12v battery maintenance, issues, etc.

[Auris Geezer]

Also, should the need arise, what is the part number of the prefered replacement Yuasa Battery please?

[Dala]

continuously

[hind]

Once a week IMO.

[CJA2002]

Good evening, everyone

I'm waiting deliver of my first Toyota - Yaris PE - and having waded through the various Battery topics across the internet, I'm still none the wiser, as to whether this remains the issue it was.

I realise the putting it in 'ready' for a week (I may have got that bit wrong!) will help - and I'm certainly expecting to do more than 20miles/week - although there will be some days when it isn't used, at all.

Can anyone please enlighten me, as I'm not looking forward to the buyer's remorse, if the issue is still occurring. 

Ta, muchly! (as opposed the Mutley Battery references)

 

[PeteChat]

I, too have been reading these posts and getting concerned about the 12 v Battery going flat. My Yaris Cross is often standing idle on my drive for a couple of days but so far I have had no problems (car was new at the end of June).

The only thing I have noticed is that the ic engine starts immediately if it has been stood, so maybe it is charging the 12v Battery 🤷🏻‍♂️

Just for peace of mind I bought a jump start pack from Aldi last week, only £30 so no problem if I never have to use it, but always in the boot “in case”.

[CPN]

42 minutes ago, CJA2002 said:

I realise the putting it in 'ready' for a week (I may have got that bit wrong!)

You are. If the car is not used frequently, 1 hour a week will suffice. (in "Ready" mode)

42 minutes ago, CJA2002 said:

Ta, muchly! (as opposed the Mutley battery references)

The Battery manufacturer is Mutlu (Turkish company)

[hind]

@CJA2002 please tell us 

a) your expected mileage per week but in hours instead of the miles

b) what would be the longest uninterrupted parking time, in days

[Chas G]

@PeteChat might be better to keep the jump pack in the glove box or door pocket because if the 12 volt Battery is flat the only door you might be able to open with key is drivers door.

Toyota Savants, please correct me if I have got this wrong.

[PeteChat]

4 minutes ago, Chas G said:

@PeteChat might be better to keep the jump pack in the glove box or door pocket because if the 12 volt battery is flat the only door you might be able to open with key is drivers door.

Toyota Savants, please correct me if I have got this wrong.

As long as I can get into the car I should be able to manually unlock a rear door (??), drop the seat back and lift the false floor of the boot. The jump pack is under the floor but not in the spare wheel well, as in its box with its leads it is too big for all the cabin storage options (a disappointing feature of the car).

[Red_Corolla]

On 9/14/2024 at 7:31 PM, Auris Geezer said:

As a low milage user of my Yaris Cross (1k miles since March 24), in the hope I can mitigate the dead battery issue, I've fitted a CTEK flylead to the 12v battery and a local ground, so I can plug the charger straight in with no faffing.   How often do you think I should give it an overnight charge?

Thanks,

Cheers, Trev.

I only put mine on the charger once a week but I make sure I leave it on until it's full. Half of the problem, IMO, is that the car's own charging system is a bit lilly-livered and fails to top up the Battery sufficiently quickly if you don't spend a lot of time driving. Once the Battery has been properly topped up with a charger, and assuming it's a healthy Battery in the first place, it should be good for several days (needs a new one if not).

[Dala]

nice solution : https://www.youtube.com/watch?v=r84ZPMOtVDY

[John Madden]

After a couple of trouble-free years my Yaris has fallen foul of the 12v Battery problem and I had to be rescued by the RAC. I would like to take the Battery out to charge it up, but I am having trouble getting the plastic cover off the positive terminal. Is there a way of getting off the rear seat base to get at it more easily?

[jthspace]

13 minutes ago, John Madden said:

After a couple of trouble-free years my Yaris has fallen foul of the 12v battery problem and I had to be rescued by the RAC. I would like to take the battery out to charge it up, but I am having trouble getting the plastic cover off the positive terminal. Is there a way of getting off the rear seat base to get at it more easily?

Charge it from under the bonnet.  Remove fuse box lid, flip up the cover over positive terminal. Connect neg to a metal part and positive to the tag.

To remove red cover, you have to slide Battery out, it's done this way as positive terminal is VERY near bare metal and a short here would be disastrous.

[dash]

2 hours ago, PeteChat said:

 

The only thing I have noticed is that the ic engine starts immediately if it has been stood, so maybe it is charging the 12v battery 🤷🏻‍♂️

The 12V Battery isn’t charged by the ICE (directly) but via an inverter powered by the HV Battery. When the car is stationary in ready mode (without the ICE running) the voltage on the 12V Battery reads over 14V. When driving the voltage can drop to 12.7V.

[dash]

1 hour ago, PeteChat said:

The jump pack is under the floor but not in the spare wheel well, as in its box with its leads it is too big for all the cabin storage options (a disappointing feature of the car).

Space beneath the seats. That’s where I keep my jump pack in its box.

[Derek.w]

8 minutes ago, dash said:

The 12V battery isn’t charged by the ICE (directly) but via an inverter powered by the HV battery. When the car is stationary in ready mode (without the ICE running) the voltage on the 12V battery reads over 14V. When driving the voltage can drop to 12.7V.

The 12.7 volts just means Battery is fully charged so the inverter has stopped charging but will start charging when voltage drops or you increase the load by turning on headlights or maybe just operating the parking brake on a vehicle with electric handbrake button when you park.

[Derek.w]

1 hour ago, John Madden said:

After a couple of trouble-free years my Yaris has fallen foul of the 12v battery problem and I had to be rescued by the RAC. I would like to take the battery out to charge it up, but I am having trouble getting the plastic cover off the positive terminal. Is there a way of getting off the rear seat base to get at it more easily?

You can find a lug for charging or jumpstarting without removing the red cover it the black part top right in picture or use the one under the bonnet/engine bay.

 

[yoty2126]

Hi, three times I have had to call out the AA because my Yaris Cross 4X4 hybrid will not start. On each occasion the AA engineer used an engine jump start to get round the problem and then said that the 12 volt Battery was too small for the job in hand. I have now purchased a Topdon jump starter (from Amazon) for the Yaris and carry it wherever I go.

So much for Toyota 'dependability'                                                                                                           

[hind]

43 minutes ago, Derek.w said:

12.7 volts just means battery is fully charged

Only if you don't put our take any current from it. And this is readout observed while driving = during charging. The problem is, the DC/DC converter might lower the voltage before the Battery is fully charged, slowing the process. To fully rebuild the capacity and saturate the electrolyte inside you need days, not half an hour. That's why the charging process is kinda defective, it should be 14.4v alll the time

[CJA2002]

2 hours ago, hind said:

@CJA2002 please tell us 

a) your expected mileage per week but in hours instead of the miles

b) what would be the longest uninterrupted parking time, in days

Mileage hours - I'd say anywhere from 5 - 14hours   (250-800miles/week)

Parking - possibly 3 days/week (unless it's for a long holiday period) 

[hind]

No need to do anything IMO. 

Just be careful with the holiday parking, charge fully with a charger prior to leaving the car, prepare (buy or borrow) jump starter just in case

[CJA2002]

3 hours ago, CPN said:

You are. If the car is not used frequently, 1 hour a week will suffice. (in "Ready" mode)

The battery manufacturer is Mutlu (Turkish company)

Thanks

Yep, I realise it's Mutlu (Mutley is my poor attempt at humour, although it does have an appeal, bearing in mind the issues) although am prepared to go straight to a Yusau, if that's the perceived wisdom

[CPN]

2 hours ago, Dala said:

nice solution : https://www.youtube.com/watch?v=r84ZPMOtVDY

?? Showing what exactly?

[CJA2002]

3 hours ago, PeteChat said:

I, too have been reading these posts and getting concerned about the 12 v battery going flat. My Yaris Cross is often standing idle on my drive for a couple of days but so far I have had no problems (car was new at the end of June).

The only thing I have noticed is that the ic engine starts immediately if it has been stood, so maybe it is charging the 12v battery 🤷🏻‍♂️

Just for peace of mind I bought a jump start pack from Aldi last week, only £30 so no problem if I never have to use it, but always in the boot “in case”.

As it happens, I have just ordered one, likewise for the 'just in case' moment

[Cyker]

4 minutes ago, CJA2002 said:

Thanks

Yep, I realise it's Mutlu (Mutley is my poor attempt at humour, although it does have an appeal, bearing in mind the issues) although am prepared to go straight to a Yusau, if that's the perceived wisdom

You're should be okay as long as you use it regularly, as I think most of the 12v problems affected the earlier builds (My running theory is us early adopters got all the duff batteries that had been left unattended during covid).

I use mine a lot, and it's about 3.5 years old now, but still on the original Battery and haven't had it let me down once. I intend to swap in the higher-capacity Yuasa when it does, and keep a portable jump starter in the car, but haven't needed it yet.

I think part of the problem is a normal alternator puts a lot more current into a 12v Battery when it's down from being left a few days, but the hybrids seem to have a constant current charger so the longer the car is left the longer it needs to charge back up to 100%. (And lead acid batteries really need to be kept as close to 100% as possible for as long as possible for maximum life, unlike e.g. Lithium which wants to be around 50% for maximum life! Ahh the joys of different Battery chemistries...)