12v battery replacement

I noted that even though Yuasa NZ recommend the LN1 MF (AGM) for the Kona EV, Yuasa UK and Europe recommend a normal flooded starter battery. I really would prefer an AGM because I can see that a flooded battery struggles with doors open for more than a few minutes. The DIN44 size format is the only size (that's available in NZ) that fits in both the battery tray and the lead length. The charging voltage (14.65) appears to suit either type.

@Rukksi , do you have a BM2 voltage logger? It would be awesome to prove the car is happy with the AGM type. BM2 is available at Supercheap and Jaycar.

The situations to watch on the BM2 are (1) that charging is at 4 hour intervals, not more frequently, and (2) for 30 min at the start of AC (traction) battery charging, not longer. I bought a (very) cheap flooded DIN44 and my Kona hates it so I'm back with the old Rocket.

Century-Yuasa told me a few days ago that the next shipment of Yuasa LN1 MF is due late Feb 2024 and that sometimes "Toyota buy them all". They won't sell me one directly or reserve one but told me I'll have to find a retailer here in Hawkes Bay who will backorder it.
 
Thanks @KiwiME , I'll add a BME to my Christmas list and see what it shows.
Next problem I have is that the Air Con isn't working - evaporator replacement needed, just the $5,000 quoted to fix.
I'm starting think the Kona is a lemon o_O
 
If it’s the evaporator or condenser in the cabin HVAC air path tell them it’s a known defect and they need to chip in.

Meanwhile I just checked with Toyota and they have a Yuasa LN1 at $800. So I walked across the street to Repco and ordered the equivalent Century AGM which they said will be available this afternoon at $450.
 
KiwiMe you are far more expert than me but I noted your comment about the flooded battery V the AGM and repeat and expand my comment above that I was told by the SuperCharge agent who sold me my new ($AU150)battery that the BMS on most EV and Hybrids don't like AGM batteries.
Since then I have travelled about 20,000kms on the new battery. No problems so far.
 
My Kona protested about the new very-inexpensive 45Ah 'Endurant' flooded battery I installed in October by charging it over and over even though it was already fully charged. That won't hurt the battery but it's not great for the car. Without a BM2 I'd never have known this. That battery is now installed as a backup for my internet hardware in case of a power failure.

I tried the Yuasa flooded battery out of my Suzuki Grand Vitara which is 55Ah and it would just fit lengthwise (222 mm, with minor tray mods) and was perfect widthwise but was 25mm too tall for the cables to reach. The Kona seemed electrically happy with it though over a few hours tested.

Now I've installed the new and very-heavy $450 Century stop-start AGM (at 1300 hours today after charging it off-line for an hour) and so far the car has simply ignored it! It should have "probed" it with couple of 20-min pulses as it has done every time I previously temporarily disconnected 12V power. I'm nervously awaiting some sign of recognition otherwise I may have bought myself a second expensive desk ornament.

It's very hard to find reliable and high-quality information about battery suitability. I recall a few Kona owners over the years have reported installing AGMs and so-far no one has reported a problem, but I'm not sure if they are checking the details as closely as I am. And, it's also possible some don't want to come back and admit their mistakes. I've asked a Hyundai tech, the dealer, and searched the service docs and all over the internet with no better information. But, the Kona's charging voltage seems suitable for an AGM and Yuasa recommend that type, so why not?

Of course I'd prefer to spend only $190 on a flooded battery but it's fairly clear to me that the capacity of that part has insufficient headroom to run the car without traction battery support past just jumping in, hitting start and driving off. The AGM offers not only more resiliency but better use of the 20 minute charging period due to the lower internal resistance.

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The new AGM 12V battery was ignored by the Kona until I placed the traction battery on charge for an hour. Then, after a series of frantic repeated charge events the car settled down into the normal routine. The Kona is charging the AGM at a slightly-higher (0.1V) voltage than the Rocket but settles to a lower level by a similar amount. Ambient temperature is in the 20-30°C range.

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KiwiME said:
The new AGM 12V battery was ignored by the Kona until I placed the traction battery on charge for an hour. Then, after a series of frantic repeated charge events the car settled down into the normal routine. The Kona is charging the AGM at a slightly-higher (0.1V) voltage than the Rocket but settles to a lower level by a similar amount. Ambient temperature is in the 20-30°C range.

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That's good to know - thanks for the detailed feedback.
 
hi KiwiMe thanks for the info above, i have a too and a half year old smooth Kona electric and am in west Australia with blue coolant.
I have just changed my 12 volt battery, no sine it was going to fail at all, it was checked by the dealer 2 months before on the 60,000 km service.
unable to get a Din44 LH any wear in west Australia, so fitted a Century Din53 LH AMG instead, its the same width 175 mm and height 190mm
and its 242 mm long instead of the din 44,s 205 mm long thanks to your i new if i removed the 4 X 14 mm battery stops on the right end of the battery carrier and cut out the lip on the left hand of the battery carrier it would fit, it dose fit very well and the leads fit good as well, i just needed to not reclip the + cable back into its hole as it pulled the cable out of line with the new battery extra length, I found the AGM battery sat at float 13.2 volts which is to high for the Kona to charge it, 12.6 volts seems to be the charging start point when the car is not driven, it charges up to 14.7 volts happily when driving and also when the main battery is on charge. I think the too best parts the din 53 was only 6 dollars dearer a $299 and has more than 50% more capacity at 640CCA
 
As tempted as I was to go for 60 Ah capacity over 50 Ah, I wasn't comfortable with modifying the plastic battery tray from a structural perspective. I had considered buying a battery tray from a S. Korean recycler to test the idea but it would have added another $90 to the $190 lost trying a cheap flooded DIN44 battery that the Kona 'rejected'. Of course if I couldn't buy a DIN44 I would have gone for the DIN53 without question.

It's good to know that the cables fit in case I eventually try that.
 
Well, I think my 2nd battery is dying. I replaced the original after about 2 years, and now it's been 20 months and this battery has needed boosted twice today. I'll give it a full charge tonight on the bench, and see if it behaves for a couple more days before replacing . . . again.

There's definitely something that Hyundai doesn't have figured out with regards to 12v battery maintenance in this EV. Water water everywhere, and not a drop to drink!
 
Hello KiwiMe,

I have a question about your AGM battery in your Kona. how did you deal with venting the battery? I remember in my Benz CLA it used to have a vent hose to be connected to a vent hole on the AGM battery. AFAIK the Kona has no such vent hose. I dont think this does anything strange, it just vents any accumulated gases to the outside of the engine compartment.
Did the AGM battery come with vent plugs? What did you do in this case?

I am reading that AGM batteries produce some gases as they charge, and they are not safe to be charged at higher than 15V.
For in-char operation we are covered, but a traditional battery charger ( such as my old wheeled Schumacher) allagedly charge at as high as 18V, some manufacturers warn against using such chargers with AGM, for fwear of the battery exploding dfrom the gas pressure.

I am also reading about manufacturers warnings about " do not leave the went holes open, the AGM battery will dry out..". So I wonder if some modern AGM batteries such as the Century or in my case the AC Delco have some venting "valve" solution, that releases over pressure but otherwise is closed
 
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coder said:
Hello KiwiMe,
\I wonder if some modern AGM batteries such as the Century or in my case the AC Delco have some venting "valve" solution, that releases over pressure but otherwise is closed
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I think the vent. caps just be release overpressure, if any. In the engine compartment, you my be able to ignore the issue alltogether
 
I haven't previously investigated how these lead-acid batteries 'vent' or handle changes in local barometric pressure but there seems to be good info here at Battery 'University' which indicates that they're sealed but with an overpressure vent. I did have a BMW in the late '90s which had a battery vent hose that would annoyingly drip acid onto the rear suspension.

It's not something that I've felt I needed to investigate on the Kona since the battery is outside the cabin. Just making sure the car was happy with it electrically was worrying enough and so far (2 months on) it still appears completely normal, just like the old 'Rocket' but with less voltage drop. There doesn't seem to be anything unusual about this AGM and it's used in stop-start type ICE cars. It's not a deep-cycle battery, just a starter battery with more capacity for the size and apparently better at quickly taking on a charge.

I had never used a battery charger on the OEM Rocket that is still good in its sixth year. I have used Utility Mode (14.5 V) a few times when I thought it needed help. The Rocket is sitting next to me here in the kitchen begging not to be dropped off at the recycler. I built a battery backup for my internet connection hardware and can use it for that.
IMG_3292.webp
The graph shows the typical behaviour after short drives. There's alway a net loss of charge on shutdown that isn't made up until the next 4-hourly scheduled charge event. At 2300 it added a second charge to make up for the low voltage found at 2100 (just before the previous charge) despite that just one charge was sufficient to recover.
 
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Thanks for the battery academy link. it points out something unexoected ( to me)
It is counter-intuitive how dramatically bad deep discharging lead-acid hatteries is. Full discharge (100%)
apparently kills a leAd acid (starter) type battery in as few as 12 such cycles.
I am reading that the lead acid batteies should ot be discharged more than 30%. If 50% depletion hwppens
the bttery can be kille in 100 sucb cycyles.
Given how he Kona BMS works, it seems to me. an AGM battery is a better fit than a typical starter battery.
Those of you with a BM, perhaps share an insight if the Kona BMS lets the battery to discharge more than 30%?
 
The only time my original battery was under that 30% would have been during dealer visits. They’re unfortunately clueless about this. Being out of warranty now I only use them for the annual safety inspection.
 
On my end, the plot thickens. I was getting by jump-starting the Kona using a Noco lithium battery based jumpstarter, but I tried to charge the car today and
it now refuses to charge. Waiting for a new Ac Delco ln1 Agm to arrive, but I get now a "Yellow triangle" warning, saying check electrical system and the car refuses to charge. The 12v Rocket battery is now totally dead, does not hold a charge at all. I put a charger on it, @13V so it powers up, but still refuses to charge. I remember this is how my Propulsion battery failure started, so I now do not dare to swap out the battery for an aftermarket one, just in case my freshly replaced propulsion battery is failing again. Here in the US we have a 10 year 100k mile power train warranty, and lifetime warranty on the propulsion battery. The unpleasant aspect is that the dealer will replace the battery with the baseline flooded battery they now use , and I likely have to pay for installing that. I expect the Ac Delco today, I wonder if I should just swap the battery and see what happens.

KiwiMe, would you expect (have you seen) the Yellow triangle "Check electrical system " warning solely caused by the 12v battery? I guess if the battery swap fails to cure my problems ( the warning and the refusing to charge) I can always put back the Rocket, and take it to the dealer.
 
coder said:
KiwiMe, would you expect (have you seen) the Yellow triangle "Check electrical system " warning solely caused by the 12v battery? I guess if the battery swap fails to cure my problems ( the warning and the refusing to charge) I can always put back the Rocket, and take it to the dealer.
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I don't have any experience with the triangular yellow warning light. I do know that it covers many issues and in some cases the car can't be driven.

The LN1 is the correct application for the Kona EV according to Century-Yuasa in NZ and Australia. For some reason they recommend a flooded type on their European site.

When you swap it out don't attempt to support the 12V system, it needs to know that the battery may have been changed. This is the process I used and it did actually come from Hyundai: After the swap, enter Run mode (foot on brake) leave it for a half minute then switch it off. With all windows (and charge door) closed and the doors locked leave the car undisturbed for 4 hours.

If you have a BM2 you can check the progress. The last time I followed this process nothing happened in those 4 hours so I put it on traction-battery charge for a couple of hours, removed the plug and that kicked it into life. Mine took a few days to settle into the normal routine.

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upload_2024-2-23_8-41-16.webp Century AGM after charging.webp
 
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Thanks, ... I'm the same person on all the Kona EV forums.

That BM2 is fine. In many cases you can install it without disturbing the battery power connections if you obtain (2) M6 nuts and use the free end of the existing studs. You can also place the negative lug under any other nearby grounded fastener.

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