Greg, if a car cannot provide the 12v charging flag it has two options: a) disable the 12v alert system by overriding the methods (as Mark did) b) provide a suitable reference value at startup. Option b can be done by yourself / script: metric set v.b.12v.voltage.ref 12.65 …or you can raise the threshold from 1.6 to whatever fits your readings. Maybe I'll add a config for the initial reference voltage on startup, as that can also be wrong due to 12v noise. Regards, Michael Am 20.05.2018 um 01:10 schrieb Greg D.:
Thanks for the overview, Michael. I have not experienced the v2 module, so didn't know how this worked.
If the reference is taken at boot, then plugging the module in with the car awake would give a too-high value vs when it's asleep. I guess the idea is that it should reset itself to a more reasonable value after the first charging session, yet I'm not seeing that. It seems to be stuck at 13v, which presumably was what it recorded at the reboot when I was playing with the SD card (car was awake and apparently annoyed at the time). I'm on the .005 code, which apparently pre-dates Mark's commits, though the commit was 30-April and the .005 build is dated 1-May... {shrug}
The algorithm sounds like it is intended to detect a weak battery by observing its behavior after being charged, but is this sensing available on all cars? I'm guessing not, and that the Roadster not one of them. For those that aren't, couldn't we just have a configured / configurable threshold that would trigger the alert? Regardless of vehicle type, 12v battery health is an important metric to watch.
Since I'm currently waiting for the modem issue to repeat, I'll just live with the alerts for now (vs resetting the module to capture a lower threshold value), and see what happens with the .006 software. The car just completed its periodic top-off, generating another pair of events (12 restored, followed by 12v alert).
Thanks again for the explanation,
Greg
Michael Balzer wrote:
Greg,
Mark disabled the 12V alerts on the roadster firmware some commits ago.
Regarding the alert configuration:
commit 9c1a991a9a27de8afdc9fd408262a2fe0be7aef4 Author: Michael Balzer <balzer@expeedo.de> Date: Mon Apr 30 22:39:05 2018 +0200
Vehicle: 12V battery monitoring & alert
New configs: - vehicle [12v.alert] = 1.6 Voltage drop alert threshold in V vs. reference
New metrics: - v.b.12v.voltage.ref 12V reference voltage [V] - v.b.12v.voltage.alert Alert status (bool)
This works like the old V2 12V monitoring, just a bit improved. The reference voltage is taken after max 15 minutes calmdown time after 12V charging stops. The initial reference is the first voltage measured at boot.
Also, the AD conversion needs to be calibrated for each module, to compensate component tolerances. If you haven't done that for your modules yet, their 12V measurements will differ. To calibrate, measure your real 12V level and change config system.adc factor12v accordingly for each module.
Regards, Michael
Am 19.05.2018 um 02:26 schrieb Greg D.:
Hi folks,
I'm getting alerts from OVMS that my 12v battery is failing, as it's dropped below the threshold, which is set to 13v for some reason. So I get a notification every time the car transitions from awake to asleep.
I don't see a configuration item, nor anything in the OVMS v2 app. Oddly, the threshold is 13.2 for my v3.0 proto module, but I can't find a config item there either.
How do I change the threshold?
Greg
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