Another Battery post

[paddywack1878]

On my last visit to Mitchell Skoda Chester 2 weeks ago i mentioned the battery at rest is showing 12.2 volts  10 minutes after a very long drive, And they done a full test on it and a test drive and they told me its working normal, I hooked it up to my smart charger and from 12.2 volts it only takes an hour to say its fully charged but soon as its unplugged its back down again to 12.1-2v, and when i press the start button the volts drop to 7.8v- 9v......so the question  are these EFB batteries a load of rubbish or is this battery behaving normal?

[JBD1974]

Option 1 for my vote. My 2 year old estate just failed to start. 

[MarkyG82]

Voltage on cranking will drop quite a bit (sometimes below 9v) 12.2v with no load or charging doesn't sound off to me but it's been a while since I checked off-load voltage. What is it at when engine is running?

[J.R.]

There will be considerable load if the voltage is taken with the bonnet open, all the systems will be awake and there is likely to be 200ma or more current draw, if you remove a terminal its likely to give a big beefy flash.

 

12.2 is not a new battery but neither is it knackered, best to have it tested with either a load tester or an electronic battery tester while disconnected from the vehicle.

[Kenny R]

As above you really need to check the resting voltage when all systems have shut down.

12.2 v does not indicate a duff battery, bearing in mind the smart alternator/ micro hybrid charging system only charges the battery to around 80% to allow capacity for the alternator space to dump charge on the overrun.

 

Edited 9 December, 2021 by Kenny R

[paddywack1878]

8 hours ago, MarkyG82 said:

Voltage on cranking will drop quite a bit (sometimes below 9v) 12.2v with no load or charging doesn't sound off to me but it's been a while since I checked off-load voltage. What is it at when engine is running?

It goes up and down when i am driving from about 13v to 15v .

[MarkyG82]

That's sounds normal to me so not an alternator issue.

[paddywack1878]

8 hours ago, J.R. said:

There will be considerable load if the voltage is taken with the bonnet open, all the systems will be awake and there is likely to be 200ma or more current draw, if you remove a terminal its likely to give a big beefy flash.

 

12.2 is not a new battery but neither is it knackered, best to have it tested with either a load tester or an electronic battery tester while disconnected from the vehicle.

Readings are always taken with everything closed and shut, I think the car was parked on a forecourt for a 10 months because of covid, that couldn't have  been to healthy for these type of batteries, But that's just a bricklayers opinion not an auto sparks,  And you're second point skoda connected it up to all there specialist equipment and just said its normal.

[paddywack1878]

8 minutes ago, MarkyG82 said:

That's sounds normal to me so not an alternator issue.

It does seem to have a life of its own...the voltage that is,  i am just used to normal old school car batteries to much i think.

[MarkyG82]

They do fluctuate depending on the charge cycle required. Dropping to 13 is fairly normal and up to something like 14.8 I think for charging. If you're genuinely seeing 15 then the alternator sounds extra healthy 😀

[paddywack1878]

8 hours ago, Kenny R said:

As above you really need to check the resting voltage when all systems have shut down.

12.2 v does not indicate a duff battery, bearing in mind the smart alternator/ micro hybrid charging system only charges the battery to around 80% to allow capacity for the alternator space to dump charge on the overrun.

 

Kenny i have done that and the readings are what i've mentioned.  i don't have much confidence in this type of system, just hope we don't get seriously low temps in the next few months. 

[paddywack1878]

3 minutes ago, MarkyG82 said:

They do fluctuate depending on the charge cycle required. Dropping to 13 is fairly normal and up to something like 14.8 I think for charging. If you're genuinely seeing 15 then the alternator sounds extra healthy 😀

I have seen 14.9v a lot but 15v is not uncommon, but as soon as its shut off it drops to 12v or 12.2v.....time will tell where this is going i suppose, I have the skoda breakdown number saved in my phone just incase.

[J.R.]

1 hour ago, paddywack1878 said:

, I think the car was parked on a forecourt for a 10 months because of covid, that couldn't have  been to healthy for these type of batteries,

 

Very incisive, I bet it went several months before being started and they used a booster pack when they found it was flat, it will have definitely reduced its capacity and life.

 

Not much you can really do about it though, they will always say that it tested OK regardless.

[paddywack1878]

23 minutes ago, J.R. said:

 

Very incisive, I bet it went several months before being started and they used a booster pack when they found it was flat, it will have definitely reduced its capacity and life.

 

Not much you can really do about it though, they will always say that it tested OK regardless.

jR I suppose every car on all these dealership forecourts for months on end all have the same problem.

[BigEjit]

Any battery will last 10 years or more of it is looked after. Like you say, 10 months lay-up for any car with the battery connected will kill it. Even if it is recovered with a recharge, years of useful life expectancy can be wiped out. 
 

After 6 weeks sitting still, it will be needing a recharge if left connected. In comparison, it can last 12+ months before requiring a recharge if disconnected.  (Checked once every 3rd month). 
 

AGM will go longer discharged and recover better than EFB but it’s not best practice to leave batteries discharged for a few days at a time. 
 

Even new cars are at risk of this if a battery care process is not in place and followed. 
 

Voltage does fluctuate on micro hybrid Stop Start systems. It’s a result of the alternator switching in and out for emissions savings. But if Stop Start function is rarely available during long drives, the battery is past its best. 

[Berisford]

10 hours ago, BigEjit said:

Any battery will last 10 years or more of it is looked after. Like you say, 10 months lay-up for any car with the battery connected will kill it. Even if it is recovered with a recharge, years of useful life expectancy can be wiped out. 
 

After 6 weeks sitting still, it will be needing a recharge if left connected. In comparison, it can last 12+ months before requiring a recharge if disconnected.  (Checked once every 3rd month)
 

AGM will go longer discharged and recover better than EFB but it’s not best practice to leave batteries discharged for a few days at a time. 
 

Even new cars are at risk of this if a battery care process is not in place and followed. 
 

Voltage does fluctuate on micro hybrid Stop Start systems. It’s a result of the alternator switching in and out for emissions savings. But if Stop Start function is rarely available during long drives, the battery is past its best. 

Hmmm……..I’m getting a little concerned about all those motors in the field to the north east of Prague, not least mine that’s been waiting for chips since the first week in August. I wonder if they disconnect’em?

[Q102]

I've had the same issues with my 718 Boxster, easier to see the battery volts as it's shown on the dash display.

I'd been trying to charge it over last winter with a CTEK , but charger was dropping out, wouldn't go to charge/maintain.

Car would start okay, volts with ignition on was 12V and dropping when started. It would generally sit at over 15V when driving.

It turned out that the -ve connection between Ctek & chassis was high resistance so CTEK was getting a bit confused!

 

Remade the chassis connection and now all okay, no further issues with the battery a year on. Car isn't used a great deal sadly but I do notice if the battery is a bit low the alternator voltage is higher than normal.

 

I'd keep it charged for a while, loads on the batteries are high at this time of year so probably struggling to keep topped up. Remember to use a chassis earth not the -ve post of the battery!

 

As KennyR has said, these cars disconnect the alternator when it thinks it's got enough charge. I remember when I first got the 718, I was driving down the M1 and the battery voltage was dropping😲 A bit further down the road, the rain came down- so lights & wipers on - then the charge voltage went back to normal 13-14V

[Patent]

9 hours ago, Berisford said:

Hmmm……..I’m getting a little concerned about all those motors in the field to the north east of Prague, not least mine that’s been waiting for chips since the first week in August. I wonder if they disconnect’em?

It's not in their interests to be fitting two batteries to every car sold, they'll be disconnected I imagine. Although I can assure you that your wiper blades will be knackered when they arrive after sitting in the baking sun all summer, as mine are!

[J.R.]

They won't have known how long they would be standing or expected it to be so long.

 

Until the PDI inspection the ECU is set to Transport Mode which minimises the standby consumption, it may even reduce it to zero and require the key to be used manually to open and start the vehicle.

 

Probably never been a requirement until now.

Edited 10 December, 2021 by J.R.

[Patent]

That's interesting knowledge! Makes a lot of sense

[paddywack1878]

On 10/12/2021 at 08:15, Berisford said:

Hmmm……..I’m getting a little concerned about all those motors in the field to the north east of Prague, not least mine that’s been waiting for chips since the first week in August. I wonder if they disconnect’em?

I wouldn't think so mate, they would have to have a team of people constantly going around doing it, they will just be left till the day before there shipped out and then someone will give them a bit of a charge.

[Nick_H]

I'm getting a little twitchy about my battery now at over 6 years old ... Do I make a pre-emptive battery replacement or wait ........ I've never used Stop / Start I'm convinced it kills batteries 

[paddywack1878]

23 hours ago, Nick_H said:

I'm getting a little twitchy about my battery now at over 6 years old ... Do I make a pre-emptive battery replacement or wait ........ I've never used Stop / Start I'm convinced it kills batteries 

nick i am the same ...always switch it off.