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Discussion Starter · #1 ·
Hi Kia,
I have a few questions regards battery discharge on my 2018 Optima s/w .
1) If I inadvertantly left car unlocked , would the battery go flat upon trying to use 6 days later ?
2) Can I take car to dealership to be checked under warranty for possible electrical fault such as parasitic drain, or if an update is required ?

Thanks in advance.
Barry

ps car has 22,000 miles clocked, and I do not use the stop start function.
 

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Hi & Welcome.

You could take it to dealer for investigation. But be aware there will be a charge for this & if nothing is found you will have to pay for it.
Not 100% sure but being unlocked could leave ACC side of the system live. Thus infotainment system would still be live as would anything connected to 12V socket or USB ports.

Personally new battery & keep a eye on it & remember to lock car (not that you will forget again) 🤦‍♂️
 

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Hi Kia,
I have a few questions regards battery discharge on my 2018 Optima s/w .
1) If I inadvertantly left car unlocked , would the battery go flat upon trying to use 6 days later ?
2) Can I take car to dealership to be checked under warranty for possible electrical fault such as parasitic drain, or if an update is required ?

Thanks in advance.
Barry

ps car has 22,000 miles clocked, and I do not use the stop start function.
If you had a parasitic drain issue I would have thought it would have shown up earlier than this. It is possible that if your car is left unlocked there may be some electrical systems left live but without detailed knowledge of the electrical systems you wouldn't know and the dealer may not be able to help either. 3 years and 22k miles is not a very long life for a battery so I would be inclined to just make sure its fully charged with a Ctech or similar charger (make sure its the right charger for the battery) if you have one and then just monitor things. If you haven't got a charger you will need a significantly long run to fully charge the battery otherwise its likely to stay in a part charged state which is not particularly good for the battery.
 

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Can I go out on a limb and suggest it may be the battery has just died? It does happen and a 3-4 year old battery is getting near the end of it's life. Perceived wisdom is 4-5 years life expectancy with good maintenance.
 

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Can I go out on a limb and suggest it may be the battery has just died? It does happen and a 3-4 year old battery is getting near the end of it's life. Perceived wisdom is 4-5 years life expectancy with good maintenance.
You might easily be right as might @iooi but there are other things that might have caused the battery to go flat and as batteries aren't cheap these days, particularly if they are AGM, I would be looking to confirm that it is the battery before shelling out for a new one.

The problem is determining whether a battery needs replacing is not always straightforward but the starting point should always be a fully charged battery.

I'm not an expert on this subject but there are some fairly simple tests that we can do provided if we have an appropreate battery charger and a cheap volt meter. A fully charged battery should read 13v+ (I would hope for 13.5v or more) 30 minutes after the charger is disconnected. If the car is then left standing for a further 12 hours or more it should still read 12.5v+. Anything under 12v suggests that the battery should probably be replaced or there is some sort of parasitic drain. However, try not to do this in very cold conditions as you would expect lower voltages which might lead you to the wrong conclusion.

If the battery then still goes flat I would check that it is being charged correctly by the alternator. In the 'old days' 🙄 this was a simple matter of checking the alternator was kicking out 13.5v at say 1000rpm raising to 15v as the revs increase. But I'm not sure how valid these tests are these days if the car is equipped with what's often called Smart Charging which seems to be good for mpg but is not good for battery life, but that's another subject all together 😳
 

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Discussion Starter · #6 ·
Thanks for your replies guys, much appreciated.
My OP was probably a little brief, so will attempt to ( briefly ! ) add a more thorough list and timeline of events.

Car was unused for 6 days pre xmas, battery totally flat and showed around 5 volts on multimeter.
Bought a smart charger, and charged to 12.8 after approx 48 hours. Refitted battery, reading just over 14 v with engine running.

Next morning reading dropped to 12.6
Next day dropped to 12.4
next day 12.2
Since given car a couple of run outs, one of 2 x 30 minutes, reading back up to 12.6, yesterday,.
Reading this morning 12.2, used to go shopping today, reading now 12.47.

So IMO the alternator is charging, but battery not holding for one of 2 reasons; dud battery or parasitic drain.
I don`t feel confident in attempting to test for drain, so booked in at kwik fit for free battery test tomorrow, at least they give a print out, unlike Halfords yesterday ,who told me they had ordered a new battery and when did I want it fitting, BEFORE doing the so called test ! ( which took 15 seconds without starting engine, and stated the battery was a ok ?! )
If it is a duff battery, which I`m now hoping it is, has anyone dealt with Advanced Battery Supplies in Stockport, who can send a Bosch s5 a11 80 v AGM for £165 compared to £299 at Euro car parts and £240 from The AA Battery Service ! ?

ATB
Barry
 

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Thanks for your replies guys, much appreciated.
My OP was probably a little brief, so will attempt to ( briefly ! ) add a more thorough list and timeline of events.

Car was unused for 6 days pre xmas, battery totally flat and showed around 5 volts on multimeter.
Bought a smart charger, and charged to 12.8 after approx 48 hours. Refitted battery, reading just over 14 v with engine running.

Next morning reading dropped to 12.6
Next day dropped to 12.4
next day 12.2
Since given car a couple of run outs, one of 2 x 30 minutes, reading back up to 12.6, yesterday,.
Reading this morning 12.2, used to go shopping today, reading now 12.47.

So IMO the alternator is charging, but battery not holding for one of 2 reasons; dud battery or parasitic drain.
I don`t feel confident in attempting to test for drain, so booked in at kwik fit for free battery test tomorrow, at least they give a print out, unlike Halfords yesterday ,who told me they had ordered a new battery and when did I want it fitting, BEFORE doing the so called test ! ( which took 15 seconds without starting engine, and stated the battery was a ok ?! )
If it is a duff battery, which I`m now hoping it is, has anyone dealt with Advanced Battery Supplies in Stockport, who can send a Bosch s5 a11 80 v AGM for £165 compared to £299 at Euro car parts and £240 from The AA Battery Service ! ?

ATB
Barry
For a battery to discharge to 5v in 6 days I would have thought there would have had to have been something like a conventional filament bulb left on and having been discharged to that level I'm surprised you have managed to charge it at all 😱. Car batteries really don't like being discharged to that level and often don't recover long term. See this chart that shows that 10.5v is considered fully discharged
Rectangle Font Parallel Symmetry Number


'IF' your battery voltage of 12.8v was straight after you disconnected the charger the battery was not fully charged (after 48 hours I would think that it was as well charged as it was capable of being) but if this was after half an hour it was very well charged 🤷‍♂️ (I was wrong above and should have said 13.5v when the charger is disconnected dropping back to 12.7v after a few minutes)

A voltage drop of 0.2v per day is not normal and suggests that if your battery is in good condition you have a current drain but if its not I think it might be typical of a battery with a duff cell 🙄

Testing battery voltage after driving is not very helpful these days due to some electrical circuits being live for up to half an hour after the car is locked and putting a load on the battery and our so called Smart Charging, on older cars the alternator just used to chuck out 14.4v at full current most of the time and was quite good at recharging batteries, the new smart charging systems vary the charge depending on the load on the engine and are not at all good at recharging batteries. So seeing seeing 12.45v may not in itself mean the battery is duff.

But having said that, and just based on what you have written, I think there's a good chance the battery needs replacing. If the Kwikfit test was inconclusive and you want more evidence before shelling out for a new battery, take it out again, fully charge it (it should show 12.7v after 15 minutes or so) and leave it disconnected over night ideally at 20c or at least not cold. If the battery was 12.7v and now shows less than 12.6v I would say it needed replacing as I wouldn't expect a di9sconnected battery in good condition to lose anything overnight unless its cold.
 

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Discussion Starter · #8 ·
For a battery to discharge to 5v in 6 days I would have thought there would have had to have been something like a conventional filament bulb left on and having been discharged to that level I'm surprised you have managed to charge it at all 😱. Car batteries really don't like being discharged to that level and often don't recover long term. See this chart that shows that 10.5v is considered fully discharged View attachment 13412

'IF' your battery voltage of 12.8v was straight after you disconnected the charger the battery was not fully charged (after 48 hours I would think that it was as well charged as it was capable of being) but if this was after half an hour it was very well charged 🤷‍♂️ (I was wrong above and should have said 13.5v when the charger is disconnected dropping back to 12.7v after a few minutes)

A voltage drop of 0.2v per day is not normal and suggests that if your battery is in good condition you have a current drain but if its not I think it might be typical of a battery with a duff cell 🙄

Testing battery voltage after driving is not very helpful these days due to some electrical circuits being live for up to half an hour after the car is locked and putting a load on the battery and our so called Smart Charging, on older cars the alternator just used to chuck out 14.4v at full current most of the time and was quite good at recharging batteries, the new smart charging systems vary the charge depending on the load on the engine and are not at all good at recharging batteries. So seeing seeing 12.45v may not in itself mean the battery is duff.

But having said that, and just based on what you have written, I think there's a good chance the battery needs replacing. If the Kwikfit test was inconclusive and you want more evidence before shelling out for a new battery, take it out again, fully charge it (it should show 12.7v after 15 minutes or so) and leave it disconnected over night ideally at 20c or at least not cold. If the battery was 12.7v and now shows less than 12.6v I would say it needed replacing as I wouldn't expect a di9sconnected battery in good condition to lose anything overnight unless its cold.
Many thanks for such a comprehensive reply.
Battery has dropped to 12.2 overnight, so is now on charge in garage. When fully charged, how long should it be left disconnected ,to see if the voltage holds ? Have seen 12 hours quoted ( can`t recall where, memory needs re charging ! )
 

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Many thanks for such a comprehensive reply.
Battery has dropped to 12.2 overnight, so is now on charge in garage. When fully charged, how long should it be left disconnected ,to see if the voltage holds ? Have seen 12 hours quoted ( can`t recall where, memory needs re charging ! )
Firstly the battery needs to be fully charged, with AGM batteries this can be quite a long process because chargers with an AMG setting charge quickly up to a certain point and then trickle charge for a while longer, or at least that's what my Ctek does and it tells me when it's fully charged or if the battery isn't holding a charge. As a guide Ctek say a 60Ah battery will take upto 12h or 26h for a 110Ah.

If your charger doesn't do this I would charge it for a good 12 hours if you can and put your multi meter on it clipping the probes on with the charger clips. Then when you take the positive clip off keep the positive probe on the terminal and I would expect the voltage to be 13.5v which will fairly rapidly drop back to 12.6v+ over 10 to15 minutes or so.

The 12.6v should then hold for weeks with nothing connected and no cold weather. As to how long you 'need' to leave it disconnected, I guess the answer if 12 hours or more, if it drops below 12.5 in 12 hours I would suspect the battery.

What did Kwikfit say?
 

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When fully charged, how long should it be left disconnected ,to see if the voltage holds ?
I don't know to what degree you may be au fait with vehicle electrics, 'Barry Smith', but if you possess, or can lay hands on, a multimeter, you can fairly easily perform some basic checks to identify whether or not there exists any parasitic drain causing your battery problem.

To accomplish that if you may be interested, there are several videos available on 'Youtube' that will lead you through the processes involved. This one I have linked to is typical and is worth watching just to get a handle on what is involved:


Apart from that, I just checked back to see exactly when I replaced the AGM battery in my Optima SW and it was at 51 months which I found disappointing at the time but due to lockdown and low usage before (and since), I resolved after checking the alternator output and finding no significant draw on the battery with everything switched off, to replace it.

With the new battery installed, the car once again behaved as it should with the IS/S system operating again frequently. The recent cold spell has not affected the battery which remains strong, as it should be, guaranteed for 5 years. AGM batteries behave differently from lead-acid in that they don't gradually slow down in the cranking process to the point where the engine might start/might not and you need a push (manual only) or to jump-start the car.

AGMs tend to be fine every day until one day, you switch on, press start and are confronted with an array of multi-coloured flashing lights and no starter motor cranking. If you are lucky, a lengthy charging period with a conditioning cycle from a modern, smart charger such as the middle-range and above CTEK models might be all that is required to restore the battery to good health for another year or more with occasional charging unless covering normal, non-lockdown mileage.

Good luck with it.
 

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Discussion Starter · #11 ·
Firstly the battery needs to be fully charged, with AGM batteries this can be quite a long process because chargers with an AMG setting charge quickly up to a certain point and then trickle charge for a while longer, or at least that's what my Ctek does and it tells me when it's fully charged or if the battery isn't holding a charge. As a guide Ctek say a 60Ah battery will take upto 12h or 26h for a 110Ah.

If your charger doesn't do this I would charge it for a good 12 hours if you can and put your multi meter on it clipping the probes on with the charger clips. Then when you take the positive clip off keep the positive probe on the terminal and I would expect the voltage to be 13.5v which will fairly rapidly drop back to 12.6v+ over 10 to15 minutes or so.

The 12.6v should then hold for weeks with nothing connected and no cold weather. As to how long you 'need' to leave it disconnected, I guess the answer if 12 hours or more, if it drops below 12.5 in 12 hours I would suspect the battery.

What did Kwikfit say?
Thanks macgd016, kwikfit said battery ok, print out showed 12.6 v, ( yesterday 12.30 ) car had over 1 hr run out, read 12.2 this morning 11.30 am, so had been parked for approx 18 hrs.
Have connected to smart charger which fully charged within 2 hrs to 100%.
Checked twice since, showing 12.78 v , 2hrs ago and just now.

Will refit tomorrow and do the " easy " drain test of removing neg clamp and connecting multimeter to battery live/ battery neg clamp, ( what setting should meter be on ? )

Thanks again,( Baz )
 

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Discussion Starter · #12 ·
I don't know to what degree you may be au fait with vehicle electrics, 'Barry Smith', but if you possess, or can lay hands on, a multimeter, you can fairly easily perform some basic checks to identify whether or not there exists any parasitic drain causing your battery problem.

To accomplish that if you may be interested, there are several videos available on 'Youtube' that will lead you through the processes involved. This one I have linked to is typical and is worth watching just to get a handle on what is involved:


Apart from that, I just checked back to see exactly when I replaced the AGM battery in my Optima SW and it was at 51 months which I found disappointing at the time but due to lockdown and low usage before (and since), I resolved after checking the alternator output and finding no significant draw on the battery with everything switched off, to replace it.

With the new battery installed, the car once again behaved as it should with the IS/S system operating again frequently. The recent cold spell has not affected the battery which remains strong, as it should be, guaranteed for 5 years. AGM batteries behave differently from lead-acid in that they don't gradually slow down in the cranking process to the point where the engine might start/might not and you need a push (manual only) or to jump-start the car.

AGMs tend to be fine every day until one day, you switch on, press start and are confronted with an array of multi-coloured flashing lights and no starter motor cranking. If you are lucky, a lengthy charging period with a conditioning cycle from a modern, smart charger such as the middle-range and above CTEK models might be all that is required to restore the battery to good health for another year or more with occasional charging unless covering normal, non-lockdown mileage.

Good luck with it.
Thanks Indalo,
will give it a go tomorrow, I `m ok doing simple voltage test, but don`t know what settings a multimeter should be on for other tests such as drain/parasitic.
In my younger days have had engines in bits, replaced brakes, ball joints etc, but that was on cars like Skoda rapids, Vauxhall Viva etc, not the computerised modern versions !
ps, I never use the ISG, just don`t like it.

Thanks again, Baz
 

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Great video @Indalo, I've never attempted this myself so wouldn't have wanted to give advice without it 😱

Baz, you are well ahead of me by the looks of it and you are right if your battery is holding 12.78v is would seem to be fine so the paracitic drain test is your next step.

The video is pretty self explanatory you just need to be sure you use the right multimeter settings. Like the video I would start from the highest Amp setting (10 or 20A NOT ma) which as they say often mean moving the probe lead position. If you are in doubt send me a close up photo of the multimeter and I'll explain what needs to be where.
 

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Also I would leave the battery disconnected till the morning because if it's still 12.78v that is pretty good.

As I have said earlier the battery voltage you have after driving is no longer a good indicator of anything much sadly
 

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@Indalo I've just watched that video right through, it is so clear and easy to understand and at the end he covers all sorts of easily missed causes of paracitic drain, I'm well impressed 😁
 

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Discussion Starter · #17 ·
Any update on this Baz?
Hi macgd016, everything ok so far.
Have learnt NOT to check battery voltage straight after turning engine off !! ( novice mistake ? ) hence readings of 12.2 v ?
I left battery connected but with bonnet catch in closed position to trick computer, then checked next morning, reading was 12.5 v ( kept key fob in house so computer would not awaken )
So my only real puzzle is why the battery died over 6 days un use ? was it due to me forgetting to lock the car, ? , there doesn`t appear to be any answers to that question od google etc.

Best wishes,

Baz
 

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Hi macgd016, everything ok so far.
Have learnt NOT to check battery voltage straight after turning engine off !! ( novice mistake ? ) hence readings of 12.2 v ?
I left battery connected but with bonnet catch in closed position to trick computer, then checked next morning, reading was 12.5 v ( kept key fob in house so computer would not awaken )
So my only real puzzle is why the battery died over 6 days un use ? was it due to me forgetting to lock the car, ? , there doesn`t appear to be any answers to that question od google etc.

Best wishes,

Baz
That's good news Baz. I can only assume that for some reason a circuit was live when the battery died, like you I can't see why this would be but it seems to be the most likely explanation.

Checking the battery voltage in situ is so difficult these days because there are so many electrical systems that in some cases don't shut down for 30 minutes or more after locking the car. You have found the solution to that part of the issue though. The other part of the issue (I'm not sure if this is the case with Kia but it was on my last Mercedes) is that Smart Charging is designed to reduce the load from the alternator, to improve mpg, except when the car is coasting. My Merc had a dashboard voltmeter and I could see that when accelerating the voltage would drop to 12.2v, cruising it was kept at 12.4-12.5v but when coasting it shot up to 14.5v. The impact of this seemed to be that the battery was very rarely being charged with full current and was therefore not kept fully charged. This became apparent for many owners during the first lockdown where many were getting a phone app message after 20+ days telling them their car battery was critical, jumping in the car the dash voltmeter showed 11.8v (due to all the electronics that had fired up putting a load on it) but it still started. As I wasn't using the car at all then I did some testing by connecting my multimeter as you have described and took meter readings three times a day, temperature varied the voltage during the day by a surprising amount but using the morning reading I found that on average the voltage dropped by 0.02v per day but this still meant that after 30 days the voltage dropped from 12.6 to 12v which is a flat battery. In my view this Smart Charging is one of the reasons modern batteries do not seem to last as long as they used to because lead acid batteries like to be kept fully charged.

Mind you parasitic drain is nothing new, I have an 08 Mercedes SL that has two batteries, one this is just for starting that is fully disconnected when the car is switched off and another for the car electrics. The start battery is the original and touch wood still in good condition despite the car not being used during the winter and only on high days and holidays during the summer. The other battery though will only hold its charge for 30 days after which its below 12v so I now keep it conditioned with a Ctek charger, this battery failed after 8 years which was not bad considering.

Glad you have it sorted though, well worked out and cheaper than a new battery 😁
 
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