12v battery maintenance, issues, etc.

[Chas G]

@Paul john judging by the few posts on the Prius forum about 12 volt Battery issues, they seem to fair much better than the Yaris. Also you use the car every day which helps.

Many people on here though only use their car for infrequent short journeys which kills the Battery.

 

[Paul john]

3 hours ago, Chas G said:

@Paul john judging by the few posts on the Prius forum about 12 volt battery issues, they seem to fair much better than the Yaris. Also you use the car every day which helps.

Many people on here though only use their car for infrequent short journeys which kills the battery.

 

Very true .but…

i think the issue lies with “active connected services” draining the Battery. All of the limited services the prius has are turned off in my vehicle so i dont see the drain… and 2016-sep 2020 did not have “active connected services” 

perhaps someone with a post 2023 car having the drain could turn off the connected services and see if it continues to drain 

[Chas G]

6 hours ago, Paul john said:

Very true .but…

i think the issue lies with “active connected services” draining the battery. All of the limited services the prius has are turned off in my vehicle so i dont see the drain… and 2016-sep 2020 did not have “active connected services” 

perhaps someone with a post 2023 car having the drain could turn off the connected services and see if it continues to drain 

I confirmed with MyToyota that my Yaris Cross "self charging plug in hybrid" is not connected to the mothership, I disabled the smart entry, turned the light sensor to the minimum setting so they don't come on when it's dull and disconnected the dash cam to minimise the drain on the 12 volt Battery.

I monitored over a few days and all it seems to do is lose charge because  I mostly do short journeys.

The solution which I am happy with is to plug the car into a Ctek charger every time I come home. Even Beagell were happy to fit tails on to the Battery under the back seat and the rear door seal doesn't nip the cable.

[152bobby]

Your comment reminds me of a Battery issue I had on a previous flag ship Google Pixel phone.

I paid close to £1000 for it and their customer support requested that I turned off all the functions which make that phone £1000....they were having a laugh 😂 

All these big manufacturers need to do their R&D and research properly before releasing their products to the public.

I stood my ground and the end result was I had a faulty handset and I got a brand new replacement which worked perfectly.

[calcium]

On 6/9/2024 at 2:10 PM, calcium said:

Ah, wish I'd paid attention to this topic sooner. I've had my Yaris Cross from new in November 2022, and I've done less mileage than I anticipated; my finance is for 8000 per year but I'm only at 8600 after a year and a half. So it seems somewhat inevitable that I'd hit this issue sooner or later. I tried to turn the car back on in Tesco's car park late last night, only to be greeted with a choir of beeps and warnings, everything from 'braking power low' to 'voltage abnormality' to simply 'low battery'. The AA were out in less than an hour and got me going immediately.

I then went for an hour drive - not necessary I know, I could've just left it in Ready. But that's less fun. Anyway I made a late night order of a NOCO battery charger from Amazon which arrived this morning, and I've had it hooked up charging all day.

I think it was probably on the brink earlier this week, but I perhaps delayed the incident with a 200-mile round trip on Tuesday/Wednesday, then a 40min drive Thursday; however last night I was sat in the car at Tesco with the engine off, ventilation off, and radio on for about 10-15mins and I guess that was enough to kill it. I will report back any further incidents after a full charge.

Latest update from me on this:

I've not had any non-start issues since that incident. One thing I'm curious about is what the actual state of the Battery is. From the NOCO charger indicator LEDs it seems I can get it into the 75%+ range (never seen it max out, maybe I need to wait longer) but when I then check the voltage from inside the car using the Vehicle Signal Check Mode it's showing 11.7-12V which implies 30-50% charged I believe. How accurate is the voltage reported in that service menu? I should probably get a multimeter.

In any case I actually also have a NOCO jump starter so I shouldn't get stranded anywhere but I just need to figure out if the Battery is actually healthy now.

[Derek.w]

Hi Callum, best advice just dont use radio unless you in ready mode.

The drawback with a multimeter is you need to unlock the car so you are powering up systems maybe a Battery Monitor is the way to go then you can check without opening a car door or even from inside the house.

[hind]

You can leave the bonnet unlocked and close the car, let it sleep and check then

[Toyo67]

My car is 5 months old and I drive it every day for a short drive to work. In May, my car sat in the garage for 7 days and after that I noticed a phenomenon. The engine needed 10 to 15 minutes of driving to start using the Hybrid Battery and EV driving mode. I noticed that my 12 V Battery is half empty. I measured the voltage and it was 12.1. If the car sits in the garage for 2 days, the voltage is 11.9 V. If I drive the car or leave it on for 1 hour in the parking lot in P, the voltage is 12.5 V, but already the next day it is 12.2  .I was at Toyota 3 weeks ago and they told me to use the car more .Yesterday I measured the voltage and the voltage was 11.9 v ,When the voltage is low, the 100% car needs more time to start using EV mode.What do you think, is this 12v Battery for replacement?  

[hind]

I'd charge it with the external charger first. And not for an hour or something, overnight would be perfect. If this doesn't help then it probably lost it's capacity and may fail if you leave the car unused for more than a week.

[Dala]

6 minutes ago, Toyo67 said:

What do you think, is this 12v battery for replacement?  

YES

[152bobby]

Following this subject, can anyone recommend a reliable non singing and dancing cigarette plug in Battery voltage meter/monitor?

I'd like to try one in the cigarette socket in the boot.

Am I correct in thinking that this should always show 12v or above for a well managed Battery?

All I'm after is the Battery voltage nothing else 👌👍, something like this...

12-24 V LED Cigarette Lighter Car Battery Tester Voltage Display Voltmeter https://amzn.eu/d/08z97gfD

 

When I connect my battery trickle charger it shows the voltage in the photo more or less immediately and then flips to FULL. Does this mean I have a decent battery ?

[Mooly]

19 hours ago, 152bobby said:

When I connect my battery trickle charger it shows the voltage in the photo more or less immediately and then flips to FULL. Does this mean I have a decent battery ?

 

Not necessarily. It shows the terminal voltage and will be showing 'full' because the Battery is drawing very little current.

For a healthy Battery that would be correctly showing showing fully charged while for a deteriorated Battery the same conditions are still met, the same voltage is present and the same small current draw occurs.

A pint pot that is full to the brim with water is what it says on the tin... full. 

Now fill that pot full of pebbles and then fill it with water. Its still full but contains much less of what we want. Its the same for a healthy vs deteriorated battery.

The only true way to get an idea of how healthy your battery is would be to do a known discharge test on it over a considerable time period by turning on electrical consumers of known current draw and seeing how it holds up under load.  

[Chas G]

@Mooly - I like your analogy. Discharge test is the only way to show whether its a good Battery.

[152bobby]

3 hours ago, Mooly said:

Not necessarily. It shows the terminal voltage and will be showing 'full' because the battery is drawing very little current.

For a healthy battery that would be correctly showing showing fully charged while for a deteriorated battery the same conditions are still met, the same voltage is present and the same small current draw occurs.

A pint pot that is full to the brim with water is what it says on the tin... full. 

Now fill that pot full of pebbles and then fill it with water. Its still full but contains much less of what we want. Its the same for a healthy vs deteriorated battery.

The only true way to get an idea of how healthy your battery is would be to do a known discharge test on it over a considerable time period by turning on electrical consumers of known current draw and seeing how it holds up under load.  

So when the AA man (sorry, person), turns up and says your Battery is knackered, what does he do to determine that, that we cannot do !!

I once went to a garage years ago and was told that my Battery was knackered and needed replacing, I then immediately after, went to another garage and they said it was fine !!!🥺🥺🥺😂

[hind]

10 minutes ago, 152bobby said:

says your battery is knackered, what does he do to determine that, that we cannot do !!

He usually connects the tester to check the voltage and max current the Battery can provide. When it doesn't start, the voltage is probably down to around 9-10V or lower. These two parameters are enough to start the typical car. 

The usable capacity and self discharge rate are different. They are not quick measurable like the ones above and usually require few days of testing (charging fully, resting, measuring discharge capacity using 1/10C load, another charge). 

We (the owners) can do both, but we either don't have required tools, knowledge or time needed to perform these diagnostics. 

Dealer doesn't have them either so they rely on the tester readout. Voltage OK, crank amperes OK, good to go!

This is usually the reason why the cars that need to be jump started and drive straight to the dealer look fine when they arrive. During the short trip, crippled Battery charges to full and the voltage after a while looks ok. But you can drive back to your home, leave the car for the night and it may not start again unless jump started - and the cycle repeats. 

[Mooly]

17 minutes ago, 152bobby said:

So when the AA man (sorry, person), turns up and says your battery is knackered, what does he do to determine that, that we cannot do !!

It depends what test equipment he has and uses or he may just make a decision based on what he observes.

Modern test methods use 'impedance testing' which tries to look at the internal resistance of the Battery and make a determination from that but I don't believe that method is totally reliable in giving a true indication of capacity.

To test it properly needs the charge voltage and corresponding current to be monitored. If you can put 14.5 volts across the terminals and see a current of only a 100 or 200ma flow then the Battery is assumed fully charged. From that position you then have to do a discharge test to get a good idea of capacity. A Battery that is deteriorated (low capacity) can hold up well initially but then the voltage falls away suddenly long before anything like its total capacity has been used.

Often one or more cells (there are 6 each of 2 volts connected in series in a 12 volt car battery) can be worse than the others and these can start 'gassing' or bubbling as discharge progresses until finally they begin to be reverse charged by the other cells that are in better shape. In other words the faulty cells voltage falls quicker than the good ones and actually passes through 0 volts and begins to become negative across that particular cell.

Same thing happens with any battery pack made up cells whether a car battery or ordinary off the shelf dry batteries (AA's etc or rechargeable like NiCad and NiMh cells. When they are in series the first to run flat gets reverse charged from the others in the pack and that damages them.      

[Dala]

According to the service and the dealer, it happens that the Battery runs down during repairs and service. The service then charges the car Battery without your knowledge. This happens quite often with these car batteries (35Ah). They do not inform the owner that the Battery has been discharged. You can only tell by the recording device, which many owners don't have.

[Dala]

driving to recharge your car Battery 🙂

about recharging by driving :  

https://www.interstatebatteries.com/blog/how-long-you-have-to-drive-to-charge-your-car-battery

[dash]

In the case of a Yaris hybrid, while the car is stationary (with gear lever at P) and in READY mode, the Battery will hold 14V and will then drop to around 12.8V while driving. So it receives a faster charge while parked in your driveway compared with when driving when it receives a gentler charge. 
No alternator in the hybrid. Doesn't need one 😉

[hind]

41 minutes ago, Dala said:

https://www.interstatebatteries.com/blog/how-long-you-have-to-drive-to-charge-your-car-battery

Sorry but lot's of nonsense there. And I'm not even talking about hybrids which work differently. For example 

Quote

Your engine needs to be running at highway speeds for the alternator to start seriously charging the battery.

That's not true. You can be stationary, just the RPM should be high enough for the alternator to produce enough power so the voltage regulator can control the charging process with maximum power allowable. So basically driving anywhere with potentially lower gear than normal should be enough - if your car allows that (manual transmission or automatic transmission with selectable gear).

[Mooly]

I will second that ^

The alternator running at idle speed should just about cope with a normal 'full load' which is headlights, wipers, heated window + ventilation A/C and radio etc. The voltage might be down to around 13v or so at that current draw (most conventional cars will 'idle up' increasing the idle speed by a 100 rpm or so to compensate) but 13v still ensures the Battery never enters a discharge condition.

Once the engine speed is above idle by even a small amount the output of the alternator is much higher with plenty of current available for charging if needed.

Also remember a typical Battery draws ever decreasing charge current as it charges and this is one of the major factors contributing to all the problems we see. It is the way this technology is.   

[flamarro]

Hi guys

I finally got my lovely Yaris Cross Square collection. ( Portugal Model ) Image from the dealer 1 hour before I got there 😁

I've got my Noco GB20, my digital led voltmeter, and all your advices from getting the best use of the little 12v Battery. One day after getting the car  

 I will drive like I use to drive and see what happens and if this values change.

 

 

[Yaris_Cross]

12 hours ago, Dala said:

driving to recharge your car battery 🙂

about recharging by driving :  

https://www.interstatebatteries.com/blog/how-long-you-have-to-drive-to-charge-your-car-battery

Is that for ICE cars 12v batteries and therefore doesn't apply to hybrids?

[Dala]

4 minutes ago, Yaris_Cross said:

Is that for ICE cars 12v batteries and therefore doesn't apply to hybrids?

This is my measurement on the Toyota Yaris Hybrid

[Yaris_Cross]

3 minutes ago, Dala said:

This is my measurement on the Toyota Yaris Hybrid

I meant the info in the link you posted