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?

 

[quaycrest]

Ok so after some further investigation I found that on my UK right hand drive i3 I can see the blower motor through the trim panel above the passenger side footwell.

I haven't had the time to remove the trim panel to see if I can access the blower motor via this route to remove it yet. I want to check both the blower motor and blower motor regulator for any damage or wear which might be causing the smoke coming through the air vents.

 

[quaycrest]

After fixing my rear parking brake actuator and my floppy/loose gear lever issues I moved onto the blower heater problem. As my car is a 2013 UK rex I was able to get access to the blower motor via the passenger footwell by removing the plastic trim panel below the dashboard but just above the top edge of the passenger footwell carpet.

Please remember to disconnect the HV battery and the 12v battery before starting this work.

I pivoted the fuse box panel down and loosened the right side of the fusebox panel to give me more room. The access is very limited and you will be working largely blind but with patience and perseverance you can remove and replace both the blower motor and blower regulator if needed. A small mirror can help locate the screws holding both parts and connectors. If you have a replacement blower motor and blower regulator this can also assist in the orientation and placement of the screws and connectors. It took me 4 hours from start to finish and you will need to contort your body into some very uncomfortable positions to complete the replacements.

My blower motor had a burned smell but the regulator seemed normal but as I had a new one of each and being a pig of a job to do I fitted both new units. All heating and cooling is working normally across all temperature ranges and fan speeds with no burning smell or smoke.