12V Battery near-dead after charging HV battery :-(

No it is NOT OK if he was measuring that current drain from the 12 V battery itself.

The current required for EVERYTHING that you quote should be provided by the charger and NOT by the battery.

And I don't like the wording of a couple of sentences in there; they should say that the battery voltage is "allowed" to drop to the point specified, not that it is "lowered" to that point.

 

To quote Carl Sagan, "Absence of evidence is not evidence of absence."

In other words, not finding a problem doesn't mean there's no problem. The OP explains in detail that there is a problem.

 

The DC-DC charges the 12 volt battery and the 12 volt battery provides current to all the 12 volt systems in the car. As such, all the 12 volt in the car goes through the terminals of the battery and the OP is measuring total amperage correctly. The charger doesn't run the fans and SMRs directly but via the 12 volt battery. The big spike in the amperage reading is module communication and the SMRs closing, then settling to the amperage the fans and AMRs need to stay closed.

I think we would all appreciate it if the OP kept us up to speed in the future with what happens. I'll bet the dealer will put a battery in there for him (if it is under warranty) and it'll be great, no new charger required.

 

Fractured logic because the battery itself does not control what comes and goes from it.

IF the current measured really is coming directly OUT of the battery during a charging cycle, then the battery is not the problem.......although it may be damaged along the way by excessive discharging.

IF the battery is replaced but the underlying condition is not fixed, then it will be in trouble again within a short time.

 

i agree with car spec, sounds like a bad 12 volt.

 

Were you able to see when the Traction Pack Charge shuts off for a few seconds ( every 15 minutes or so ) ?
When the charge shuts down the pack cooling fan shuts off and the charge rate drops to 0 kw.
Than after a few seconds the charge ramps back up to it's previous level and continues normally.

I noticed in the video that you are using an L2
Mine charges at approximately 1.9 kw when plugged into an L2 and takes about 90 minutes to charge the pack from empty..
Do you get the same parasitic draw numbers as shown in the video when using the OEM L1 plug?

 

The on board charger provides voltage to run all these systems via the converter when the SMRs are closed. The current you are reading is coming from the plug via the converter. The battery isn't putting out this amperage on its own, but being supplied by the converter once the SMRs close.

If the converter was failing to supply current you'd have codes like "P0A08-264 DC/DC Converter Status Circuit" and the system would never charge the 12 volt, the car would never start and you wouldn't see the car charge at 13.5 then drop to 11.75 - you'd see a constant drop in voltage until everything had shut down.

You can test your no-charging the 12 volt theory by monitoring the battery voltage over the course of the entire charge. If the voltage doesn't drop below 11.5, you know the converter is supplying voltage at 11.5 volts in "low temperature" mode.

Please keep us updated on what your dealer says. I've been wrong on diagnosis many time before and learned each time (and am learning more as I make mistakes), so I'm especially interested in seeing how this gets repaired and learning more about what happens.

 

My guts tells me it follows the repair manual too closely to be an issue with 12 volt charging. Here's a photo of the spec sheet I keep referencing.

All of the voltages listed fit with what you and others are saying, so I suspect something else causing your no start (and lack of codes). The system is so closely monitored it doesn't fit.

 

AND...if there is something draining the 12 V system, which apparently there is, the 12.6 volt battery will supply more current than the converter to run those things; net current will come OUT of the battery and none will go back in. If that lasts long enough, the battery will settle at 11.5 too, at which point it will be substantially discharged. THAT is the whole point.

P.S. Where do you get this "cold charging" 11.5 volts thing ?
Applying 11.5 volts to a 12.6 V battery can't hardly be described as "charging" because it won't......unless the battery is REALLY low to start with.

 

You're correct in saying it isn't charging if it is holding 11.5 volts - it is discharging. I was very wrong there. The converter does supply current at 11.5 volts when plugged in (as per the linked specification sheet) when cold, and this fits with what the OP is experiencing, hence me doubting he has any failure other than a 12 volt battery.

The converter won't let the battery get below 11.5 volts though, and a healthy 12 volt battery has enough voltage and capacity at 11.5 to arm the SMRs and wake the computers. If it didn't, every PiP every winter would fail to start.

 

This whole thing makes no sense to me at all.
It would have to be EXTREMELY cold, like -40F to worry about charging the 12 V battery too fast.
There is no reason that the system could not first TEST the system voltage and use that as a starting point.......instead of arbitrarily picking 11.5.
There is no practical reason to purposely DIS-charge the battery when the converter is running. NONE.

If that IS a real design feature of the charging system, then it is kicking in at WAY too high a temperature.

 

Anecdote:

When I worked at the dealer we would occasionally get on the horn with tech assistance (TAS) to report weird issues, production problems, etc. They are in CA, I'm in MN. The following conversation ensued every time I had an issue that pertained to a cold start:

Me: "It only acts up when the car is cold"
TAS: "Are we talking cold engine or like 50 degrees out?"
Me: "Negative 20"
TAS: "whoa."

To TAS 50 degrees was cold. I can absolutely see Toyota doing what we think is silly in this case.

 

Toyota has a testing facility in northern Manitoba.

 

I keep watching this thread, waiting for iluvmacs to tell us that he replaced the 12V battery and now everything works.

 

Any update yet?

 

Anyone have a wiring diagram for the vehicle?