Long term parking and battery discharge

[parb]

There has been lots of talk about the battery losing charge quickly when parked long term.

I've had my car parked, locked and with the alarm on for 3 weeks and 2 days. I was overseas for work.
Just connected to my victron battery monitor with a shunt, it shows 97% battery after 3 weeks.
I don't have my fridge in the car but otherwise it's been just turned off and parked after I came home from work the day before I left for my trip.

I'm very happy with that.

Just sharing since there has been some concern about it on the forum.

 

[HereinDaRockies]

When people report these anecdotes, you need to indicate your build month/year.

 

[Zimm]

Mine will drop 9% overnight and it wont charge over the mid 70's anymore. Nothing plugged in but wolfbox that auto offs. it'll be at 73%, charge at 2a and 14.2v. The system sucks. If I could rip out the alt for an old school GM 1 wire I would.

 

[parb]

When people report these anecdotes, you need to indicate your build month/year.

Mine was built December 2023. I took delivery in april 2024.
I have a wolfbox with the power controller setup to auto-off at the middle level (I think that is 11.6v? The screen auto offs 30 Seconds after the ignition is off.

 

[Ovrland Bill]

There has been lots of talk about the battery losing charge quickly when parked long term.

I've had my car parked, locked and with the alarm on for 3 weeks and 2 days. I was overseas for work.
Just connected to my victron battery monitor with a shunt, it shows 97% battery after 3 weeks.
I don't have my fridge in the car but otherwise it's been just turned off and parked after I came home from work the day before I left for my trip.

I'm very happy with that.

Just sharing since there has been some concern about it on the forum.View attachment 7894473

How does the 97% on your battery monitor compare to the battery % reading on the vehicle’s infotainment screen?

 

[parb]

I'll update it in the morning. Been busy today with an unexpected emergency (water leak in the house), sorted it out now but I'm tired from working on it for most of the day.

 

[DenisM]

There has been lots of talk about the battery losing charge quickly when parked long term.

I've had my car parked, locked and with the alarm on for 3 weeks and 2 days. I was overseas for work.
Just connected to my victron battery monitor with a shunt, it shows 97% battery after 3 weeks.
I don't have my fridge in the car but otherwise it's been just turned off and parked after I came home from work the day before I left for my trip.

I'm very happy with that.

Just sharing since there has been some concern about it on the forum.View attachment 7894473

The Smart shunt reading seems way optimistic...
Sundry other SOC vs Voltage charts for lead acid batteries estimate a voltage of 12 4-12.5v to represent a SOC at 75%, which after 3 weeks is still rather good considering parasitic drag e.g. from the alarm/securitysystem.....
Perhaps the Smart Shunt requires re-calibrating?
See also the discussion regarding the "true" function of the secondary battery/Ctek 120S device in https://www.theineosforum.com/threa...tures-and-install-information.12412843/unread
a video by Robert Pepper where he interviews Ctek engineers (video posting courtesy of @TheDocAUS)

 

[TheDocAUS]

The Smart shunt reading seems way optimistic...
Sundry other SOC vs Voltage charts for lead acid batteries estimate a voltage of 12 4-12.5v to represent a SOC at 75%, which after 3 weeks is still rather good considering parasitic drag e.g. from the alarm/securitysystem.....
Perhaps the Smart Shunt requires re-calibrating?
See also the discussion regarding the "true" function of the secondary battery/Ctek 120S device in https://www.theineosforum.com/threa...tures-and-install-information.12412843/unread
a video by Robert Pepper where he interviews Ctek engineers (video posting courtesy of @TheDocAUS)

I do not have much experience with smart shunts, but what I do have suggests these shunts do not accurately monitor small power drains over longer periods. However, they are pretty good for bigger draws from fridges to induction cooktops.

 

[Tazzieman]

From Paul Oddy on Robert Pepper's video above:
"Your alternator will never fully charge your battery "

 

[Tom109]

Mine will drop 9% overnight and it wont charge over the mid 70's anymore. Nothing plugged in but wolfbox that auto offs. it'll be at 73%, charge at 2a and 14.2v. The system sucks. If I could rip out the alt for an old school GM 1 wire I would.

The recharge is horrible. I have never seen more than 2a displayed.

I’m coming up on 3+ weeks parked. I’ll post the indicated battery level. In the past mine had dropped to low-/mid-80%.

Tangent: I want to put solar on the roof to offset my fridge but I’m afraid any further research and I’ll pull the whole factory dual battery system out.

 

[pmatusov]

The recharge is horrible. I have never seen more than 2a displayed.

I’m coming up on 3+ weeks parked. I’ll post the indicated battery level. In the past mine had dropped to low-/mid-80%.

Tangent: I want to put solar on the roof to offset my fridge but I’m afraid any further research and I’ll pull the whole factory dual battery system out.

Upon a start-up, I've seen the charge current go up to 27A (after running a fridge overnight). That is probably much lower than initial surge - between the time the engine starts and I go through the "pilot's checklist," probably a minute passes.

 

[pmatusov]

Mine will drop 9% overnight and it wont charge over the mid 70's anymore. Nothing plugged in but wolfbox that auto offs. it'll be at 73%, charge at 2a and 14.2v. The system sucks. If I could rip out the alt for an old school GM 1 wire I would.

Zimm, you have to love your truck and bitch less about it - 'cause that's all you've been doing lately
Generally, I don't trust anything about listing the SOC of a lead-acid battery. The only thing matters is the battery voltage in the morning - if it's over 12.5V, there isn't anything to worry about.
Charge at 2A @ 14.2V only means that the battery is either charged to capacity, or its internal resistance is so high that it simply cannot take a larger current than 2A at 14.2V.
It is easy to design the system that detects the second condition (momentarily run 1-5A discharge current and measure the voltage drop), but I'd be amazed if that's how it is done in a Grenadier.
Ripping out the alternator for an old school 1-wire accomplishes nothing. Zero.

 

[parb]

Two more pictures.
The ineos builtin bms thinks the battery is at 67% discharge after 3 weeks and 3 days being parked on my driveway. I do not think this is a real number. I did the math and with my fully charged battery it would suggest that my vehicle consumed 1.5A continuously since I parked. I don't believe that for a second, it's way too much of an low power draw in an parked car with no active accessories. Perhaps the ineos is calibrated with a wrong a peukert coefficient?

My victron on the other hand believes my car consumed 145mA continuously since I parked it. That I believe totally. Sounds about right for low power mode of an alarm and no other active vehicle electronics. Maybe a touch optimistic since I think my Wolfbox parking monitor pulls about 100mA when parked but I don't think it's far off.

Shunts are generally really good at measuring low power, I got to imagine they have really good op-amps to measure the power loss across the shunt at very low currents. I have an EE degree and while it's been a while since I designed these types of circuits, they are really trivial to do. And low power digital circuits are easy these days.


Pics

 

[siseb]

Wir hatten einmal eine (fast) leere Batterie, obwohl die Anzeige nicht ausging. Der Motor sprang trotzdem an und die Batterie wurde über 30 Minuten mit über 100A geladen.

 

[carpetman]

Hi Parb, Can you show the Trends tab and show the graph for the starting voltage and the discharge over the 3 weeks ( you can zoom out to see this)? It maybe possible to show the cumulated power consumption.

Regards,
Carpetman

 

[carpetman]

Two more pictures.
The ineos builtin bms thinks the battery is at 67% discharge after 3 weeks and 3 days being parked on my driveway. I do not think this is a real number. I did the math and with my fully charged battery it would suggest that my vehicle consumed 1.5A continuously since I parked. I don't believe that for a second, it's way too much of an low power draw in an parked car with no active accessories. Perhaps the ineos is calibrated with a wrong a peukert coefficient?

My victron on the other hand believes my car consumed 145mA continuously since I parked it. That I believe totally. Sounds about right for low power mode of an alarm and no other active vehicle electronics. Maybe a touch optimistic since I think my Wolfbox parking monitor pulls about 100mA when parked but I don't think it's far off.

Shunts are generally really good at measuring low power, I got to imagine they have really good op-amps to measure the power loss across the shunt at very low currents. I have an EE degree and while it's been a while since I designed these types of circuits, they are really trivial to do. And low power digital circuits are easy these days.


Pics
View attachment 7894553


View attachment 7894554

Hi Parb,

Can you check you calculations as I don't think it is correct.

You were gone for 576hrs (3weeks and 3 days). Therefore if I assume your battery was as 100% state of charge at the start and 67% at the end you would have consume 34.65Ah. If you divide that by the time you were gone that would be 34.65/576=0.06A (60mA) static current.
If the battery was only 90% charged at the start of your trip that would be 0.042A static current.


I also have a smartshunt on my starter battery, I installed it before I went of vacation for 2 weeks. It was at 12.74V when I left, and gradually discharged to 12.49V. The SOC from the car was at 65% when I got back. I don't have the starting number but I think it was about 80%.

The smartshunt did not show a significant reduction in the SoC, but from the manual, if the current is below 0.1A it will record as zero.

Regards,
Carpetman

 

[DaneJa]

Wir hatten einmal eine (fast) leere Batterie, obwohl die Anzeige nicht ausging. Der Motor sprang trotzdem an und die Batterie wurde über 30 Minuten mit über 100A geladen.
View attachment 7894557

Damn, I never got that high, but after a couple days working on the truck using Android Auto and the audio system the recharge was pretty steady at around 60A once the battery warmed up for the 30 mins I drove it.