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Discussion Starter · #1 ·
Hi all :)

I’m a very happy 2019 e-Niro owner, and have enjoyed 35k trouble-free miles … until last weekend when the car seemed completely dead when I tried to turn the car on! :oops: The dash just made some quiet bonging sounds and I could hear some relays clicking but that was about it …

Fortunately I was staying at a campsite where the owner had a 12V battery charger to hand, and after a few minutes of being connected I was able to start the car no problem and it’s been fine since (probably done a good 500 miles since).

I’ve just tried connecting a battery tester to the 12V battery and it read around 12V with no load, and plummeted to 9.8V under a heavy resistive load …!!

Is the 12V battery shot? Or is there a problem with the way it’s being charged? The car was new in September 2019 and it’s done 35k miles since then.

Many thanks for your help!

David
 

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Discussion Starter · #3 ·
Looks like your battery is goosed with a bad cell. I would replace.
Thanks for the very quick reply Chris 🙂

I’ve just realised my service is actually overdue (always think it’s every year instead of every 10k miles or year whichever is sooner …), and reading in the Kia warranty blurb it says the 12V battery is covered for 24 months … and I got the car on the 13th September 2019! 😬

Fingers crossed I can get the car serviced and the battery exchanged for free in time!

it seems unusual for it to fail so quickly, or not? Or do modern EVs still not look after their 12V batteries well enough for them to last?

Thanks again for your help 🙂

David
 

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2022 Bolt EUV Premier
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The 12v battery in the Kia Niro is famous for being undersized. They don't seem to last very long. I never had an issue with my Niro PHEV for 2 1/2 years, but heard many user reports about failing 12v batteries.
 

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Discussion Starter · #5 ·
The 12v battery in the Kia Niro is famous for being undersized. They don't seem to last very long. I never had an issue with my Niro PHEV for 2 1/2 years, but heard many user reports about failing 12v batteries.
Hi Dan,

Thanks for your feedback, it’s good (in a way!) to know that I’m not alone in having this problem.

Will let you know whether Kia agree to replace it for me during the next service.

Thanks again,

David
 

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Hi Dan,

Thanks for your feedback, it’s good (in a way!) to know that I’m not alone in having this problem.

Will let you know whether Kia agree to replace it for me during the next service.

Thanks again,

David
You don’t have to wait for a service to report the faulty battery. If reported during the warranty period your claim should still be valid.
 

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Kia e-Niro 4 MY20, Zoe Z.E.50 GT Line
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The battery saver function on the Hyundai/Kia seems to do a good job. This runs a periodic charge routine when the car isn’t being used. Trouble is it isn’t turned on by default. Also it’s likely some cars had the 12v battery deep drained while being shipped to the UK. Deep cycling a lead acid battery that isn’t designed for it will damage it and, at best, significantly reduce its life.
 

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Discussion Starter · #8 ·
You don’t have to wait for a service to report the faulty battery. If reported during the warranty period your claim should still be valid.
Ah ok that's good to know, I was going to report it tomorrow when I book in the service with the garage 🙂

The battery saver function on the Hyundai/Kia seems to do a good job. This runs a periodic charge routine when the car isn’t being used. Trouble is it isn’t turned on by default. Also it’s likely some cars had the 12v battery deep drained while being shipped to the UK. Deep cycling a lead acid battery that isn’t designed for it will damage it and, at best, significantly reduce its life.
What is this battery saver function and how does one enable it? Is it this?


Thanks!

David
 

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Ah ok that's good to know, I was going to report it tomorrow when I book in the service with the garage 🙂


What is this battery saver function and how does one enable it? Is it this?


Thanks!

David

Page 55

System Setting The driver can activate the Aux. Bat‐ tery Saver+ function by placing the POWER button to the ON position and by selecting: 'User Settings Other Aux. Battery Saver+'


This assumes your car has it, if it's a FE. I thought they all did. I note the manual states it's on when delivered, mine wasn't.
 

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Discussion Starter · #11 ·
So I took the car in for its service today and they said there's nothing wrong with the 12V battery ... when I asked them why it dropped to 9.8v under load they asked how I tested that, and I said with a resistive load 12V battery tester ... and they said doing that isn't covered by warranty and that Kia don't advise doing it! :oops:

Furthermore, I was told you would only do that for 'old technology' 12V lead acids, not modern 12V gel-cell batteries, and that I need to go out and BUY a 'Smart Charger' if I still think there's a problem with the battery, and that there are 'loads' available from places like Halfords.

I think one of two things are happening here ...

1) They don't know what they're talking about, resistive load testing is valid for any 12V battery technology, and the battery has a problem and needs to be replaced
2) They do know what they're talking about and gel-cell batteries do drop significant voltage under load and perhaps I left the lights on longer than I thought / something was drawing power overnight on the one occasion where I ended up with the car not starting the following morning

... but I'm now really not sure who or what to believe!

I don't mind buying a 'Smart Charger' as it would be a useful thing to have, but even that doesn't seem so straight forward as most I've looked at on Amazon have both positive and negative reviews. Is there a brand you would recommend I purchase? Would a charger like this be able to detect if there was a defective cell in the battery?

Oh, and the Aux Battery Saver has been on since I bought the car as I think I may have switched it on when rummaging through the menus when I first got the car – it was at least on when I looked today.

Thanks so much for your help :)

David
 

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Discussion Starter · #13 ·

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CTEK chargers are awesome. I use/used a MX5 on a Leaf, Volt and MG5.

You just need to switch the mode to the right battery type first (FLA, AGM or GEL).
 

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Discussion Starter · #16 ·

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Discussion Starter · #17 ·
I'm also wondering if what they said at the garage is true – is putting a resistive load on a 12V battery no longer a good way of checking its health? Surely that's what a battery is designed to do, push power through resistive loads! This is what I used to test it:


Thanks!
 

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I'm not crazy, the attack has begun.
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Is the 12V battery shot? Or is there a problem with the way it’s being charged?
The latter. Like many EVs, your battery is being abused with undercharging (in a mistaken belief it gives you more miles).

Use a high quality desulphation cycle battery charger and set it to a desulphation cycle for 48 hours for a weekend every month or two.

Shouldn't be necessary, but it is.
 

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Whilst it's true to say that an EV 12v battery isn't normally subjected to cold cranking current drain, I wouldn't say it's as clear cut as you'd like to imagine. Most of my cars drop to 9.x volts when cranking the engine from one time to another so if your resistive load tester is dumping a couple of hundred amps that's not outlandish given the small size of the battery. The real question is how far and how quickly does the voltage recover after a load test like this, not how low it gets during the load test.
Your best method of measuring the real battery state is to track charge state over use and see if it drops excessively quickly.

On the topic of undercharging, do they do this on EVs too?? I am aware that ICE car batteries are often subject only to float charge rather than being put under full charge rate when the car is cruising at part throttle (and this probably does eke out a little more mpg overall). I doubt there's any benefit to doing this in an EV tho ..
 
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