Hi all,
First post so be kind!
Really don't know where to go with this one, had a problem with battery drain, bought a new battery 2 months ago, everything seemed fine, then kept draining again, took a reading with multimeter battery is 12.3v with no load, and was going up to 15.5v at idle, no lights warning lights on dash, so presumed it must be the alternator regulator not working.
Purchased a rtx alternator, mechanic installed, all readings fine, when I started car later on, started ok, press gas pedal, yellow warning light on dash, sat nav blinking on and off, special programs unavailable warning on dash, and what seems like electrical power going up and down, tested with multimeter and volts were actually going from around 14 up to 16 and down again very quickly, after 30 seconds or so voltage stabilised at 15.3.... Mechanic said the alternator must have been duff, going to purchase a denso alternator and see how it goes...
My question is, from your experiences could there be anything else that might be frying the alternator? Should I change battery as well as alternator? I'm confused as although reading high, the original alternator wasn't giving me the warnings on dash! Only had the car a few months, and any help/ ideas would be greatly appreciated! Just a bit worried there might be deeper rooted problems..

Thanks in advance guys

Matt

First I'd find out if the battery is draining because something is pulling power from it when the car is off. A new battery or alternator won't fix a "current leak".

Once you've determined that there is no leak, a poor battery won't charge any better with a new or old alternator. If it can't hold charge, it's had it. You should be able to get the battery tested, more tyre places have battery testers (tested under load).

Finally, it seems RRS's are particular when it comes to batteries and only LR approved ones seem to work properly (so I've read on the internet ). Likewise rear brake bulbs... go figure  

"Roads ? Where we're going there are no roads." Back to the future.

This is probably wishful thinking, but I changed rear brake bulb before all this started happening! Just a halfords one, surely that can't cause all this!..the bulb hasn't blown or anything though, does anyone know the correct battery for rrs 2.7 2006.. Spec etc, thanks so far mrfrog

Believe it or not, brake bulbs have been responsible for gearbox faults amongst others. I have Bosch bulbs from Halfords, a little more expensive than the halfords branded ones and no problems. Might be worth an upgrade if you have the cheap o es before shelling out on new battery, etc....

Only a few quid spent if it turns out to be a false alarm. 

"Roads ? Where we're going there are no roads." Back to the future.

Check the button for the upper tailgate, it corrodes and provides a path for the battery to drain, just had to replace mine, and it is an known problem with MY07/08 vehicles Sons of dogs come hither and get flesh
Clan Cameron

Agree check upper tailgate , heard of this often and anywhere else in this area where water can get in