Flat Car Battery Issues

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Mad Scientist
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#3369665 2-May-2025 07:36

tweake:

i had an idea for an in car recharger for those cars who do short runs and can't connect a charger (eg parked on the street). nothing more than a trickle charger thats powered by a small battery, which in turn is charged from the car and/or solar. driving for a week chargers the small battery. when its charged and engine is off, it starts the trickle charger to top up the car battery. one day i might get around to making it.

i had one of those when i was 10 years old. not sure where i put it ...

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#3369671 2-May-2025 08:05

The above system had no battery. As soon as you stopped you went dark, possibly a reason cyclists kept moving.

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#3369687 2-May-2025 09:53

I never had much luck with batteries in my previous car (an old Toyota Allion) as I only lived 10 minutes away from work and most of my travel was within about 15 mins of home. After coming out for the third time to rescue me the AA Battery service guy confirmed that my latest battery was kaput and sold me a new battery and also a charger (this one) and gave me the advice to charge up the battery once a month or so. He claimed this is what he did with both his car and he wife's car and it fixed any battery problems they had due to short trips/not using the car much. The charger claimed to recondition the battery as well as charge it. It would take about 8 - 10 hours to go through the various stages and I would leave it on overnight to do its thing. Doing that I had no more battery problems.

Fast forward to last year and I bought a 2024 Kia Stonic that I bought brand new. I now work from home so my wife would be the primary driver but she only works about 15 mins from home so I was keen to keep the battery in top shape. When the car went in for it's one month check with the Kia dealership we bought it from I gave my wife a few questions to ask the mechanic about the battery. First I wanted to know if it was ok to charge the battery while it was sitting in and connected to the car. The answer was no, I should disconnect it. I also asked what sort of battery it was as the car's manual says "Your vehicle has a maintenance-free calcium battery" but I had noticed that the model number on the battery is AGM60L-DIN, which suggests an AGM battery and not calcium. The mechanic confirmed that it was AGM. My charger can handle calcium, AGM, GEL and WET type batteries. But then mechanic told my wife that it's best not to charge the battery as it's designed to be maintenance-free and we shouldn't have any problems with it even if we don't travel far.

I'm not sure how much I trust this mechanic, but he does work for a Kia dealership so I would hope he knows what he's talking about. So far I haven't tried charging the battery as I'm not sure what disconnecting it from the car for several hours would do to the car's computer and entertainment system.

Comments on any of the above? Are modern cars/batteries less immune to battery problems like the Kia mechanic was suggesting? The car does turn the engine off at stops if that matters.

Asteros

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#3369701 2-May-2025 10:23

I'm not an expert but it seems safe to disregard the Kia mechanic. From experience modern cars rely heavily on their 12V batteries - auto stop/start, electrics etc. Charge the 12V battery regularly using your charger and it is fine to not remove it from the vehicle.

https://www.kia.com/sg/discover-kia/ask/how-to-charge-a-car-battery.html

In fact most luxury European marques sell rebadged Ctek chargers.

You might have to hunt around for an earth point ( for the Negative or black coloured terminal) which is connected to the body of the car instead of the Negative terminal of the battery.

Ge0rge

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#3369704 2-May-2025 10:27

That mechanic is on crack and I would take everything he says with a shovel-load of salt - or two.

Maintenance free for batteries means that there is no requirement to top up the electrolyte, not that it doesn't need to be charged. It's simple math - if you take more charge out than you put back in, say by doing short journeys, the battery will go flat. There's no magic sauce in "maintenance free" that allows the battery to make more charge out of thin air.

As for disconnecting the battery while charging, I've never heard of that before, at least not in relation to vehicles. If the battery charger you have is of the appropriate type for the battery in the vehicle, then you're not going to apply any higher voltage levels than the car's charging system will apply when you're driving.

The charger you have linked likely won't have a high enough voltage output to fully charge a calcium battery. Something like a CTEK MXS5 would be perfect for your situation.

Bung

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#3369705 2-May-2025 10:28

I wouldn't take that mechanic's word on batteries. Maintenance free doesn't mean it doesn't need charging. It just means that it is designed not to need topping up with water.

Email Kia NZ. See was sort of response they give.

The Ctek charger comes with a quick connect socket for the battery. I have no qualms about plugging my charger into it without disconnecting the battery.

MurrayM

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#3369759 2-May-2025 11:02

Thanks for the advice guys, I too was sceptical about the mechanic's advice. I'll email Kia NZ and see what they say.

My question about disconnecting the battery from the car prior to charging it was because the car's manual has a section on battery charging and it says:

Recharging battery
When recharging the battery, observe the following precautions:
* The battery must be removed from the vehicle and placed in an area with good ventilation.

Is this just Kia being overly cautious?

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nitro

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#3369863 2-May-2025 11:30

MurrayM:

Thanks for the advice guys, I too was sceptical about the mechanic's advice. I'll email Kia NZ and see what they say.

My question about disconnecting the battery from the car prior to charging it was because the car's manual has a section on battery charging and it says:

Recharging battery
When recharging the battery, observe the following precautions:
* The battery must be removed from the vehicle and placed in an area with good ventilation.

Is this just Kia being overly cautious?

i would put it in that bucket. probably something the legal department insisted upon.

tweake

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#3369872 2-May-2025 11:41

MurrayM:

Fast forward to last year and I bought a 2024 Kia Stonic that I bought brand new. I now work from home so my wife would be the primary driver but she only works about 15 mins from home so I was keen to keep the battery in top shape. When the car went in for it's one month check with the Kia dealership we bought it from I gave my wife a few questions to ask the mechanic about the battery. First I wanted to know if it was ok to charge the battery while it was sitting in and connected to the car. The answer was no, I should disconnect it. I also asked what sort of battery it was as the car's manual says "Your vehicle has a maintenance-free calcium battery" but I had noticed that the model number on the battery is AGM60L-DIN, which suggests an AGM battery and not calcium. The mechanic confirmed that it was AGM. My charger can handle calcium, AGM, GEL and WET type batteries. But then mechanic told my wife that it's best not to charge the battery as it's designed to be maintenance-free and we shouldn't have any problems with it even if we don't travel far.

I'm not sure how much I trust this mechanic, but he does work for a Kia dealership so I would hope he knows what he's talking about. So far I haven't tried charging the battery as I'm not sure what disconnecting it from the car for several hours would do to the car's computer and entertainment system.

Comments on any of the above? Are modern cars/batteries less immune to battery problems like the Kia mechanic was suggesting? The car does turn the engine off at stops if that matters.

its perfectly fine to charge while battery is still connected with modern chargers, in fact with modern vehicles its preferred as disconnecting the battery can sometimes cause issues. its only with old school unregulated chargers that you need to disconnect as their voltage can get very high.

with stop/starts engines, you have an agm battery. they tend not to last long and are expensive to replace so take care of it the best you can. also you can't just replace the battery, they often need programming into the car. imho i would look to see if the stop/start can be disabled.

richms

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#3369887 2-May-2025 12:11

There are some very industrial old chargers in use in parts of the world that do not even isolate from the mains. Same chargers that bought about the whole dont charge on concrete problems from back when batterys were not made out of plastic.

Disconnecting from the car is important if you are doing any desulphate etc pulse charging, as otherwise the capacitance of all the stuff in the car and over voltage shunting will mean at best nothing happens to recondition, and at worst you burn out the over voltage protections in your ECUs etc. Chances are small on a little plug in charger, but the giant buzz boxes that put out absurdly high voltages to get 60+ amps into a battery so you can crank it after its been on charge for a minuite will see over 20v on the terminals which is gonna harm things in a modern car.

Richard rich.ms

johno1234

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#3369891 2-May-2025 12:24

Asteros:

I'm not an expert but it seems safe to disregard the Kia mechanic. From experience modern cars rely heavily on their 12V batteries - auto stop/start, electrics etc. Charge the 12V battery regularly using your charger and it is fine to not remove it from the vehicle.

https://www.kia.com/sg/discover-kia/ask/how-to-charge-a-car-battery.html

In fact most luxury European marques sell rebadged Ctek chargers.

You might have to hunt around for an earth point ( for the Negative or black coloured terminal) which is connected to the body of the car instead of the Negative terminal of the battery.

You can get a quick connect plug adapter for the ctek which you permanently install to the battery terminals. Makes connecting and disconnecting a lot easier and more reliable. I Installed this on my jet ski which is left on the ctek over winter. I don't know what it is about jet skis but if you don't do this or disconnect the battery they all seem to drain it over winter to dead.

johno1234

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#3369892 2-May-2025 12:29

tweake:

MurrayM:

Fast forward to last year and I bought a 2024 Kia Stonic that I bought brand new. I now work from home so my wife would be the primary driver but she only works about 15 mins from home so I was keen to keep the battery in top shape. When the car went in for it's one month check with the Kia dealership we bought it from I gave my wife a few questions to ask the mechanic about the battery. First I wanted to know if it was ok to charge the battery while it was sitting in and connected to the car. The answer was no, I should disconnect it. I also asked what sort of battery it was as the car's manual says "Your vehicle has a maintenance-free calcium battery" but I had noticed that the model number on the battery is AGM60L-DIN, which suggests an AGM battery and not calcium. The mechanic confirmed that it was AGM. My charger can handle calcium, AGM, GEL and WET type batteries. But then mechanic told my wife that it's best not to charge the battery as it's designed to be maintenance-free and we shouldn't have any problems with it even if we don't travel far.

I'm not sure how much I trust this mechanic, but he does work for a Kia dealership so I would hope he knows what he's talking about. So far I haven't tried charging the battery as I'm not sure what disconnecting it from the car for several hours would do to the car's computer and entertainment system.

Comments on any of the above? Are modern cars/batteries less immune to battery problems like the Kia mechanic was suggesting? The car does turn the engine off at stops if that matters.

its perfectly fine to charge while battery is still connected with modern chargers, in fact with modern vehicles its preferred as disconnecting the battery can sometimes cause issues. its only with old school unregulated chargers that you need to disconnect as their voltage can get very high.

with stop/starts engines, you have an agm battery. they tend not to last long and are expensive to replace so take care of it the best you can. also you can't just replace the battery, they often need programming into the car. imho i would look to see if the stop/start can be disabled.

The stop/start battery on our Touareg finally gave up after an incredible 12 or 13 years old. I wish I could remember what brand it was but it was likely to be the factory original as the car was only 2 years old when we bought it. It's a huge, very expensive battery and a pain to replace as involves removing the front passenger seat to access it.

I can't stand the stop-start feature. It is hard on batteries, ring gear, pinion and starter. Worst of all, the engine decides to conk out just when you need to hoof it into a gap in the traffic. It's almost a reflex reaction to hit the deactivate button when I start the car. As far as I can tell it can't be re-programmed to default inactive instead of default active.

richms

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#3369904 2-May-2025 13:03

johno1234:

The stop/start battery on our Touareg finally gave up after an incredible 12 or 13 years old. I wish I could remember what brand it was but it was likely to be the factory original as the car was only 2 years old when we bought it. It's a huge, very expensive battery and a pain to replace as involves removing the front passenger seat to access it.

I can't stand the stop-start feature. It is hard on batteries, ring gear, pinion and starter. Worst of all, the engine decides to conk out just when you need to hoof it into a gap in the traffic. It's almost a reflex reaction to hit the deactivate button when I start the car. As far as I can tell it can't be re-programmed to default inactive instead of default active.

My concern is that you are going straight from a stop to full load with no chance for the oil pressure to come back, and noone can explain what magic they have to prevent bad wear when hitting high loads as soon as its started.

You can get little wiring looms that connect to tbe button and have a microcontroller that will see if its on or not and press the button to turn it off every time. Some modern cars are a ritual to get going with turning them on, turning off lane keep assist, agreeing to the stereo being a stereo, turning off start stop, and my friend in the UK has got a car now that has a speed warning nag that needs turning off every time. Sounds like something that a resoursful person could make a OBD2 module to automate.

Richard rich.ms

tweake

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#3369909 2-May-2025 13:10

johno1234:

The stop/start battery on our Touareg finally gave up after an incredible 12 or 13 years old. I wish I could remember what brand it was but it was likely to be the factory original as the car was only 2 years old when we bought it. It's a huge, very expensive battery and a pain to replace as involves removing the front passenger seat to access it.

I can't stand the stop-start feature. It is hard on batteries, ring gear, pinion and starter. Worst of all, the engine decides to conk out just when you need to hoof it into a gap in the traffic. It's almost a reflex reaction to hit the deactivate button when I start the car. As far as I can tell it can't be re-programmed to default inactive instead of default active.

i was looking at buying one of the bluemotions. i saw a mention of some vw you can turn it off if you use vw diagnostic tools.

tweake

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#3369910 2-May-2025 13:12

richms:

My concern is that you are going straight from a stop to full load with no chance for the oil pressure to come back, and noone can explain what magic they have to prevent bad wear when hitting high loads as soon as its started.

that doesn't appear to be an issue. starter, gears, battery tends to be the major issues.

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