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Quick FYI on bug or lesson on how not to drain the 12v Bat.


swoop5511
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Hi, 

Found a bug or un-intendent "feature". I was rushing to do school run yesterday afternoon and didn't allow the car to fully boot up before putting into drive. Which bugged the system out and causing it not to shut down properly on parking the car. Result was a completely depleted 12v Battery - dead car this morning. 

Having said that following a call this morning to my Toyota dealer who passed me on to Toyota road side assistance I had someone on site within 60min. Mechanical unlock all worked and chap was gone within 15min. Apparently this is not uncommon for EVs, the 12v Battery drain for x or y reason. Fortunately the Battery was recoverable and had to drive casually around for an hour. 

Quick note, all settings and user details staid saved in the settings. I did have to request the factory password for the media system. So long story short, wait 10 sec - safe a few hours.

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It’s also a potentially similar story for a PHEV and they also have a small capacity 12v Battery. This has been an active topic on the RAV 4 forum for some time with plenty of solutions and experiences shared, maybe worth a look?

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3 hours ago, swoop5511 said:

Hi, 

Found a bug or un-intendent "feature". I was rushing to do school run yesterday afternoon and didn't allow the car to fully boot up before putting into drive. Which bugged the system out and causing it not to shut down properly on parking the car. Result was a completely depleted 12v battery - dead car this morning. 

Having said that following a call this morning to my Toyota dealer who passed me on to Toyota road side assistance I had someone on site within 60min. Mechanical unlock all worked and chap was gone within 15min. Apparently this is not uncommon for EVs, the 12v battery drain for x or y reason. Fortunately the battery was recoverable and had to drive casually around for an hour. 

Quick note, all settings and user details staid saved in the settings. I did have to request the factory password for the media system. So long story short, wait 10 sec - safe a few hours.

Thank you for sharing.

 

What does it mean "causing it not to shut down properly"? What happend with the car, did you see any warning?

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1 hour ago, bZ4X said:

Thank you for sharing.

 

What does it mean "causing it not to shut down properly"? What happend with the car, did you see any warning?

back ground systems. think of phone or laptop not shut down but running and draining the Battery. To me it looked like always

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4 hours ago, ernieb said:

It’s also a potentially similar story for a PHEV and they also have a small capacity 12v battery. This has been an active topic on the RAV 4 forum for some time with plenty of solutions and experiences shared, maybe worth a look?

With my old 2008 Prius hybrid the 12V Battery was a problem. Very easy to run it flat with lights left on, during winter months or if the car was left standing for any time etc. Learned A) to keep the 12V Battery charged up maybe a couple of times over the winter  and B) always keep a small 12V lithium booster with large crock clips to power up 12V if Battery dead. I've treated the small 12V battery in the bZ4X the same way. As a bonus in the bZ4X  it is easy to leave the 12V booster plugged in to one of the USBC sockets all the time.

I've monitored the 12V battery in my bZ4X and, although it has never failed, it has drifted to below 12V a couple of times (should be 12.6V) and needed charging.

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13 hours ago, dab1054 said:

With my old 2008 Prius hybrid the 12V battery was a problem. Very easy to run it flat with lights left on, during winter months or if the car was left standing for any time etc. Learned A) to keep the 12V battery charged up maybe a couple of times over the winter  and B) always keep a small 12V lithium booster with large crock clips to power up 12V if battery dead. I've treated the small 12V battery in the bZ4X the same way. As a bonus in the bZ4X  it is easy to leave the 12V booster plugged in to one of the USBC sockets all the time.

I've monitored the 12V battery in my bZ4X and, although it has never failed, it has drifted to below 12V a couple of times (should be 12.6V) and needed charging.

Good info! Which brand and model is your 12v booster? 

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1 hour ago, bZ4X said:

Good info! Which brand and model is your 12v booster? 

I carry a Noco Boost Sport GB20 available from places like Halfords and Amazon but there are plenty of suitable alternatives. You don't need anything particularly powerful in order to simply turn a hybrid or EV back on.

It's a known issue with hybrids that the small 12v auxiliary Battery used to keep the car 'alive' while it is switched off will eventually run flat if the car is left unused for too long - where too long is usually more than two weeks and probably less than six but it will depend on the state of charge of the 12v Battery when the car is left. The same will be true of EVs like the bZ4X.

The easy way to flatten the Battery is to put the car into accessory mode only and listen to the radio or run the aircon - under those circumstances the 12v auxiliary battery is NOT charged from the traction battery and the use of accessories can flatten it quite quickly.

It's not entirely clear from the OP's report whether his issue was  a 'fault' with the car / software or an 'operator error' due to not being aware of the restrictions and limitations. But the basic rule is to leave the car either entirely off and unused, or 'on' (Ready mode on the hybrid) but never to use accessory mode for more than a few seconds if at all.

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1 hour ago, bZ4X said:

Good info! Which brand and model is your 12v booster? 

It’s an unbranded unit I bought years ago on eBay. There are plenty of them about. Just makes sure it is 12V (most are 5V) and has the ability to deliver high current with cables which can easily be attached to the Battery terminals. I had a look on Amazon and there are loads available. 

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  • 1 month later...

Hello, 

 

I left my car unlocked for 45 minutes. Opened and closed the powered boot maybe 5 times. Eventually my 12V Battery drained! Car showed me parking break error.  I couldn't start the car to charge it even. I waited 30 miutes and Battery and the Battery has recovered some to enable me to start the car. We better keep lithium ion jump starter, just in case! 

 

 

 

 

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1 hour ago, bZ4X said:

Hello, 

 

I left my car unlocked for 45 minutes. Opened and closed the powered boot maybe 5 times. Eventually my 12V battery drained! Car showed me parking break error.  I couldn't start the car to charge it even. I waited 30 miutes and battery and the battery has recovered some to enable me to start the car. We better keep lithium ion jump starter, just in case! 

 

 

 

 

It’s what many with the RAV PHEV do for similar reason.

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I was just thinking that you didn't need a big pack, that clarke pack is a nice size to keep in the glove box

Has anyone checked what the voltage was of the Battery when it was flat? 

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8 hours ago, egg said:

https://www.machinemart.co.uk/p/clarke-jsm180-5400mah-lithium-polymer-jumpstar/

The above is what i carry around in my car for just such an event. It's only the size of a large powerbank. You don't need anything large as there is no physical engine to crank over.

Thank you for sharing this. 

 

I read somewhere that the problem here these jump starters are not functional if 12V Battery drops to a certion level of Volt. For example (I am just making up the numbers) : If 12V below 7V then Jump starter will not run the car.

 

I had this problem 2 times so far. I will ask my delaer to replace Battery under warranty. 

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bZ4X, I know the jumper will work below 8v.  The clue may be the car response to low voltage. 

I have had 3 fail to start on my last car. Inability to unlock was one symptom but lots of strange light behaviour was common to all 3.  These indicated some life in the Battery but insufficient to activate the systems.  Jumpers worked each time. 

I don't have experience of a Norwegian Blue Parrot as in DEAD.  In that case you are probably right and only a new Battery will work. 

Even if a jump pack works it is a warning that your Battery may have suffered irreparable damage and may fail again in the future. 

I store my jump pack, in its case, in the engine compartment. 

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I was warned by my salesman to not shut-off the car without pressing the brake pedal. Not shutting it down properly may result things not turning off and still run in background.

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12 hours ago, cavities said:

I was warned by my salesman to not shut-off the car without pressing the brake pedal. Not shutting it down properly may result things not turning off and still run in background.

This is not something written in the user manual right? 

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These modern cars are actually quite sophisticated, with copmputers , apps and more.

The My-T App can tell us the SOC when the car is off and parked up.

The app can also send an alert of the doors are not locked.

Would it not be quite simple to send an alert if the 12v Battery level dropped below a certain amount of volts ?

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On 5/6/2023 at 10:28 PM, lightboxcar said:

These modern cars are actually quite sophisticated, with copmputers , apps and more.

The My-T App can tell us the SOC when the car is off and parked up.

The app can also send an alert of the doors are not locked.

Would it not be quite simple to send an alert if the 12v battery level dropped below a certain amount of volts ?

Very good idea, I like it 😊

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