Next, LYRIQ plugged in, finished charging an hour or so before test, some current draws, pulsed patterns similar to, but not the same as above. Using the iPhone Cadillac App, I repeated App update requests to intentionally draw down the 12V battery. On the tenth update request, the charge station came on at about 1kW with the LYRIQ 12V internal charger, and the 12V started to recharge. The chargepoint flex normally does regular charging at 48A, 11kW. Very roughly, I estimate each App update to be on the order of 0.4 Ah or around 4.8 Wh of draw. The 12V battery voltage at rest (short time since use) was around 12.68V. By the end of the ninth update with very little rest, 12.50V. As mentioned above, the loaded battery voltage is very different. For example during peak current in the first update, the voltage fell to 12.35V loaded at about 11A. By the ninth update, 12.20V similarly loaded. Bottom line, at least plugged in, LYRIQ seems to charge the 12V as needed, as advertised. Later, after charging, the unloaded voltage was back up to 12.89V, presumably near full charge. But, note that unloaded voltage should really be considered after hours with absolute zero load, and even then can be battery dependent, so use published AGM tables found on the Web with care and skepticism.

 

I need a spare battery to swap out during 12V system testing. We have a 60 Ah, BCI group 47, DIN H5 battery. I decided to try this one, but there are any number of choices. Fortunately, we have a very common 12V size and capacity. Not yet a recommendation, will confirm fit later.
ACDelco Gold Automotive AGM Batteries 88866188 ADO-EVLN2AGM 60 Ah
BCI Group Number: 47
Cold Cranking Amps (0 degrees F): 660 amps
Reserve Capacity: 105 minutes
Length (in.): 9.510 in., Width (in.):6.880 in., Height (in.): 7.450 in.
Weight: 39.500 lbs.

 

Last night woke up to a thunderstorm and went out and unplugged L2. Forgot to plug L2 in again until this evening when I pulled the data logger to have a look. Also, I accidentally left the key in LYRIQ during this entire time, no idea how that might change things.

Anyway, it is an example of LYRIQ charging the 12V while unplugged L2. Pulled the L2 charge cord at 12:33am and LYRIQ charged the 12V for 25 minutes from 2:13am to 2:38am while L2 was unplugged. Just one observation, wouldn't make too much of it. Blue is voltage, orange rough current.

 

Fob in the car shouldn't have much impact as it goes to sleep if not moved.

 

My spare 12V battery arrived from Summit triple boxed and not too badly handled by FedEx. I want to have a look at the OEM battery on the bench and check its sulfation condition from the time to delivery. Not something a regular owner needs to do or should be concerned about. This was among the most difficult 12V change outs that I have done in recent years. Most time consuming is the 12V positive fuse block assembly. The 12V positive fuse block is snapped onto the side ridges of the battery both side and end. Also, there are two plastic posts underneath the fuse block that seat into the two holes on the plastic top of the battery. Finally, the alignment of the positive terminal has to be spot on; if not, the nut above the 12V jump lug has to be loosened to very slightly rotate the 12V positive terminal. It would go faster the next time around, but still way more difficult than most others I've seen in recent years. If anyone ever has swap out the 12V battery in an emergency make sure that you have lots of light to see how everything aligns, otherwise another project best left to the dealership for most.

 

I got two 12V battery charges by LYRIQ on its own within 24 hours, while unplugged. There was one drive between charges.

The first 12V charge event began with a battery voltage of about 12.52V, minimal current (-1.1A is an instrument offset error, should be about zero). The second 12V charge event began at 12.55V. No idea if this is the new 12V battery maintenance routine. This is the latest BECM module software as of 4/11/24. If LYRIQ maintains its 12V battery above about 12.5V, this seems like an acceptable 12V battery maintenance strategy. A bit higher could be better, but I can certainly live with 12.5V if that is how it works now. Still only very limited data and observations, and only for my 2024 sport2. Note that this setup cannot measure a 50mA typical sleep current which would be on the order of 10 microvolts, current data is rough 10% accurate at best.

 

Just pulled into garage a couple of minutes before, L2 unplugged.

In this about two minute portion of the recording, look at the dark blue line, 12V battery voltage, from lower left to center. No load, the battery voltage was about 12.7V. Then LYRIQ was doing something which gradually increased the load, probably from about 8A to 15A. The battery voltage fell under load as expected, first to 12.6V, then gradually to 12.4V, at which point probably the DC/DC converter started to power up on the hv battery. During the power up sequence, currents were momentarily over 20A. Then the 12V battery started to charge from the hv traction battery.

Here, it would seem the trigger voltage which initiated a 12V re-charge was about 12.4V (even through entry into the check routine was 12.7V unloaded). 12.4V is consistent with the LYRIQ technical documentation as to when a battery charge might occur.

This is about two minutes of data (3:39 to 3:41) taken at 200 millisecond intervals (5 points per second).

 

Another overnight 1/2 hour 12V battery charge L2 unplugged yesterday evening. Cannot say anything about the 4 day thing for L2 unplugged yet, but 12V maintenance first day unplugged seems reliable so far (Sport2 AWD, latest software).

About 24 hours (detail below is leading edge of the 12V 1/2 hour charge two divisions in on top graph)

couple of minutes at moment LYRIQ decides to self maintain charge 12V battery around 5:04pm in detail

 

FYI.
The vehicle gets all of its battery information from the IBS (Integrated or Intelligent Battey Sensor) built into the negitive battery terminal. It measures battery current and voltage. It is a stand alone computer that also measure the battery state of charge and state of health. It is awake all the time but has microamp current draw. It measures SOC by waiting at least 4 hours after vehicle sleep and the measuring the open circuit battery voltage. It then uses a look up table to determine SOC. If it sees excessive battery current It will not make the measurment. When you disconnect the battery the sensor will set the SOC to 80% but flag that as invalid data. The vehicle will need to sit and sleep a minimum of 4 hours before it will attempt to measure the SOC. On conventional vehicle this is why stop/start doenst work for a while after a battery change. (Stop start is disabled if battery SOC =< 80%)
The sensor receives data from the vehicle for part of thes calculations. The vehicle is programmed with the type of battery that was installed at the factory (conventional, AGM or others) along with the size of the battery. This information is not updated if you change the type or size of the battery.
The sensor communicates with the vehicle over LIN data on pin 1 of the connector and gets power on pin 2. Ground comes right from the battery.

Just thought you might be interested. Love what you did with the datalogger!

 

FYI.

This has info has been shared before. What @Luxiondrive is trying to gauge is what the car really does now, as he has the most up to date software. 12V battery charging behavior on the Lyriq has evolved, and is likely not in sync with the generic service info for all elements.

 

Do these 12V refresh cycles explain the sporadic low-level power outputs I see from the EVSE when the car is plugged in?