Hi I seam to have a short on my battery even with the car switched off it drains really quickly. if you remove the cable to the fuse box it still drains so its the cable going down into the engine bay. Does this go to the alternator.do I need to replace the alternator?

back ground... I went out yesterday evening and used my lowering suspension first time in ages. whilst out it was wet and went through puddles and along bumpy roads. dropped my passengers off and lifted the suspension up and it started coming up with suspension fault. I got home and reversed on my drive and stop the car I then tried to start it to see if it would clear and the car wouldn't start it was as if the battery was flat. I went out this morning and it started and had the same fault I checked the battery and it was low and stopped it again and it wouldn't start so i jumped it off another battery but the voltage was going down so to me its shorting out with the voltage going down very quickly. checked it with the ignition switched off and it goes straight down to 6 or 7 volts. I'm not thinking its the alternator what are your thoughts??

Thanks in advance

well yes the thick cable goes down to the alternator and starter

best to disconnect it over night else the battery will be knackered in no time.

Yes the battery is disconnected So the battery goes to the starter as well so how do I find if its the starter or the alternator?
I have checked for continuity between the + that goes down to the engine bay and earth and there is continuity between them both which I believe there shouldn't be?

very unlikely to be starter.

there is sometime a stud on the top side of the alternator that you could undo and isolate the wire, just not worth bothering with

I have ordered an alternator so we will see if it sorts the problem out.

Check the obvious first. Batteries can fail as well . Have your battery load tested as a faulty cell will give you grief as you described. M16 SVD8 ,4.4 HSE with a few extras, Sold R50 , Wife SQ5 , BMW R1200GSW.