Friday, March 29, 2019

Trip Planning; Speed To Charge?

I have to admit to a sense of anticipation planning an EV trip with charging stops and a not so small sense of accomplishment when things work as planned.  Unlike most people, I look forward to the challenge of planning charging stops but still with a minimal compromise upon my life and the very limited amount of time I have here on Earth.

So planning stops around my personal needs and desires is truly what its all about.  Whether its food, stretching legs, pix opps or a bathroom break, I simply make it work.  To some, its a compromise and it is but what decisions in life don't have compromises?  A year ago, I made a dramatic decision to quit my job where I spent a lot of time on the road 5-6 days a week to take a job that was a 4 day work week 10 miles from home.  There was a VERY large pay cut doing this but what I lost in income, I gained in time.  My LEAF gives me the benefit of a lower cost to operate along with extreme convenience (hard to beat plugging in at home!) that a gasser cannot touch.  OBTW, did you notice the price of gas is going up?  Me neither!   Another way to put it; Rationalization is part of every decision we make. We pay more for convenience or we pay less and compromise.  Which you choose is completely you.

But a lot of EVers have had a lot of obstacles changing their mindset of "beating last year's time to Grandma's house" along with being a member of the most overworked country in the World. This means limited time off and the desire to get the most of out that precious time off. So now the question becomes; "what is the most efficient way to get somewhere when time is a limiting consideration?"


Along with range comes one's comfort level with pushing the limits of the pack.  This can be scary especially if all you have to rely on is your EV's instrumentation.  Now some are better than others but the issue of someone being caught short on a route they know well does not seem to have any exceptions. Just as hundreds run out of gas daily, EVers are no different.  Now, before you say something; Brian, a fellow EVer has rescued Teslaites TWICE in the past week when they ran short on range without an SC in site and with their J-1772 adapter snug... AT HOME!  But the true reality for an alarming number of us is that we don't know, understand or use our full usable range.

So preparation and education is the key here. It seems like this is a no brainer among the degraded 24 kwh LEAF crowd but much less so among the 200 mile + EV crowd.  I guess we get a bit complacent when we normally have 2 or 3X the range we need most of the time.  I admit to being there. I don't charge over 80% which really only means I don't do full charges that often.  But sometimes I lose track of how much charge I do have so sometimes a bump at the QC needs to be scheduled into my day.  This only seems to happen when I have nothing specific planned. IOW, nothing that has a specific time constraint, etc. So the time to juice up is simply another errand to schedule in a day that has minimal demands on my time. But most of us don't have that luxury so being prepared with knowledge is the key.

Now if you have a LEAF, prep is easy.  Set up the charge to complete just before you departure time,  have LEAF Spy running and review the night before and during your trip to ensure the stations you plan to stop at are functioning.  I generally avoid stations that have not had a recent successful check in.  There is nothing worse than wasting time to find a station that doesn't work and worse; wasting your range detouring to find out!   I do add stations to check if they had been reliable in the past and have no recent check ins if time permits and its "somewhat" convenient to my trip plans.

More Speed, More Charging?

This is one of the greatest debates on the web today.  Its an EV so the farther you can go on a charge, the less time you have to spend to charge, right?  As straightforward as the statement is, there is still some considerations to ponder.

The LEAF has changed year over year.  The 24 kwh LEAF fast charged to a knee around 35-40% SOC.  The knee is the point when the current starts to taper. IOW; your "added range per minute" starts to drop.  But  then the 30 kwh pack (Nissan's best pack ever!) came out and I was seeing full speed charge of 125 amps past 80% SOC, it was AWESOME!!  I once registered a 49.19 KW charging rate.  So I was anticipating the same with the 40 kwh LEAF and WOW! what a change.

First off, the knee dropped to around 63% during optimal conditions.  Hot battery (RapidGate) meant not starting at the max amperage. Cold battery (IceGate) meant the knee moved DRAMATICALLY down!  In side by side tests (accessing LEAF Spy logs) my 30 kwh LEAF knee moved from around 83% SOC to about 77% SOC with pack temps in the mid to upper 40's.  But the 40 kwh pack knee went from 63% to 48% at the same temperatures!  This equates to a 15 mile range reduction for the same 30 minute charge! (YMMV)

Bottom line; Know your car! Now, I don't generally stay with the car when its fast charging (since stopping to charge is almost never the reason for the stop!) so this is where LEAF Spy logs come in handy.  The logs are rather extensive providing tons of information allowing easy charting of charging speed verses starting battery temps,  time and SOC.

This allows you to get an idea of how much range you are adding.  Now, typically I add 18-22 kwh in 30 mins of charging if my SOC is low and batteries are about 85ΒΊF or cooler.  So overall, I am adding 80 to 100 miles of range or about  3 miles per minute if driving 65 mph (LEAF speedo)

Another way to look at it is I am adding just over 90 mins of driving time which would be freeway plus time from the station back to the freeway.  This is my preferred stop interval most of the time.  Sure sometimes I would rather go 3 hours (rare) or only an hour (unfortunately more common than I want it to be)

Time To Charge

The flipside to the above is the question of driving faster between charging stops. This question pops up in social media about once a month.  What people lose is the time it takes to get off the route, find the charger, charge and then get back on the route so 30 min charges can take 35 to 45+ mins.  The Soul EV is very good as maintaining a high knee even with multiple quick charge stops but this not the quickest way to travel because;

The faster you go, the greater the heat buildup,  the less range you have not to mention less time for pack temperatures to drop.

The more stops you make,  the more likely you are to run into a queue.

This only works if the stations are situated close enough

Driving fast has legal ramifications!

Now more stops does allow more personal breaks which is always a good thing but you are better off to make more stops with shorter charging stints.

Cost To Charge

Maintaining a super low TCO is something many EVers enjoy as a challenge which does cause some problems with overuse of local free charging stations.  I admit to doing just that although I don't consider my use as abuse but will admit I do go to the theater at the mall that has 6 free level 2's and plug in no matter what my immediate needs are. (Yes, I do plan to have plenty of storage room in my pack...)

Road trips are no different. Right now, its easy for me since I have an active NCTC (No Charge To Charge) account which provides free charging from Blink, EVGO and Webasto.  But that has not always been the case. Of my 4 LEAFs, only two have had this benefit. But my NCTC is good for only two years so I am less than a year from having to consider the cost of that QC.

What this means is the best way to charge is to use stations that don't have a connect fee (EVGO, Blink) and don't charge long past the knee.  Although my charging is free, I generally only charge until my rate drops to 35 KW unless my need is more than that which is quite rare.  I will admit that my personal needs are not always met as quickly (thanks to the low SOC the knee occurs) but its all about me first, right!

But for most of us, we are paying most of the time which means planning around the freebies.  This is where comes in handy.  The app allows you to sort for free stations. If any are on your route, investigate whether an extended stop there is feasible. Maybe a meal and nap or simply a chance to do a walkabout.

For some of you lucky ones, Electrify America is installing faster CCS plugs and should have most of the operational kinks worked out eventually.  Now, EA does have a connect fee of a buck and a high per minute rate but that can be overcome if your EV charges at 100 KW which most 2019/2020 models will do.   FYI; EA states that the current billing is a temporary thing put in place to allow immediate use of the stations as they come on line.  They are still working on their "real" pricing structure. Hopefully connect fees will disappear along with reduced rates for subscriptions, etc.  Either way, the lack of a connect fee favors the more frequent but shorter charging stops.   Queuing (if you don't have Chademo) will not be as much of an issue either as several EA locations have several plugs

Six Station EA location; Walmart Lacey, WA

Fast?? Charging

Not all chargers are created equally.  Some run at 100 amps (somewhat loosely known as 40 KW chargers) Some only run at 62.5 amps (or 25 KW).  Originally EVGO chargers were 100 amps but turned up to 125 amps in many areas 1½ years ago. So if there are choices to charge and not sure which to choose, check Plugshare comments. Many list charging speeds.  

Not only are Fast Chargers running at different speeds but don't be surprised to find out that several chargers in the SAME LOCATION don't run at the same speed.  Tacoma Mall EVGO is a good example. They have 3 QCs. Dual format CCS/Chademo.  They run at 118, 121 and 125 amps!  I would tell you which was the fastest one but then I would have to settle for the slower ones in the future!

So there you have it.  In a nutshell; slow and steady wins in nearly every scenario. Now, I used to think it was an age thing but in the past 2 months, I have known two people in their 30's who started suffering from Deep Vein Thrombosis.  Both had no overt health issues but both did a lot of sitting at work.  Luckily neither will be at risk for major health issues down the road as long as they follow their doctor's recommendation of not sitting for more than an hour at a time.  Just a brief break for the butt as little as a few minutes is all that is needed.

Now for me, I am a LOT older than 30 so my needs are different. In my previous job, being stuck in traffic was a daily occurance so 3 hours driving in a 30 kwh LEAF left me with plenty of range left along with very stiff legs!  So give your body a break. It was not designed to spend two hours sitting.

Above I mentioned that my preferred stop interval was 90 mins but TBT, that is the high end for me.  Every 45 mins would be better but then its tough to get anywhere! So again; its a compromise I have to put up with now that the range of my 40 kwh LEAF is more than my body can handle.  😊  Its a tough life we EVers have to deal with! πŸ˜‰