The car has been parked up for about a month now so thought id use it to go out earlier, jumped in and started it up, it struggled to start but thought must just be due to not being started up for a while left it to warm up then went out done wat i had to do jumped back in and just made a large clicking noise at first i thought starter motor, but looked at my volt gauge to see it on 0 volts got a mate out with jump leads got her going volts went up to about 12 volts then turned it off with just the ignition on and could see the volt gauge very slowly dropping fired it up again and it did slowly start going back up, so could it be the battery not holding charge even tho it was a brand new battery about a year ago or the alternator dead but there is no warning lights.
Please help