Range Test Day – My ActiveE Made Me Accidentally Environmental

First Tesla Roadster range test in standard mode, July 9-July 12, 2014.

I was advised by the Service Center to have my wife do her normal drive and not plug the car in until about ten miles.

So, over the course of several days (from July 9th to July 12th) we did just that. Thank goodness we have OVMS, since I use that to let me know when the SOC has dropped to around 25% and have a good gauge of how much more driving we can do. I used to have it set at 50%, but decided to lower the threshhold since we’re not planning on plugging it in until it’s closer to ten (ideal) miles in standard driving mode. This was just a matter of sending a text message “FEATURE 9 25” to OVMS to configure the SMS Alert when the state of charge drops to 25%. OVMS will send a text back saying “Feature has been set.”

I created a log file to track what the miles would be overnight to see what sort of vampire loss the Roadster had in comparison to the Model S and was pleasantly surprised to see that the car lost 1% over the course of almost 1.64 days from the time I parked the car at home.

Date	Park at Home	Leave Home	SOC	CAC
July 9, 2014 at 6:00 PM	142		81%	145.73
July 11, 2014 at 9:23 AM		142	80%	145.74
July 11, 2014 at 9:10 PM	76		44%	145.66
July 12, 2014 at 11:41 AM		76	44%	145.66
July 12, 2014 at 1:07 PM	13		7%	145.66

July 13, 2014 at 12:00 AM	234V/40A	325 Minutes	5.416666667	hours
July 13, 2014 at 6:30 AM	175		97%	145.66

As you can see from the spreadsheet above, I actually had the car at the Service Center and back home the first day, July 9th. I parked the car around 6pm with 142 Ideal Miles of Range left and the car sat unplugged at home for a little over a day and a half, before my wife took the car out on Friday. Per OVMS readings, it had lost about 1% SOC (and no ideal miles). She drove the car for about 66 ideal miles (closer to 60 actual miles) and got home on Friday night with 76 ideal miles (and 44% SOC) of range left in the car.

Overnight, the car did not lose either ideal miles or % SOC and we drove off. Around 20 ideal miles left (and on the way home) on Saturday, we got the following error:

Though it mentions that power is limited, I was on the freeway, and the power seemed to be fine.

We finally plugged in with 13 ideal miles of range last night. Interesting, the rated range was down to 12 miles.

So, after 158.4 miles for the past few days, we recharged at standard mode.

7% SOC in Standard mode left, and the CAC values dropped to 145.66. We recharged overnight and ended up with 175 ideal miles at 6:30 AM. Basically, I checked the status when I woke up, and wrote it down. Because by the time I rolled out earlier today I already lost a mile of range. We will have to do this again for a few more times this next month, but that didn’t seem to have helped any. It’s going to be a long month.

Update on Tesla Roadster CAC and Ideal Miles testing

So, I started a new thread at teslamotorsclub.com on this issue which has helped me a lot on figuring out what I can and can’t see on the vehicle.

So, I’ve followed some of the advice and used VMSParser and the Tesla Graphical Log Parser (Tesla GLoP) to copy the logs down from the Roadster and see what values are generated from it. Aside from OVMS, my favorite telematics product, providing me with realtime statistics on the vehicle. I love the nearly six years of user experience that are the long-time Roadster owners/community. They’ve created tools such as the two log parsing programs to extract knowledge about the vehicle.

I posted a sample of the last month:

timestamp, brickahmin, brickahave, bricknumber
6/9/2014 14:29:11 143.26 148.67 74
6/10/2014 14:29:09 143.14 148.62 74
6/11/2014 14:29:11 142.8 148.39 74
6/12/2014 14:29:12 142.63 148.05 74
6/13/2014 14:29:11 142.4 147.7 74
6/14/2014 14:29:11 142.63 147.88 74
6/15/2014 14:29:11 142.69 147.88 74
6/16/2014 14:29:11 142.97 148.16 74
6/17/2014 14:29:12 142.92 148.27 74
6/18/2014 14:29:11 143.2 148.62 74
6/19/2014 14:29:12 143.03 148.22 74
6/20/2014 14:29:11 142.8 148.1 74
6/21/2014 14:29:11 142.46 147.76 74
6/22/2014 14:29:12 142.63 147.88 74
6/23/2014 14:29:12 142.8 147.99 74
6/24/2014 14:29:13 142.75 148.1 74
6/25/2014 14:29:13 142.52 147.76 74
6/26/2014 14:29:13 142.46 147.42 74
6/27/2014 14:29:13 142.57 147.19 74
6/28/2014 17:09:38 143.03 147.59 74
6/29/2014 17:09:38 142.8 147.08 54
6/30/2014 17:09:38 143.2 147.36 54
7/1/2014 17:09:36 143.37 147.65 54
7/2/2014 17:20:32 144.17 148.39 54
7/3/2014 17:20:32 145.03 148.67 54
7/4/2014 17:20:31 145.03 148.67 54
7/5/2014 17:20:31 145.14 148.79 54
7/6/2014 17:20:33 145.14 148.79 54
7/7/2014 17:20:33 145.31 148.9 54
7/8/2014 17:20:34 145.65 149.3 54

And was advised that if the last value does not change for a while that it could be the issue (a bad brick that is dragging the whole sheet down.). The fact that the brick has changed throughout the month, shows that I probably don’t have a single deficient brick. In the thread, Kevin Sharpe showed his Roadster log values and shows what a bad brick problem looks like.

Aside from the self-help stuff, one of the advantages of purchasing a Roadster under the Certified Pre-Owned program, is the access to the SC at no additional charge (for warranty issues). I was already scheduled to bring the car into service for an issue with fogging in the headlights, so I had them look into the loss of Ideal Miles and CAC values.

So, the Service Technician/Shop Foreman for the Southern California Service Center that I took my car too have provided the following plan of attack after they’ve looked at the car (and did the bleed test, updated the firmware (to support the >70A bug)) considering that our annual maintenance for the Roadster is upcoming.

Since my better half’s daily drive is approximately 60 miles a day, he suggested that we drive the vehicle in Standard Mode and run the car down to about 10 Ideal miles for at least three times over the next month and charge back up in Standard Mode. On those evenings that the car has NOT been driven down to the 10 Ideal miles, we were advised to park it, but do not plug it in overnight. I’d like to track the vampire loss for the vehicle as we do this.

During an extended period of non-use, the tech suggested that we plug in the Roadster using storage mode during that time.

After the month, and possibly during the annual maintenance, they’ll look at what happened to the pack after these tests.

I did see some improvement in minimum CAC values over the past week since I did my test on July 2nd and July 3rd… So, we’ll see. Will report here (as well as on teslamotorsclub.com).

First Daily “Standard” charge after the weekend’s Range charge test

No pictures, ’cause I had to head to work quickly…

Step two of the Range Test Days and Tesla Roadster pack rebalancing that I was doing was to get to my first daily “standard” charge to see if it made a difference.

Following Michael Thwaite’s suggestion to maintain the charge (and not drain too low) we plugged in the Roadster on Saturday night with about 102 Ideal Miles on Storage mode.

On Sunday, drove the car out for some further errands, etc. and ended up home with 21% SOC/37 Ideal Miles/34 Rated Miles left (thanks to OVMS again).

This time, I plugged it in and performed a STANDARD charge starting at midnight… (a few hours earlier than I normally set the car to charge. To maximize the amount of 40A/240V charging that I will do at super-off-peak EV rates.

When I rolled out at 9am, the car had 174 Ideal Miles on it and the CAC values were at 145.44. It was a slight improvement to the 171 Ideal Miles that I observed last week, but definitely nothing to write home about.

I guess we’ll have to see if we can change my better half’s behavior and see if she can plug it in every other day so that we can drain the battery down 120 miles in two days of driving vs. the 60 miles a day that she normally charges under to see if that will do something to improve the CAC values and ideal miles after a full charge.

I cross posted questions on these tests to teslamotors.com, so wanted to put the CAC values here –

Values from October 2013, when I first started to use OVMS.
Standard – Charging Done SOC: 96% Ideal Range: 183 mi Est. Range: 173 mi ODO: 3,578.8 mi CAC: 154.38

Values from today overnight charged in Standard mode and 174 miles (the CAC value is the same from the evening before it started to charge.) (unfortunately after my wife drove about 30 miles)

Not charging SOC: 82% Ideal Range: 147 mi Est. Range: 144 mi ODO: 10,901.2 mi CAC: 145.44.

Rebalancing the Telsa Roadster battery pack

One of the things that one should be concerned with when buying a used Electric Vehicle is battery health. We were confident with purchasing our 2008 Signature 100 Tesla Roadster from Tesla Motors because they warranted the vehicle for 37 months or 37,000 miles, whichever comes first. Additionally, the vehicle we purchased only had 2,220 miles when we bought it, so it would seem that the previous owner took good care of the vehicle. When we first picked up the car, its daily charge was around 185-186 miles. At the actual day that we picked it up, we range charged it for the first time the numbers were closer to 240 miles (don’t remember exactly what it was)

However, since September 2013, the car’s daily range has gone down to around 172 ideal miles. That’s about a 7.5% drop in ideal miles since we acquired the vehicle. Understanding that a 2008 vehicle isn’t that new and I should expect some loss, the question is how much loss is acceptable for something that has a warranty. Is the loss even real? There have been reports to indicate that a Tesla Roadster’s algorithm for range calculation isn’t very good.

Apparently an approximately 60 mile daily roundtrip is too short and could also lead to an “artificial” loss of range. So, I’m unsure whether there is a real loss or whether it is unreal.

To combat this challenge, I’ve looked at some sources to see what I can do to rebalance the pack. The first method I tried to do was several months ago at teslamotorsclub.com. Having followed the process gained a few miles temporarily, but the decline still occurred. So, this week, I figured to go ahead and see what else I can do.

I spoke with some of the Tesla Service Advisors and I was told by one of the advisors who uses a Roadster to try something different. Range charge and drain the battery down to at least 30% SOC and then do another range charge. Then repeat. So, the pictures will be what I’ve done on July 2nd and July 3rd.

So, my first range charge was done from the evening of July 1st to July 2nd. Started at 219 miles of range and decided to do a long drive to the desert.

Here is the car with the top-down. After all, it’s the summer in Southern California.

So, after 165.5 miles of driving, I encountered the following error:

Now, I’m not sure if the second half of my drive was in Range Mode or Standard mode, but I did drain the battery, so I miscalculated and ended up back home at 10% SOC.

Range was estimated at zero, because it couldn’t calculate things, luckily I use OVMS, and that told me that I had 10% SOC left. So, I wasn’t nervous.

So, after the first day, I charged the car all the way back in Range Mode and got the following the next day:

That’s 222 ideal miles and 201 rated miles. Ideal miles are based on the ideal 55mph in flat terrain vs what I actually drove the previous drive. Granted, another reason I had really low range was because I was “inspired” to drive a little faster than the speed limit for quite some distance.

So, in day two, I tried to drive with a lot more restraint, and after 162.2 miles of driving, I decided to go home.

Using OVMS, I could see that I still had 16% SOC left and a rating of 38 ideal miles left.

So, did that do it? Well, day two ended, and this morning, I saw that the car charged at 222 ideal miles again. The CAC values was higher than before the test, but not much more. So, I guess we’ll have to see what happens after the Fourth of July Holiday weekend.

To see if the theory that charging the car less will help, the next trick is to drive the car down before plugging it in rather than plugging the car in on a daily basis. This would also mean we’ll have to pay attention to any vampire drain and plug in the vehicle as soon as it needs it. Fingers crossed, hope that works. In the meantime, Tesla’s downloaded the logs, and if they see something there, then we get it fixed or validated. The Service Center guys were talking a bleed test, so, who knows. Either way, 172 miles daily range is still almost double what we got from the Active E.

And lastly, it does help to drive conservatively to get closer to ideal range than driving with a heavy foot… But it’s a Tesla Roadster for crying out loud, it just screams to be driven with a lot of speed, especially when the top is down in beautiful weather.