I made an interesting observation: the "energy information" screen does not measure the power consumed by a 12V inverter

[LMF5000]

I've just finished wiring in an inverter so I can use our 2016 leaf to power the house during power cuts. I did it in the usual way, by tapping into the 12V system (more on that below).

Now, you know the "energy information" screen, that has a big gauge for the power consumption of the traction motor, and smaller gauges for the air conditioner compressor and one for "other loads"?

Well, it turns out that the "other loads" gauge does not react to the inverter draw. I tested up to 1,000 watts (80 Amps at 13V) and the gauge on the leaf's screen didn't budge, BUT when monitoring over leafspy, the wattage drawn by the inverter WAS actually sensed, in the total power coming out of the traction battery (380V x 3.1A = 1178 watts).

Just to be sure, I tried several different wiring schemes for tapping into the 12V system. For positive terminal I tried either at the battery positive terminal, or at the large rubber-covered positive lug coming from the side of the motor stack (which is where I assume the onboard DC/DC converter is located). For negative terminal, I tried either at the negative battery terminal or at the negative post that ties the aforementioned motor stack to the chassis (the nut on the side of the stack, where the yellow and black wire originates).

In both cases, the car's "other loads" indicator was oblivious to it but leafspy registered it as unexplained power coming from the traction battery (unexplained because it didn't register in any other category like motor, A/C or Aux).

Just thought I'd share this find because I found it interesting. I thought the leaf would be measuring actual 12V loads, but now I think it either just guesses based on assumed values for what loads you have turned on and off, or it measures them somewhere far downstream of the battery (like maybe at the fuse box) so the inverter is not being measured.

 

[LeftieBiker]

Thanks for that. I've speculated before that many of the values shown on that screen are programmed in as algorithms rather than being actual measurements. It will also not show the extra load when both the PTC heater and heatpump are running together in front Defrost mode.

 

[GerryAZ]

I believe the LEAF uses a lookup table for the 12V loads rather than actually measuring them. As an example, turning on the fog lights results in about the same jump in "other" loads as some other accessories which clearly draw less than the halogen fog lights. Also, the load jump when an accessory is turned on is always consistent regardless of conditions.

I have also set up a 2KW sine wave inverter to use for power tools. I used heavy-duty jumper cables cut and permanently connected to the input terminals of the inverter. This allows me to move it between vehicles. If I connect the cable clamps directly to the battery, then LEAF Spy will measure the combined current going into the 12V battery and inverter so it shows about 100 amperes when running my small air compressor and the DC-DC converter runs at about 14V. If I connect the negative cable to chassis ground, then LEAF Spy shows only the current flowing into the 12V battery and the DC-DC converter output is about 13V (assuming battery is fully charged). I did not look at the dash display while using the inverter--I will make a point to look at the dash display the next time I use the inverter to see if it shows on the energy screen.