12v battery maintenance, issues, etc.

[Parts-King]

15 hours ago, Trewithy said:

I have just read motoring journalist Mike Rutherford in Auto Express having a rant at the number of hi-tech state-of-the-art, factory fresh manufacturer supplied vehicles that suffered from dead 12v batteries at the recent British Motor Show simply because showgoers were opening the doors.

Nothing new in that, when new cars are delivered, the dome fuse (interior light) is removed for this exact reason, another journo who is talking complete

[Derek.w]

If you set up a solar panel my system is not disconnected if I just moving the car it just stays on the dash.

Lets hope Toyota at least fit it to the options list if the car is updated.

If your solar panel is pluged into the ODB port then you have to disconnect it if plug is in the way plus this is only a push in socket so I hate for it to move when the car running.

[CPN]

It's never left plugged in whilst driving and that would be redundant anyway so there would be no point. Besides, I need the port for my OBDLink LX so that I can make use of Hybrid Assistant whilst driving (which is more useful).

[smith1194]

On 8/9/2022 at 9:17 PM, taff109 said:

 

if you have any issue related to your car's Battery or any thing you can find experts at royal tech auto

[TruBlu]

My 2021 Yaris had its fourth jump start today in 1 and a half years. Last drive was 5 days ago and did 35 miles. Today no start and Battery reading was 4 volts. Useless, unreliable, £22,000 Toyota Hybrid embarrassment. Toyota's slogan for the new Yaris Hybrid was 'Why Stop?' .... that's if you can get it going in the first place. Would I buy another?..... NO!... If you don't use your car that much don't buy a 'small 12V battery' Toyota Hybrid. How pensioners would cope with this car I don't know.

[Max_Headroom]

59 minutes ago, TruBlu said:

If you don't use your car that much don't buy a 'small 12V battery' Toyota Hybrid. How pensioners would cope with this car I don't know.

If this is such a big problem why haven't they replaced the Battery with a bigger one that will hold a charge longer?

Is there a reason why the car cannot start using the bigger Battery? (Not a hybrid driver just interested)

 

 

[Roy124]

TruBlu, it is a common hybrid issue.  I am a pensioner, I cope.  The problem is for people that don't visit forums such as these or who do not get good advice from their garage. 

The Toyota advice is put the car in Ready mode for an hour a week.  There is other good advice here. 

A different solution is possible with other makes with Kia enabling start using the big Battery. 

Max, a larger Battery weights more.  My garage fitted one 20% larger and it still went flat. 

The best fix is like Kia which enables a charge from the hybrid Battery but that is not an option from Toyota. 

 

[Max_Headroom]

9 minutes ago, Roy124 said:

Max, a larger battery weights more.  My garage fitted one 20% larger and it still went flat. 

The best fix is like Kia which enables a charge from the hybrid battery but that is not an option from Toyota. 

Thanks.

They missed a trick there.

[Cyker]

I think partly the problem is the hybrids use a DC-DC converter to charge the 12v Battery from the big traction Battery, but it charges at a lower current than the maximum you can get from an alternator, so if you drive the car for short periods it never has a chance to put enough charge into the Battery - In that case even a bigger battery wouldn't help.

In normal cars, the alternator can put a much higher load on the engine when the 12v battery is low to charge it faster, but the hybrids seem to have a lower current ceiling.

I've never had an issue but I'm driving most of the day - The car is super efficient so maybe go on a long pleasure drive on the weekend... it won't hurt the wallet anywhere near as much as other cars and it's more fun than watching TV  

[Roy124]

I think the hybrid Battery is a number of small cells arranged in series. A smaller number could be connected to provide a 12v source that could activate the system. 

It maybe the way Kia manage the system. 

I don't know if Tesla uses a 2 Battery system or just one. 

[Derek.w]

My method was to attach a 20 watt solar charger directly to Battery via it own 5 amp fuse.

I do not always unplug it just sometimes if all seats are in use.

[Max_Headroom]

How long does it take to recharge the Battery from 25% by driving the car. 

[funky2nite]

Apologies been following this endless thread for quite some time. just an FYI I'm a daily user for my yaris hybrid - eventually I've grown dubious of the AGM (12V) Battery (but had more than one incident where my kids left stuff turned on in the car - I've installed a roof mount dvd player) - in which case I always jump started it with an other (lying around) 12V lead-acid Battery in parallel. 

My point (hopefully worthy) for sharing here is that you don't need to replace AGM with AGM which costs three times as much - yes they're tentatively taking longer to discharge etc - so to less frequent drivers it might tip the scale. Just for you to know I didn't "risk" it on own initiative, I called up local toyota dealership and the guy suggested so..and I've gone ahead with it and haven't regret it - it's now been close to a yr - for anyone still in doubt.

 

[Roy124]

3 hours ago, funky2nite said:

My point (hopefully worthy) for sharing here is that you don't need to replace AGM with AGM which costs three times as much - yes they're tentatively taking longer to discharge etc - so to less frequent drivers it might tip the scale. Just for you to know I didn't "risk" it on own initiative, I called up local toyota dealership and the guy suggested so..and I've gone ahead with it and haven't regret it - it's now been close to a yr - for anyone still in doubt.

 

Funky, you are quite right, any 12v Battery will work.  But ask yourself why Toyota goes to the additional cost of fitting an AGM Battery under a seat or in the boot when any cheaper wet Battery would do? 

Perceived wisdom on the forum is that a wet battery inside the passenger compartment would be a hazard in the event of a crash. 

 

[Derek.w]

You still can have a problem before your warranty expires, depending on if you have stop start technology fitted and of course use it.

[Derek.w]

Wet batterys are vented to outside ie under the floor via tubing.

So if Battery splits in a crash you thats going to be the least of your problems...if you survive.

 

[Dala]

9 hours ago, Roy124 said:

... any 12v battery will work....

how long ?

[Max_Headroom]

23 hours ago, Max_Headroom said:

How long does it take to recharge the battery from 25% by driving the car. 

As no one answered why not take the car for a short drive every 3 days if it goes flat after 5 or trade it for a non hybrid if you are doing so few miles. 

[mjjferreira]

For periods longer than a week, can't the Battery be disconnected?

i think there is a switch under the hood  that disconnects the 12v Battery.

[APS]

For sure there are several workarounds. But, we're just trying to accommodate for something that clearly appears to be a design flaw.  

Leaving a car unused for up to one month, should not be a problem, providing you have a healthy Battery. We have done this multiple times, with Toyota hybrids too. 

Beyond this period, then yes, even older cars may have trouble getting going again, depending on weather. 

Two weeks is perfectly reasonable to expect without doing anything extra. It's a normal holiday away, or just a quiet time. I'd complain to Toyota and possibly swap the car for something else if your usage pattern repeatedly leaves a flat Battery. It's stress you could do without.

[Mooly]

On 9/23/2022 at 6:29 AM, Max_Headroom said:

How long does it take to recharge the battery from 25% by driving the car. 

Probably a lot longer than you think. If the Battery is 100% healthy and the voltage limited to around 14 volts (and it will be current limited as well) then I would estimate around 8 hours or more. As the charge increases the current falls away and so it takes a lot lot longer to put that last 10% back.

If the Battery is deteriorated then it will take longer still and you will have a lower overall capacity even when it appears fully charged.

On 9/22/2022 at 9:29 PM, Roy124 said:

I think the hybrid battery is a number of small cells arranged in series. A smaller number could be connected to provide a 12v source that could activate the system. 

A good idea in theory but may be problematic in practice. Draining some cells in a series chain makes managing and equalising charge on all the cells much more difficult. The cells in a high voltage Battery are also surprisingly small in capacity, only a few Ah, far far less than the cells in the 12v battery. 

It would also require that the hybrid battery is 'referenced' to ground (chassis, zero volts) which it may well be but isn't necessarily a requirement given the invertor technology.

The real answer to all these issues is better battery management and crucially better management of background consumers of power.

[Roy124]

I wonder how Kia manage it

 

[Max_Headroom]

2 hours ago, Mooly said:

Probably a lot longer than you think. If the battery is 100% healthy and the voltage limited to around 14 volts (and it will be current limited as well) then I would estimate around 8 hours or more. As the charge increases the current falls away and so it takes a lot lot longer to put that last 10% back.

Thats shocking they really do need to have a look at this problem if it becomes well known they are going to lose sales.

[Roy124]

Max, trouble is I think the volume of problems only occurred in 2020 with Covid lock down.  Their Ready Mode advice probably reduced many instances (complaints) and work around such as Battery packs and solar chargers reduced complaints even more. 

Now if the motoring press picked this up and caused widespread criticism of Toyota then maybe they would be moved to get out a fix. 

Just a thought, dies BZ4X have an auxiliary Battery? 

[Graham47]

1 hour ago, Roy124 said:

Max, trouble is I think the volume of problems only occurred in 2020 with Covid lock down.  Their Ready Mode advice probably reduced many instances (complaints) and work around such as battery packs and solar chargers reduced complaints even more. 

Now if the motoring press picked this up and caused widespread criticism of Toyota then maybe they would be moved to get out a fix. 

Just a thought, dies BZ4X have an auxiliary battery? 

What is “the volume of problems” ?
Is there any evidence (outside this forum) that there is a ‘significant’ problem ?
 

From time to time I look in on a Honda Jazz forum.  Not seeing any such issues with their new Hybrid model (and there are a number of ex-Toyota owners posting).

Similarly, nothing on HonestJohn.