[Techy]

Hi. The battery in my 2019 Kia Niro PHEV died due to keeping an interior light on. I got my car jumped but it has died again. I did some research and now understand that the alternator alone should not be used to fully recharge a dead battery. I'm thinking about getting a smart battery charger. I'd appreciate some input from this great community.

Any general suggestions about this situation and using a battery charger?
Any suggestions on a specific smart charger?
Do you need to remove the battery to do this? (I might go ahead and do this anyway because it's quite rainy here now and I don't have a garage).

Thanks so much for any input!

You are going to have to replace the battery and then a smart charger several times per year would be a good idea. I personally like the Battery Tender charger but there are many others out there. You do not have to remove the battery to charge in fact, removing is a bit of a pain.
The Niro does not have an alternator per se but rather a DC to DC converter and the charging algorithm is not good - Kia's fault.

 

[Techy]

Thanks for this reply, and thank you to the other posts as well. Yes, my battery is the original and probably will need to be replaced. I've got an appointment at the Kia dealer this week. Interesting about the Niro not having an alternator. I haven't even heard of a DC to DC converter; will have to do some research to understand that. One more question regarding your Battery Tender use. You said you use it several times a year. How do you decide when to use it? Do you test the battery and use the charger if it's low, or do you just do it on regular intervals? I'm considering getting such a device, but a bit hesitant as it's one more thing to add to a long house / cars routine maintenance list. Thanks again.

I understand the routine maintenance list and I guess you have to weigh the possible benefits of a smart charger vs battery life and is it really worth it.
I have 2 motorcycles and a convertible that spend the winters indoors. I simply hook a battery tender (smart charger) to each one for the whole winter and leave the charger plugged in.
When I purchase a 2023 Niro PHEV, I am going to add a dongle to the battery posts and then plan to connect the smart charger every 2 - 3 months for a 24 hour period and should be good to go.
Lead acid batteries do not like being drained even slightly and then not charge up immediately and that operation was well handled by an alternator.
Hybrids and EV do not have an alternator so the immediate charging does not always occur.
The Niro HEV has a lithium battery which does much better with not being fully charged for periods of time.

 

[Techy]

My original 12v battery lasted 4 yrs/4mos before I decided to proactively replace it last fall (dealer cost $222 battery & labor). I use a battery tender year round on my Honda scooter but never used a smart charger on the Niro battery. For the past year I did check the 12v battery bi-monthly with a voltmeter. The reading was down to 12.1 volts with the engine off when I was already scheduled for an oil change and decided it was time for a new 12v battery. I should note I never once accidentally left an interior light on or the rear hatch door open for hours at a time or not shut completely. I've owned a portable lithium jump battery from the start but I still never want to be in a position where I need to use it and even more so the tire sealant kit. I gladly keep my AAA membership current.

Yes, leaving a hatch light and/or interior light on is a quick way to shorten the life of the battery.
Your battery lasted well and you made a good choice in replacing before it gave you problems.
I will use a smart charger occasionally as it is quite easy to do. I also carry a lithium battery pack as that again is very easy to do and I know how to use it and will use it. As for the tire sealant I totally agree with you - will not use it - ever.

 

[Techy]

The one thing I don't yet understand is the difference (to battery life) between manually maintaining the 12V battery charge periodically vs. having its charge maintained automatically from the traction battery.

Is it an issue of going a long time without charging the PHEV via AC, and given the lack of alternator, discharging the 12V battery too deep too often?

The benefit of "smart chargers" is their ability to determine when desulfation is required and provide a brief high charge to perform that function.
The DC to DC converter will not perform that function - in fact, an alternator will not do that either.
12V lead acid batteries like to be fully charged at all times and hybrid/EV vehicles do not regularly do that whereas an alternator on the ICE cars will attempt to keep fully charged.

 

[Techy]

most of the modern vehicles in the past few years now uses AGM types for accessory battery except for Niro HEV which uses Lithium. so getting a standard lead acid battery is not recommended as it will not hold/perform to meet the requirements.

I'm not so sure AGM is as "standard" as you think.
The HEV does use lithium but it is not the HEV battery that is a problem. It is the PHEV and EV batteries that are lead acid and they need the extra help from a smart charger.

 

[Techy]

Also, in a month or two when I put a little Noco Genius 1(A) on it for a recondition and push to 100%, I will first disconnect the negative terminal. For one, the voltage pulses I've seen during conditioning of another battery are too high to consider leaving it connected to the car. At best I would expect a too-high battery voltage DTC to be thrown, and at worst outright damage to expensive electronics.

You might be overthinking this charging stuff. If the car is "off" and you are not charging the traction battery, I doubt there is any circuit of consequence that is connected to the 12V battery.
You may disconnect the 12V negative from the battery when connecting the smart charger but in my opinion, you are wasting your time.

 

[Techy]

The one exception was when my 12v battery completely discharged in 2019 I did remove it from the vehicle before charging it. It voltage was 5.1 volts before the BatteryMinder bought it back to life. It was the original battery, and it is still working fine after it was bought back to life.

That is amazing as 5.1V would have been the death of your battery if it had been 2 - 3 yrs old.

 

[Techy]

Are there any gotchas with disconnecting the 12V PHEV battery for hours? (e.g. any loss of data, or need to input a stereo anti-theft code as was the case in my old Honda)

(Thanks to all who've contributed to this informative thread!)

I don't think there will be any "gotchas" but since I do not have a PHEV (with use of smart charger), I cannot definitively answer.

 

[Techy]

After this happened, I did buy a Noco Battery Booster so that if my battery died, I would be able to start the car immediately - even with a dead battery. The Noco Battery Boosters have a setting so that it will start the car even with a completely dead battery.

Yes, if voltage is below 3V, boosters will not operate but they all have an over ride feature that allows boosting when basically dead. If the over ride feature is used, the polarity safety is not available so if the cables are connected incorrectly, there is definitely the probability of sparking and blowing up the battery and/or booster.

 

[Techy]

Another quick note to this thread- one of the post could confuse individuals that the NIRO EV or PHEV use an OEM AGM battery. Unless KIA changed this year NIRO EV and PHEV are using Closed Maintenance Free Lead Acid batteries.

Replacement AGM batteries will work if an induvial wants to go that way

I was reading through the owners manual for the 2023 Niro and it mentions "maintenance free, calcium-based". Certainly sounds similar to lead acid to me and certainly not AGM

 

[Techy]

I've been spending some time on the Ford Escape site and noticed that Ford HEVs have a very similar problem with their OEM 12v batteries dying in 2-3 years. I wonder if it just cheap OEM batteries or an unintended "design feature" of HEVs & PHEVs???

I would go with the unintended "design feature" of PHEV/EV
The Niro HEV's are fine because they have a lithium 12V battery and the PHEV/EV would be fine as well if they had a 12V lithium but that is not currently gonna happen - cost!!