Hi

I have had and still have an intermiitent drain on car battery, new battery {bossch s3} fitted only a year ago,daily mileage 28/30 - annual 6-8k car will be fine for a period of 3 /6 weeks with no problem or 12/48 hours then battery totally flat,but starts first time when jump started. after a 4 or 5 times of this happening and becoming increasingly frustrated i booked the car into a reputable auto electrican who had the car on test for 12 hours but could not detect a drain but then would he ?? as it was intermittent and i had no idea when the battery would discharge, again totally frustrating at o.4.40 am when i left the house for work and the battery was totally flat - anyway cut a long story short on the advice of my garage/auto electician decieded to have a promax 12 v isolator fitted and it was explained that this would work if the isolator sensed a drain via the battery it would shut down everything, preserving enough power in the battery to restart the car - i know the isolator works as i have experienced drain on 3 or 4 occasions since having fitted and never failed UNTIL the a couple of days ago, a recent cold snap with tempratures down to +1 - -3 degrees, went to the car as normal tried to open with fob but nothing, opened with key as i could see that isolator had kicked in - nothing at all on dash display, no concerns at this point, expexting isolator to kick back in, when turning the ignition key as normal - but nothing at all, had to jump off the wifes audi, it was only then that the isolator kciked back in and it started first time - now not taking any chances due to early start, and disconnecting the positive termial after 14 mile journey, but have tested the isolator since and hey presto works fine after each 14 mile journey

advice appreciated