BeCM Faraday cage may fill gap in market

Hi all,

I had a fault with the BeCM the other day, well not with it directly but while locked and unattended, the indicators went on permanently and my battery died. Jump start got it going and after a lot of discussion and advice from the lovely members here, it seemed that an under performing battery was probably to blame.

Theory being that the BeCM doesn't like a poorly battery. I've heard this before so it made sense. All good now.

However... member zzr1200 referred to something today in the thread "aircon" that lead me to an article on de-mystifying the BeCM and guess what...

The BeCM is very vulnerable to external electromagnetic interference. So if the vehicle is left near an active source of RF transmission, possibly wifi but there are so many sources around these days, could be a mobile phone cell, the BeCM keeps 'waking up'. The place where it was parked uses a lot of radio equipment.

When it is 'sleeping' (locked, alarm set) the BeCM draws 40ma but when it's awake it draws a whole 1 amp!

It usually waits 30 secs after the alarm is set before going dormant but if external interference keeps alerting it, your battery could be buggered in a day.

I know that the remote receiver could be where the signals get in but what if it's actually getting to the BeCM directly?

Does anyone else have a solution to this? Some way of protecting the BeCM from outside RF? A faraday cage perhaps?

Or, am I just going a bit bonkers?

D

It is not the BeCM that is sensative - it is the RF Receiver.....

The RF Rec. picks up spurious signals and wakes up the BeCM to check the signal for the right unlock/lock code....

There are newer versions out there that are not as sensitive and little bit more clever.....

The BeCM (like other electrical equipment) is fairly robust in the RF sense and I am sure that the RF won't disturb the BeCM directly

The source of the interferance is the RF receiver. A Faraday cage will do nothing for you. Very occasionally aberations in operation are cause by alpha particles knocking out a memory bit, but this is pretty rare. The BECM is reasonably well screened, apart from the RF receiver, most problems are caused by voltage, battery, alternator or the fuse box.