HEV 12V Battery investigations

[Indalo]

I find all this stuff fascinating - I just wish we could get some real facts from Hyundai on some (any?) of this.

I have to agree with you, ‘Philr’.

Basic electrickery is within my grasp and has been since I first got involved in motor vehicle electrics back in the early 1960s. However, as electronics have been increasingly utilised in vehicles over recent years, I find myself out of my depth trying to understand some of the problems and hiccups that occur in our 2020s cars.

My difficulty was recently highlighted by my ‘allegedly’ high-end dashcam (well, that’s what they called it!) which insists on talking to me every time I enter the car. I try to pay it no attention as I can’t find a way to switch off the dialogue without switching off the parking mode motion detection which looks as though that would require completely disabling the dashcam.

That said, the information seems to include (and I’m guessing) perhaps a passing HGV or gusting wind causing an alert that might be construed as an attempt to enter the car. Sometimes, overnight, the camera system may pick up one ‘event’ and on other occasions if I haven’t used the car for a few days, there could be 8,9 or 10 ‘events’.

I haven’t found a way to alter the sensitivity of motion detection which was pretty simple to achieve on my previous Next Base model so I wonder if the activity that the ‘lady’? insists on disseminating to me is having any significant effect on battery charge. So far, I have never required to perform a battery refresh but I shall continue with things as they are for the time being.

[PhilHornby]

The Battery Saver triggered at a voltage of 12.41V (much higher than the 11.2 seen in the earlier tests).

Thinking about it, the voltage may have momentarily dipped to 11.2V but it was missed by my meter (since it only monitors once per second). So as far as it was concerned, at one interval it was 12.4V and the next it was virtually zero. This implies that something placed an additional, sizeable load on the battery.

but could this 'background activity' be related to Bluelink?

Would it be worthwhile doing some further tests with Bluelink on/off and/or simple Bluelink app connections to interrogate the car.

Bluelink would be a good candidate, though I only received two notifications during the test ("Door not locked and bonnet not closed" and "Vehicle Off, but Tail light still On"). Perhaps I should have locked the car and dangled my test wires out of the engine bay.

Can Bluelink actually be disabled? - I don't remember seeing a setting to do that. When I checked the web for documentation, I found two (radically different) Bluelink PDF manuals, one for the USA and one for Oz. The UK web page is very sparse and doesn't really match the app. any way

Hitting the Bluelink connection repeatedly may be a possibility, using the Home Assistant plug-in. Hyundai have already had to take 'throttling' action against this, because they blamed it for flattening batteries

I wonder if the dips are scheduled events maybe checks on any status changes e.g. has a door opened or whether events like that are treated as interrupts and not checked regularly only when they happen.

I put my hands up to causing a dip, very early in the test, when I opened a door. I filtered it out of the data I tried really hard not touch anything after that
(I know from previous cars, that innocuous actions (like opening a door) can have unexpected consequences (such as priming the fuel pump!)).

I find all this stuff fascinating - I just wish we could get some real facts from Hyundai on some (any?) of this.

They are a really secretive bunch

[roadster]

They are a really secretive bunch

That is unfortunately true. I've always had a sneaking suspicion that its because they have copied technology from other companies and want to keep that under wraps. Toyota are much more open about their developments and their faults and they are almost certainly the technical leaders and innovators when it comes to powertrain engineering.

Much as I like the Tucson I am very tempted to switch back to Toyota for my next hybrid car.

[Philr]

I do wonder if Roadster is correct about copied technology.
We had a number of new Toyotas over 30 years and I am considering returning to them for our next new car. Toyota and their dealer network were much easier to deal with than Hyundai and the only reason we went with a Tuscon was to see what they are like. The car is OK, the support is not.

[OzJock]

Thanks PhilH, interesting results with the side lights on - mine can’t remember its trip reading after the boot is open for a few mins.
I do wonder how much Bluelink drains the 12v when ‘off’. I noticed a few more aircon/trip resets when on holiday in a poor signal area and I was sending map/destinations to the car for next day. Poor phone signal seems to drain my phone battery faster as it ramps up the 4g/5g signal, maybe the car is doing the same.
Might all contribute to 12v drain but doesn’t really explain why the car forgets some settings but not all - probably just needs a small software tweak by Hyundai.

[PhilHornby]

Thanks PhilH, interesting results with the side lights on - mine can’t remember its trip reading after the boot is open for a few mins.

Yes, I saw your other post. It's distinctly odd that yours is so poor . Quite what the difference is, anybody's guess, but the 'Signal strength' theory is as good as any at the moment. I would have suggested resetting Bluelink as a test, but the Hyundai Live services may still be active without Bluelink.

As to why settings are lost, without the Battery Saver triggering, my only theory is that something effectively creates a very brief 'brownout' condition that results in some control modules rebooting. Given that they run on 5V or 3.3V or even 1.8V, it would have to be quite a load - but of very short duration (a coolant pump, or something like that maybe?).

(The theory that the modules themselves are trying to save the battery - though possible - does not seem at all likely to me. (Sleeping microcontrollers should be drawing negligible current. In fact, they would draw more, if awake and trying to monitor the battery!))

[PhilHornby]

mine can’t remember its trip reading after the boot is open for a few mins.

If it's really that short a time-frame (and reproducible), it would be interesting to perform a little test...

With the car "ON", but not "READY" (i.e. don't press the Brake pedal, when hitting 'START'), do the affected settings still get reset (you should be able to sit and watch it happen)
In this state, the car's 12V electrics are all being run by the 12V Battery, with no input from the LDC, so you would expect it to still occur.

If you had a multi-meter to hand (even a cheap one like this), it would be interesting to know at what voltage, that reset occurs. (Also the starting voltage).

[OzJock]

Thanks Phil, sorry haven’t been on for a couple of days.
Yes I’ve got a multi-meter, for consistency, where do you take your readings from and I’ll try that tomorrow?
Hope I wasn’t exaggerating with the “boot open for a few mins” comment but some weeks it does happen a few times and all I’ll I’ve done is open doors or the hatch for a few mins loading and unloading tools and equipment. Of course it hasn’t happened for the past week.
G

[PhilHornby]

Sod's law says it won't happen if you monitor it (a watched kettle and all that...)

There's a photo here: https://www.hyundai-forums.com/attachme ... pg.459525/ of the 12V terminal. Any convenient earth will do for the -ve connection. I expect a voltage of ~13.2V when you start.
I don't know if a) the settings will 'disappear', with the car in the Accessory position and b) even if they do, if the voltage will have dropped significantly by then.

Whatever you see, it's still data to add to the pot.

(My only theory is still that 'something' makes the 12V supply sag for long enough to upset things, but not long enough for the Battery Saver to trigger).

[terryp]

The other morning, I started the car (all normal) and drove to the end of the drive and stopped for traffic. At that point, the car reset. I was actually looking at the dash when it happened. Never done that before. It was always when I initially started the car.
Three days before I had completed an 80 mile round journey taking about two hours.
Other than that there have been few resets in the past few months. There doesn't seem to be a pattern.