Hybrid 12 volt systems 2022

Faults and Technical chat for the Hyundai Tucson
roadster
Posts: 125
Joined: Fri Feb 04, 2022 3:01 pm
Location: South Coast

Post by roadster » Sun Feb 27, 2022 10:44 am

There has been much confusion about the 12 volt battery types for the hybrid vehicles and its not helped by the european owners manual which has a considerable description of a Lithium type 12 volt supply without saying which versions its fitted to. So first let me show and describe what is actually fitted to my new PHEV premium model.

DSCF2628s.jpg

Yes its a 12 volt lead-acid battery.

DSCF2629s.jpg

... and a pretty big one at 68 AH.

So manual page 9-23 applies and the description on page 8-5 does not. Its very possible that the lithium 12 volt supply only applies to the "ordinary" hybrid. This could just be a pragmatic decision by Hyundai that the spare space in the housing of the much smaller hybrid battery might as well be used for some extra cells for the 12 volt supply.

This brings us to the battery reset button ( also not present in my car). Cars that have this ( can a hybrid owner please confirm that they do) have a battery management system which monitors battery charge state even when the car is not in use. This is to prevent over depletion of the battery caused by alarms and on-line services etc. At a certain level of depletion all non-essential systems are switched off and can only be (briefly) reactivated using the reset switch. This is just long enough for the main part of the lithium battery to begin replenishment of the 12 volt side once switched on. The engine would normally be run immediately in this case.

The unknown for PHEV owners is whether a similar 12 volt maintenance arrangement is active for the lead-acid battery when the car is switched off. Because the lithium battery has about ten times the capacity of the ordinary hybrid it would certainly be capable of doing this for a long period. There will be times during the summer months when I make little use of the car so I will monitor the 12 volt status and report back.

One observation of interest is that monitoring battery voltage via the OBD port showed 14.8 volts while switched on. This indicates a high charging rate from the Lithium source ( engine was not running).

Another observation: When charging via the ICCB cable the 12 volt battery is also put on charge. I'll take another reading near the end of the charge cycle but I would guess that charge rate will be independently managed.
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Glenorchy
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Joined: Tue Jan 11, 2022 1:37 pm

Post by Glenorchy » Fri Mar 04, 2022 9:19 pm

I have 230 HEV. Yes, it does have the 12v battery reset button on the dash. No separate 12v battery in the boot. It has a 12v tap from the lithium battery pack.

roadster
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Joined: Fri Feb 04, 2022 3:01 pm
Location: South Coast

Post by roadster » Tue Mar 15, 2022 9:34 am

I have now measured ( via a contactless ammeter ) the charging current to the 12 volt system at 10 amps during plug-in charging. This was hitting the sensible voltage limit of around 14.8 volts when the battery started at a no-load voltage of 12.3. The charging stopped when the plug-in was switched off automatically by the car because the Lithium battery was fully charged. So the 12 volt system won't necessarily be fully maintained if maximum effective plug-in time is six hours ( for the 10 amp AC setting). I have yet to find out whether there is any provision for maintenance of the 12 volt system from the Lithium battery if the car is unused for a long period. In any case it should be possible to jump start or charge using the live terminal under the fuse box in the engine compartment.
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DrElectron
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Joined: Wed Sep 22, 2021 5:37 am

Post by DrElectron » Mon Mar 21, 2022 7:55 pm

There was also some confusion previously about the battery arrangement for the ultimate model, with some rumours suggesting the 12v battery was relocated to make space for some other features. I can confirm that is not the case, my boot floor looks the same as yours (PHEV Ultimate).
It also does have the battery reset button

roadster
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Location: South Coast

Post by roadster » Tue Mar 22, 2022 9:04 am

DrElectron wrote:
Mon Mar 21, 2022 7:55 pm
There was also some confusion previously about the battery arrangement for the ultimate model, with some rumours suggesting the 12v battery was relocated to make space for some other features. I can confirm that is not the case, my boot floor looks the same as yours (PHEV Ultimate).
It also does have the battery reset button
Now that really is confusing. You have a (current European model? ) PHEV with a 12 volt lead-acid battery but you also have a battery reset button? So the battery reset function is omitted from the lower spec PHEV only? (mine)
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DrElectron
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Post by DrElectron » Tue Mar 22, 2022 7:33 pm

roadster wrote:
Tue Mar 22, 2022 9:04 am
DrElectron wrote:
Mon Mar 21, 2022 7:55 pm
There was also some confusion previously about the battery arrangement for the ultimate model, with some rumours suggesting the 12v battery was relocated to make space for some other features. I can confirm that is not the case, my boot floor looks the same as yours (PHEV Ultimate).
It also does have the battery reset button
Now that really is confusing. You have a (current European model? ) PHEV with a 12 volt lead-acid battery but you also have a battery reset button? So the battery reset function is omitted from the lower spec PHEV only? (mine)
Yes mine is a UK model.
I wonder if it is something to do with bluelink connectivity potentially draining the battery, maybe the base models don't have it?

DrElectron
Posts: 82
Joined: Wed Sep 22, 2021 5:37 am

Post by DrElectron » Wed Mar 23, 2022 3:15 pm

Just realised mine actually doesn't have a battery reset button, although I remember the dealer explaining it to me so no idea?!

roadster
Posts: 125
Joined: Fri Feb 04, 2022 3:01 pm
Location: South Coast

Post by roadster » Thu Mar 24, 2022 10:02 am

DrElectron wrote:
Wed Mar 23, 2022 3:15 pm
Just realised mine actually doesn't have a battery reset button, although I remember the dealer explaining it to me so no idea?!
OK that makes more sense. I would still like to know whether there is any kind of automatic monitoring of the 12 volt battery and I have noticed that there is a theoretical red colour of the external status light which the manual says comes on when it is necessary to charge the 12 volt battery from the traction battery. I suspect this may only refer to the lithium one and I'm not prepared to deliberately discharge mine in order to find out. Hopefully with the months of lockdown behind us there won't be so many owners finding that their car wont start after standing idle for weeks on end.
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roadster
Posts: 125
Joined: Fri Feb 04, 2022 3:01 pm
Location: South Coast

Post by roadster » Tue Apr 12, 2022 8:17 am

I have monitored the 12 volt charge after not using the car for a few weeks and so far haven't seen the voltage drop below 12.1v . After a certain time the car cut back on some functions to save power. I noticed that Bluelink services de-activated and the automatic mirror proximity deployment stopped working. Door locks worked as expected when the button was pressed but I didn't check key fob unlocking.
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johhan
Posts: 1
Joined: Wed Jul 06, 2022 9:23 pm

Post by johhan » Wed Jul 06, 2022 9:26 pm

roadster wrote:
Tue Mar 15, 2022 9:34 am
I have now measured ( via a contactless ammeter ) the charging current to the 12 volt system at 10 amps during plug-in charging. This was hitting the sensible voltage limit of around 14.8 volts when the battery started at a no-load voltage of 12.3. The charging stopped when the plug-in was switched off automatically by the car because the Lithium battery was fully charged. So the 12 volt system won't necessarily be fully maintained if maximum effective plug-in time is six hours ( for the 10 amp AC setting). I have yet to find out whether there is any provision for maintenance of the 12 volt system from the Lithium battery if the car is unused for a long period. In any case it should be possible to jump start or charge using the live terminal under the fuse box in the engine compartment.
Would you share the amps at which it charges when the vehicle is on (ready to drive)?

I was using the 12v with an external inverter to power some tools but couldn’t find anything online about the charging current when the vehicle is on.

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