Parasitic draw story

[jratzlaf]

I have a story to share here; hopefully it will be informative to someone, and I'm also interested in your comments on the situation.

Yesterday my wife and I headed out in our '21 Leaf SV Plus with around 80% charge on it. Just a mile or 2 from home a warning came up on the dash display that I'd never seen before: "Service EV Sys." along with something that indicated that once I shut the car off, it would not start again. I should have immediately driven it home, but in hopes that it was a transient error that would clear with a power cycle, I just pulled over into a largely unused parking area and shut it off. Of course it would not come back up. I googled the message and saw that it most commonly means the 12v battery needs to be replaced. We had that happen on our previous '16 Leaf, so I figured that was the case again. But later when I got our "gas hog" (as I like to call it) and tried to jump the batteries, it still wouldn't start; and then I took the 12v battery out, took it home and charged it (according to the charger, it took the charge fine), and put it back in, and it still wouldn't start. Same message: "Service EV sys." So I figured a tow-truck ride to a battery store was called for. When I called AAA this morning, the guy said "Are you sure you really want it towed? I can just bring a battery and put it in." So I said OK and met him there. But before putting in a new battery, he put his tester on the old one--and it said the battery was fine! So he recognized that he shouldn't be selling me a new battery, and said he'd call a tow truck to take the Leaf somewhere to fix the problem.

Now what I haven't mentioned is LeafSpy. I have it, but I don't use it as much on this newer model Leaf as I did on the previous model. But the OBD dongle is always plugged in. In googling on the issue with the car, I saw comments here on this forum about DTCs and reading/clearing them with LeafSpy. But not having used it much I didn't know how to do that. So when he said he'd call a tow truck but it wouldn't arrive for 90 minutes, I thought now is the time to learn where DTCs are found in LeafSpy. I found it, and I cleared them... and it started! That's great! If I'd known that yesterday, I could at least have driven the car home. Oh well. The AAA guy was still there in his truck so I told him to cancel the tow truck call (which delighted him because they were "slammed.")

But that still left the question: Does the 12v battery need to be replaced? Operating on the assumption that if it failed once, it will probably fail again, I headed for the Interstate battery store. When I got there and told the guy the story so far, he said "Let's put it on the tester." His tester suggested that the voltage was being pulled down, but that the battery was being charged just fine, and the battery appeared to be OK. So he didn't think he should sell me a new battery either.

So... I bit the bullet and headed for the Nissan dealer. I had just been there a few days ago to have a couple of recalls installed, and at the time I observed that some Service Advisors were more fluent in Leaf than others. So this time I asked for and got a Service Advisor who was more familiar with Leafs. He listened patiently to my story and put it all into the system, and said they'd have to run diagnostics which could take a long time depending on how difficult the cause of the "parasitic draw" was to find. He suggested it could be many things, from terminal corrosion or bad cables, to more serious EV battery issues. He said the diagnostic charge would be $180, probably not covered under warranty (~47k miles) unless it turned out to be a "power train" issue which has a 100k mile warranty.

I left it all day and at the end of the day finally heard back from him. I was rather surprised by what he reported. He said they finally tracked it down to... can you see this coming???... the OBD dongle!!! He said I should just unplug it unless I'm using it. But by the way, the battery should probably be replaced... not under warranty. Or at least trickle-charged overnight, for which they'd charge me, I'm not sure what he said but it seems like it was $90. I said forget it, I'd trickle-charge it myself.

I know this forum is filled with LeafSpy users. Have you ever known the little bluetooth OBD dongles to be a problem? Mine has been plugged in as long as I've owned this car, and most of the life of the previous one. I was certainly never aware of a problem before. However, I'm also certainly willing to leave it unplugged if it will make the problem go away. But apparently it just cost me $180 today. By the way, I'm sure someone is going to ask which one I have. I bought it from a recommendation on here, and I just looked it up in my Amazon order history; it's the LELink model; I believe I paid $30 for it in 2021.

Comments are welcome! - JR

PS: One more possibly interesting part to the story: At the end of the day when the Service Advisor got back to me, he send me a link to a video. I've never seen anything like this before--I'm sure many of you have, but it was new to me. It shows the technician who worked on my car, explaining the diagnosis and demonstrating it by showing the meter displaying the parasitic draw numbers before and after removing the OBD dongle. Quite a nice feature!

 

[cornbinder89]

Yes, the dongle does stay "on" and I only use mine for diagnostics or to check operation while driving, then I unplug it.

 

[nlspace]

by showing the meter displaying the parasitic draw numbers before and after removing the OBD dongle.

So what were the values--how much is the parasitic draw with the dongle and how much without?

What is the date code/age of your 12V battery? if it is several years old then it is likely shot and you should replace it, especially with winter and cold weather approaching. If it had been kept fully charged then it might have lasted longer, but the laef charging routine is lacking.

You, or Them, would have to measure the specific gravity of the electrolyte, or do a full discharge capacity measurement, to know if the battery was okay or how much life was left. Measuring CCA voltage for 20 seconds might show a "good" battery, but not for one that is actually worn out and with degraded capacity.

 

[Jeffs231Leafp]

So what were the values--how much is the parasitic draw with the dongle and how much without?

What is the date code/age of your 12V battery? if it is several years old then it is likely shot and you should replace it, especially with winter and cold weather approaching. If it had been kept fully charged then it might have lasted longer, but the laef charging routine is lacking.

You, or Them, would have to measure the specific gravity of the electrolyte, or do a full discharge capacity measurement, to know if the battery was okay or how much life was left. Measuring CCA voltagee for 20 seconds might show a "good" battery, but for one that is actually worn out and with degraded capacity.

I have a story to share here; hopefully it will be informative to someone, and I'm also interested in your comments on the situation.

Yesterday my wife and I headed out in our '21 Leaf SV Plus with around 80% charge on it. Just a mile or 2 from home a warning came up on the dash display that I'd never seen before: "Service EV Sys." along with something that indicated that once I shut the car off, it would not start again. I should have immediately driven it home, but in hopes that it was a transient error that would clear with a power cycle, I just pulled over into a largely unused parking area and shut it off. Of course it would not come back up. I googled the message and saw that it most commonly means the 12v battery needs to be replaced. We had that happen on our previous '16 Leaf, so I figured that was the case again. But later when I got our "gas hog" (as I like to call it) and tried to jump the batteries, it still wouldn't start; and then I took the 12v battery out, took it home and charged it (according to the charger, it took the charge fine), and put it back in, and it still wouldn't start. Same message: "Service EV sys." So I figured a tow-truck ride to a battery store was called for. When I called AAA this morning, the guy said "Are you sure you really want it towed? I can just bring a battery and put it in." So I said OK and met him there. But before putting in a new battery, he put his tester on the old one--and it said the battery was fine! So he recognized that he shouldn't be selling me a new battery, and said he'd call a tow truck to take the Leaf somewhere to fix the problem.

Now what I haven't mentioned is LeafSpy. I have it, but I don't use it as much on this newer model Leaf as I did on the previous model. But the OBD dongle is always plugged in. In googling on the issue with the car, I saw comments here on this forum about DTCs and reading/clearing them with LeafSpy. But not having used it much I didn't know how to do that. So when he said he'd call a tow truck but it wouldn't arrive for 90 minutes, I thought now is the time to learn where DTCs are found in LeafSpy. I found it, and I cleared them... and it started! That's great! If I'd known that yesterday, I could at least have driven the car home. Oh well. The AAA guy was still there in his truck so I told him to cancel the tow truck call (which delighted him because they were "slammed.")

But that still left the question: Does the 12v battery need to be replaced? Operating on the assumption that if it failed once, it will probably fail again, I headed for the Interstate battery store. When I got there and told the guy the story so far, he said "Let's put it on the tester." His tester suggested that the voltage was being pulled down, but that the battery was being charged just fine, and the battery appeared to be OK. So he didn't think he should sell me a new battery either.

So... I bit the bullet and headed for the Nissan dealer. I had just been there a few days ago to have a couple of recalls installed, and at the time I observed that some Service Advisors were more fluent in Leaf than others. So this time I asked for and got a Service Advisor who was more familiar with Leafs. He listened patiently to my story and put it all into the system, and said they'd have to run diagnostics which could take a long time depending on how difficult the cause of the "parasitic draw" was to find. He suggested it could be many things, from terminal corrosion or bad cables, to more serious EV battery issues. He said the diagnostic charge would be $180, probably not covered under warranty (~47k miles) unless it turned out to be a "power train" issue which has a 100k mile warranty.

I left it all day and at the end of the day finally heard back from him. I was rather surprised by what he reported. He said they finally tracked it down to... can you see this coming???... the OBD dongle!!! He said I should just unplug it unless I'm using it. But by the way, the battery should probably be replaced... not under warranty. Or at least trickle-charged overnight, for which they'd charge me, I'm not sure what he said but it seems like it was $90. I said forget it, I'd trickle-charge it myself.

I know this forum is filled with LeafSpy users. Have you ever known the little bluetooth OBD dongles to be a problem? Mine has been plugged in as long as I've owned this car, and most of the life of the previous one. I was certainly never aware of a problem before. However, I'm also certainly willing to leave it unplugged if it will make the problem go away. But apparently it just cost me $180 today. By the way, I'm sure someone is going to ask which one I have. I bought it from a recommendation on here, and I just looked it up in my Amazon order history; it's the LELink model; I believe I paid $30 for it in 2021.

Comments are welcome! - JR

PS: One more possibly interesting part to the story: At the end of the day when the Service Advisor got back to me, he send me a link to a video. I've never seen anything like this before--I'm sure many of you have, but it was new to me. It shows the technician who worked on my car, explaining the diagnosis and demonstrating it by showing the meter displaying the parasitic draw numbers before and after removing the OBD dongle. Quite a nice feature!

If I were you I would replace the 12VDC battery and switch to the CARISTA OBD2 port dongle. WHY: I have had a 2023 and now have a 2024 Leaf SV Plus and they both have the dongle in all the time and I have never had a 12VDC battery issue. 12 VDC Batteries typically last 4 to 5 years. The testers that are used , outside of Nissan, are typically testing for cranking amps and not a stable 12 Volts that the ECUs need.

 

[RPaulThomas]

For exactly that reason I bought a dongle with an off/on switch. Been in place for >5 yrs and still have the OEM 12v battery in my 2018.

 

[woeful]

LEAF (and e-NV200, possibly other Nissan models) has, in addition to the standard 12V power feed to pin 16 of the ODB connector, a 12V only-when-power-switch-on power feed on pin 8. I bought an all-wires "Y" OBD splitter (one in, two separate sockets out) and re-wired it so that the supply pin 8 now goes to one of the sockets' pin 16. Now I can leave a dongle plugged in all the time, but it's got no power when the car is off.

A good OBD device should draw only a few microamps when there's nothing happening on the car's CAN bus, but a cheap, possibly an old, one may draw rather more current.

 

[Ancient1]

My LeLink dates from late 2019, and I found within just a couple of months that if it was left plugged in and the car wasn't used for a few days, it would run the 12 volt battery down to the point the car could not be started. Apparently the newer versions shut off automatically when the ignition is off, but I can't make my older one do that. I just take it out, and only put it back in when I am going to be going more than just a few in-town miles. Once I started doing that, no more battery problems.

 

[jratzlaf]

So what were the values--how much is the parasitic draw with the dongle and how much without?

What is the date code/age of your 12V battery? if it is several years old then it is likely shot and you should replace it, especially with winter and cold weather approaching. If it had been kept fully charged then it might have lasted longer, but the laef charging routine is lacking.

The meter on the video I mentioned, with the dongle in place, was showing 0.045-0.06, whereas after the dongle was removed it was showing 0.01-0.015. I haven't gotten the car back yet so I can't report the date code on the battery, but I assume it is ~3 years old.

 

[Easy]

My dongle has the auto-off. The only way to wake it up is to unplug it and plug it back in. At least I always know where it is.

 

[cornbinder89]

The meter on the video I mentioned, with the dongle in place, was showing 0.045-0.06, whereas after the dongle was removed it was showing 0.01-0.015. I haven't gotten the car back yet so I can't report the date code on the battery, but I assume it is ~3 years old.

Service manual says 50ma is the max, and you are right there. This is good info to know. Esp the dark draw with it off (10 15ma).
I suspect that many of the Leaf's with early failure of the 12 volt come down to dark draw and incomplete recharge.
As your experience has shown are relatively small dark draw that is not corrected will, over time cause a problem.
True IUoU charging would be able to deal with greater dark draws, but Nissan's charge protocol is neither constant voltage nor IUoU.
I'd be interested to see what the dark draw is on those cars that experience short 12 volt life.
It is false to say a battery could start an ICE vehicle yet not be able to start a Leaf. The Leaf needs far fewer amps to pull in the contactors. What is true, is the battery can, until it can't and will give no warning, unlike the ICE where slow cranking will be noticed.

 

[nlspace]

My point is that i have seen and experienced numerous times where the autopart's or dealer shop battery test indicated "good", but the battery was insufficient for the EV. They printed out a CCA value, but it was worthless as the EV still wouldn't start. i replaced batteries with new, fully charged on the bench, and success!

The Nissan shop even said that the 12V was good, and the issue was that the car needed a new traction pack.

Don't know if it would have started an ICE, never tried it, and never said it would. Just know that the EVs weren't happy until they had a good, strong and fully charged battery.

 

[nlspace]

60mA draw would consume 1.44 A-hrs per day, so a 35 A-hr battery would be discharged to half-dead in 12 days. An older battery with lesser capacity would die sooner.

 

[Ihalsema]

I don’t have a dongle for my 2019 Leaf, and the oem 12V battery is likely approaching end of life. If the battery dies and I have AAA replace it, is there any need for me to take the car to the dealer (inconveniently located), or otherwise have the car serviced?

 

[Jarichus]

I have a Toyota Highlander Hybrid with the same problem of low reserve and the Interstate battery has failed more than once even though it will pass the load test. I quick charge the battery and then charge it with a two amp de-sulfate trickle charger for a couple days. The battery is then fine for another 6 months. I am thinking the battery builds up sulfation in the bottom of the battery and shorts out the cells. I use the de-sulfating charger once a month on the Leafs and the Highlander. At first I did not believe the charger made any difference, but I do see batteries going further with it.

 

[nlspace]

If the battery dies and I have AAA replace it, is there any need for me to take the car to the dealer (inconveniently located), or otherwise have the car serviced?

No, you should be good to go

 

[cornbinder89]

I have a Toyota Highlander Hybrid with the same problem of low reserve and the Interstate battery has failed more than once even though it will pass the load test. I quick charge the battery and then charge it with a two amp de-sulfate trickle charger for a couple days. The battery is then fine for another 6 months. I am thinking the battery builds up sulfation in the bottom of the battery and shorts out the cells. I use the de-sulfating charger once a month on the Leafs and the Highlander. At first I did not believe the charger made any difference, but I do see batteries going further with it.

I don't know if you care, but:
When a Lead acid cell "sulfates" it builds up a layer on the plate reducing the surface area to "make current". The available current slowly decreases but the battery will show normal voltage, just not be able to provide much current.
When a battery is discharged and recharged a small amount of plate material is "sluffed off" and falls to the bottom of the cell. In a healthy but well used cell, the surface area stays mostly as built, and there for the current providing ability, until enough sluffed off stuff accumulates at the bottom and it shorts the cell, killing it.
It is rare to see an automotive battery die in this method. One day it will crank an engine fine, the next day it shows little to no life. I had a 12 year old battery fail in that method.
Most suffer some sort sulphation choking off the output and the engine cranks slower and slower until it can't supply enough current to crank, but will still "light the lights".
EV's are a odd problem. Not really a cranking use, but not really a deep cycle use either. The battery needs to pull in the main contactors and charge the capacitors via the pre-charge resistors. The need to do this without dropping the voltage enough to cause Communication errors on the CAN BUS.
So it works until it doesn't, but offers no indication that it is sulfating, as there is no high current draw to show that a large part of the plates is either covered with hard sulfate or discharged. In short, it isn't a battery failure but a charging failure.
When dark draw is added in, it compounds the problem, you never see it coming and have no idea there is a problem until one day when the car will not work.
In theory, An EV should be able to optimize charging, as there is no engine that needs to be running to charge. The car doesn't even have to be "on" for the battery to charge. Nissan chose to optimize for minimum HV battery draw, over optimal 12 volt life.
It is why I always say, fully recharge and test. No point in replacing a battery that is merely discharged, and will function just fine if fully charged.
You could forestall any problems by replacing every few years, but the same could be said about replacing the whole car. Better to get to the bottom and address the problem.

 

[DaveinOlyWA]

I have a story to share here; hopefully it will be informative to someone, and I'm also interested in your comments on the situation.

Yesterday my wife and I headed out in our '21 Leaf SV Plus with around 80% charge on it. Just a mile or 2 from home a warning came up on the dash display that I'd never seen before: "Service EV Sys." along with something that indicated that once I shut the car off, it would not start again. I should have immediately driven it home, but in hopes that it was a transient error that would clear with a power cycle, I just pulled over into a largely unused parking area and shut it off. Of course it would not come back up. I googled the message and saw that it most commonly means the 12v battery needs to be replaced. We had that happen on our previous '16 Leaf, so I figured that was the case again. But later when I got our "gas hog" (as I like to call it) and tried to jump the batteries, it still wouldn't start; and then I took the 12v battery out, took it home and charged it (according to the charger, it took the charge fine), and put it back in, and it still wouldn't start. Same message: "Service EV sys." So I figured a tow-truck ride to a battery store was called for. When I called AAA this morning, the guy said "Are you sure you really want it towed? I can just bring a battery and put it in." So I said OK and met him there. But before putting in a new battery, he put his tester on the old one--and it said the battery was fine! So he recognized that he shouldn't be selling me a new battery, and said he'd call a tow truck to take the Leaf somewhere to fix the problem.

Now what I haven't mentioned is LeafSpy. I have it, but I don't use it as much on this newer model Leaf as I did on the previous model. But the OBD dongle is always plugged in. In googling on the issue with the car, I saw comments here on this forum about DTCs and reading/clearing them with LeafSpy. But not having used it much I didn't know how to do that. So when he said he'd call a tow truck but it wouldn't arrive for 90 minutes, I thought now is the time to learn where DTCs are found in LeafSpy. I found it, and I cleared them... and it started! That's great! If I'd known that yesterday, I could at least have driven the car home. Oh well. The AAA guy was still there in his truck so I told him to cancel the tow truck call (which delighted him because they were "slammed.")

But that still left the question: Does the 12v battery need to be replaced? Operating on the assumption that if it failed once, it will probably fail again, I headed for the Interstate battery store. When I got there and told the guy the story so far, he said "Let's put it on the tester." His tester suggested that the voltage was being pulled down, but that the battery was being charged just fine, and the battery appeared to be OK. So he didn't think he should sell me a new battery either.

So... I bit the bullet and headed for the Nissan dealer. I had just been there a few days ago to have a couple of recalls installed, and at the time I observed that some Service Advisors were more fluent in Leaf than others. So this time I asked for and got a Service Advisor who was more familiar with Leafs. He listened patiently to my story and put it all into the system, and said they'd have to run diagnostics which could take a long time depending on how difficult the cause of the "parasitic draw" was to find. He suggested it could be many things, from terminal corrosion or bad cables, to more serious EV battery issues. He said the diagnostic charge would be $180, probably not covered under warranty (~47k miles) unless it turned out to be a "power train" issue which has a 100k mile warranty.

I left it all day and at the end of the day finally heard back from him. I was rather surprised by what he reported. He said they finally tracked it down to... can you see this coming???... the OBD dongle!!! He said I should just unplug it unless I'm using it. But by the way, the battery should probably be replaced... not under warranty. Or at least trickle-charged overnight, for which they'd charge me, I'm not sure what he said but it seems like it was $90. I said forget it, I'd trickle-charge it myself.

I know this forum is filled with LeafSpy users. Have you ever known the little bluetooth OBD dongles to be a problem? Mine has been plugged in as long as I've owned this car, and most of the life of the previous one. I was certainly never aware of a problem before. However, I'm also certainly willing to leave it unplugged if it will make the problem go away. But apparently it just cost me $180 today. By the way, I'm sure someone is going to ask which one I have. I bought it from a recommendation on here, and I just looked it up in my Amazon order history; it's the LELink model; I believe I paid $30 for it in 2021.

Comments are welcome! - JR

PS: One more possibly interesting part to the story: At the end of the day when the Service Advisor got back to me, he send me a link to a video. I've never seen anything like this before--I'm sure many of you have, but it was new to me. It shows the technician who worked on my car, explaining the diagnosis and demonstrating it by showing the meter displaying the parasitic draw numbers before and after removing the OBD dongle. Quite a nice feature!

Could be a lot of things but after you charged the 12 volt and tried it and it failed, the next step is to clear codes with LSP and try again.
As far as the paralytic draw? I have had my OBD device plugged in ALL the time since 2013 over 4 different versions of the LEAF without an issue INCLUDING a 23 stint at an airport park and ride lot.

I will stop short of saying it wasn't your issue since OBDs are not created equally but I used one for 4 years before switching to another one sooo...

 

[cornbinder89]

I will stop short of saying it wasn't your issue since OBDs are not created equally but I used one for 4 years before switching to another one sooo...

It is interesting that the draw he saw was right at the tipping point that the service manual says is "acceptable" and when action must be taken to resolve.
A lot will depend on if it is constant, 24/7 or not, how often the car is switched on and for how long, even how often the wipers are in use.
All factors will go into whether the outcome is a dead car or hardly noticeable.

 

[Learjet]

When I leave my dongle in, I can hear relays click every once in a while when the car is off. My theory is the dongle stops the car computers from going to sleep properly. I have a LElink dongle.

 

[cornbinder89]

When I leave my dongle in, I can hear relays click every once in a while when the car is off. My theory is the dongle stops the car computers from going to sleep properly. I have a LElink dongle.

I think I have the same dongle, it stays in the glovebox unless I need to diagnose something or want to log a trip.