Could Ancel battery monitor be causing the saw tooth pattern?
I guess more specifically maybe the repeated testing the voltage and recording the voltage and temperature every two minutes is causing the DCM to wake up after about 3 hours and say wtf and does some diagnostic and send a error code then goes to sleep. The Ancel continues and this time the car only waits 30-40 minutes before repeating the diagnostic and send a error code.
My short story. I had a dead battery about 2 weeks of getting the car. took it to the dealer. they looked for a parasitic draw. The said i had a "bad water valve".
I don't drive much so I've been keeping and eye on the battery manually with a multimeter. The top of my battery terminal are crated like a little moon now.
When the battery gets low I drive it even if it mostly in the garage and parked most of the time.
I have had periods over 12hrs with a steady battery and times when it drops. I think I start to notice the drop after I charge the Traction battery. I start manual logging stuff but it is a p.i.t.a. so I decide to get an Ancel BM200. I clamped it on last night hoping to track things on my charging today.
I wake up and and see the Infamous saw tooth beginning 3 hours and 4 minutes after I power down the car and go to bed. Wow just like clock work.
Has anyone see the sawtooth with a battery monitor that doesn't read and record ever two minutes?
When it is connected to you phone with bluetooth the voltage sampling is even more frequent and you can see the voltage fluctuate about every time the reading and recorded in the device.
Posted Jul 11, 2026, 1:09 PM UTC