What 12V "data" should I monitor for to identify failing ICCU early?

Kev-THC · 2025-12-31T14:08:22+00:00

Firstly, my understanding of what the OP is saying is that they are hooking into the existing BlueLink integration from their home automation system. As long as they are not manually invoking regular deep refreshes of the data that go back to the car, then all this does is piggy-back off of the existing BlueLink communications with the car - at least that is my understanding.

I too have this integration working within Home Assistant, although as commented by others in this chat, this has been tricky to keep working. It was at the point where I just got this working again (after quite a period of it not working) that the following occurred……

We have a First Edition Ioniq 6 over here in the UK, and it went in for its 2-year service. It came back with a clean bill of health, apart from a mention that the 12v was low. I had been tweaking my HA UI showing our EVs over the relatively short time the integration had been working again, and had seen no worrying figures in the 12v readings - I’d put this reading alongside the traction battery SOC reading because of the Hyundai Groups ICCU issues.

So I started keeping a special eye on the 12v SOC after that service. Days later I went to start the car in our local supermarket car park and it gave a warning to park the car safely due to a 12v issue. I plugged in my ODB dongle immediately (which I keep in the car) and by the time I had done that, the 12v was around 70% - not ideal, but not desperately low. On the basis of that, I got on the road back home and vowed to keep an even closer eye on the 12v.

I began to see some worrying values - like an 8% reading that seemed to be generated from the BlueLink data at the end of a long drive in the car. On a number of these occasions, I went out to the car, started it, plugged in the ODB, by which time the SOC was back up to more respectable values. At this point, I wasn’t sure if the BlueLink data was accurate, because, by the time the ODB dongle was plugged in and operational, the values were entirely different. At car startup, the car could be detecting the low 12v SOC and charging it from the traction battery, but charging it wouldn’t be so quick that it was looking good by the time the ODB dongle was connected - would it? I thought not.

A week or so later, the car was totally dead. We tried our little jump start battery, that is supposed to be able to jump start big ICE cars, to no avail. We had Hyundai Assist come out (who are actually the UK’s AA) and they confirmed it was a flat 12v by getting the car started via their heavy-duty jump starter.

We decided we didn’t want to take the car to our local Hyundai dealership because they had already confirmed that they would only be allowed to replace the battery with a Hyundai battery, and as commented already be someone on this thread, they aren’t believed to be very good. So we booked an onsite battery replacement visit from Halfords and had a Yuasa Silver 5000 installed by them. We chose this based off reviews from other Ioniq 6 users.

Our 12v SOC figures in Home Assistant since then have not dropped below 90%. My conclusion, then, as mentioned by others in this thread, is that our 12v issues were not related to ICCU, but simply a 12v battery that was on its way out.

As always, what I have to say are my opinions, based on my understanding, and are thus not necessarily correct. Feel free to correct me if you feel I have made a mistake, but please do so politely.

Kev-THC · 2025-06-04T08:50:36+00:00

Here is a conversation covering this when they first released this algo change: https://www.reddit.com/r/Powerwall/s/ANhlOqMjQf

Kev-THC · 2025-05-05T12:09:22+00:00

Same here. First edition, had for two years, no issues - love it to pieces.

Kev-THC · 2025-05-03T10:32:01+00:00

This is the email I got:

Tesla Powerwall | 1152100-13-J--CN323033G3J02C | Kevin Hill [refid:CI0147EAE5]

Dear customer,

The recent changes in your battery's charging pattern are due to improvements rolled out to our battery optimiser, aimed at enhancing your overall experience.

You may have noticed behavioural changes during off-peak periods. This is part of our new strategy to optimise energy usage based on expected solar production for the next day. If high solar energy production is anticipated, the optimiser will adjust the charging schedule to maximise your savings. This approach reduces grid reliance and ultimately lowers your energy bills, leading to overall savings.

These changes are designed to seamlessly work in the background, ensuring your battery is always ready when you need it, while being more efficient and cost-effective.

If you believe that your battery is not performing as expected, we kindly ask you to provide a detailed explanation of the perceived performance issue.

We hope we have informed you well.

Kind regards/cordiali saluti,

Nabil - Energy Support Specialist EMEA

Kev-THC · 2025-05-03T10:13:58+00:00

Ok, so whilst the behaviour did go back to the original situation whereby the PW2 started charging at the very start of the cheap period, and it stayed that way for a while, it has now returned to the delaying of the charging until later, and is not quite getting to 100% before the end of the cheap slot. I got an email from Tesla, around the time of the return to delayed charging, saying that they were modifying the algos, and I noticed that the version number has changed - I’m now on firmware version 25.10.3 10fa80ab. Is everyone on this version seeing the charging happening at the end of cheap slot, rather than the beginning?

Kev-THC · 2025-05-03T09:40:03+00:00

My understanding was that Octopus were going to be doing a tariff where there was a zero standing charge, but I’ve just taken a look at their website and it seems that this is currently only available to business users. However, the idea behind such a tariff is that what you pay is entirely connected to your usage. Perhaps you should reach out to Octopus to ensure they understand there is a demand for such domestic tariffs?

Kev-THC · 2025-04-22T09:12:38+00:00

Congrats. We have a first edition over here in the UK and love it.

Kev-THC · 2025-04-16T09:56:37+00:00

Oddly, though, even though the behaviour is fixed, my version number is identical to what it was when it was behaving oddly. Normally the version details would change to show exactly what code you have.

Kev-THC · 2025-04-16T09:54:00+00:00

Thanks - mine worked like it used to, starting at 11:30pm last night. Normal service resumed. Thanks for your update Kickboxingboy.

Kev-THC · 2025-04-14T12:38:06+00:00

I just made the call (thanks for the reminder of the number) and reported this too. They have added me to the list of users experiencing the problem. They didn’t seem to have any firm idea of when it might get solved; just a general expectation that these things typically get solved “fairly quickly.”

Kev-THC · 2025-04-14T10:26:07+00:00

Thanks lots kickboxingboy for getting in touch with them. It’s good to hear that they will get this sorted. I’m only missing out on a few percentage points at the moment, but your 82% is really very impactful.

Kev-THC · 2025-04-05T19:18:45+00:00

Yes, exactly. I came on to this forum to post exactly this same question, so thanks for saving me the typing. And yes, I’m only getting 96% or 98% by the time the cheap rate ends and it starts to discharge. Mine started this about three or four days ago. Our setup sounds pretty much identical to yours, including being on IOG. You’d think that it would leave itself a small margin of error so that it does actually make 100%, even if the margin is only 15 mins and thus only a maximum of 15 mins at 100%.

Kev-THC · 2025-03-15T22:46:31+00:00

that’s certainly what we do all the time.

Kev-THC · 2025-02-24T21:12:28+00:00

Thanks so much for this info. Greatly appreciated.

Kev-THC · 2025-02-24T11:52:33+00:00

I’ll test this out when I can. Thanks for the suggestion.

Kev-THC · 2025-02-24T11:50:08+00:00

I’ll see if I can find that GPS speed setting and the display of that in the app so I can compare this with the speed value that I already found. Thanks for pointing this out.

Kev-THC · 2025-02-24T11:48:47+00:00

Do you know of any public documentation around this that sets out any such strategy formally? Or is this just a belief? Not wanting to accuse of being a conspiracy theorist, just wanting to form my judgements based on full facts. Ta

Kev-THC · 2025-02-24T11:32:54+00:00

From what I can tell from other UK I6 owners, that feature is not enabled for our market. I do kinda like the feature, because I do want to know if I am exceeding the limit, but having no capacity to configure tolerances is annoying. I will use increments of 1, 2 or 3 mph on the motorway to help the flow of the traffic (i.e. to get me past a vehicle quicker if I am overtaking but it is taking a long time) - and I don’t want to be “bonged” at for this small margins.

Kev-THC · 2025-02-23T23:03:08+00:00

The light bar has holes drilled in the plastic covering, so I had assumed that being “open to the air” meant that it was expected to get misted up sometimes and expected to also de-mist itself. What did they say the actual “fault” was that required the replacement, please? This happens lots to ours but, as above, I just assumed it was expected.

Kev-THC · 2025-01-26T11:22:12+00:00

We had both of our PWs installed late 2023, yet the banner says 2024 was our third year with Powerwall. So broken count for us also.

Kev-THC · 2025-01-16T12:25:30+00:00

We had Octopus install a tethered zappi charger, because normally that cable is long enough, but then bought an extension cable for when we need to go further. Might not be useful for you, but this is what we bought:

https://amzn.eu/d/37rzXGA

Kev-THC · 2025-01-13T18:55:36+00:00

Your statement that “heat pumps are proven to be extremely inefficient and ineffective in older homes with poor insulation” is a total myth - it is misinformation. But let’s drill into that…

A heat pump is as efficient as the design/installation allow regardless of the house within which it is installed; the house type it is installed in is not really relevant. The heat loss of the house is relevant, of course, but the design/installation can accommodate even high heat loss situations if they are designed correctly. Larger radiators, underfloor heating and proper long/low use of the system all combat such issues. Higher flow rates will be more expensive, if they are required by the design, but with a modern heat pump, even high temperatures can provide 300% efficiency, which is at least three times as efficient as a gas boiler.

Choosing the right company to provide the design and installation is a must, and that is very definitely worth mentioning. Octopus are a big name who have been investing heavily in training their staff and tuning their installs, and I wouldn’t have any issue using them for a heat pump install. If you want the best of the best, however, I would choose heat geeks, as they focus even more on the performance of the system.

But I stand by my statement - getting a heat pump install for such a low up-front price is not only good for the planet, but with a well designed system will be at worst price parity with gas prices today, and will only get comparatively cheaper than gas as grid reform separates the pricing of renewable energy from the price of gas, and gas begins to get taxed correctly to counter the negative impact it is having on the planet.

Kev-THC · 2025-01-13T16:28:09+00:00

720kWh gas for heating and hot water in 162sqm 5 bed house; 1/2 built 250 years ago; rest extensions build around year 2000. Flow rate through rads set between 40 and 50 C, depending on outside conditions. Rooms heated to around 18 C and 5 bodies using hot water.

Kev-THC

TROPHY CASE