12v battery maintenance, issues, etc.

[Cyker]

Yeah your basic stop-start system essentially just adds a higher-capacity 12v Battery and a very beefy starter motor to a normal car. Fancy ones like the one in my old Mk2 Yaris also add a memory for the engine state, so it can immediately resume without having to fully crank the engine (When it worked it was amazingly quick and smooth to restart! Most stop-start cars bog down when they restart but I could immediately launch the Mk2 as soon as it restarted, which was pretty impressive. I'm not sure how much of that was aided by the vast quantities of oil it was consuming though   )

The Battery is usually rated high enough to do 3-4 restarts in a row before the system stops working in order to give a chance to recharge the Battery back up.

It also has to keep the fans and infotainment running for an extended period while the engine is off.

Higher end ones used higher-capacity AGMs but those are expensive so the 'EFB' type was 'invented' as a cheaper alternative. I'm convinced they just took diesel batteries and stuck "EFB" labels on them  

One good thing about stop-start cars is you can often run them in AUX mode for a lot longer than normal cars because of the higher 12v capacity (Definitely a lot longer than e.g. the Mk4 Yaris  )

 

[Mooly]

The Battery not lasting was one of my first thoughts when I got the Auris (2010) but the reality has been very different. I changed the Battery at 11 yrs old simply because according to my very own unofficial tests (of turning headlights and front and rear fog lights together with the heated rear window on) saw the voltage head south pretty quickly after about 10 minutes.

Bear in mind that is a massive current draw and in comparison to what I read on here of batteries not even being able to run the radio for than five minutes would, if done on these batteries flatten them in about 5 seconds...

The Stop/Start is so quick in operation (starter runs for under 1 second to fire the engine up) and you can never beat it with a quick pulling away from stationary. 

The energy taken from the Battery per start is miniscule, under a percentage point per start.

After doing the above test the engine can sometimes 'fail' to start and idle at the first attempt because the loading on the alternator is so high (alternator hard to turn) as it sees a partially discharged but reasonably healthy battery. You have to feather the accelerator for a few moments as it recalculates a new idle setting for the unexpected loading.  

[liquidv]

Hello, I been pondering trading in my current car for the new 2024 Excel Yaris, however been following this forum regarding Battery issues.
Does anyone know if the new 2024 Yaris comes with a different Battery manufacturer which doesn't have this 12v Battery issue?
This is the only thing stopping me from buying yet. Thanks

[CPN]

I know that in my 2024 Yaris Premiere Edition that it is the same Battery as was in my 2020 Launch Edition but you should not let this stop you from considering the 2024 Yaris Excel.

Whether anyone suffers these "Battery issues" (discussed here and affecting most other makes of HEV and EV cars also) depends entirely on their driving habits and how long the car is in "Ready" mode each time it is driven.

If you don't plan to leave the car sitting unused for weeks at a time, you'll be fine...

This was my 2020 Launch Edition Battery...

...and this is my 2024 Premiere Edition battery...

(the eagle eyed amongst you will notice that there is a "1" difference in the part number. Whether this means it's improved or not, I have no idea...)

 

[Derek.w]

5 hours ago, liquidv said:

Hello, I been pondering trading in my current car for the new 2024 Excel Yaris, however been following this forum regarding battery issues.
Does anyone know if the new 2024 Yaris comes with a different battery manufacturer which doesn't have this 12v battery issue?
This is the only thing stopping me from buying yet. Thanks

It all down to the time spent driving or in ready mode and how short the trips are lets say a week of short trips with lots of stops then you need to top up the Battery using CTEK or NOCO mains chargers or a solar charger but note solar may not give you a full charge in the winter months.

Without checking I used a solar charger for the last 10 weeks or more.

[AndyN01]

I have stop-start on the RAV.

I tend to keep cars for many, many years and I turn it off.

I have serious doubts that the "savings" made in fuel are outweighed by the long term damage and subsequent replacement cost of other components such as batteries, starter motors etc. Start-stop-start-stop is a great way to wear out mechanical stuff.

If you're only keeping a car for, say, 3 years on PCP from new I very much doubt it's an issue or worth any consideration. But for something older and looking to be kept for several years?

As for batteries I've had a decent amount of success with using tech that de-sulphates the Battery. I've had batteries that couldn't turn over a 1.6 petrol and rapidly lost charge even when disconnected that have been recovered, hold charge and used in a 2 litre diesel for a few years.

Andy.

[Dala]

I know that driving does not always charge these car batteries.

I can't do anything about the parasitic drain either.

I replaced the 35Ah car Battery with a 44Ah. I regularly recharge and maintain this new car Battery with a solar panel or CTEK charger.
That's all I can do. I have a 45W solar panel in my car this weekend (for testing) and even though the sky is mostly cloudy and the car is not in direct sunlight, the effect is perfect.

[152bobby]

Need I say that all these concerns and worries are absolutely ridiculous for owners of a new modern car !!!

I use my car just about every day and at weekends on a long run, so I "should" be ok.  What REALLY worries me is when I plan to leave it at the airport multi story car park for 6 days and I come back and it's flat and I can't get it to start with my own jump starter and I then would have to call the AA out and inform them that I'm in multi story car park....and all this being at about 1am in the morning.  That's NOT a good scenario ending to a well deserved holiday !!

[Countryside]

1 hour ago, 152bobby said:

Need I say that all these concerns and worries are absolutely ridiculous for owners of a new modern car !!!

I use my car just about every day and at weekends on a long run, so I "should" be ok.  What REALLY worries me is when I plan to leave it at the airport multi story car park for 6 days and I come back and it's flat and I can't get it to start with my own jump starter and I then would have to call the AA out and inform them that I'm in multi story car park....and all this being at about 1am in the morning.  That's NOT a good scenario ending to a well deserved holiday !!

Surely after just 6 days it would be ok ? 

[152bobby]

I hope so, but there's been a few instances when people have came back from holiday to a flat Battery !!  Maybe, I'm just overly concerned about nothing 🥺

[ColinB]

The amount of power required to start the car is fairly small, unlike a normal ICE it doesn't need to turn the engine over. During the dreaded c***d time when I hardly used my C-HR I had to call the AA out once, the next time I had a Battery pack which readily started the car. I've not had any problems with my RAV4, but I keep the Battery pack at the front of the boot where I can reach it from the rear seats if the tailgate won't open. 

[Yaris_Cross]

26 minutes ago, Countryside said:

I come back and it's flat and I can't get it to start with my own jump starter

If the jump pack is full when you leave why wouldn't it start the car?

[152bobby]

8 minutes ago, Yaris_Cross said:

If the jump pack is full when you leave why wouldn't it start the car?

Again, there are a few instances when people could not jump it using their pack.  Whether it was because they were doing it wrong or not, I don't know.

I flattened mine the other week, totally my fault and my pack wouldn't start my car, all I got was Blackpool Illuminations on the dash. But I left the pack connected whilst I got advice from the forum members (about 15 mins)and then when I went back to the car (on my drive), it started!!

PS: I keep my jumper starter FULLY charged at all times and it's kept under the passenger seat.

 

[Yaris_Cross]

24 minutes ago, 152bobby said:

flattened mine the other week, totally my fault and my pack wouldn't start my car, all I got was Blackpool Illuminations on the dash. But I left the pack connected whilst I got advice from the forum members (about 15 mins)and then when I went back to the car (on my drive), it started!!

This can happen with an ICE car if the Battery gets too low leaving the  jump cables connected and the donor car running for a few minutes usually sorts the problem.

[152bobby]

1 minute ago, Yaris_Cross said:

This can happen with an ICE car if the battery gets too low leaving the  jump cables connected and the donor car running for a few minutes usually sorts the problem.

I agree, that's old school stuff.  In my case I only had my jump starter pack connected, no donor car involved.

[Yaris_Cross]

Just now, 152bobby said:

I agree, that's old school stuff.  In my case I only had my jump starter pack connected, no donor car involved.

 

I was trying to point out if the Battery is very low or totally dead the jump pack or cables (in the case of the ICE car) may not get it going straight away and it may need a few minutes to get a bit of juice into the Battery.

[Dala]

IMHO the problem is in the low voltage maintenance setting of the car Battery. It's enough to start the hybrid, but the Battery dies much sooner after that. Low voltage = sulphation. Permanently low voltage = permanent sulfation.  

https://support.rollsbattery.com/en/support/solutions/articles/5964-battery-sulfation

[Paul john]

9 hours ago, 152bobby said:

Need I say that all these concerns and worries are absolutely ridiculous for owners of a new modern car !!!

I use my car just about every day and at weekends on a long run, so I "should" be ok.  What REALLY worries me is when I plan to leave it at the airport multi story car park for 6 days and I come back and it's flat and I can't get it to start with my own jump starter and I then would have to call the AA out and inform them that I'm in multi story car park....and all this being at about 1am in the morning.  That's NOT a good scenario ending to a well deserved holiday !!

I drive every day. 
i parked my prius at heathrow for 3 weeks for an american holiday

i returned and drove home. 
nuff said. 
why so much drama here ?

[hind]

56 minutes ago, Paul john said:

I drive every day. 
i parked my prius at heathrow for 3 weeks for an american holiday

i returned and drove home. 
nuff said. 
why so much drama here ?

I drive every day. I left my 6 month Yaris at home when going for 2.5 week vacation. When I returned, the car barely unlocked itself and died when I turned ignition. 

There was no drama as I was not in a hurry and had everything needed to start the car. It would look very differently if I was in a long term parking in the pouring rain at 1 am. 

So what was your point again? 🙂

[Paul john]

2 minutes ago, hind said:

I drive every day. I left my 6 month Yaris at home when going for 2.5 week vacation. When I returned, the car barely unlocked itself and died when I turned ignition. 

There was no drama as I was not in a hurry and had everything needed to start the car. It would look very differently if I was in a long term parking in the pouring rain at 1 am. 

So what was your point again? 🙂

Like me you said “no drama” and car started. 

[hind]

Car started because I spent an hour trying to charge it's 3V-dead Battery before I took another one from a different car and used it to jump start it old fashioned way. This was no drama only because I knew what I was doing, I was not in a hurry and I was prepared that it would fail as many others had. 

This is a drama in terms of general car reliability, when I take my 16 year old diesel when I'm flying abroad because I know it just would not fail after being parked for a week, two or four. 

[Derek.w]

I disconnected my solar panels today journey just under 200 miles with 3 stops Battery was still fully charged on the return.

Normally I do 10 miles & 3 stops. 

Note the lowest point of the curve the voltage is around 12.5 volts so Battery voltage is exelant.

[dcweather]

My wife's Yari hybrid is 10 years old. The auxillary Battery has failed once - during covid. It hadn't been used for a couple of week and it was in cold weather. But it was nothing to do with being a hybrid. It wa 8 years old and one of the cells had completely shorted. Happens in all cars except the effect is more catastrophic. Not sure why the computer doesn't realise and draw some power from the hybrid Battery just to get it started, doors unlocked etc.
My Yaris Cross is 6 months old. Has been left undriven for two weeks with no issues.

[ShiftedReality1990]

If I may have my very, very useless input? 😂  Seems to be alot of worry with all these newer cars and EV's about their batteries. Especially reading the other replies on here. I feel for you guys and girls. I really do.

 

Unfortunately, I'm too poor to afford a modern car 😭 Perhaps it's not worth owning a newer car? My trusty old reliable 04' Yaris starts over 1st time every time even if I leave the car for a week or 2. I did change the Battery when I obtained ownership back in late 2021. Not had a problem with starting at all in all seasons. Maybe I'm old school but I think modern technology crammed into new cars has serious repercussions when they fail. Especially for the wallet 💰💰 Do you guys and girls who own newer cars feel like the build quality isn't what it was, say a decade ago? Interested in hearing your opinions 👍

[hind]

The car is not only a Battery. And it's not only an engine, too. It's a combination of multiple elements. Nobody can say that older was better - overall. It was better maybe in terms of the ease of maintenance, maybe in reliability, definitely in simplicity. But it lacked of many modern features which make the drive enjoyable. And I'm saying this from a perspective of a guy who drove 2002 Yaris and really liked the car. But I'm not going to idealize it. There were flaws and I'm attaching a photo of one of them. 

There are really A LOT of things I absolutely love in new Yaris, starting with HSD and ending with the remote control from the app. 

But there are also flaws, where the poor quality Battery is a main thing, but there are also others (no light in the back row, clock drift etc)

There are also non-functional changes which most people tend to forget about, like the safety features. You really have better chances to survive the car crash in the modern Yaris than in old one. 

So if you are happy with the current car, there is no need to replace it.