Leave OBDII plugged in all the time for Leafspy?
- Thread starter Driver8
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If you want to leave it plugged in, find a unit that turns off with the car, or at least goes into a very low current mode. Otherwise you risk draining the 12 volt battery.
jlv
Well-known member
I left the bluetooth ODB-II dongle plugged into my 2013 SL for nearly 4 years without any issues with the 12V battery. I did not have an unit that turned off with the car or anything. I'll note that the SL comes with the little solar panel trickle charger for the 12V; although almost always my car was parked in a garage (at work and home). The only time I unplugged it was the two periods where the car sat unused for 2 weeks (I was out of the country), and I only unplugged it then because of concerns I got from this forum.
If you do decide to unplug the ODB-II dongle, do yourself a favor and get an ODB-II extension cord. Leave that plugged in and just unplug the dongle from that. This way you don't wear out the ODB-II port. I bought a Y extension, thinking that would let service or my state inspection plug into the free connection, but both always just unplugged the Y.
If you do decide to unplug the ODB-II dongle, do yourself a favor and get an ODB-II extension cord. Leave that plugged in and just unplug the dongle from that. This way you don't wear out the ODB-II port. I bought a Y extension, thinking that would let service or my state inspection plug into the free connection, but both always just unplugged the Y.
I only unplug the Bluetooth OBDII adapter when parking the car for extended time. As long as I am driving at least every couple of days, I leave it plugged in to minimize wear on the connector. The 2011 drained its 12V battery when I inadvertently left the adapter plugged in while out of town for 5 or 6 days. I inadvertently left the adapter plugged in to the 2015 during a short out of town trip (less than a week) and there was no issue. I suspect the 2019 would handle leaving the adapter plugged in, but I try to remember to unplug it during out of town trips anyway.
Given the rest voltages I'm seeing on our Gen 2 Leafs, I wouldn't count on that.
Nubo
Well-known member
I don't need LeafSpy info for normal driving and only use it occasionally to check cell levels or error codes. So I unplug the dongle the rest of the time. I figure the handful of insertions per year is within reason for the port and I want to minimize the chance of having something act up on the CAN bus.
My car was last charged two nights ago and just driven a few short trips since then. It has been sitting for about 5 hours since the last 3-mile short trip (with OBDII adapter plugged in) and the OEM 12V battery is reading 12.576 so I am not worried about the charging algorithm or battery condition. I understand Nubo's concern about CAN Bus interference, but I like to let Leaf Spy log data while I drive and I like the audible tire pressure warning that I can set for the pressures I run (48 psi cold and alarm set for 42 psi with the run flat tires I have now). The car's built-in pressure alarm does not activate until pressure gets really low.LeftieBiker said:
Nubo
Well-known member
GerryAZ said:
Perfectly reasonable. If I used it more, I'd get a dongle with an on/off switch, or a port extension cable with same.
UPDATE. I have left my OBDII plugged in basically since we got the car (2017 S) about two months ago and we have not noticed any 12V battery issues. I don't use LeafSpy nearly as much as I thought I might, so I will probably just unplug it at this point (my wife is VERY not interested in the data, and she's been the majority of trips on the car).
SueC56
Well-known member
Also, it probably matters if you have LeafSpy open on your phone or have it closed. I would think the car would draw more power if it were constantly feeding LeafSpy.
Right or not?
Sue C
Right or not?
Sue C
The dongle becomes active when plugged in, even with no phone nearby. I don't know if the energy used increases while the app is running.
The dongle draws a small amount of power if just plugged in. If the car is OFF, the power for the dongle is minimal when the phone app is not running. If the phone app is running, it causes the dongle to send commands to collect data from various modules. This keeps the modules from going into low power (sleep) mode so the net effect is to increase the power draw from the 12V battery.LeftieBiker said:
GerryAZ said:
Great. Thanks for the very useful info.
GerryAZ said:
Have you measured the Leaf's standby current with and without the dongle plugged in? If so, what were those values?
Remember, different dongles function differently in standby, so a universal value doesn't apply.
Yep.lorenfb said:
BT LE is a good option to choose. I use the OBDLink brand, in part of that reason.
I've used my adapter for ~ 15 years, first with our Prius, then LEAF and now Tesla. It really has stood the test of time. IIRC it only draws power when the car is "on" but that may be a reference to the ICE age and I cannot say for sure how it acts in our EV
I have tried several different brands (cheap ones ordered online) and OBDLink units purchased directly from their Phoenix facility. Some work better than others with different Android devices. I am currently using an OBDLink MX that I originally purchased to use with ICE vehicles because it is the most stable with the Motorola unlocked phone that I keep in the LEAF for Leaf Spy. They all draw minimal current when the car is not on (based on the fact that they don't change the voltage measured at the battery terminals when plugged in or unplugged). The voltage at the battery terminals really drops for a short time when doors are unlocked or something else happens to wake up the car's computers. One of the things that either frequently wakes up the car's modules or keeps them awake is having Leaf Spy running so that it is requesting data over the CAN Bus.
GerryAZ said:
You really need to actually measure the current, i.e. get a clamp-on amp meter or carefully attach a series amp meter.
You can't rely on a change in battery voltage to indicate an excessive current, which could be in excess of a few hundred milliamps( ma),
e.g. remember the battery problems with TCU hanging. Typically the standby current (ECUs asleep) should less than 60-70 ma.
lorenfb said:
The milliamp current draw of the OBDII is too small to accurately measure with a clamp-on ammeter. On the other hand, the 10 to 20 amperes short duration current draw when control modules wake up is easy to measure.
