a data anomaly when trickle charging my new S

[lopezmusic]

I have a brand new S, less than 350 miles on it. We set up an XL spreadsheet to log charge times. The first time we recharged, the SOC was 48%, and it took 7.6 KwH to bring it back to 100% SOC. The next two charges we made the mistake of charging when the SOC was only 80% or so. No data was recorded for those charge times, another mistake. We got that figured out. Yesterday the SOC was 42% but it took 13.6 KwH to bring it back to 100%. We are using a Kill-a-Watt device to measure the KwH used for the charge. Before the use, we remove the Kill-a-Watt from the wall to clear the memory, then plug it into the wall outlet which is a dedicated 15 amp circuit. Very mysterious. We estimated prior to the charge that it would be around 6.5 KwH or so. Not 13.6. Any idea what might be happening?

 

[DaveInAvl]

The amount of energy for that first charge seems low... perhaps there was a momentary drop in your household power which reset the Kill-A-Watt to zero partway through the charge? When you read the kwh from it at the end of that first charge, was the meter showing line voltage when you looked at it? That's what the display defaults to each time the Kill-A-Watt is plugged in, so seeing that might indicate there had been an interruption...

 

[lopezmusic]

Dave, thanks for your reply. Because of our renewable energy systems in the house and attendant software monitoring of same, I can verify that there was no voltage drop during the time period we were recharging the Leaf. The amount of energy consumed by the house during that time period never wavered from our standard background baseline of about 1.75 KwH per hour. The increase in consumption during the charge is clearly visible in the graph. No voltage drops. Likewise, the Kill-a-Watt showed the KwH number, not line voltage. However, that is very interesting info you have provided about the Kill-a-Watt. We're always on the lookout for indications we may have had or are having an outage. In our type of RE grid connection, it's not always easy to tell when there is an outage! Do you know of any data that shows KwHs consumed vs. begining SOC %s? Thanks!

 

[DaveInAvl]

Do you know of any data that shows KwHs consumed vs. begining SOC %s?

A leftover of my growing up in the 1960s is that I still love being able to "turn someone on" to something cool: in this case, an app called LeafSpy. There are both Android and iOS versions. When used in conjunction with a code-reader unit plugged into the LEAF's onboard diagnostic port, you'll have access to a great deal of data. Just one of the many screens the app presents is this one - this is a recent QC of my own LEAF. Charging was at about 28kw until SOC reached about 60% then began to taper. (The stair-stepping in the red line is an anomaly in the test version of the app I'm running.)

Suggest you head to the Accessories/Mods section of this site, and look at the LEAF CANBus subtopic. For not a lot of money, it's possible to have LOTS of nice data to pore over

 

[lopezmusic]

Wow, thank you very much Dave! That looks pretty cool, but is also much more than we can use. Since we live on an Island, the WiFi thing isn't even possible, since there is no wifi. Some people are really agitating for it though, so one day we might be able to use things like this. Very cool! I saw on the App Store description that it has a "charge and trip log". That's all we really need, so I will continue to go analog. Thanks very much for your help!

 

[mjblazin]

How did you get battery temp on your charging graph?

 

[gbarry42]

Since your LEAF is new, we will assume the battery is operating at full capacity. After accounting for the high and low limits imposed by the charge controller, the usable part of the 24 kWh battery is around 21 kWh. If you've used half of that (48%), then you'd expect to need about 10.5 kWh to get back to 100%. Charging inefficiencies will make that number be closer to 12 kWh.

That said, I think you just Need More Data. Charge on!

 

[dhanson865]

Wow, thank you very much Dave! That looks pretty cool, but is also much more than we can use. Since we live on an Island, the WiFi thing isn't even possible, since there is no wifi. Some people are really agitating for it though, so one day we might be able to use things like this. Very cool! I saw on the App Store description that it has a "charge and trip log". That's all we really need, so I will continue to go analog. Thanks very much for your help!

I think you misunderstand the wifi aspect.

Bluetooth or wifi can be used as the connection from the ODBII adapter to the phone. Neither requires active internet access for the car or phone at the time of logging. The phone would have to be within range of the car to get the data.

 

[DaveInAvl]

How did you get battery temp on your charging graph?

I'm one of the folks who tests new versions of the app before it's released to all the other users, and I don't recall offhand which version started showing battery temp. If yours doesn't, it ought to soon - take a look at the Leaf Spy threads in the "LEAF CANBus" subsection of the Accessories/Mods section of this board for more info.