Practicality and charging revisited. Why you don’t need to know recharge times, and that capacitors won’t help.

Just shy of a year ago I wrote a post about charging and practicality.  It really is amazing how far things have come in just a year.  It easy for us elmoto and EV obsessed to take all this progress for granted.  If you are like me most days you are checking the internet for news.  But that is only because generally there is news to find, and we get spoiled.  But a little retrospect and reflection is fun too.

A year ago the only electric street motorcycles that had been sold were the Brammo Enertia, Zero S, and the Native GPR-S.  All of them had maybe 20hp and 30+ miles real world range.  The new 2012 Zero wasn’t supposed to be in dealerships until early spring and Brammo had announced a year delay in both the Empulse and Enertia+ and we were thinking it would be available shortly there after that post.  The 2012 Zeros ended up hitting dealers a couple of months early,  just a few weeks after the post, and the Empulse and and Enertia+ are just now being delivered.  The 2012 Zero S and DS showed up with AC motors with packs twice as big and Hollywood Electrics sold at least as many in the first month than all of 2011, making them the top Zero dealer, period. The 2013 Zero line is another big jump as basically every bike gets motors with twice the power output, and even bigger packs, and we should see deliveries to dealers start any time now.  So now we have bikes with about 54hp and 75 to 100 miles of real world range and 60 to 75 miles of tearing up the twisties range, in just over a year (end of 2011 to beginning of 2013).

But, are these bikes more practical?  Since when has a motorcycle ever been practical other than in 3rd world nations?  For those few who live with motorcycles, you understand they can be more practical.  But they are more maintenance intensive and tires are more expensive and last no where near as long, but the performance is staggering for the money.  And their size and fuel efficiency, especially considering performance, make them very efficient vehicles in the space they take up as well as how much they consume.  In my personal experience, it always seemed my bikes were easier to fix, maintain, more reliable, and simply sucked less money from my wallet than a car or truck.  Electric motorcycles promise to be even more practical, but range, performance, and cost were keeping them from that promise.  However, big gains have been had within the last year, with the recent jump in the production bikes power numbers.  In my interview with Gavin McCullough, he said how simply doubling the pack size, combined with some improvements in efficiency, meant that he went from having to charge the Enertia every day to only having to charge the Enertia+ once a week when doing commuting duty.  Double the pack size and you quintuple the convince.  That’s substantial, and the Plus only has a 6.2kWh pack.  I’d like to see how the 9.3kWh pack of the Empulse would effect Gavin’s week, although I have a feeling. not much.  Anyway, other than the 35+ crowd that is obsessed with farkle, most motorcyclists in the US use their bikes for recreation.  All they want is something faster and/or cooler than their gas bikes.  And that is the real question, not practicality.

Well, in 2013 elmotos should be waxing anything with 500cc or less, and neck to neck with 650cc twins.  As far as the H-D crowd goes, well Bell Custom Motorcycles might have something for you in 2013, as well as a few other custom builders.  Funny enough weight has stayed pretty competitive in the production bikes, when compared to the ICE bikes.  And prices and performance for custom bikes like the Lightning are competitive too.  I really want to see a stock Lightning (when it ever hits the street) and an EBR 1190RS go toe to toe.  Although, the EBR is much lighter for it’s $40,00, I bet it doesn’t get any further on a tank than the Lightning gets on a charge.  However, when you look at the 2013 Zero S and Brammo Empulse you get 650cc twin motor performance for almost Ducati Panigale prices.  Compare them to say a Ninja 650, and we’ll have to see how they stack up on track and street, but I have a feeling the Ninja will be gasping for air.  However it costs about 2.5 times less than it’s electric counter parts.  So, there is still a lot of progress made there.  But I suspect Brammo will have something for those liter bikes in two or three years.  And Zero should have already burned the MX world to a crisp by then.  And that reminds me.  If we want to talk recreational, MX elmotos are on par with 250s, and maybe even 450s this year.  So all in all, elmotos aren’t there yet.  Why am I saying not yet when I just pointed how theses bikes are quite competitive performance wise with many ICE models on the street and trail?  Well, because no one will concede ICE defeat until production elmotos can crush the fastest gas bikes out there (and then the issue will still be price and on the street and range).  So Liter bikes (1000cc sport bikes) and 450cc Motocross bikes are the bench marks.  Now, you maybe thinking, oh I have him.  The hyper bikes are faster.  Nope.  The Lightning weighs less and has way more power.  It just costs more.  The Liter bike’s weight, power and cost is the benchmark.  So, the elmotos have closed the performance gap considerably, but aren’t there yet.  Maybe one more year off road, but street will be a few more years.

As I went over in the post from a year ago it was clear that some people thought, and clearly some still do, that charging is a problem.  I don’t believe it is.  One that stands out currently is that people think the batteries are the hold up in charging times.  But really, they aren’t.  It’s the chargers.  What needs to change is people asking how long it takes to charge, but knowing enough to figure it out themselves.  This will keep the marketing guys honest.  As we went over last year charging a pack from empty to full is to charge at a 1C rate.  So to fill the 9.31kWh pack on the Empulse in an hour you need a 9.31kW charger (in simplest terms).  Or, to fully charge a Tesla Model S 40kWh pack in an hour, you need a 40kW charger, the 60kWh pack needs a 60kW charger, and the 85kWh pack needs an 85kW charger.  See a pattern?  To continue with this theme, at a 2C rate an Empulse would need a 18.62kW charger, and an P85  Model S would need 170kW charger, etc..  Now, some of you well informed are probably getting ready to write nasty comment.   For those who don’t know, it is because really you can charge at good rate up to 80% (or even up to 95%) because the last 20% needs to balance or trickle charge to maintain pack health.  So really, charging at 1C really would take a bit longer than an hour, but for ease of understanding I am going to keep it simple.  I really don’t know of any batteries in production cars today that couldn’t take at least a 1C charge, if not a 2C (1/2 hour charge time) or better.  So why does a Leaf, Volt, or Empulse take so long to charge?  Because the on board AC chargers are so small.  If you could fit a Manzinita Micro 18kW AC charger on the Empulse, you could charge it in about a half hour.  But that charger is freakin’ huge, and weighs 35lbs.  But, even if there was room for this giant charger, you’d be hard pressed to find an outlet that could supply that much juice.  Your normal wall socket is only going to give you 1.3kW max.  Your drier socket is better an will cough up about 6 to 7 kW.  A J1772 level 2 charging station by 2009 standards could give you as much as 16.5kW, but more than likely you’ll be looking at about 7kW with the older 2001 standard.  Now RV sockets at camp grounds will give you close to 12kW.  But here is the problem with all of the supplies I have mentioned, such as the level 2 charging stations.  They aren’t chargers, they are fancy electrical sockets meant to keep idiots from electrocuting themselves.  As much juice as they can provide, they are still pointless if you only have only a 3kW charger on board.  This is why the Tesla comes with at least one 10kW charger on board, with an option for 2 if you outfit your house with some serious juice and one of their home charging stations.  Now, really none of these options are useless, especially for motorcycles.  Topping off your Empluse in town would be cake.  But filling it after a hour run in the canyons is a 3.5 hour wait.  That’s too long to be competitive, and for the average ICE rider to tolerate.  These are great ideas for the home though.  With as relatively small as the Empulse’s or Zero S’s packs are, even plugging into a 110 socket means you’re topped off by morning.  Even if you had a giant 36kWh pack, if you were doing normal commuting (40 miles a day) during the week, just by plugging into the 110 every afternoon you’d have a full pack the next weekend’s ride.  So, the Level 2/J1772 technology is not pointless or useless, and works very well within the current confines of our homes today, and even public grounds.  But people aren’t worried about the everyday.  They immediately think of the 5% or even 1% of their lives that their ICE vehicles afford them.

Well that is where DC charging comes in.  What is DC charging?  Well instead of AC going to the vehicle and the on board charger (who’s size is limited by the  confines of the vehicle it is in) converting it to DC and then sending that to the batteries, in a DC charger the vehicle talks to the big ass charger in the charging station, tells it how much juice it can take and by passes the on board charger and feeds the batteries.  So to boil it down to scary simple, an AC charging station sends power to the (small) on board charger, where as DC charging stations have big chargers built in to them, and are able to feed way more juice to the vehicle.  That is how the 2013 Zero S with its puny 1.3kW charger can plug into a CHAdeMO charger an go from empty to full in about an hour.  Really, the CHAdeMO chargers are capable of sending up to 62.5kW to a vehicle.  That could potentially fill a Zero S 11.4 in 11 minutes, and an Empulse, if it had a CHAdeMO adapter, in about 10.  But that would be over a 5C rate, and not particularly healthy for anyone.  But say you had that magical elmoto with a 36kWh pack.  You could be full from empty in a half hour, which is at a more reasonable 2C rate.  But these CHAdeMO stations require some pretty good juice available to them, and I suspect you can’t install them just any where like you can a level 2.  But we’re not done yet, oh no.  Have you seen the new Tesla Super Charging stations?  90kW!  90!!  Now that charges a Model S P85 at a 1C rate, but would fry an Empulse in less than 7 minutes.  And Mr. Musk has plans for them to go up to 120kW.  Sweet mother of all that is holy.  But, here’s the thing.  Potentially, I think these can go up pretty much where ever, and run on sunlight.  Now, how do they do that, you may be wondering.  Well, from what I can understand it’s really simple and quite clever, and I’m about to over simplify again, and possibly get it wrong.  As I understand it the Tesla stations have three power sources: the grid, solar panels, and a giant battery pack.  Basically, your Tesla will be charged from this giant battery pack.  The clever thing about this is that the battery can be slowly charged by the grid and the solar panels all day long at a lower rate than it discharges at.  This way there is no need for massive power thingies from the power company or a huge demand on the grid when a car plugs in to charge.  If I have this part right, it means the pack can discharge huge amounts of power quickly without affecting everything else around it.  The pack can re-charge off the solar panels, but if they aren’t enough, or its night, or its been raining for days, they charge off the grid.  However, if the pack is full and it’s bright a hell, then the solar panels send their energy to the grid instead, paying back the energy used.  And I bet you dollars to doughnuts the Super Charger uses the same cells as the cars.  And, Lightning uses basically a small mobile version of that for their race bike, that allows them to charge the bike in about 30 minutes.  Only I think they can just leave the solar panels set up when they are home so that the pack is ready for the next round, instead of plugging it in.  But this is pretty big because now we know we have a way of charging our EVs at high rates that doesn’t involve lithium-air levels of technological breakthroughs, and can see a way of providing even more powerful chargers without the need for massive substations to accompany every charging station.  But there are still limits.

You can only supply so much power to an EV before you get into wiring that’s the same diameter as your head.  And this is why capacitors will be of little advantage for charging.  The current batteries are pretty good and can take more than manufacturers are willing to gamble that they can.  Well that, and the chemistries currently in the vehicles might be a few years old technology wise, which is par for the course.  To charge a Tesla P85 at a 5C rate, or in 12 minutes, would take at least a 425kW charger.  That is ludicrous, and frankly I’m not sure physically possible to build a station or charging equipment that could handle that much power, but I don’t know.  However, it’s also not really needed.  But my point is that capacitors aren’t going to fix that.  You are going to run into the physical limitations of wire size and power availability before you will reach the limits of battery technology. I just don’t see being able to put enough power through a small enough charging system (ie. wires, cables, receptacles, etc.) to warrant capacitors over batteries as far as recharge times are concerned.

Looking at the numbers of cars using 320Wh/mile and bikes 180Wh/mile on the interstate, if we want 400 miles rage out of a car you’d want a 128kWh pack, and a 200 mile range on a bike would be a 36kWh pack.  Now, on 400 mile range car, I just don’t feel that we need to charge it in 5 minutes.  I think that on a long road trip pulling over every few hours and taking a break while charging for 15 minutes to a half hour is a good way to do a road trip.  The same goes for a bike.  The difference is in the car you could have driven for 3 hours and only used half the pack, or most of it in a normal Tesla P85.  I though a half hour is a good break for a full charge, which would mean a 15 minute break for a half charge.  It would also mean a 170kW charger for a P85 at a 2c rate.  If you drove 210 miles that 320Wh/mile rate (just over 3 hours), and you had left with a full charge it doesn’t matter which pack you have, a 170kW charger would have you topped off  in just over 2o minutes.  It’s just with the bigger pack you could get away with only charging for 15 minutes and know you could drive another 210 miles with no problem.  On the motorcycle you could charge a drained pack in less than 15 minutes with this magical 170kW charging station.  If you were averaging 70mph on the bike and rode for 2 hours, it would only maybe 10 minutes to fully charge the bike.  If the batteries could take a 4C charge rate that is.  But even then a 3C rate would be 15 minutes, and 2C would be 21 minutes.  Is that really so bad or impractical?

I feel that charge rates of 2C would be a huge leap forward in the convenience of elmotos, and are currently possible with CHAdeMO chargers and the current production offerings, but we’ll just have to wait for the manufactures to either use new battery technology, or be more sure of the battery technology already in these vehicles.  As we can see, the needed C rates drop as the packs get bigger, which is good because there are some issues with getting big big power into the cars.  Also, I don’t really see needing anything more than a 2C rate with the current Tesla P85, or 170kW charging stations.  But we are Americans, and needing and demanding are two very different things.

Sources for info:

http://en.wikipedia.org/wiki/SAE_J1772

http://en.wikipedia.org/wiki/CH%CE%9BdeMO

http://www.teslamotors.com/supercharger

http://www.manzanitamicro.com/products?page=shop.product_details&flypage=flypage.tpl&product_id=43&category_id=14

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