Hybrid 12 volt systems 2022

Faults and Technical chat for the Hyundai Tucson
Proterra
Posts: 14
Joined: Sat Jul 17, 2021 10:15 am

Post by Proterra »

Earlier this year my Phev 12v system went dead, no remote access ,anything. The car was checked over for duff battery drainage current etc and found to be ok.
The conclusion was that I wasn’t doing much mileage but using aircon,heated seats, rear window etc,all of run off the 12v battery.
In bought a plug in voltmeter which goes in the fag lighter socket to keep an eye on the battery. No problems since but be interesting to see what happens come winter.

roadster
Posts: 206
Joined: Fri Feb 04, 2022 3:01 pm
Location: South Coast

Post by roadster »

Proterra wrote: Fri Jul 08, 2022 4:13 pm Earlier this year my Phev 12v system went dead, no remote access ,anything. The car was checked over for duff battery drainage current etc and found to be ok.
The conclusion was that I wasn’t doing much mileage but using aircon,heated seats, rear window etc,all of run off the 12v battery.
In bought a plug in voltmeter which goes in the fag lighter socket to keep an eye on the battery. No problems since but be interesting to see what happens come winter.
I think this is the first report of this happening to a PHEV on the forum. The 12 volt battery is pretty big and the car does switch to a lower consumption mode if not used for some weeks. Once switched on the battery will be recharged from the traction battery but of course if you can't switch it on the charging circuits won't activate. Cars which sit in showrooms for a long period can result in them being delivered to customers with low batteries ( both traction and 12 volt ) but I know mine had the electrical systems disabled because the salesman needed a mechanic to reenable it before it could be moved out of the showroom. There is some protection from the traction battery charging system because it does simultaneously charge the 12 volt one.

I don't think use of the ancilliaries will make too much difference once the car is on because there is plenty of reserve in the traction battery and the engine will recharge it if it becomes critical.
Tucson PHEV Premium
Proterra
Posts: 14
Joined: Sat Jul 17, 2021 10:15 am

Post by Proterra »

The conclusion was that being winter I had on the heated seats windscreen etc but was only doing a few miles a day, (Covid didn’t help as we were keeping a low profile as my wife was due for surgery and didn’t want to catch it)
With a plug in voltmeter I can now see what the 12v battery is at.
I also used my Ctek charger a couple of times over winter to give it a charge via the +ve connection in the fuse box under the bonnet.
xtrailman
Posts: 46
Joined: Fri Dec 10, 2021 1:49 pm

Post by xtrailman »

What sort of reading are you getting?
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