gwscheil
Member
Does anyone know exactly what the 12V battery powers? I assume climate control, headlights, would kill it fast. So essentially what is powered from the main battery via the DC converter vs the 12V one?
gwscheil said:...So essentially what is powered from the main battery via the DC converter vs the 12V one?
gwscheil said:Once the power is ON and system is ready to roll - does the 12V battery still supply power to anything while driving? Or does it need just enough to maintain idle standbypower, then unlock doors and power up the main computer and display? I suspect lazy engineers may have used the 12V battery as a large "capacitor" on the DC downconverter - thus a dead 12V becomes a dead Leaf? I remember my parents Prius had frequent problems with that tiny 12V battery it used.
LeftieBiker said:If the battery will still absorb current, then the car will drive, even if the battery can't restart it. If the battery is so dead that it acts as a giant resistor, though, the car won't run.
* I saw some videos on YouTube last week. Apparently, you can use an electric welder to revive and recondition really dead batteries. It's one of those "Are you feeling LUCKY, PUNK?" scenarios, though.
That won't be the OBD II dongle. There are many computers in the car that draw power, and after you power down and close the last door, the draw will be 1-5A for 5-15 minutes. The 5A doesn't last long, it should be under 2.5A after 10-30 seconds. After the 5-15 minutes, the drain should be of the order of 50mA, difficult to measure with a clamp meter. Especially with their offset and drift. These are all observations from my 2012 model. Later models may well be different.gwscheil said:after power off, voltage drops to 12.25V, with drain (negative sign) of about 1A! Can the OBD be drawing that much?
coulomb said:That won't be the OBD II dongle. There are many computers in the car that draw power, and after you power down and close the last door, the draw will be 1-5A for 5-15 minutes. The 5A doesn't last long, it should be under 2.5A after 10-30 seconds. After the 5-15 minutes, the drain should be of the order of 50mA, difficult to measure with a clamp meter. Especially with their offset and drift. These are all observations from my 2012 model. Later models may well be different.gwscheil said:after power off, voltage drops to 12.25V, with drain (negative sign) of about 1A! Can the OBD be drawing that much?
So I suspect that you weren't waiting long enough, or the computers had some reason not to go to sleep, like a door was open or the charge plug is in. Or some other auxiliary battery load, like a camera.
I don't know. Not the key fob system, that has to be on all the time. There is the courtesy light, but it can't be just that. Maybe it's checking for the need to power fans and/or cooling pumps in case the power delivery system, on-board charger, etc need cooling. After 5-10 minutes if there was no need, then cooling won't be needed and the car computers can properly sleep. Likely not needed in your present weather, but the car doesn't take chances.gwscheil said:So what is drawing that 1A+ for a few minutes after power off?
gwscheil said:So what is drawing that 1A+ for a few minutes after power off? No phone home feature in my Leaf. Amazon will deliver a switchable OBD extension this weekend. The key fob system? As long as it detects a FOB in range, it must be ready to lock/unlock doors. With no FOB in range is it only checking intermittently?
Winter weather is limiting my outdoor test time and my clamp type meter is borrowed at present across town. Or do the computers just take that long to shut down like my PC?
I am in very slow test mode here with an early winter - only an occasional near normal temperature day.
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