battery light staying on + car alarm going off

[dub-disaster]

  hi all, i have a problem with my g and it is that when i start it sometimes the battery light stays on until i lightly press the throttle then it goes out, my car has no problems starting the headlights do not change brightness when i rev the engine at al , they only dip when i star tthe car wich is normal,
   so firstly checked the voltages on the battery wich was fine with the ignition switched of it was just a bit over 12v i then start the engine and the battery light stays on and the voltage dips down to 9v as the engine starts then comes back up and settles at 11.5v while the battery light is on in the car then i lightly tap the throttle the light goes out and the voltage goes up to 14v roughly so i assume that the altenator is charging ok also if it wasnt charging ok i would assume i would have problems turning the starter motor over especialy when left for a couple of days without driving .
   Ok so next i got an ameter and put it in series with the neutral at strangly it was pulling 700 ma ish down to earth with the ignition of so i assumed that somthing was draining the battery so i went to dissconnect the amp to see if it was that and i accidently touched my metal screwdriver against the metal casing of the amp whils undoing the live terminal , now no damage was done and every thing works fine but when i went back the the ameter it was reading 0 with the ignition turned of , and following this i recconteced the battery and checked the abttery with a battery tester from work wich said it was detecting a surface charge which genrally means theres somthing pulling current of the battery , no this batery light staying on doesnt cause me any major problems but my car alarm keeps going off all the time and im not sure if it could be the car alarm that is effected by a charging problem and going off when the battery goes flat or if the battery is going flat due to the car alarm but it is annoying and im not sure what eelse i can do . the car alarm is a sigma car alarm that was fitted by a previous owner but as i do not have any insturctions or wiring diagrams i cannont do many more checks also sigma has now gone bust or has ceaced trading so i can't even ring them up and find out any more information , the wiring is very hard to follow around the engine bay and im not evan sure where the fuse box is in this car as i have only owned it a couple of months any help would be appreciated thanks

[supercharged spaniel]

Well from you've told us I'd say the voltage is too low. 11v isn't high enough. It should as far as I can remember be around 13v. There is a guide in the FAQ here that gives exact figures for testing numerous components. The fuse box is on the opposite side to the battery in the compartment at the back of the bay on the bulkhead. Passenger side. It has a clear cover over it and a small Phillips head screw that secures it shut.

[supercharged spaniel]

Reading it again it does sound like the alarm is fucking with something. If you want to remove it it's pretty simple. I removed mine and just dismantled everything under the dash and slowly took bits out bit at a time, resoldering neatly the wires and wrapping in original loom tape which you can buy from the dealers. You can't really go wrong cos original wires are fairly obvious. Obviously don't cut anything until you've traced it's path and are happy. It'll probably connect into the relays next to the ecu if it's an immobiliser as that's the fuel pump relay I think. Any redundant holes just bung them up with some rubber grommets but if they've been good in fitting they will have used original holes as there are the odd one. Anyways that's just if you wanting to remove it lol.