Hybrid 12 volt systems 2022
Posted: 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.
... 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.
Yes its a 12 volt lead-acid battery.... 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.