Intermittent Battery Drain With Pictures

[SeanC]

This has been happening on and off for a number of years. Very infrequent but once took a brand new starting battery so low over 5 days, the central locking wouldn’t operate. The level of voltage loss vs. time isn’t consistent between events.

So I have my new Bluetooth battery monitor which has been showing a loss of between 0.01 and 0.02 volts / 24 hours over 6 days of not driving.

This afternoon the voltage was 12.38 volts.

Looking at the history. Drove to work Friday. About 12.30 Saturday drove down the back to do some work. Voltage 12.73v. Drove back to the house. Same time Sunday drove down the back.
In that 24 hour period the voltage dropped almost 0.3 volts. After driving back to the house. The next 24 hours saw a drop of 0.01 volts.

The starting and auxiliary systems are separate.
No the interior lights weren’t left on as I have them set so they need to be turned on manually.

Wished I knew what was going on. Go for months with no problem. This is why I keep the battery on the charger. Haven’t had it on the charger because monitor showed no appreciable voltage loss.

Looks like it’s going back on.

Re. Pictures. Feb 12th is a “normal” 24 hours. 16th and 17th are the Saturday and Sunday just gone.

Untitled - Google Photos (https://photos.app.goo.gl/FiHZ1GeWUZ3dnHt86)
Untitled - Google Photos (https://photos.app.goo.gl/eDngUCKKN4X6f1pW8)
Untitled - Google Photos (https://photos.app.goo.gl/emeHPE6WUMSh3nj9A)

[RobA]

OK you have LifePO4 auxiliary batteries? Where are the located, under the bonnet or away from the heat? As well what is charging them, how old, what make and are they connected to the starting battery in any way at all

Rob

[drivesafe]

Hi Sean and need a lot more info.

How often do you drive?

When you drive, how long do you drive for?

How long do you leave your vehicle between drives?

How old is the battery?

When you use your charger, what routine do you go through?

[SeanC]

Hi Sean and need a lot more info.

How often do you drive?

When you drive, how long do you drive for?

How long do you leave your vehicle between drives?

How old is the battery?

When you use your charger, what routine do you go through?

Hi Tim,

This is the cranking battery. It is an Odyssey PC1350. Brand new.
The cranking and lithium’s aren’t connected when the vehicle is off.
Usually take it to work once a week. A 100km round trip on the highway.
And longer trips some weekends. Not many short trips.
Before I had the battery monitor I would have the old battery connected to the Ctek battery charger when not in use as I never knew when the drain will occur.
I haven’t had the charger on the Odyssey as I could monitor the battery and over 6 days of not driving it was losing 0.01 to 0.02 volts per 24 hours which I thought was pretty good.
Used the charger to recharge after the drain which was Monday and battery is at 12.8 volts.
So it was interesting to see that it only lasted between two stop start cycles. Would not have known that without the battery monitor.
Have taken it to an auto-electrician but couldn’t find anything but most probably wasn’t happening at the time.
This monitor is very useful as every afternoon I can check the battery history and see what is happening. I don’t need to leave it on the charger all the time and over time I may be able get an idea of how often it happens when it happens and if the drain is the same each time or variable. $45 well spent. Just wish I knew what was going on.

[DiscoJeffster]

Are the cranking and lithium physically separated when the vehicle is stopped - Eg you manually separate or do you have an isolator?

Identify every single non-factory device fitted to the car no matter how innocuous.

Have you owned the car from new? Eg could there be something fitted somewhere you know nothing about?

[DiscoMick]

Hi Tim,

This is the cranking battery. It is an Odyssey PC1350. Brand new.
The cranking and lithium’s aren’t connected when the vehicle is off.
Usually take it to work once a week. A 100km round trip on the highway.
And longer trips some weekends. Not many short trips.
Before I had the battery monitor I would have the old battery connected to the Ctek battery charger when not in use as I never knew when the drain will occur.
I haven’t had the charger on the Odyssey as I could monitor the battery and over 6 days of not driving it was losing 0.01 to 0.02 volts per 24 hours which I thought was pretty good.
Used the charger to recharge after the drain which was Monday and battery is at 12.8 volts.
So it was interesting to see that it only lasted between two stop start cycles. Would not have known that without the battery monitor.
Have taken it to an auto-electrician but couldn’t find anything but most probably wasn’t happening at the time.
This monitor is very useful as every afternoon I can check the battery history and see what is happening. I don’t need to leave it on the charger all the time and over time I may be able get an idea of how often it happens when it happens and if the drain is the same each time or variable. $45 well spent. Just wish I knew what was going on.
Losing 0.01 to 0.02 volts per 24 hours is not a problem. Losing 0.3 in 24 hours seems high.
12.8 is fully charged. 12.38 is about 75-80% I think from memory.
Is it right that D4s have systems which start up intermittently to check various things are OK and then shut down?
You could just plug in a small solar panel to put some charge in each day and replace any battery drain.

[SeanC]

Are the cranking and lithium physically separated when the vehicle is stopped - Eg you manually separate or do you have an isolator?

Identify every single non-factory device fitted to the car no matter how innocuous.

Have you owned the car from new? Eg could there be something fitted somewhere you know nothing about?

Yes the cranking and lithiums are separated by a DCDC charger that isolates when the ignition is off.

Not from new. Non standard items connected to the cranking battery that I know about are transfer pump for the long range fuel tank. Trailer brake controller. Module for LED trailer lights. LLAMS but this problem occurred before I had LLAMS.

It's the randomness that makes it difficult. Can go for months with no issue.

[scarry]

Is it right that D4s have systems which start up intermittently to check various things are OK and then shut down?
.

Yes it definitely does.

One check is relevelling the vehicle every so often,while it is asleep.

Also when it wakes up when a door opens,it will do different checks to other times.

It will even do different checks as the start button is pushed.
Sometimes it will start immediately,other times there is a delay for a good few seconds before it will energise the starter,while it is doing system checks.

[DiscoJeffster]

Yes the cranking and lithiums are separated by a DCDC charger that isolates when the ignition is off.

Not from new. Non standard items connected to the cranking battery that I know about are transfer pump for the long range fuel tank. Trailer brake controller. Module for LED trailer lights. LLAMS but this problem occurred before I had LLAMS.

It's the randomness that makes it difficult. Can go for months with no issue.

You need to now physically disconnect each device until you find what the issue is. At the end of the day, one of those devices is likely the cause.

[rocket rod]

Try locking the car if you don't already.

[DiscoMick]

Use a solar panel to keep it charged.

[weeds]

Use a solar panel to keep it charged.

I think I’d rather find the cause......solar panel isn’t fixing the actual issue.

[DiscoMick]

It's normal for some drains to deplete a parked vehicle. Solar charging would keep it charged and allow the normal cycles to operate. Solar charging also keeps batteries healthy.

[SeanC]

I think I’d rather find the cause......solar panel isn’t fixing the actual issue.
All back to normal at the moment like it is 95% of the time. Thanks to Brian Elloy. The BM2 battery monitor will definitely help to solve the problem.

[justinc]

I had a similar fault with a customers vehicle, at random intervals the trailer brake controller would turn on the brake lamps... was intermittent in its occurrence however would drain the battery quite a lot over 12 to 15 hours.

[SeanC]

So I was in and out of the vehicle installing a coulomb counter to monitor the lithium batteries.
The dips are each time I unlocked the vehicle. No interior lights. Just the vehicle waking up and going back to sleep. Love this monitor. Can even get a connection in bed. How good is that!! Most closely watched battery on the planet.

I didn’t know what a coulomb counter was until I googled LiFePo4 battery gauge. The one I got looked identical to the one below but a third the cost from Hong Kong. With the mandatory Chinglish instruction sheet of course. Seem to be working so far....

Lithium-Ion State of Charge (SoC) measurement – PowerTech Systems (https://www.powertechsystems.eu/home/tech-corner/lithium-ion-state-of-charge-soc-measurement/)