12v battery maintenance, issues, etc.

[Jasper.]

I fitted the Yuasa replacement this afternoon and then out of curiosity I tested the original Battery that I had removed. 

Interestingly,  i had fully charged this Battery yesterday after it failed to start the car , showing only 8 volts. I then went out for a local drive before swapping the batteries , this is what shows on my Battery tester after removing the battery. 

[hind]

The meter doesn't measure the capacity and that's where the Battery fails in our use case.

When I replaced the Battery in my other (diesel engine) car, it's capacity dropped from designed 64Ah to something around 3Ah = 5% (measured by charging from 11.8V with the engine barely starting to 14.4V). Yet when I took it to the Battery shop when they swapped it with the new one, I asked them to measure the old one. Surprisingly, it was in good condition according to the measurements. It still managed to produce around 320 Amps (should be 640A). That's why it was able to start the diesel engine, but it didn't matter for me because leaving it for a week meant that it won't start again because of the ridiculously small capacity.

[Roy124]

4 hours ago, skidlid said:

So its +ve to the pin/contact and -ve to the alternator bracket (think that is hat is shown for jump starting)?

No alternator.   Any bare metal though there is a recommended point if your charger lead can reach.   Obviously you can lengthen it.

[Primus1]

I’m thinking of buying a jump starter just in case, I have a ctek smart charger but, I’m thinking if I ever need to quickly get it going, such as for work, I need to be able to jump start it, I had a look in Halfords but am not sure which to get as they have a few different options, anyone know which is best..?

[Derek.w]

You can hook up positive lead to this see red blade that I have opened under the bonnet for negitive wire just use a strut bolt or engine mounting bolt of your choice.

Connect first before switching on your charger.

[Cyker]

52 minutes ago, Primus1 said:

I’m thinking of buying a jump starter just in case, I have a ctek smart charger but, I’m thinking if I ever need to quickly get it going, such as for work, I need to be able to jump start it, I had a look in halfords but am not sure which to get as they have a few different options, anyone know which is best..?

I just got the cheapest one they had on sale (Noco GB20) as the hybrids don't need the high cranking amps the higher models provide.

If you can find that one someone mentioned above that uses lithium iron phosphate that'd be better tho', as I found out afterwards the Nocos use the normal lithium cells that are of the flamey variety, and given it's going to live in the car in summer I am a bit concerned about that...!

 

[Chas G]

18 minutes ago, Cyker said:

 

If you can find that one someone mentioned above that uses lithium iron phosphate that'd be better tho', as I found out afterwards the Nocos use the normal lithium cells that are of the flamey variety, and given it's going to live in the car in summer I am a bit concerned about that...!

 

They say there is a silver lining to every cloud 😀

[hind]

46 minutes ago, Cyker said:

 I found out afterwards the Nocos use the normal lithium cells that are of the flamey variety, and given it's going to live in the car in summer I am a bit concerned about that...!

 

Just like your hybrid Battery which also lives in your car in summer 😛 BTW why not keep it at home? The Battery issue will happen after some time of not using the car. This either happens when you can't drive and the car is sitting at your place (so the starter can be taken from home) or you left it on the parking lot of the airport / harbour when you expect to have the issue and can throw the starter into the trunk 🙂

[Cyker]

Hmm, good point, I'm not actually sure what the hybrid battery's chemistry is! TBH it's a relatively minor concern as it won't be exposed to direct sunlight, and if it was I would have returned it and gone looking for that Lidl one, but some slight paranoia is always going to be there as I've watched too many videos of pouch cells turning into fireworks!    

I was going to keep it in the house and plugged in so there's no way it wouldn't be ready, but I just know when the 12v goes it'll happen away from home because that's the sort of luck I have.

Also, at least one person here had it die on them when they went to drive home from work, and had to call the AA, and because mine isn't giving me any trouble at all right now, I have a feeling when it does happen it'll be very sudden like that!

 

[Chas G]

I really dont understand :-

I fully charge the Battery, drive 8 miles to Watford which takes about 20 to 25 minutes. Do my shopping and drive 8 miles home. Check the voltage and it has dropped. If I worked in watford doing the 16 mile round trip every day, my Battery would go flat.

I put the Battery on charge and it goes to 4 lights on the ctek in a minute or 2 and fully charges in an hour which makes me think there is nothing wrong with my battery.

If i put it in ready mode for a couple of hours it fully charges.

Lots of people round here drive a mile or 2 to the tube station every day, do their weekly shop locally at sainsburys/tesco/waitrose etc on Saturdays and maybe a few miles on Sundays. Perfectly normal motoring for people living on the outskirts of London.

The only time my battery voltage has gone up is when I drove about 60 miles without stopping. 

[hind]

What is the charging voltage when you drive (or the car is in Ready mode)?

[RickyC]

According my voltmeter connected in the 12V plug is usually between 14 and 14.3 V if Battery is low and needs charge.  Then it drops to around 13V. 

[skidlid]

Just been and got the Fabia out of the garage. Battery is the original 6 year old EFB that was charged late last week and used once since. Plugged the digital volt meter into the ciggy socket and it showed a remarkably low 11.8 volts. I have always been told any less than about 12.5 volts the Battery is knackered and will not start a car. Pressed the start button and car bursts into life, volts dropped to 10.5 during startup. By the time I was out of the garage the meter was reading 14.8 volts and when I turned the car off it dropped back to 12.2 volts.

Meter is accurate but based on batteries of old this one is breaking the laws of science.

[hind]

6 minutes ago, skidlid said:

I have always been told any less than about 12.5 volts the battery is knackered and will not start a car

They lied to you 😛 I successfully started diesel with 11.8V (although it hesitated a little). I also started Yaris 1.0 with a Battery discharged to 9V (and 5 amp charger connected at the same time). The thing is, voltage of less than 12V begins the sulfation process which lowers the max power output and capacity of the Battery. It also means that the density of the electrolyte of 1.10 g/cm3 (which corresponds to voltage of around 11.7V) means that the Battery can freeze and burst in -9 oC so if we live in the north when we can expect such conditions, having discharged battery means risking damaging it from expanding ice inside. And nobody wants to have spilled pool of sulfuric acid because of the burst battery case 😜

28 minutes ago, RickyC said:

According my voltmeter connected in the 12V plug is usually between 14 and 14.3 V if battery is low and needs charge.  Then it drops to around 13V. 

There is a theory around other Yaris forums and groups that this is too low to charge the battery effectively. It should be 14.4V if the temperature is around +20 oC and should be compensated to even higher value if the temperature drops. There was a case when a guy drove his Yaris non-hybrid car everyday, doing 100 miles or so and despite that his battery failed after 2 years. So it was either faulty (I'm opting for this as this was supposedly Mutli) or the charging process was incorrect, charging the battery with not enough current to rebuild the charge. 

But any voltage higher than the battery voltage means charging it, even slightly, so no idea why this:

11 hours ago, Chas G said:

I fully charge the battery, drive 8 miles to Watford which takes about 20 to 25 minutes. Do my shopping and drive 8 miles home. Check the voltage and it has dropped.

has happened. Apart from the scenario that the battery didn't stabilise yet after charging. 

[Chas G]

1 hour ago, hind said:

What is the charging voltage when you drive (or the car is in Ready mode)?

In ready mode and charging the voltage is 14.5 volts ish at the red connection in the fuse box under the bonnet.

[skidlid]

24 minutes ago, hind said:

They lied to you 😛

Well I know from experience with one of our cars (had it 31 years now) that when the Battery becomes unable to hold at least 12.5 volts when standing the car will not start and its new Battery time. Car stands 5 months a year with the Battery off and I charge it every month or so, originally used a Gunsons smart charger since the car had a Gel battery (that's another story, never got more than 2 years from one) and for the past 4 winters a conditioner. The Gel and wet cell batteries were originally about 330 to 350 CCA but the 3 more recent ones have been in the region of 500 CCA (all have been 063 type batteries) and these have lasted 6 years at least.

The 11.8 volts the Fabia's battery showed this morning suggests its only 30% charged and should not start the car but that is how its been since the start of the first lockdown when I kept one eye on the battery. Seems from the Skoda forum that voltage is normal but not yet seen an explanation why or had conformation that the chemistry of an EFB gives a different voltage. The 10.5 volts during cranking is perfectly normal and that is what we get with a healthy battery in the old car. But when the battery voltage drops to 12.5 or less in that car the cranking volts fall to 10 or less and it struggles even to turn over. Hate to think what it would do with only 11.8 volts.

[skidlid]

Just found this on the Varta website for wet cell batteries, pretty much confirms what I have been told in the past.

Does not apply to EFB and AGM which are more complex to test which suggests there is more to it than simple voltage like a wet cell Battery.

 

[Dezzer21]

Wife’s 10 year old Picanto stood out in all weathers has never failed to start (touch wood) only does short journeys.

[skidlid]

2 hours ago, Dezzer21 said:

Wife’s 10 year old Picanto stood out in all weathers has never failed to start (touch wood) only does short journeys.

Well done, just proves what a load of idiots populate the Kia forums. When we had a Ceed some posters were forever telling us what rubbish Kia's were especially the batteries. We sold ours at 5 years old still on the original Battery so yours is a clear winner but at the same time we had a Micra which we sold at almost 8 years old still on the original Battery (actually it was still on the original everything except for a front spring).

[Cyker]

You tend to find the lower-tech and older the car, the less trouble it has with 12v Battery issues because the off-line draw is so low. I think my Mk1 diesel was still on its original Battery judging by how dirty it was  

From what I've gleaned, the biggest draws in the Toyota hybrids are the keyless entry system, the brake booster, and the internet connectivity.

I reckon the brake booster is a significant culprit - It's something most petrol cars don't have to deal with, as they just use engine vacuum, but the hybrids need an electric vacuum pump which draws a lot of current from the Battery when it runs, and it takes a while to put that charge back in, which is partly why short use can cause problems.

 

[Dala]

I measured with a clamp meter in the summer
consumption 9.48A - opening the passenger door
consumption 9.60 A - opening the driver's door
consumption 15.66A - starting READY mode (engine start)

if 12.2V means 50% of the car Battery capacity, then it is interesting that the car start at 17.5A  (reduction of capacity in winter, max charging by driving 80%, age of car Battery....)

  

[CPN]

8 hours ago, Dala said:

I measured with a clamp meter in the summer
consumption 9.48A - opening the passenger door
consumption 9.60 A - opening the driver's door
consumption 15.66A - starting READY mode (engine start)

if 12.2V means 50% of the car battery capacity, then it is interesting that the car start at 17.5A  (reduction of capacity in winter, max charging by driving 80%, age of car battery....)

  

Surely there's something a bit amiss with the scaling factor there Dala? (decimal point one place to the left perhaps?)

[Dala]

The smallest consumption I measured was 70mA
Yes, I know, clamp meters are not very accurate
especially for small values it can be less accurate
but for higher ones it will give me some value

ADD : I forgot, a new and good Battery should give a maximum of 264A

[dannyboy413]

On 1/2/2024 at 5:35 PM, Max_Headroom said:

I think i will pass, my little 12v socket meter tells me all i need to know 😉

 

@Max_Headroom can you give me a link to that unit please Max?

[dannyboy413]

@Max_Headroom Cancel that Max - I am presuming that is is the one -

https://www.amazon.co.uk/dp/B0BDRN8MPH/ref=sspa_dk_detail_1?psc=1&pd_rd_i=B0BDRN8MPH&pd_rd_w=1yyFO&content-id=amzn1.sym.67430c1d-696a-45e1-be6b-972213775cc6&pf_rd_p=67430c1d-696a-45e1-be6b-972213775cc6&pf_rd_r=N2ZSW5MJFAW150Y10T09&pd_rd_wg=qImms&pd_rd_r=6be082b0-71d9-414d-81b8-9ccc428b7147&s=electronics&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWwy

 

Does it work okay?