battery draining overnight

[Dirtbag]

Had my car up on blocks for week while suspo was getting repaired, then had to jumpstart it when I bought it back down, drove it a couple of places, started fine, but overnight it sat ther, didnt wanna start about an hour ago, ma RSM was giving me 9.8V as the battery feed. Jumpstart it again, it goes fine, RSM giving me 14V, so ruling out alternator, last night with demister,heater, lights on RSM was returning 13.6-13.8V so yet again, reason to rule out problem with alt. RSM/Stereo only work with ignition, have alarm installed for about a month, but havent had any problems untill now with it, anyone have any ideas what could b causing it to drain overnight?

[Lloyd]

Get a multimeter on it and see if any current is flowing from the battery with the key off. If nothing it might just be a sad battery

[Leon]

I've had two alternators fail (on 4AGE's ), and the symptom was in both cases that it drained the battery in a couple of hours while switched off, not in fact lack of charging.

[trueno_20v]

for a start disconect the alt over night then reconnect in the morning and see what happens, then let us know, ive just fixed the same problem - turned out to be the factory amp under my passengers seat, looked water damaged..

[Dirtbag]

ah thanks, getting the car back 2moro from brother so ill try that multimeter trick.