper for 10km for example) with usage of 13.5kWh/100km with average speed of 50km/h

parked car for 10 days in the sun, no loss of SOC visible on dash meter

64km return trip using 55% of battery with constant use of kickdown averaging 15.5kWh/100km and average speed of 80km/h, many times exceeding 100km/h

I was very happy with the range estimates and power availability, even under 20% SOC when the reserve battery warning comes up.

[steveyfrac 73]

it's almost exactly 140 km I need to travel, and the charge is almost perfectly equidistant between my destinations.

It'll be 35 km to charger, charge up for a bit, 35 km to arrive at destination.

Then, 35 km back to charger, charge up whatever I need, then 35 km back home. Longest sprint is the 70 from the charger, then back to the charger. Worst case, I'm at the charger for 2 hours each way, but I think I can beat that.

Plotted a new route that doesn't take me over any 400 series highways, so max speed should be 80 during the whole trip. That'll help a lot. Car seems to do well at 80. I'll precondition before I leave home, and again at the charger.

[darren 192]

Cool. Which charger are you going to? Flamborough or Ancaster?

[steveyfrac 73]

There is one west of Brantford, straight south of Paris. If it's full, I may be screwed...

[darren 192]

Ah, okay… there are something like 10 chargers at a t Flamborough, but looking at the map, that's going to be way too far east. I always forget how far west Brantford is.

[steveyfrac 73]

I want to go to the flamborough chargers just to see them. Perhaps I'll stop there are my way home, charge level depending!

[darren 192]

I've been meaning to swing by on my way home from the Warplane Heritage Museum the last two Sundays, but more pressing things took me straight home both days. Perhaps this weekend.

We're such nerds!