[andyswarbs]

Our 12v has been dying quite regularly recently. The lithium charger has been getting us going. But whatever the 12v goes dead time and time again. Obvious conclusion was the 12v battery was dying. This was very sad since our car is just a year old.

Obviously lockdown hasn't helped since we're often not doing many miles. But even after a long journey the 12v goes dead.

A call to our dealership recommended getting the AA to do a quick diagnosis since they couldn't book the car in for a week. The AA came out and the guy spent about an hour doing tests and concluded:

1. The 12v was perfectly good. Big surprise of course.
2. Even when the car was locked there was a continual drain of about 1 volt from the 12v battery.
3. Book it into the dealership for full analysis.

By way of comparison the AA man concluded that my OBD2 connector was drawing 0.1 of a volt. Which he said was acceptable.

So our car is now at the dealership. They've had it for a full day so far and are keeping it overnight for more tests.

All thoughts welcome.

 

[mikeselectricstuff]

Drains are measured in amps/milliamps not volts.
The car takes about 5 minutes to fully power down, so it needs to be left for a while before measuring.
Water in a door (locking controller/switch) has been reported by at least one other user causing battery drain. A more common cause seems to be the boot not latching properly, though this should be accompanied by a warning on the dash, it could be missed if you close the boot and walk away.
If te battery has been left very low for significant time it probably needs replacing - don't recall ofhand what the battery warranty is, maybe 2 years

 

[Gadget Geek]

Was the 4 hourly top up not working?

 

[andyswarbs]

Drains are measured in amps/milliamps not volts.
The car takes about 5 minutes to fully power down, so it needs to be left for a while before measuring.
Water in a door (locking controller/switch) has been reported by at least one other user causing battery drain. A more common cause seems to be the boot not latching properly, though this should be accompanied by a warning on the dash, it could be missed if you close the boot and walk away.
If te battery has been left very low for significant time it probably needs replacing - don't recall ofhand what the battery warranty is, maybe 2 years

The AA man left it for 5 minutes for full power down every time. We checked (as I have often done) the boot latching. I was happy to buy a replacement but, as I originally posted, the AA man (and presumably now our dealership) cannot fault the 12v battery itself.

 

[andyswarbs]

Was the 4 hourly top up not working?

I have seen the light go on at the front occasionally. But, of course, that could be the problem.

 

[freddym]

Drains are measured in amps/milliamps not volts.
The car takes about 5 minutes to fully power down, so it needs to be left for a while before measuring.
Water in a door (locking controller/switch) has been reported by at least one other user causing battery drain. A more common cause seems to be the boot not latching properly, though this should be accompanied by a warning on the dash, it could be missed if you close the boot and walk away.
If te battery has been left very low for significant time it probably needs replacing - don't recall ofhand what the battery warranty is, maybe 2 years

All good points. The battery drain in mA needs logging over a period of hours. A scope with a suitable high sensitivity current clamp will do the job.

 

[KiwiME]

... By way of comparison the AA man concluded that my OBD2 connector was drawing 0.1 of a volt. Which he said was acceptable.

I don't know what mystery units your AA man is using but if you have a dongle in place and it's drawing 0.1 amp, that would likely cause this problem.

If you're not certain the OBD dongle has a functional sleep mode, don't leave it plugged in. In sleep mode the drain will be more like 0.0006 amp.

Treat yourself to a BM-2 and you can track any issues yourself.

 

[GMat]

Did he disable the bonnet switch, the dash in my Ioniq is still alive showing the bonnet is open, although I haven't tried with the doors locked.

 

[Steven4]

OBD adapters often brick 12v batteries in diesel cars (80-90 Ah), let alone the 45Ah battery in Kona. Unplug the OBD dongle after each trip or get a better one - iCar Vgate adapters turn down after 30 minutes.

The AGM battery once flat never truly recovers, they are more sensitive to full discharge than regular lead batteries.

 

[davesul]

In another forum, stageshoot wrote

" I can tell you from experience that if you leave anything connected to the OBD Port on the Hyundai Kona EV it will flatten the 12v battery in less than 12 hours, not because of the item connected to the OBD, but because it keeps all the other computers in the car awake thinking there is diagnostics going on.."

 

[andyswarbs]

I don't know what mystery units your AA man is using but if you have a dongle in place and it's drawing 0.1 amp, that would likely cause this problem.

If you're not certain the OBD dongle has a functional sleep mode, don't leave it plugged in. In sleep mode the drain will be more like 0.0006 amp.

Treat yourself to a BM-2 and you can track any issues yourself.

We took out the OBD dongle and the problem was still there. It has been out ever since. The problem is still there. So clearly the dongle isn't the main problem.

 

[andyswarbs]

In another forum, stageshoot wrote

" I can tell you from experience that if you leave anything connected to the OBD Port on the Hyundai Kona EV it will flatten the 12v battery in less than 12 hours, not because of the item connected to the OBD, but because it keeps all the other computers in the car awake thinking there is diagnostics going on.."

I have had my OBD2 connector in for a full year. No problems. This problem is new.

Yes, @stageshoot is correct for some OBD dongles. I chose one that was supposed to not cause batter drain. And, as I say for almost a year it has performed perfectly.

 

[andyswarbs]

Okay so the dealership had the car for 36 hours and certified everything okay (and yes the dongle still isn't connected.)

My wife drove the car home. I prepared to go out (delivery of clothes etc to Oxfam). Bang. Flat 12v battery.

So the car is now booked in again for Friday.

Btw I had a brainwave. I have deleted all bluetooth connections (I had four devices connected). Not saying this is a deal-breaker at all. But (as with the OBD2 dongle) I am trying to simplify. And if the car is no longer searching for bluetooth connections that can't be a bad thing.

 

[rompik]

@andyswarbs ,
My Kona is already on 3rd battery and the car is just over 2 years old.
I definitely recommend buying BM2 on Amazon. At least you will see what is going on. In my case there was definitely some problem with software - despite having all updates (some of them were applied twice as they were not done correctly first time). Yet I still didn't have automatic top-up every 4hrs like everyone else.

This issue has now been resolved, they also applied another update to ECU (some new "improvement campaign"). I don't have the number of that campaign on the invoice but they mentioned it was the first car to do it
They also replaced battery sensor saying it was faulty. I very much doubt they know it was faulty (I know Hyundai UK told them to replace it "just in case").

But BM2 graphs look very "healthy" now: top ups happening every 4hrs, no big dips in voltage when I start the car, no noticeable drops in voltage when the car is parked. So fingers crossed it will behave better now

 

[donald]

The AA man left it for 5 minutes for full power down every time. We checked (as I have often done) the boot latching. I was happy to buy a replacement but, as I originally posted, the AA man (and presumably now our dealership) cannot fault the 12v battery itself.

Lead acid batteries are (if you have ever read my long, boring, longwinded posts on the fascinating subject of such) able to do all sorts of things you (and those chaps) will not have anticipated.

I have had batteries that were measurably faultless that just didn't work, and ones that had all sorts of measurable issues that still delivered reliably for years afterwards.

You can usually do two things to help you out of the problem of not knowing if the battery is properly faulty;
1) get a top quality battery charger that can be manually set to run a 'desulphation' cycle. Do that, a desulphation cycle. Do it twice. Should take 48 hours, so do it once one weekend when you are not going anywhere and then again the next weekend.
If this (1) does not work then do (2)
2) Buy another battery. If this (2) does not work, do (1) on the new battery.

If (1) or (2), or (1) and (2), or (2) and (1), don't work, buy another battery.

Nah, just kidding on the last one, although it is not impossible that you might buy a faulty battery so keep your wits about you.

There is singularly no way at all to properly test, measure or check if your battery is in perfect shape. It is not a digital device. It will never work 'either' perfectly 'or' completely faulty (the latter, assuming it can still complete an electrical circuit, of course).

Good luck!

 

[andyswarbs]

@andyswarbs ,
My Kona is already on 3rd battery and the car is just over 2 years old.
I definitely recommend buying BM2 on Amazon. At least you will see what is going on. In my case there was definitely some problem with software - despite having all updates (some of them were applied twice as they were not done correctly first time). Yet I still didn't have automatic top-up every 4hrs like everyone else.

This issue has now been resolved, they also applied another update to ECU (some new "improvement campaign"). I don't have the number of that campaign on the invoice but they mentioned it was the first car to do it
They also replaced battery sensor saying it was faulty. I very much doubt they know it was faulty (I know Hyundai UK told them to replace it "just in case").

But BM2 graphs look very "healthy" now: top ups happening every 4hrs, no big dips in voltage when I start the car, no noticeable drops in voltage when the car is parked. So fingers crossed it will behave better now

Thanks @rompik. interesting comments - and it makes me feel like I have a similar problem.

Can I ask a few questions... Does your BM2 attach quasi-permanenty? Do you disconnect before driving? Can you monitor from your mobile phone?

 

[andyswarbs]

Lead acid batteries are (if you have ever read my long, boring, longwinded posts on the fascinating subject of such) able to do all sorts of things you (and those chaps) will not have anticipated.

I have had batteries that were measurably faultless that just didn't work, and ones that had all sorts of measurable issues that still delivered reliably for years afterwards.

You can usually do two things to help you out of the problem of not knowing if the battery is properly faulty;
1) get a top quality battery charger that can be manually set to run a 'desulphation' cycle. Do that, a desulphation cycle. Do it twice. Should take 48 hours, so do it once one weekend when you are not going anywhere and then again the next weekend.
If this (1) does not work then do (2)
2) Buy another battery. If this (2) does not work, do (1) on the new battery.

If (1) or (2), or (1) and (2), or (2) and (1), don't work, buy another battery.

Nah, just kidding on the last one, although it is not impossible that you might buy a faulty battery so keep your wits about you.

There is singularly no way at all to properly test, measure or check if your battery is in perfect shape. It is not a digital device. It will never work 'either' perfectly 'or' completely faulty (the latter, assuming it can still complete an electrical circuit, of course).

Good luck!

Cheers Donald. You're confirming what I began to feel was the case, that is that there is no way to properly say that a 12v battery is healthy. Yes, you can prove it is failing, but the opposite is not easily provable.

No I haven't read your long winded posts. if you can link to one that would be appreciated.

The garage did at least one deep discharge cycle. Is that the same as a desulphur cycle?

 

[MikeS]

Thanks @rompik. interesting comments - and it makes me feel like I have a similar problem.

Can I ask a few questions... Does your BM2 attach quasi-permanenty? Do you disconnect before driving? Can you monitor from your mobile phone?

The BM2 are connected permanently across the battery. Takes about 10 mins once you have the correct spanner.

 

[rompik]

@andyswarbs
Yes BM2 is connected permanently - directly to battery terminals. Even Hyundai connected it after replacing the battery 3 weeks ago.
There is no need to disconnect it.

Yes you can monitor the battery on your mobile - via bluetooth. Way easier to set it up than any eg. OBD2 dongle. Everytime you you start the app is synchronizes data from last time. So you always have full history.

In my case you can see there was no 4hr top-ups:

And when car was starting - huge dips in voltage. This is where booster came to rescue (usually once/twice a day):

BM2 also showed some crazy stuff like voltage > 15v only to drop <9v shortly after. The battery was definitely totally broken (although Hyundai "tested" is ans said the battery was fine)

Luckily the schedule looks much better after software update:

Anyway, good toy for about £25

 

[donald]

The garage did at least one deep discharge cycle. Is that the same as a desulphur cycle?

Regrettably no, but is a route to ensure permanent damage if the battery has started sulphating.

Basically, manufacturers seem to be trying to 'save electricity' (more range) by deliberately (through ignorance) under-charging lead acid.

I think this is sheer ignorance from a digital-electronics generation because all the grey-beards have retired.

What happens is the hydrous lead sulphate turns to solidified lead sulphate and will not resolvate in the battery acid under charge.

Worse of all, get the charge just a little bit low but not much and you end up with one or two of the 6 cells sulphating.

Then you can't tell anything at all. The battery might, for example, look like 10V open circuit when in fact only 2 cells are badly discharged.

It's a nightmare to try to figure this out and the only way (short of old fashioned ways involving draining out battery acid and weighing it .. another post for that) is to give it a desulphation charge, this is a series of pulsed over-voltages which turn the solid sulphate back into spongy.

It is an absolute and total classic way to kill a lead acid by 'charging' it at less than 13.5V whilst it is also forming part of a circuit, which is precisely what some of these companies are doing.

In an ICE, batteries get a good blast of 14.4V for a long time after they have done their cranking business, to get them topped back up. This is a life saver for the battery and any that are routinely held up to 14.4V (and higher still for AGM) will last for years.

So, all of you, every one of you, just get a high quality desulphation charger and blast your battery with that cycle every so often over a weekend. You are then very unlikely to see a problem.

This is a problem purely of the manufacturer's own creation, because they got rid of engineers like me that know this stuff, as a false economy to try to save money (at their customer's expense, so all they end up with is lost business).

Lead acid chemistry is quite a black art. In fact, the commonly held ideas of how it even works (chemically speaking), like wikipedia might offer, are clearly wrong. It's a magical mystery!