Battery discharging

[ani]

Hi all, I'm still here! Poppy the red one has been sold - had lots of interest so now left with just the little blue one - that's more than enough for me!
Car battery is new and has been checked - once charged it fine for a couple of days but then discharges whether or not the car has been driven. I know it might be the altenator but would it still discharge even if the car is standing still - that doesn't make sense to me! I did ask someone to do a test and looks like I'm only getting about 12 volts from the altenator. Before I try to find another one (how do I do that?) is there anything else I should check first.
I changed the altenator on Simon's hilux pickup and then found out the problem was the voltage regulator which would have cost £20 !!!!! But, of course, all garages just say "needs a new altenator"
Let me know your thoughts - thanks - Ani

[bmcecosse]

Welcome back - you got the Swine Flu under control now ????
So -to test the system - charge it all up and then leave the battery disconnected - does it discharge then ?? The alternator can develop a fault whereby it drains the battery when not in use - test is to unplug the alternator and see if the battery still discharges. When it's connected and the engine is running - it should develop 13.8 to 14 volts........... The 'voltage regulator' is generally built in to the alternator (few early types ie 11AC had an external VR) - so it would have meant dismantling the alternator to change the VR. I tend to pick up spare alternators for 31 at autojumbles - but try ebay - you want a 16/17/18 ACR Lucas unit.... Alternatively (sorry!) you can probably get a service exchange unit from your local autoparts place - or even Hellfrauds....... One last point - is the 'fan' belt nice and tight?

[ani]

Hi there, Yep Swine Flu seems to be under control - it's cucumbers we all have to be worried about!! Many thanks for all this - the battery holds it charge ok when not connected to the car. Certainly wouldn't help tightening up the fan-belt as there is a bit of give there - perhaps fitting a new one at the same time would be a good idea. Once I've ruled that out I'll try disconnecting the altenator and see what happens. Back within the next few days I expect!

[ani]

Just to say that it was the altenator - a big thank you to Charlie who now doesn't have a spare It was good to watch how it was all done - I'll know for next time.