Jump to content
Do Not Sell My Personal Information


12 v battery flat


Knitswithbeer
 Share

Recommended Posts

Please forgive me if this is the wrong place to ask.

I bought a new Yaris Hybrid on 27 May this year and I love it. Trouble is the car has failed to start twice now (11/8 and today) after only a few days not being used.

Both times the AA said Battery is fine. Car was in for a Recall on 12/8 and the dealer said the Battery was fine.

AA man today wonders if something is not switching off properly and draining the Battery. Only thing I can think of is I sometimes (not every time) get a warning to check the back seat (always empty) when I switch off.

I've got it booked in for 15/16 August but is this a known issue?

My car was sat in the showroom when I first went to arrange a test drive (not my car) and the salesman had to jump-start it so he could open the doors.

Brassed off tbh

Link to comment
Share on other sites


Tina, welcome to the forum and join the club.  "the car has failed to start twice now (11/8 and today) after only a few days not being used."  This sound exactly like most here have experienced.  You say after only a few days not being used.  This is only half the story.  The important thing is how was it used on the previous trip and ones before that.  It doesn't have an alternator so what would provide a good charge in a few minutes in another car might not be sufficient in the hybrid.

If you had done a run of say 20 minutes that might be sufficient time for the main Battery to recharge the 12v Battery.  If it was just a quick trip to the shops even on several days that might not be sufficient.  Toyota's advice it to put the car in Ready mode for an hour a week.  The engine will start and stop several times during this period but will ensure a charged 12v Battery.  You must of course be with the car during this period.

Are they all like this?  Possibly not.  You mention the demonstrator had a flat Battery.  Your car may also have had similar Battery issues after build and before delivery.  This could lead to premature cell failure.  In my case, after one AA call out and two further flats, the dealer changed the Battery and installed a 52Ah instead of the original 45ah.

This also raises the question of how you car might fare when you go on  a fortnights holiday.  Some of us have bought Battery boosters .  We have also invested in a Battery charger with CTEK MX5 being a favourite.  This is a conditioning float charger and can be left connected when the car is not in use.  That of course assumes you have access to a power point.

  • Like 1
Link to comment
Share on other sites

Thanks for this.

Funny this didn't show up in my pre-purchase research.

The last journey was indeed a short one but the previous day I'd done an Euxton-Harrogate-Leeds-Euxton trip.

We'll have to see what the dealer says when they check it over.

 

Link to comment
Share on other sites

"AA man today wonders if something is not switching off properly and draining the battery"

There are things that might be drawing power.  The journey stats are sent back to the Toyota server.  Does this occur after switch off?  How often is there a handshake between car and server?  The remote keys may also handshake with the car always listening.  If the car is locked the alarm system will be active.  There are several possibilities but I have seen nothing definitive.

  • Like 1
Link to comment
Share on other sites

A small tip for everyone and is a habit I've gotten into because of car theft around here: when you are in the house, make sure that both of your keys are on standby (a sort of sleep mode) so that they can't be cloned from outside your house. How to do this? After locking the car, click and hold down the lock button whilst you double click the unlock button at the same time. They key's LED will respond with 4 flashes in two pairs of two and then go out and stop flashing. Your key now cannot be cloned! You're welcome! 🙂

(to "wake up" your key fob, just press either button)

  • Like 1
  • Thanks 2
Link to comment
Share on other sites


15 hours ago, Knitswithbeer said:

AA man today wonders if something is not switching off properly and draining the battery. Only thing I can think of is I sometimes (not every time) get a warning to check the back seat (always empty) when I switch off.

Have you a black box for insurance ? The black box could drain your Battery if you don't use thecar frequently.

Regarding the warning on back seat is triggered by default if you open and close a rear door after unlocking the car. It helps you to remember that you could have put something on back seats ( e.g. a bag ).  This warning can be disabled through steering wheel menu. 

If you're getting this warning but you don't have opened the back door then there's somethng strange that you could report to AA.

Link to comment
Share on other sites

  • 3 weeks later...
On 8/31/2021 at 7:43 PM, Roy124 said:

"AA man today wonders if something is not switching off properly and draining the battery"

There are things that might be drawing power.  The journey stats are sent back to the Toyota server.  Does this occur after switch off?  How often is there a handshake between car and server?  The remote keys may also handshake with the car always listening.  If the car is locked the alarm system will be active.  There are several possibilities but I have seen nothing definitive.

Thanks Roy. I was explicit in my insistence they look at if anything was draining the 12volt when I dropped the car off yesterday.

Collected today and... the Dashcam was faulty and always on so was draining the Battery

I now have a new Dashcam at no extra cost.

Thanks again.

  • Like 1
Link to comment
Share on other sites

KWB, interesting.  At least easy to check, see if the recordings are continuous.  As they changed the Dashcam one must suspect it was at fault.  If something doesn't switch ogg one might suspect it was wired to an always live feed, but they wouldn't have done that would they 😊

  • Haha 1
Link to comment
Share on other sites


This is ridiculous. Car batteries for that class of car are between 40 and 50 amp hours.

I have no idea why it needs so much power on idle. My current car (Hyundai Atos) can sit unused for months with a measly Battery.

Still waiting for my Yaris to arrive but I'm getting a bit scared since I'm not commuting with it regularly.

Link to comment
Share on other sites

36 minutes ago, baxuz said:

This is ridiculous. Car batteries for that class of car are between 40 and 50 amp hours.

I have no idea why it needs so much power on idle. My current car (Hyundai Atos) can sit unused for months with a measly battery.

Still waiting for my Yaris to arrive but I'm getting a bit scared since I'm not commuting with it regularly.

Hi, 

you can do with solar power Battery charger to help top up your 12v Battery when you don’t use the car regularly or when you are going on holidays and leaving it for a long time without driving. 

  • Like 1
Link to comment
Share on other sites

The hybrid yaris has a 12V car Battery located under the rear seats

very poor access to the connection from the solar charger

It would be better to connect to a cigarette lighter - 12 V socket.

The bad thing is that it turns off when the car is turned off

Link to comment
Share on other sites

4 minutes ago, Dala said:

The hybrid yaris has a 12V car battery located under the rear seats

very poor access to the connection from the solar charger

It would be better to connect to a cigarette lighter - 12 V socket.

The bad thing is that it turns off when the car is turned off

Not true if you buy a Solar Charger that has an OBDII connector option. It then plugs directly into the OBDII connector which gives direct access to the 12V Battery. No need to mess about under the rear seats...

Like this one...

PXL_20210108_133253492.thumb.jpg.fc7abd546a2f428806d28bae98b034b5.jpgPXL_20210108_133342468_MP.thumb.jpg.62fd37db311bdcfe83d6f97a652c0691.jpg

Link to comment
Share on other sites

I tried it, but my car also turns off OBDII when the car is off - maybe a bad OBDII connector
I'm not sure if with a 20W solar charger - max. 1.11A for the OBDII port is not much

Link to comment
Share on other sites

21 minutes ago, Dala said:

I tried it, but my car also turns off OBDII when the car is off - maybe a bad OBDII connector

The OBDII connector is never turned "off" in terms of 12V and ground. If yours is going really off, there is a problem with your car. If you are judging its on/off status by using an OBDII dongle, you can't. Most OBDII dongles go to sleep when they realise that the CANBUS has gone to sleep (i.e. car ignition is off) or detection of Pin 1 up/down.

21 minutes ago, Dala said:

I'm not sure if with a 20W solar charger - max. 1.11A for the OBDII port is not much

The 12V Battery in our Toyota Hybrids is meant to be charged low and slow. The solar panel in my pictures works perfectly for that.

250px-OBD_connector_shape.svg.png

image.thumb.png.5f11cedd5c80d72291bc787a7baafc8d.png

Note that pin 16 and pin 4 are always connected.

Link to comment
Share on other sites

"If you are judging its on/off status by using an OBDII dongle, you can't. Most OBDII dongles go to sleep when they realise that the CANBUS has gone to sleep"  - there was a problem here, I thought exactly

How much power does your charger have in watts, please?

Link to comment
Share on other sites

19 minutes ago, Dala said:

How much power does your charger have in watts, please?

1956125135_Screenshot2021-09-17212755.thumb.png.d3bc260c600a07a9a973b9abef068379.png

(note: it does not require a "20W" charger to trickle charge over an extended period of time)

Link to comment
Share on other sites

Now, in a week, when the car is stationary, I will drop from 12.7 V to 12V

in the future I would like to use the "motion detection" function of my car camera - the camera automatically starts recording when it detects movement around the vehicle

then the voltage drop would be much higher

2.4 W is not enough for me

Link to comment
Share on other sites

20 minutes ago, Dala said:

Now, in a week, when the car is stationary, I will drop from 12.7 V to 12V

in the future I would like to use the "motion detection" function of my car camera - the camera automatically starts recording when it detects movement around the vehicle

then the voltage drop would be much higher

2.4 W is not enough for me

I have a similar camera with a similar "motion detection" facility (that I never use) and I would suggest to you that on any Toyota Hybrid, you will flatten the Battery in no time at all if you use such a facility 24/7 while the car is not being used. (and is why I never switch the motion detection in my camera on) So, yes, of course 2.4W will not be enough in that situation. The problem with the batteries used by Toyota in all its HSD vehicles is that if you just leave an interior light on accidently (5W bulb) you'll drain the Battery in hours; much quicker than a normal car with a normal size Battery. Even the normal systems of the hybrid car with the ignition off, provide a faster drain compared to a normal car/battery and is why Toyota recommend running the car in "Ready" mode for at least 1Hr/week for extended periods of not being used.

  • Like 1
Link to comment
Share on other sites

If you're going to run a Dashcam in 'sentry mode', it is a good idea to plug it into a USB power bank, and plug the car's usb charger into the power bank's charging port.

That way the car will charge the power bank while you drive, and it will power the Dashcam when it's off, and there is no way the Dashcam can drain the 12V Battery. If you leave it too long it'll just discharge the powerbank and stop recording.

Just make sure you get one that can supply power while charging, and get a good quality one - You don't want one of those nasty chinese ebay specials catching fire on a hot day...!

A colleague uses his jump-starter as a power bank for his Dashcam as it has USB power sockets - His is quite a fiddly setup tho' as it won't charge and supply power at the same time, so he has to keep swapping leads around when he gets in and out of the car... i.e. plug the Dashcam and powerbank into his car USB to charge when he gets in, then when he gets out unplug both from the car and plug the Dashcam into the powerbank... Personally I think I'd get annoyed doing that all the time!

 

 

 

  • Like 1
Link to comment
Share on other sites

13 minutes ago, Dala said:

I use this: HK3 ACC HARDWIRE KIT CABLE

I don't know if it was a mistake 😕

Possibly not? It looks as if it might be ok if it works as described? It would seem that it requires a constant 12v supply as well as an ignition switched 12v supply so wiring it up might present a bit of a challenge to do neatly...

Link to comment
Share on other sites

38 minutes ago, Cyker said:

Just make sure you get one that can supply power while charging...

Do you know of any that work like that? I've had a look on Amazon and most of them turn their outputs off as soon as you plug a charging source into them?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...




Forums


News


Membership