Parked for 2 weeks ... lost 10% SOC. Normal?

I've had (and been quite happy with), a '13 SV for the past 32 months. This certainly isn't the first time I've parked it this long while I was out of town, but it is the first time I've made explicit note of the starting- and ending SOC's.

Here's the scenario: The car was charged to 80% the night before my departure (meant to only leave it @ 60, but forgot to unplug it). Pulled the plug in the morning as I was headed out the door. Gone for 2 weeks, with temps in the low-70's to mid-80's. Turn car on and I see that the dash is showing 70% SOC. AHr and Hx are pretty much what I expected them to be (59.9, 91, 32k Miles).

I've read about significant Tesla vampire drains, but I always assumed given the much smaller amount of tech in a Leaf, that its vampire drains might not be quite as bad. But like I said, I've never really paid attention to this in the past, so I'm wondering, is this really normal?

Also...the Leaf gets used daily, so it's not like I have an opportunity in the near future to try and repeat this experiment...

The most likely explanation is that the 12 volt battery was low, and while you were away the car automatically recharged it twice. Did you leave a small light on in the car, or an OBDII device plugged in?

No, no lights on, but I do have an OBDII adapter. Still, 10% SOC loss seems quite high.

Using idealized numbers:

10% SOC = 2.4 kWh

2400 Wh / 12v = 200 Ah
200 Ah / (15*24) = 555 mA

500+ mA seems like really high drain for the OBDII adapter. Unfortunately, I don't have a clamp meter to actually check it, and I don't really want to unbolt the neg terminal on the battery so I can put a meter in series...

I'm sure someone has measured it, but I can't find it with searching: Anybody know what the baseline 12v load is?

gmikol said:

No, no lights on, but I do have an OBDII adapter. Still, 10% SOC loss seems quite high.

Using idealized numbers:

10% SOC = 2.4 kWh

Click to expand...

The bold part is unfortunately not true, even when the car is brand new. The most, even '15's get is 22.6 kWh but 13's I think max between 21 and 22 kWh.

Now that your battery has degraded even more, 10% may only be 1.5-1.8 kWh. Still quite a bit to drop in 2 weeks but much less than 2.4 kWh.

Also, on a degraded battery, the top 50% SOC does not have as much kWh as the bottom 50% of SOC.

I just came home from a 9 day trip and my soc dropped 3% from 49 to 46, without the OBD in, so probably mostly 12v charging. Plus, I'm only 25 months into this battery.

I travel 2-3 weeks 4 times a year. One of the early postings in the forum recommended not leaving the car plugged in while gone , or at 100%. I follow this guideline, and have not had significant loss.

It was said that loss was due to a daily deep discharge of the 12v battery. Consider shipping from Japan by ship, or long lot delays after assembly. The cars arrive at dealer ships with enough time charge after weeks of no charging.

I would be willing to bet that the leafs that were shipping from japan probably had the big main pack fuse pulled, and probably the battery disconnected while on the ship....

500 mA average draw from 12-volt battery with OBDII plugged in is possible because it keeps LEAF control modules awake that would normally sleep. I routinely park at the office or airport for up to 3 weeks at a time and see almost no change in SOC. 12-volt battery was completely dead after 6 days the one time I forgot to unplug the OBDII on the 2011.

Gerry

GerryAZ said:

500 mA average draw from 12-volt battery with OBDII plugged in is possible because it keeps LEAF control modules awake that would normally sleep. I routinely park at the office or airport for up to 3 weeks at a time and see almost no change in SOC. 12-volt battery was completely dead after 6 days the one time I forgot to unplug the OBDII on the 2011.

Gerry

Click to expand...

My 12V battery went flat after about 5 days with the OBDII plugged in. Now I always unplug it if not using the car for more than a day or 2. That thing stays pretty warm, so it must be dissipating quite a lot of heat.

Aussie said:

My 12V battery went flat after about 5 days with the OBDII plugged in. Now I always unplug it if not using the car for more than a day or 2. That thing stays pretty warm, so it must be dissipating quite a lot of heat.

Click to expand...

And it's not just the heat it dissipates, but also all the additional loads it places on the 12V battery by activating various systems within the car.

RegGuheert said:

Aussie said:

My 12V battery went flat after about 5 days with the OBDII plugged in. Now I always unplug it if not using the car for more than a day or 2. That thing stays pretty warm, so it must be dissipating quite a lot of heat.

Click to expand...

And it's not just the heat it dissipates, but also all the additional loads it places on the 12V battery by activating various systems within the car.

Click to expand...

Can you clarify this? I always thought the OBDII device was a passive listener, at least as used with LeafSpy Pro.

Does the ODBII device by itself acutally poll systems in the car? I'm not talking about leaving LeafSpy Pro running on a device that's sitting in the car...just talking about the OBDII device by itself.

gmikol said:

RegGuheert said:

Aussie said:

My 12V battery went flat after about 5 days with the OBDII plugged in. Now I always unplug it if not using the car for more than a day or 2. That thing stays pretty warm, so it must be dissipating quite a lot of heat.

Click to expand...

And it's not just the heat it dissipates, but also all the additional loads it places on the 12V battery by activating various systems within the car.

Click to expand...

Can you clarify this? I always thought the OBDII device was a passive listener, at least as used with LeafSpy Pro.

Click to expand...

No, LeafSpy polls the car to collect the data that it displays. You can actually here relays clicking in the car when LeafSpy Pro is active.

gmikol said:

Does the ODBII device by itself acutally poll systems in the car? I'm not talking about leaving LeafSpy Pro running on a device that's sitting in the car...just talking about the OBDII device by itself.

Click to expand...

Without LeafSpy Pro running, I doubt that it does any polling. (But note that if your phone's Bluetooth can reach into the garage, it will poll the systems in the car continuously when LeafSpy is on.) Still, I measure 175 mA draw from the battery when the Elm327 is plugged into the test port versus about 25 mA without it. That's about a 2 W increase in load. It's possible that the Elm could dissipate that much power, but I would think it would be hotter than it gets if it did. I wonder if some of the modules in the car go into a listening mode when there is something plugged into the test port, but I don't know.

I can verify that my ELM adapter does consume some power. Somewhere between 1-2W.
I can estimate that because it is dissipating a lot of heat even when not transmitting anything.
Also sometimes there is rapid relay clicking noise from one of the relays when car is just parked.
It might be because of OBD adapter tries to do something and wakes something using any BUS line.

Anyway there is definitely a vampire drain with chinese dongle in OBD port and if it keeps
something awake then it will be massive. I also try to keep it disconnected if not used.