Which 12v battery for 2013 rex UK?

[quaycrest]

I think my 12v battery might need replacing as I am getting some error messages esp when HV battery is very low such as parking brake errors. So I wondered what battery to buy and from where in the UK. Although I am a bit concerned about a few cars being bricked after a 12v battery change!
Many thanks for any help or guidance.

 

[mojo]

In the UK it's about as simple as you can get: just buy one from a BMW parts department.

 

[quaycrest]

Ok replaced my 12v battery with an equivalent motorcycle/leisure one and following the procedure found on this site all went well. No issues with restarting car and even managed to clear some error codes that would not clear beforehand. Just as I was feeling pleased with myself for a job well done I turned on the heater at full temperature with blower at full speed and pungent smoke started coming out of the window vents. Immediately turned the heater off and the smoke stopped. My first thoughts were my car is going to go on fire any minute!

After getting out the car sharpish I left it for a while to see if anything developed or got worse. I looked out my home fire extinguisher just in case. It didn't get worse or ignite so I got back in and restarted the engine with no heater. All was well, no smoke. I turned the heater on at lowest temperature and fan at low speed but still smoke appeared all being much less than before.

So my question is has the new fully charged 12v battery taken out the blower and or the blower regulator?

Or something else.

 

[mojo]

Realistically, all you can do is re-check what you've done. The common problem, and the reason why I recommended going to a BMW dealer for *exactly* the right battery, is that the terminal connections can be slightly different on similar but not identical motorbike batteries, and they apparently need slight modification to seat correctly. Although that might lead to the battery connections overheating, I can't see that happening in the timescales that you are talking about. But... I would examine any terminals that you may have removed/replaced carefully to look for overheating.

Typically if the fan speed regulator has failed you should expect to get no fan operation, or only fan operation on the highest speed.

 

[EvanstonI3]

If you have "pungent smoke" coming through your vents, it is most likely coming from wherever it is drawing "fresh" air and perhaps you have a short in the Frunk area? Or perhaps the heater element has failed? If so I rather doubt it has anything to do with the new battery.

 

[quaycrest]

I had to modify the negative terminal attachment post to allow correct seating on the new battery by taking about 3mm off one side of the terminal connection attachment post allowing clearance to the top battery casing. The positive terminal attachment post seated correctly on both old and new batteries. I will recheck the battery connections and inspect the frunk area for damage or burning. Thanks for the help and advice.

 

[quaycrest]

Is there any way to access parts of the heater matrix without removing it from the dashboard?