OK couple of things here.
First the trickle charge thing. Does your lighter work? is it nice and clean in the lighter socket? Remember that a trickle charger power output, in terms of amps is quite low so with the resistance build up through all the wiring probably not much power gets to the battery. Plus does the lighter work with the ignition off?. If no then well your kind of stuffed! Try using it directly on the battery to see if it works.
Disconnect both the +ve and -ve leads from the battery and charge it up. Leave it for a couple of weeks, has it gone flat, yes -> duff battery, no, then you have a chronic electrical drain somewhere.
Now you probably don't want to wait that long so...
Next:
You need a multimeter that is capable of reading up to 10amps DC These are cheap from any good electrical or car parts shop
Charge battery as above, connect -ve (ground) lead.
between the +ve lead and the battery +ve terminal connect up the multimeter. Make sure the ignition is off and all circuits are off, if you get a reading then you have an electrical drain somewhere if not then I suspect your battery.
Remember that the clock runs all the time so see if you can disconnect it to eliminate it.
Remove each fuse in turn to see if you can isolate the circuit concerned. If that doesn't work I would then suspect the charging or starting circuit. Now you say you have replace the alternator but did you replace the voltage regulator???
Sticky soleniods on starter
I am assuming that your new altenator is ok, you never know though... :twisted:
Silly things could be. (applies to all cars)
doors not closed properly, interior lights on
bonnet or boot lids not shut properly, compartment lights on
Indicators (turn signals) left "on" activates the parking lights with ignition off, especially german cars
Radio on "standby" instead of off
No disrespect to your mechanics but you really need an auto electrician to look at this problem if the above doesn't work or you don't want to do it yourself. However with a bit of time and a methodical way of working you should get to the root of the problem.
HTH
Malc
Scotland
