Kia Niro Forum banner
  • Welcome to the Kia Niro forum! We discuss all models of the Niro, including the Hybrid, PHEV and EV versions. We are glad you stopped by. Feel free to browse the various topics, along with out FAQs. To enable posting, you need to register for a user account. There is no cost for this. Just click in the upper right corner where it says Login/Join. We look forward to your continued parcipitation.

Got 12V battery problems?

17K views 31 replies 12 participants last post by  perk1329 
#1 ·
A handful of forum members have reported unexplained problems with the 12V battery going flat. I noticed that Kia released TSB 163 in May that might be relevant. It applies to Niro PHEV, Optima PHEV, and Soul EV (Niro HEV is not in this list).

For Niro PHEV's it seems to be limited to the 2018 model year, with production dates between September 26, 2017 and March 30, 2018. I think that leaves me out, which is kind of a bummer, because I've been looking for an explanation as to why I'm now seeing the notification that battery saver plus ran almost every time I start my 2018 PHEV (meaning it runs almost every night).

For anyone who is interested, you can find the TSB on the NHTSA web site: hopefully this link will work for you: https://static.nhtsa.gov/odi/tsbs/2019/MC-10160618-0001.pdf

It talks about how a technician can investigate the possibility that the rear door latches might be putting a parasitic drain on the 12 V battery while the car is off.

For the DIYers in the crowd, unfortunately it refers to a shop manual that most of us don't have free access to. But it does make the point that if you know how to correctly connect an ammeter in the 12V circuit, then after the vehicle is in sleep mode (presumably the shop manual describes how to discover whether it's in that mode or not - I'm pretty sure that having your key-fob far away is part of the formula), then if the parasitic draw is less than 50 mA, you don't have a situation that the factory considers problematic. If you have more than 50 mA draw in sleep mode, they seem to be suggesting that the rear door latches should be replaced.

For me, the 50 mA number is new information that's good to know. Unfortunately, I still have a blind spot in that I don't have all of the other information mentioned in the shop manual about "Prepare the vehicle for a parasitic draw inspection".

Hope this info helps someone. Anyone who has a concern that this might apply to them can first check their date of manufacture, which appears on a label on the driver's door jam. If you fall into the date range specified above and if you have a concern about this, you could ask your dealer to evaluate your car for this TSB. The title of the TSB is "PARASITIC DRAW INSPECTION AND REAR DOOR LATCH REPLACEMENT"








 
See less See more
#2 ·
Checking for parasitic draw is as simple as hooking an ammeter in line and pulling fuses one at a time until the draw goes way down. That fuse is the offending circuit. Trace that circuit until you find the issue.

Its really common practice, especially on old cars that are subject to worn or cracked insulation.
 
#4 ·
The problem for modern cars is that the car is never really "Off". That's why the info posted by deltasmith talks about "sleep mode" and "preparing the vehicle for a parasitic draw inspection". On newer cars just opening the door (a requirement to access the fuse panel in most of them) causes the car to "wake up" in anticipation of being started. I've seen procedures for troubleshooting battery drain issues that include instructions to wait several minutes after closing the doors to begin the test among other requirements. Finding an extra amp or so of draw is a lot more complicated now that it was a decade or so ago.

Here's a link to a generic procedure for modern cars:

https://www.aa1car.com/library/battery_runs_down.htm

Note that the spec is to measure current draw 1 hour after shutting the car off! :eek:

The fact that some cars can continue to draw around an amp for over 20 minutes after shutdown is nuts to me. I think that alone might explain some of the issues PHEV and EV people have been having with the 12V battery. It's pretty puny, doesn't get charged continuously by the ICE and it has to power a whole bunch of stuff. It could just be a case of the battery being just a bit undersized for the load in real world conditions.
 
  • Like
Reactions: HRMaine
#3 ·
Other than a specific fault, the battery saver + found in PHEVs has issues. It actually increases "vampire" loads. Below is some quoted text and a chart from an Ioniq post - they have the same issues with PHEVs.
I have also taken current measurements (several for each series) and found:
When BS+ is enabled the current flow from battery is 225-230 mA (fluctuating between the two numbers but consistent in all measurements).
When BS+ is disabled the current flow from battery is 60-65 mA (fluctuating between the two numbers but consistent in all measurements).

Now, what can be concluded from the tests (at least with my car)?
1. Battery saver triggers in at about 12.4 V. In my car it takes about 22-24 hours of rest to happen.
2. As @Patrick suspected, BS+ is using the battery when in standby and it seems it consumes significant energy relatively (~160 mA while rest of standby features use only 60-65 mA.
3. In usual everyday use of the car when it is in rest less than a day, it make sense, in my opinion, to disable BS+.
4. I do not know for how long (over one day) the battery will stay at the plateau of 12.5-12.55 V but it may be worth not to activate BS+ even in several days rest?
 

Attachments

#7 ·
Interesting information, thanks for posting that.

This thought seems kind of a stretch, but I wonder if it's really BS+ causing the observed drain, or if the sleep logic behaves differently when it knows that BS+ is enabled.

The way I drive my PHEV (the ICE might not run for a couple of weeks at a time), the BS+ is probably necessary. The thing is, even when I do run the ICE for three or four hours of driving, if I don't see the alert that BS+ ran the next day when I start the car, I'll usually see it two days after running the ICE.

I do wish that Kia had thought to include in addition to BS+ the mechanical switch in the PHEV that they provided to HEV owners The idea that you could have a depleted 12V battery, a fully charged traction battery, but no way to boost the 12V from the traction because BS+ already ran three times and then gave up, seems to reflect an engineering decision that could have been better thought out. If there's some technique for inducing BS+ to come on again after it's timed out, I'd love to know, but my guess is that the logic is driven by the computer running on the 12V battery and by the time you notice a problem, the computer probably won't run. This is where the mechanical switch is likely to have a significant advantage.
 
#8 ·
Interesting and useful information. I was hoping that the 12v battery would be charged every time I plugged in to charge the HEV battery, but I guess not. I get this message a lot but my ICE engine is sometimes not used for a week.
My car was in for annual service about a month ago. They told me there was a recall for the door handles, I bet this was the issue. They will call me when they get the parts, but I still haven’t heard back.
I also wonder how long this small battery will last. Tesla uses a smallish 12v battery (at least on the S), and it only lasts about 18 months. Most users replace it with a special lithium battery but I have not investigated that. Tesla charges $$$ to replace, assume Kia is the same, so DIY is definitely called for.
This is a great forum - IMHO, much better than Tesla forums overrun with fanboys.
 
#10 ·
Problem solved! ... I think.

To recap: my 2018 PHEV has the "Battery Saver Plus" logic enabled, which is the default configuration for the PHEV. Previously, I had noticed that when I "started" my PHEV, it would often chime an alert immediately after the usual start up chimes completed, indicating that the BS+ logic had run while the car was shut off to recharge my 12V battery from the traction battery. I would see this somewhere between every third day and every day that I started the PHEV.

My driving habits are a little unusual, in that I can go for a really long time (months) without starting the ICE. And I had noticed that when I take a long trip and I do run the ICE for several hours, I wouldn't see the BS+ alert for several days, suggesting to me that running the ICE helps to boost the charge in the 12V battery, relative to what happens when I'm driving in pure EV mode. So I initially thought that maybe the fact that I don't run the ICE a lot was the explanation.

But... it seems that the problem was actually caused by a parasitic load from an alarm/security system that was installed by a dealer. Recently, I unplugged that system and I haven't seen a BS+ alert in four days, which is kind of a record relative to my recent experience prior to that.

When I was shopping for my Niro, I was simultaneously impressed and put off by the fact that the sales people I met at different dealerships had a "magic" key fob that could unlock the car doors on any car in the lot. The dealership I ultimately purchased my car from didn't have that: the sales person had to go and collect the key fob out of a box in the sales office if I wanted to look at a particular car on their lot (and I liked them for that, even though it meant I had to wait an extra few minutes). But they didn't have the model and package I wanted, so when I told them what I was looking for, they arranged for an "interdealer trade". My car came to them from a different dealer that had installed the module that enables the sales people to have a single magic key fob to unlock the doors of any car on the lot.

There's a well-known dealer "scam" that often comes with these dealer-installed security modules. Some dealers install these modules on every car on their lot, because they have had problems with theft and because it facilitates their sales staff's ability to show a car. Depending on which security system the dealer is using, if you finance the car and you fail to make the finance payments, the dealer might be able to use this same module to disable your car. In my case, I didn't use dealer financing, and so when I purchased the car, they pitched me on spending an extra several hundred dollars for a custom security system -that's the scam part. (My understanding is that the first dealer probably paid about $60 for the hardware plus additional technician time to install it). If someone steals your Niro, then unless they take steps to prevent it from communicating, you already have the same ability to recover it built in if you have the UVO app that can tell you where your car is currently located, so purchasing a dealer-installed security system would probably be a waste. So I passed on the offer to spend something like $800 on a dealer-installed security system. What the dealer is supposed to do that point is swap out a plug-in module in the security system and replace it with a "dummy" module that does nothing. Maybe my dealer didn't do that because they weren't the dealer that installed the system in the first place, or maybe my dealer did do that, not sure.

But last weekend, I finally crawled under the dashboard, located the security module (it's actually visible from the driver's seat, near my left knee, but installed under the dash and so not likely to attract attention). It had a simple plug-in connector that I unplugged and then verified that I could still start my Niro. I haven't heard a BS+ chime since I did that!
 
#11 ·
battery died (3v) so i charged it and it’s running again but it’s only holding around 12.3v so i think it needs to be replaced. i used a trickle charger to get it going but could i have just jumped it to wake the car up and left it on to charge it from the traction battery? how long would it take to make sure that it would later turn on? someone else mentioned that they carry a portable jumper. seems like a good idea to me. agree? disagree?
 
#22 ·
battery died (3v) so i charged it and it’s running again but it’s only holding around 12.3v so i think it needs to be replaced.
took the car to the dealer where he tested the battery, for no charge by the way, and told me it was fine; good for my wallet, not so good for my peace of mind because now i’m worried about vampire discharge. i told them i’d monitor the voltage.

since then no problems but in an attempt to duplicate the failure i charged it up to 12.6v and then let it sit for 30 hrs during which the battery varied from 12.3v to 12.5v except for a single reading of 12.7v. isn’t 12.3v like a 30% discharge? is this normal? how low can it go and still start the car?

when i started the car the battery saver notice came on which maybe accounts for the 12.7v reading. what is the threshold level for the battery saver to kick in?

i also measured the current with the car off between the positive battery terminal and the cable and got 0.5 mA, which x30hrs is 0.2 Ah. (the tsp regarding the rear door locks draining the battery requires putting the car in sleep mode which of course i didn’t do since i have no idea what it is.) find it hard to believe this would drop the voltage 0.3v

found an internet post that said as a rule-of-thumb SOC (state of charge) could be directly related to remaining Ah. so if a voltage drop from 12.6v to 12.3v takes it to around 70% that would be 31.5 Ah (45 Ah x 0.7) remaining. where did my other 13.5 Ah go?

all things considered, i can’t help but think that i caused the problem. what’s aggravating is that i just can’t imagine what i did.......
 
#12 ·
After parking my Niro the battery voltage goes down to roundabout 11,4 V, never had problems with starting my Niro.
This is a cutout from my dashcam, it starts, when I open the door and it is before I start the engine:
6799
 
#13 ·
The battery in the PHEV is very small, and needing a replacement after 3 years is not unheard of. The battery doesn't actually start the engine, but it does need sufficient charge to energize the system to allow the traction battery to be used. Carrying a portable jumping unit wouldn't hurt, but if it's needed on a regular basis then it's time to replace the battery.

How well it would have charged by the main system it dependent on the condition of the battery. If it's on its last legs, the system might have brought it to a useful level for a time, but it won't do anything to improve a battery that needs replacement.
 
#14 ·
This forum and the Ioniq forum are filled with posts of PHEV/BEV owners who suffered early 12 volt battery failures, many inside of a year. Also many on other BEV forums. The issue is that these car charge the 12 volt battery intermittently as triggered by falling voltage. Regular alternator equipped cars provide a constant (around) 15 volts so charging is happening when the car is running. Early battery failure on electric cars can happen with an electrical fault just like regular cars which confuses things a bit.

The cure reported on other forums is preventative battery maintenance once a month or so with a smart trickle charger. These devices are capable of reversing damage to lead acid batteries. Or you can simply replace your battery every so often.

Super annoying that the engineering requires such steps, either a smart trickle charger or a jump starter (or both for those once stranded by a dead car). As a side note, 11.4 volts would indicate really bad battery health in a lead acid battery. The member posting that has an HEV with a lithium battery (unless he owns a 2016/2017 model from Europe) - but anyway, failures of that lithium battery and car electrical design are super rare.
 
#19 ·
My experience with acid batteries is, when they are bad, they do not get down volt by volt, it happens mostly over night and then you can not start your car.
I have now 11,4 V over one year when my car is parked, but for safety I have a jump-starter!
 
#20 ·
Yes, normal internal charging voltage is somewhere around 14.4 to 14.7. External chargers can go higher. And that is what your Niro should read during charging - which is intermittent and triggered by voltage drops as low as 12.2 volts (as reported by observant owners). Those voltage drops damage lead acid batteries. Seems like a simple fix, either provide constant 14.x voltage as suggested above, or raise the trigger voltage to say 12.8 volts. But I'm not an engineer so the reasons why they don't fix this are murky indeed.

This is true even in modern alternator equipped cars that are left for weeks or months between drives. The reason is all modern cars have some vampire current for the doors or alarms which can drain the battery left long enough. I remember once around 1980 flying into an island with my girlfriend and her family car from the 1960's which hadn't been driven for several months started right up! No vampire current drain on old cars.
 
#21 ·
Y’all might want to try this trick to keep your battery being charged all the time. It worked on my HEV.

Keep your headlights turned on all the time. Not on automatic, but on. The car automatically turns them off when you turn the car off so you don’t have to worry about them draining the battery.

On my HEV, I found the voltage fluctuated a lot from high 11 volts up to over 14. Low voltage is not good on an amplifier so I started experimenting. After a while I found that when your headlights are on, the battery voltage stays at above 14 volts! Perfect!

Try it on one of the PHEV or a BEL and let us know what it does.
 
#23 ·
I'm not sure of the exact number but I don't think you need too many volts at all, just enough to get the computers running. I'd like to know the number too LOL. How many volts do the computers need to fire up?
 
#25 ·
Computer chips have very tight limits of operational voltages. Most chips are either 5VDC or 12VDC. They'll tolerate about 10-15% high/low, but that's about it. A 12V device likely either won't work or behave strangely at about 10 volts.
 
#24 ·
My dashcam shows the volt before I start my Niro, it is roundabout 11.4 V ... I see this over more than one year and no probs to start the car ...
Here it was 11.5 V:
6827
 
#30 ·
Just chiming in with a similar problem. I have a 2019 Niro PHEV and have no issues unless I leave a door or the rear hatch open. If I do that I'll have a dead battery in something like an hour. I measured the parasitic draw with door and hatch open and it's about 5A. With doors closed (and waiting for the interior lights to go out) it's around 0.5A. I have the battery saver + enabled and see the message upon startup occasionally that it was used, but it definitely doesn't work when leaving a door open. It's been a real pain on camping trips where I'm in and out of the vehicle without running it for a couple days. I have a lithium jump starter now but climbing into the back of the car to release the trunk can be problematic with a packed car (the battery is low enough where the fob won't open the trunk. It's also fun when I trigger the alarm in the whole unlocking/jumping process).
Brought it to the dealer today for 30k service and asked them to test the battery and look at parasitic draw. I don't think they did a load test, though, and they definitely didn't look at parasitic draw. I'm not sure what battery test they do for the standard multi point inspection... basically voltage test? It passed whatever they did.

I probably need to have a proper load test done and I'm thinking that swapping in LEDs for the interior lights would lower the draw to a point where I don't have to be so paranoid about leaving a door/trunk open!
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top