12v battery...that old chestnut!

[Mim]

Already carry a Noco booster pack under the back seats just in case the 12v Battery decides to aggravate..would anyone support "swapping out the oem Battery for a Yuasa battery" if so which one would suit a 2023 2.0l GR sport? 

[Dylanfan]

Unless the car in not used much or you’re only doing short journeys I can’t see why you need a booster. 
In normal use the Battery should last 5-6 years.

[Chainbreaker]

40 minutes ago, Dylanfan said:

Unless the car in not used much or you’re only doing short journeys I can’t see why you need a booster. 
In normal use the battery should last 5-6 years.

You must be new to the Corolla forum!

[Roy124]

46 minutes ago, Dylanfan said:

In normal use the battery should last 5-6 years.

Define normal.   I think normal has evolved.

More retired folk so normal is infrequent shorter journeys.   WFH so the daily commute is less.

I am long retired but my normal is 1,000 miles per month.

[RabButler]

Which is more than enough to keep the 12v Battery happy.

8 minutes ago, Roy124 said:

I am long retired but my normal is 1,000 miles per month.

 

[DavidTC]

I've had a flat Battery on a couple of occasions, admittedly do to my own fault.

Just the other day I used the tyre inflator in accessory mode and forgot to turn off the car afterwards as I was cleaning it. No radio, no ac, 10 mins later dead. 

The 12V battery/car is not designed to be used in that mode, does make you wonder why it's there 🤔 

[trashman1965]

Surprised it didn't turn off itself...First hybrid was an auris for me and waiting to pick up my daughter I was listening to music in accessory mode and a warning came up - pretty sure it said it was switching off to save the Battery or at least a warning. Mind you if you aren't there to see the warning it doesn't help much.

Pretty sure it was longer than ten mins, but not very long, but if it was already in the weak side it may have dropped really quickly.

If I'm waiting for someone now I just sit there was HVAC and headlights off.

 

 

[Niky]

Just an idea - might be wrong though

For those who drive only short distances I think using Sport mode should help maintaining the batteries.  When on sport mode generators have more resistance, and keep charging the hybrid Battery as much as possible, so there is extra power to support the sport setting.

Just had a 5 minutes of normal drive on sport mode. Started with approx 30% of Battery charge and finished with almost full charge. Think this should also help if the car will be parked for more than 10 days...

What did you think?

[trashman1965]

36 minutes ago, Niky said:

Just an idea - might be wrong though

For those who drive only short distances I think using Sport mode should help maintaining the batteries.  When on sport mode generators have more resistance, and keep charging the hybrid battery as much as possible, so there is extra power to support the sport setting.

Just had a 5 minutes of normal drive on sport mode. Started with approx 30% of battery charge and finished with almost full charge. Think this should also help if the car will be parked for more than 10 days...

What did you think?

I imagine that won't help - problem is the 12v Battery which is not impacted by regenerative braking, that's only the HV Battery that might benefit. 12v Battery needs time in "Ready" mode rather than engine/road speed/distance.

[TonyHSD]

The auto off function should have worked and it’s timed at 30 min in ON mode, then message pops in and the car will go sleep again turning off 12v supply. 
For the 12v Battery and the hybrid Battery soc indeed there is no relation. 
The trick with sport mode perjured only helpful if you worry about the high voltage Battery and leaving the car for long , however even with low soc the car should be able to start the engine even after two months or more. 
Another trick to keep high voltage battery topped up when in ready mode is to keep hvac ON and AC on. These drain the high voltage battery and the engine keeps coming on to recharge so the high voltage battery will remain at higher soc. 👍

[Dylanfan]

21 hours ago, Chainbreaker said:

You must be new to the Corolla forum!

No, bought my car in 2019, covered about 25k and never missed a beat. Plus, the car has sat twice for over 3 weeks, still started first push.

 

[Pannett]

Our 12v Battery went below operational voltage today, so the car would not start. Our recent driving pattern was 30 miles last Sunday, 4 miles on last Thursday and Friday. Toyota Assist (AA) came out and added enough charge to start the car, then I went for an hours' drive to recharge the 12v Battery on the AA man's advice. I have two queries: what drains the 12v Battery and is a booster pack a good idea and if so, which model. I'm recharging the 12v battery overnight with a trickle charger in AGM mode, so I'll be interested in the resting voltage tomorrow morning as it's usually been around 11.5 volts. This incident brings back bad memories of our Octavia PHEV, which we dumped after the 4th time its 12v battery dropped below 10v, so nothing except the emergency key worked.

[Dylanfan]

I think I’d be straight back to the main dealer, there must be something draining the Battery! As I said above, never had a problem & now at over 4 years old.

I have noticed that most people on here with this problem have cars that are not very old, strange!!

[ThomasL]

I'm pretty sure the buggy "connected services" on recent Toyotas are causing high Battery drain sporadically when the car is sitting doing nothing (probably stuck repeatedly trying to upload your data to servers).

I have no evidence to back that up, but it makes sense to me based on my experiences with modern technology!

[W1P30UT]

Took delivery of a new car last week, first day 12v warnings, second day 12v warnings, etc etc, now the car is with the dealer.

[Roy124]

On 4/29/2024 at 7:27 PM, Pannett said:

Our 12v battery went below operational voltage today, so the car would not start. Our recent driving pattern was 30 miles last Sunday, 4 miles on last Thursday and Friday. ....

I have two queries: what drains the 12v battery and is a booster pack a good idea and if so, which model.

I'm recharging the 12v battery overnight with a trickle charger in AGM mode, so I'll be interested in the resting voltage tomorrow morning as it's usually been around 11.5 volts. 

1.  The 4 miles each on Thursday and Friday after the dwell Mon-Wed will have probably had a negative effect.

2. A booster pack is a good idea, not just because of any fault in the Battery but you might cause a problem too by leaving lights on etc.  You can get one on Amazon for under £40.  I have had one for some years now and it needs little care as it holds a charge of 75% plus for months.

3.  11.5v is much too low for comfort.  You should expect at least 12v, ideally 12.2v minimum.  The question therefore is how accurate is you voltmeter?

I have measured the Battery voltage on my car using a BM6 monitor, and OBD reader and a digital voltmeter.  None read the same.  The BM6 gives a stabilised reading, the OBD gives an instantaneous readout and the voltmeter tends to show higher than then the BM6.  On my Yaris Cross in 18 months I have had no issues.

[Roy124]

44 minutes ago, W1P30UT said:

Took delivery of a new car last week, first day 12v warnings, second day 12v warnings, etc etc, now the car is with the dealer.

Good move.  How long between order and delivery?  If is was a short time that would suggest the car has been in the pound for some time.

[Pannett]

Thanks for your replies. Roy: I used a cheap plug-in voltmeter plugged into the socket under the armrest, so today I used my 'proper' voltmeter to check and it was about one volt higher ie a resting voltage of 12.6 rather than 11.6v after a trickle charge. This still doesn't explain why the Battery lost charge so that the car wouldn't start. I've ordered a Battery booster pack so in future I'll be able to start the car if it happens again.

[TonyHSD]

Generally speaking the latest models has some DCM issues and this is the major reason for flat Battery. Older models without connected services very rarely to get flat Battery and mostly when not used for very long time or left in acc mode repeatedly etc. 

[Trewithy]

If you want to charge the 12v Battery rapidly drive around with the headlights on.  The cars' electronics recognises there is a drain on the Battery and switches to charging  the Battery at the highest rate.  

[Roy124]

David, that is reassuring your Battery is probably OK.  Just need another voltmeter - best 2 from 3 😁

[AndrueC]

Being the owner of an older Corolla still on its original Battery - do we get a warning if/when the Battery starts to become weak? On non-hybrids slow engine turnover at start was a good clue. Do we get something appearing on the dashboard advising us that it's time to replace it?

[TonyHSD]

1 hour ago, AndrueC said:

Being the owner of an older Corolla still on its original battery - do we get a warning if/when the battery starts to become weak? On non-hybrids slow engine turnover at start was a good clue. Do we get something appearing on the dashboard advising us that it's time to replace it?

I don’t think there are any warnings on display about low 12v Battery. 
I sign for low voltage or weak Battery can be the interior lights, if you keep your door open at dark and let the car depressurised the brake system the interior lights will dim at exactly this moment and then get back to normal. Another sign is central locking, if it’s slow on unlocking locking also will point to weak Battery and then lost of keyless lock unlock for example. 

[AndrueC]

Well that's something. Seems like Toyota missed a trick here. I know from past cars that a dying Battery is noticeable before it becomes a problem. But it seems like for me and other hybrid Corolla owners we could be heading for a problem with little or no warning.

I suppose I'd better start planning to replace my 12v Battery just as a precaution since it's now over five years old 😞

[TonyHSD]

Well, we have been talking about Battery and my one has died today. 🪫🪦

The symptoms above I had for over 3 years now and no surprises it died today after 13.5 years and 273000 miles covered. 
Off to Toyota tomorrow for a new Battery but if they don’t have then will buy just anything of this size and specs, perhaps from Eurocarparts. 
The agm batteries seems been fitted for longevity rather than safety as been discussed here many times before. 
Most new Toyota cars comes with non agm and batteries are often fitted inside the car under the rear seat so I don’t see an issue to have a Bosch standard Battery instead of Yuassa agm. Left on charger for overnight to see if I can use the car to go get new battery or i may need to use a transport.