12v battery replacement

Dag, how long have you had this battery in, and have you had any problems with it?

 

"... if you properly engineered the thing." Unfortunately they didn't. With all the instances of the car draining the battery 100%, the more headroom the better.

Whenever the car wakes up - Bluelink ping, opening a door, or just rolling over in its sleep (I can show you BM2 graphs), the systems stay on for (I believe) 3 minutes. That drains 1% of the battery capacity.

Some AGM batteries have a rating for cycles at 100% depth of discharge. My car'll be out of warranty before the next time it kills the 12v battery, so I might replace it with one with that rating.

 

I think I observed more like 10 or 15 minutes for full deep-sleep shutdown, and that's without
Bluelink at all [cell modem removed]. Might be shorter after just a drivers-door open.

_H*

 

I'll bore everyone again with the video I made a few months ago, current drawn from the 12V battery.



For what it's worth Telematics are "off". No point, it tries to call Ireland.

 

My 'Rocket' 12V battery turned "5" today without ever letting me down so I decided to return the favour and retire it for other uses. I was hoping to install a higher capacity battery than the original 45 Ah but options seem limited here in NZ. The next size up is 55Ah and it's nearly 40 mm wider. So, I pulled out the battery tray for close inspection, see below.

In the end I decided that modifying the nicely-engineered plastic tray would weaken it more than I'm comfortable with so opted for another 45 Ah calcium-lead maintenance-free in the same DIN44 size (205 w x 175 d x 190 h). Luckily it was on sale (NZ$188) with free shipping and appeared the next day on my doorstep.

Tray measurements below in case anyone else is considering a larger battery.

 

I beleive they fixed the lets kill the battery issue with better firmware. I know I see the little orange light in the front is on from time to time in the driveway. Especially on the weekends when it just sits there.

 

Just a comment on the agm batteries. I've been told the Kona BMS is not designed for agm batteries. (?)

 

I had thought that renewing the 12V battery would have gone smoothly but I was mistaken. The old Rocket always sat just under 13.0 V in between 4-hourly charges but the new Endurant battery has a lower "happy" place, 12.75 to 12.85 V. Sometimes the car treats the battery as expected but at other times it hammers it mercilessly with repeated charges, especially during traction-battery charging where it sits at 14.7 for the entire duration instead of just the first 30 minutes. This can't be good for it.

I'm on my second attempt at "resetting" the system, basically following the Hyundai guideline of "(a) ignition on then off, (b) then with doors and windows closed let the car sit without being disturbed for 4 hours". I may have to take the Rocket off life support and put it back in.

 

Good luck with that
My Rocket will be 5 come March - no concerns still. Unllike yours, 12.75 - 12.8V has long been its normal during 4-hr topups.
I asked my dealer about a replacement; they suggested the Century DIN44LX MF @$185+gst. However, the Century website battery checker brings up the Century LN1 MF for Kona EV, and not the DIN44. I won't be asking the dealer to replace it..

 

Direct replacement batteries seem hard to find here so I was glad I stumbled upon the 'Endurant', which if I recall was a Bosch brand once upon a time. However it doesn't feel like a 'Bosch' construction-wise ... for whatever that's worth. I was thinking about buying a Varta but the DIN44 equivalent doesn't seem to be offered by our importer. There is also a Yuasa that is intended for hybrids, here's the response:



After a reset by dropping all 12V power for several minutes and doing the "power on/off (brake pedal depressed) then leave it be for 4 hours", once it settled into a routine I tried a short traction charge and got a similar effect, completely different than the Rocket. The Kona is being passive-aggressive with my new battery - letting it drain then bashing it with multiple charges. The question is of course "am I overthinking this?"

 

On second thoughts, maybe I will! Yes, the hybrid LN1 will be available next month, but at an eye-watering $900+ - the Century Yuasa DIN44LX MF is the standard Century replacement, available now at $265 incl. gst retail direct from Century. So, my Hyundai dealer price @$185+gst is competitive..

 

My Kona seemed happy on the outside with its new Endurant "starting" battery because it works just fine, but I can see from the BM2 data that it's over-working itself.

I've put the old "Rocket" back in until I can resolve this. I can only deduce that the lower post-charge voltage is causing the car to think it needs further 20-min charge events, which at seemingly random times it issues en-masse. The new battery (an "Endurant Start Master") seems to have a different characteristic curve when fully charged; it's not a matter of capacity. Whenever the Rocket became discharged, under 12.5 V the response was much the same.

Perhaps I'm not able to get the car to "re-calibrate" itself despite following what I think is the correct procedure, cycle ignition then leave car alone for 4+ hours. Without having a BM2 I'd never know what was happening. The downside of ignoring it is increased wear of the contactors and drain on the traction battery.



I've enquired with Century Yuasa here in NZ who's website recommends the pricey LN1-MF "hybrid auxiliary" model which is not currently in stock. They also suggest an DIN44 AGM as a possible substitute. I'd find it hard to believe that the old Rocket is an AGM because it's not marked as such, but who knows?

This was the verbatim response from Yuasa:

I think the response was mostly generic advice and that the issue I'm seeing is more a vehicle calibration than capacity issue based on the fact that most other Kona owners such as @hieronymous see similar post-charge voltages the Endurant is providing, yet don't seem to have a problem. I can't see any reason why the Kona can't use a starting battery if lifetime is ignored, it just has to understand that this is the case. If the Rocket is not an AGM the lifetime has certainly not been a problem.

My options are to pay for access to the service website to see if there is a better calibration procedure, ask the dealer for a recommended battery, or just buy an AGM (perhaps the LN1 MF when available) and cross fingers that it works better.

EDIT: just noted that Hyundai Global Service won't allow access from NZ.

 

Perhaps another option is that, given you have had 5 good years, and that you might move on in another couple, that you stick with your choice; given the suggested high prices for optimal alternatives, perhaps it's time for a cost/benefit approach. The Endurant was a good price - how long does it need to last to prove to be of strategic benefit?

 

That's certainly the pragmatic approach but the engineer in me won't let the car take the abuse, plus I have a need to understand what's happening. I'm probably going to order a Yuasa LN1-MF when available (NZ$410, which I'm assuming is an AGM) and see if that works any better. I spoke to a customer service person at the importer today and they referred me to the dealer regarding the choice of a replacement battery. Asking about pending campaigns, they mentioned the ancient compressor fuse (30A -> 40A, which I turned down) but not any regarding the DC charging issue that has been a major complaint for months for many owners. Perhaps earlier examples are not affected?

 

The nice man at Century Yuasa suggested I might get a better price for a replacement through my dealer or a retailer, rather than direct from them..
As for the DC charging issue, my early example is certainly not affected, but I would have to try it and see, something I haven't done this year..

 

Had trouble fi ding a replacement 12v battery for my Kona 64kwh 2019.

Eventually found an LN1 AGM at super start. Right size, easy to fit.

https://superstart.net.nz/products/toyota-prius-hybrid-battery-ln1-agm-345ln1-mf