12v battery maintenance, issues, etc.

[Roy124]

Had a 12v alarm a couple of days ago when it flagged up a voltage on my 17 month old YC of just under 12v.  However this appeared to be a transient.  Nevertheless I gave it a long charging session and after a settling period it stabilized as 12.75v on the 4th.

On the 16th it was 12.56v with my car being driven normally every couple of days and 5 hrs on the 15th.  This morning, the 18th, the voltage had dropped to 12.36v.  Quite a drop in 2 days.

The car had been driven for 42 min on the 16th and 3 hr on the 17th.  The drop in voltage shows as a linear decline not withstanding the peaks on the 16th  with2 cycles and 17th with 3 cycles.

I shall certainly be watching it over the next week.  In June we are away for 15 days so best I ensure my jumper pack is charged.

[Countryside]

My goodness Roy it would drive me mad ! I pick up my new CHR Monday morning 

[Roy124]

33 minutes ago, Countryside said:

My goodness Roy it would drive me mad ! I pick up my new CHR Monday morning 

Probably best, ignorance etc

[Countryside]

I wasn’t being ignorant I was just saying looking at the voltage all the time would drive me mad we are all different 

[Jenny_L]

To add my ha'pence worth:  I bought a 71 plate Yaris cross last June.  Had no problems with the 12V Battery, despite only driving 400-500 miles per month... until I had an operation in March and couldn't drive for 5 weeks.  I went into Jemca Reading before my op and specifically asked, do I need to do anything to maintain the car for the next few weeks, eg. get someone to drive it once a week etc?  I was advised, just turn it on at least once a week and let the engine run as long as it wants, to top up the hybrid Battery.  Nothing was said about the 12V Battery being so naff that it would go flat within 2-3 weeks.  Which it did.  Toyota Assist (AA) jump-started it and advised me to leave the car in 'Ready' mode for at least 2 hours (!) and then similarly for 30-60 minutes every other day, given I still couldn't drive it.  This indeed charged the battery enough to keep it functional: the AA man demonstrated how the hybrid battery was trickle-charging the 12V battery, and periodically the engine fired up for a few minutes to recharge the hybrid battery.  Big downside, of course, is that either I sat in the car for 30-60 mins (or 2 hours on the day the AA came) or trusted that no-one would nick the car, as it needed the key in it to stay in 'Ready' mode and it refused to be locked with the spare key while a key was still inside but with no-one sitting in there too! 🙄 (too flippin' clever for its own good).

The AA man said the battery was probably defunct, if it went flat in 3 weeks.  I phoned Toyota to ask for a battery replacement, and was offered next day... but when I mentioned "under warranty", the man on the phone quickly changed his tune and said this would need booking in for a battery check first, which they couldn't do for 2 weeks!  The 'next day' job would have been a non-warranty replacement at a cost of about £150 to me.  Not impressed at Toyota's transparency (ie. utter lack thereof).

I drove it (yay!! 😁) to Jemca Reading yesterday.  They did the battery check - their machine told them to charge it overnight.  This morning the conclusion was that it's absolutely fine and just needed charging properly.  Guess what?  I was told that I don't drive it enough blah blah blah - same weary excuse clearly being trotted out to everyone; but this wasn't my problem, it was due to the car being unused for 2+ weeks.  The service lady did explain that, when the car is not in use, the 12V battery will be used to trickle charge the hybrid battery (I guess the hybrid battery is a more expensive failure?), so that would explain why the 12V battery died.  And yes, she said they recommend a solar battery charger, especially if the car is left unused when you go on holiday etc.  Other car maintenance websites point out that cars these days have so many systems running in the background - keyless entry, alarms, wi-fi, numerous other processes - that the 12V battery is being drained far more than used to be the case.

As other owners have said, it's a shame that Toyota can't train its staff to inform prospective buyers about these things.  There's certainly nothing in the manual about it, that I can find.  And it's a shame that the advice I got in March was so severely inadequate.  Seems to be the way of dealerships these days, hey ho.

[CPN]

1 hour ago, Jenny_L said:

 The service lady did explain that, when the car is not in use, the 12V battery will be used to trickle charge the hybrid battery (I guess the hybrid battery is a more expensive failure?), so that would explain why the 12V battery died.

Wow Jenny! That lady is talking so much rubbish!!! The 12v Battery is incapable of even giving the HV Battery a sniff let alone a trickle charge! That lady needs to go back to Toyota's training sessions to learn a bit more about the cars she is servicing!!

1 hour ago, Jenny_L said:

And yes, she said they recommend a solar battery charger, especially if the car is left unused when you go on holiday etc.  Other car maintenance websites point out that cars these days have so many systems running in the background - keyless entry, alarms, wi-fi, numerous other processes - that the 12V battery is being drained far more than used to be the case.

(in red) That is where the main drainage of the 12v Battery occurs when left unused for extended periods and it does not just apply to hybrid cars these days either!

1 hour ago, Jenny_L said:

As other owners have said, it's a shame that Toyota can't train its staff to inform prospective buyers about these things.  There's certainly nothing in the manual about it, that I can find.  And it's a shame that the advice I got in March was so severely inadequate.  Seems to be the way of dealerships these days, hey ho.

There is a section in the manual that describes the process... (but I don't have it just now)

[Chas G]

I am still plugging in every day and it takes less than a minute to get the ctek5  to show 4 lights.

Yesterday I went to the doctors and had to park in a side road about 15 minutes walk from the surgery. I got out of the car and pressed the key......nothing happened so I thought pollocks, the fob Battery must be flat. No choice but to walk to my appointment and leave the car unlocked. For the next 45 minutes all I could think of was whether the key fob would start the car.

Got back to the car I pressed the fob a few more times with no flashing lights, tentatively got in and.........no wonder it wouldn't lock. It was sitting there in ready mode.

At least it had probably charged up the Battery but good job it didn't get pinched.

[Roy124]

16 hours ago, Countryside said:

I wasn’t being ignorant I was just saying looking at the voltage all the time would drive me mad we are all different 

Not suggesting that at all, just 'ignorance is bliss' or 'don't cross the bridge until ...' or don't worry unnecessarily. 

[Roy124]

Chas, been there, done that.

Next wish list is Remote Stop.

[RickyC]

16 hours ago, Chas G said:

....no wonder it wouldn't lock. It was sitting there in ready mode.

I've stopped to count the times that happened to me 😇.  

I park, get down from te car, press the keyfob and.... nothing.

Open the door and a big READY label explains why !!!!!! 😉

[einfachGaer]

Mine beeps very loud if I exit the car with the key in my pocket and close ANY door ... This could never happen to me. No idea why yours doesn't do that?!

[Roy124]

13 minutes ago, einfachGaer said:

Mine beeps very loud if I exit the car with the key in my pocket and close ANY door ... This could never happen to me. No idea why yours doesn't do that?!

Oh they do, but we get nagged so many times that one more is just as easy to ignore.

Anyway, our point is you are now out if the door and have to get back inside,  just as you do.

[Dala]

18 minutes ago, einfachGaer said:

Mine beeps very loud if I exit the car with the key in my pocket and close ANY door ... This could never happen to me. No idea why yours doesn't do that?!

It is normal for me

Areas in which the electronic key is detected

A - locking or unlocking the door

B - starting or switching

 

[einfachGaer]

9 minutes ago, Roy124 said:

Oh they do, but we get nagged so many times that one more is just as easy to ignore.

Anyway, our point is you are now out if the door and have to get back inside,  just as you do.

Yes, because the steering wheel lock only engages when you turn off the car and the driver's door is closed.

[RickyC]

1 hour ago, einfachGaer said:

Mine beeps very loud if I exit the car with the key in my pocket and close ANY door ... This could never happen to me. No idea why yours doesn't do that?!

Also mine does.

But I'm so used to beeps that often I ignore them.

Moreover very often there's so much ambiental noise that the loud beeps are lost in the background.

[Chas G]

19 hours ago, RickyC said:

Also mine does.

But I'm so used to beeps that often I ignore them.

Moreover very often there's so much ambiental noise that the loud beeps are lost in the background.

@einfachGaer and @RickyC

My keyless entry is turned off which probably explains the lack of beeping noise.

[mr_blibby]

 Appologies if posted before ....FYI on the approach Toyota seem to be taking in Poland

[hind]

Yeah I've posted this a while ago but the reality is that absolutely nothing has changed 😞 a week ago one of the owners of the YC who has issues with 12v Battery after even 3 days of parking checked the actual capacity using professional Battery meter which indicated the capacity to be around 12Ah (should be 35Ah). He raised this to the dealer and they tested it themselves. Result? Battery fine, needs recharging. End of story 😕

 

[Roy124]

On 4/19/2024 at 9:35 PM, Dala said:

 

Areas in which the electronic key is detected

B - starting or switching

 

Thanks for the B reminder.  Shows clearly why it can't detect my key when I put it in the dash stowage. 

PITA as I have to drop it in a cup holder.

Mind you, my wife as a passenger is even better with the house keys.   They may be in the left door pocket, her handbag, on the floor by her right foot, in a cup holder,  or the front cubby.  NTST 😮‍💨

[ChrisJohn]

I am continuing to have 12v Battery issues with just a couple of short journeys resulting in starting failure. I now have a Battery boost starter and also am aware of Toyota's advice to leave car in "Ready" for up to an hour to allow the system to charge up the 12v Battery. 

However, the car has just had its first service and another overnight trickle charge and the battery has reported as OK. The Toyota service manager has told me that Toyota is aware of this issue and is planning to introduce a battery with greater capacity but still fits in the space available. Has anyone heard about this or have any more details? I have no details of timing but the service adviser has just told me that they are expecting a bulletin on the subject.  Clearly the battery is inadequate for the tasks required of it as things stand now.

[Roy124]

Chris,  nothing new there.  My dealer fitted a 42AHr v 35AHr 3 years ago.  

[ChrisJohn]

I don't know what capacity is fitted to my Yaris Cross but the dealer has told me that Toyota will not authorise a Battery change under warranty if the one fitted passes their test.

[Dala]

A Toyota dealer will allow Battery replacement under warranty, but you must purchase this 12V Battery.

[hind]

In other words, as long as the OEM Battery fulfills the test procedure criteria, they won't pay for the replacement under warranty. 

If the OEM Battery fails the test procedure (during the warranty period), they will install the replacement - probably identical to what you have. The cost will be covered by Toyota.

If you'd like to have a Battery of a different brand (eg. Yuasa or Varta of larger capacity) which has identical dimensions and all required features (like a vent) then you have to pay for it but installing it won't void the warranty as it meets the manufacturer requirements. 

[Roy124]

2 hours ago, ChrisJohn said:

I don't know what capacity is fitted to my Yaris Cross but the dealer has told me that Toyota will not authorise a battery change under warranty if the one fitted passes their test.

That seems reasonable but is not the end of the matter.

I went through that loop.  I then logged the Battery voltage each day over a week when I did not drive it.

I took it in, presented my figures, and collected the car a couple of hours later with a new, higher capacity,  Battery.

a.  They might refuse to change it.

b.  They might change like for like.

c.  They might fit a higher capacity Battery.