I’ve driven the BX and Freelander a total of 5 times in the last two months, neither is on the freshest battery. I’ve been a little concerned about needing to go somewhere and having no go in the battery, but my little CTEK trickle charger has become my go-to solution for positive battery preservation!
The standby power consumption of the two cars is quite different. The Freelander is a drive-able computer with many ECUs, but a clever system to isolate many of its systems from the battery. The BX only has only two micro-controllers. One for the engine and one for the alarm/immobiliser, however, it is seldom driven far enough to charge an AA battery.
I first bought a trickle charger in 2015, a CTEK XS3.3, for the princely sum of £35 on Amazon. At the time this was cheaper than even the lowest cost Aldi clones. With a modest 3.3A charging capacity, it’s not designed to charge batteries from flat (although given enough time, it will). I bought it with the sole intention of preserving the ageing Bosch battery which was already 10 years old.
Both cars now have a permanent CTEK connection to the battery, a very convenient addition at about £4 each. The XS3.3 is no longer made, the nearest equivalent is the MXS3.8. This newer model has better conditioning and recovery features and just a little bit more output power
The XS3.3 weighs little, is very compact and quick to install under the bonnet. I typically run a 230v extension lead up from the floor into the engine bay and plug the CTEK unit in there. Not strictly a dry zone, but the bonnet keeps the rain off when parked. The CTEK its self has a (low) IP rating so condensation and humidity aren’t a problem.
The initial investment has more than paid for its self, I’m really glad I bought it. The BX battery has limped another 5 years until being swapped out at nearly 15 years old. The CTEK has been used to charge the kids second-hand electric quad bike (2x6v) which came without a charger. It has been used to test small 12v items like motors, bulbs and lights, and now in the midst of Covid19, is on a rotation with the Freelander. The Landy started first time yesterday after very little use and a 7-year-old battery. I would strongly recommend the CTEK brand if you’re looking for a trickle charger!