Tag Archives: Charging

A couple of ARS articles relevant to EVs

One article details the dramatic price drop we’ve been seeing in the cost of Li-ion batteries. The drop has been faster than predicted and bodes well for future EVs.

The other, however, repeats much of the information from a recent study on “how much do EVs pollute”. This study is another in a line that attempts to calculate how much better (or worse) EVs are to conventional ICE cars. These studies are popping up now about once every 6 months. Some show EVs as being dramatically better, some show them as dramatically worse. Most of them have some flaws. At the moment I think the jury is still out (for some of the “EVs are worse” studies, though, there are some really obvious flaws in them). The one thing that is true, however, is that EVs will get greener as the power grid gets greener–that cannot be said for ICE cars.


Public chargers don’t affect EV sales?? what?

Here is some interesting research:

When we account for the relevant factors, our analysis suggests that the relationship between public charger awareness and plug‐in electric vehicle demand is weak or non‐existent,

In short: When people are considering if they want to drive/purchase an EV the availability of public chargers doesn’t factor into their decision. In interesting result. Granted when people are considering a conventional ICE car the availability of local gas stations doesn’t factor either–but this is simply because gas stations are found everywhere. If you are considering a Diesel vehicle, however, you’ll be interested in how many local stations sell Diesel fuel (simply because not all gas stations have Diesel–at least in the U.S.).

When I was considering getting the Focus Electric local public chargers did not factor into my decision process. My main concern was: can I get to and from work on a charge and have sufficient reserve to be able to run errands and/or be able to charge sufficiently at home in order to go out later after work. Obviously the answer to both those questions was yes (I already knew before I got the car that workplace charging was not available and wouldn’t be available to me). Thus my experience fits in with the results of that research.

This makes perfect sense: Your house already has an electric “feed” going to it. You know that if you get an electric car you’ll be able to charge at home. Your main consideration will be: can I get everything I need to do with the EV charge I can get at home on a daily basis. This would lead to some “range anxiety” concerns (a really bad term coined by the media–you get “range anxiety” in a gas car too when the low fuel light turns on). If you’ve done your homework and determined that an EV is the right fit for you; you quickly realize what the EV can and cannot do with the home charge. Its only at that point where you even begin to consider public charging: When you’ve determined it all works for you and then ask “Hey! Where else can I take my EV?” that is when you start looking for public charging which is long after the initial purchase decision.


A PowerXPress “recall”?

Interesting, I got the following note in the mail from Bosch:
PowerXPress note
Here is the text:

Our records indicate that you are using your Power Xpress to charge an electric
vehicle(s) with a charging system that operates at 30A or higher. Recent
incidents have occurred in which customers have expressed concerns related
to the performance of the Power Xpress while charging at 30A or higher. Some
consumers have reported incidences of sticking or melting within the connection
between the charging station coupler and the vehicle inlet.
The. Power Xpress is designed to charge vehicles up to 32A. A new cable/coupler
assembly has been designed to address the customer concerns while charging
at 30A or higher. In an effort to secure your complete satisfaction, Bosch will
upgrade your Power Xpress with a new cable/coupler assembly — completely at
your convenience, and at our cost.
The division of SPX Corporation that originally designed and sold the Power
Xpress became part of the Bosch group of companies and now operates as Bosch
Automotive Services Solutions Inc. (“Bosch”). Therefore, Bosch will be addressing
your charging needs going forward, including the upcoming interaction with you
regarding your charging station.
A Bosch customer service representative will be contacting you within the next
30 days in order to arrange for this upgrade. We will coordinate with you to have
a Bosch certified electrical contractor visit your installation at a time of your
choosing to complete the exchange of the coupler and cable. Because the Power
Xpress was designed for field replacement of the cable/coupler assembly, this
repair will take less than one hour and will not disturb your installation or its
environment in any way. A licensed electrician will detach the existing cable/
coupler from the unit and simply install the new one.
Should you no longer own your Power Xpress, we ask that you forward this
message along to the new owner if possible, or provide the new owner’s contact
information if available.

If you have any questions in advance of our contacting you,
please call Bosch at +1 888 823-9877.
Bosch Automotive Service Solutions

This is interesting! You may remember that my coworker suffered from this very problem. A technician eventually did replace the cable in his unit at no cost. The issue must have happened to more than a few EV owners for Bosch to issue this recall.


How does the FFE Charge?

This question could be answered in many ways depending on how you interpret the question: There is a technical answer (it uses a 6.6kW charger inside the car), simply (you just plug it in and it charges), how much current is used, how fast does it get to 100%.

In this case I was interested in the last answer above: Does the FFE’s % battery full “meter”/value increase linearly when charging? Li-Ion batteries themselves don’t charge up linearly. As the battery gets closer to full the internal resistance of the battery increases making it harder to force more electrons in and thus the charging rate of the battery slows down the closer to full it gets. If you were to plot this you’d get a curve where charging is quite fast at the beginning then as you approach 100% it flattens out slowly approaching 100%.

Having done a little reverse engineering on the API that the mobile app and the website use I was able to make a program that logs the % battery value and the range over time. Now if I were to log these values during a charge cycle I could produce a graph to see the charge curve. The graph could be a line as the internal software in the FFE could normalize the % value to a line while charging (to simplify it for users). Frankly I don’t think they would go through that much effort–there would be no benefit to anyone (other than geeky people like me who write blog posts about graphing the car charging! LOL). So I give you my FFE’s charging plot from about 35% to full on a freezing Friday evening:
Charge Plot
The blue line is the % battery value and the orange line is the estimated range value (only topping out at 70 miles here due to the cold days we’ve been having and the fact that I’ve been using the heater).
What surprises me the most about this plot is how flat it is. I was expecting it to be much steeper with a pronounced knee near the end as it flattened out. Note that there are a few gaps in the data as the API timed out or otherwise gave an error. There is also an unexpected turn faster around 10:00pm where it charges slightly faster. I wonder if this is where the temperature management system kicked in to cool the battery a bit allowing for a slightly faster charge..

I have another idea for this logging: What if I were to let it log while I was driving the car around? That plot may also prove interesting as the % battery value would decrease in a predictable manner but the estimated range (the guess-O-meter) value would be all over the place depending on if the heat was on or off, if I was on the freeway, etc. Some more experimentation is in order here…

Another novel use for the FFE

Found another novel use for the FFE:
Another novel use

What am I doing here? It would appear that I’m charging the FFE off of a covered RV. The novel use here is to provide a load for the generator in the RV. While in extended storage (say over winter) the engines have to be run about once a month or so. For the generator the Onan people told me that when you do run it you have to provide a load. I don’t think I could provide a better load to the generator than having the FFE charge with its Level 1 EVSE (which will draw about 12 amps).

Other options for drawing a load would be the A/C (which shouldn’t be run in cold weather), or a ceramic heater (which would have the benefit of heating the interior of the RV). In both of those cases, though, the electricity produced will simply vanish into the air. With the FFE the electricity goes to good use charging the battery (granted only using Level 1 for about 20 minutes I’ll be lucky enough to get a mile…maybe).




Disco pants and haircuts….Yeah

In an earlier post I mused on how effective it is to have public chargers at motels and hotels. Other optimal locations for public charging are locations where people tend to stay for a few hours. These locations include:

We happen to take advantage of one of these types of locations this past weekend which worked out quite well: A Mall.
At the mall

This mall in particular lies slightly beyond the 1/2 “tank” range from our house and thus a short charge is required to complete the round trip. These chargers were recently added about 6 months ago (four Level 2 chargers to be specific). We took a little over an hour browsing and shopping in which time the car gained about 20% in battery charge (don’t know how many kWh that was because these were simple chargers–no card access required, no 800# to call, just plug in and they charge with just some status LEDs indicating charging, fault, ready, etc.). At the time all four parking spots were available which can be unusual for some areas of the country.

This is great as more and more companies realize the benefits of having a charger (shows a progressive business, encourages those who own EVs to shop there, etc.) we’ll see more of this–especially if EV sales continue to grow.


Ford to build Michigan’s largest solar array

More news from Inside EV’s: Ford to build Michigan’s largest solar array.

Interesting, to me, of note is this quote:

The project, funded by DTE Energy, will provide employees with 360 covered parking spaces and 30 charging stations for plug-in electric vehicles such as the company’s Ford Fusion Energi and C-MAX Hybrid Energi. A kiosk will also be on site offering general information to visitors about solar power and specific details about the Ford carport.

No mention of the FFE? (It is mentioned later on in the press release when they talk about the solar array at Michigan Assembly where the Focus and C-Max are built.) Was this an oversight, simple error, or does it indicate that the FFE may not have a future? Am I reading too much into this one statement–most likely! LOL


Testing EVSE’s

From Inside EV’s: Testing interoperability of 11 different EVSEs.

This is something to keep an eye on, how well will the EVSE(s) you use stack up against all the others?

When I watched the video I noticed the exact same connectors on the power side of the EVSE’s that I’ve been using in my garage–given that they are in Plymouth, Michigan it wouldn’t surprise me if they purchased them at the same Home Depot that I did! LOL

Here is a link to more details about the study.




How efficient is charging?

These days everyone is concerned with how much resources do they use. Tracking things down to the penny/gallon/kWh/etc. When you have an ICE vehicle there are no losses from fueling the tank: The amount of gas that went into your tank is exactly equal to the amount of gas that was extracted from the tank in the ground and is equal to the amount of gas that was in the tanker truck, etc. (within reason). When you plug in your EV its not the same: When you charge what happens? The battery and the electronics heat up. That heat is wasted energy. Not all of the electrons going through the charge cable end up in the battery. But how many? Is there a way to measure this?

Many modern charge stations will report out the kWh value they put into the car (Chargepoint, for one), in addition some home stations (like the Juicebox) also report out the kWh value. This gives us one figure, but to figure out the charge efficiency we also need another number: The kWh the car used from the battery. This value is the amount of kWh the car consumed that the charger replaced. Divide these two values into each other and you’ll get a measure of how efficient the charge process is in the FFE.

For example: This morning my commute in to work consumed 3.5 kWh according to Ford’s online application (one of the few values in the trip history that have been accurately reported here). Once at work I used a local Chargepoint station to top it off. Chargepoint reported that the car consumed 4.14 kWh during charging. This would work out to a 85% efficiency while charging (at least for the top 20% of the battery or so which is what these values amount to).

I’ll have to do the math again with a deeper charge and using the Juiceboxes values for a different comparison (I’m not expecting it to be much different but more datapoints is always better).

Update: The commute home consumed 3.3 kWh according to the trip meter and the Juicebox put in 4.2 kWh to charge it back up (about 79% efficient).

Also note that the amount of energy going in also is used to run the TMS (temperature management system) and thus when its running will lower the efficiency.

Update 2: After a deeper discharge (9.6) charging took 11.7 for an efficiency of 82%

Update 3: A normal commute usage (11.1) and overnight charge (13.0) yields: 85%.

Update 4: Another normal (10.3/12.4): 83%

Update 5: 10.5/12.8: 82%


Drop by any time you like and stay for the charge.

Locally in Southeastern Michigan I’m noticing more and more hotels add charge stations. In the area here are but a few:

A charge station at a hotel makes perfect sense: You’ll be there more than long enough to charge up any EV available today with a Level 2 charge (e.g. overnight). It works out for the hotel since they will get the extra customers who are looking for such an amenity.

That last one on the list is what prompted this posting: I only just noticed that they had a charge station and are advertising it. Even prominently on their website:

Weber’s Boutique Hotel and Restaurant in Ann Arbor, Michigan has complimentary EV charging stations for their guests. We offer the PEP STATIONS PS1500. It is a commercial 208 volt, 30 amp EV charging station with SAEJ1772 connectors that can accommodate two cars at once. Owners of Volt, Leaf, Tesla will be pleased with this complimentary service while in Ann Arbor. Please notify Weber’s when reserving your room so we can block off a protected carport space exclusively for you. Weber’s is among Michigan’s first hotels and restaurants to offer EV charging stations.

This is great, while we’ve never stayed at the hotel we have dined there a few times. Looks like its time again to go visit for a meal and perhaps a charge (if they also allow patrons of the restaurant access to the charge stations as well…).