K11 Auto Battery Problems

[mdmuddin]

Hi,
My M-reg 1.3 5-door Auto has never really given any problems. On Tuesday, it wouldn't start and I discovered the battery was totally flat (even the clock stopped).
I bought a used battery from the local scrapyard and it stared instantly.
Today, it was turning over but not starting. Got a jump start from a neighbor and it started after about 5 mins of charging.
Is it likely to just be a bad battery and should I just buy a brand new battery (finances are a bit tight atm), or is there a possibility that something else could be causing the problem.
The car's stationary daily between 9pm and 11am.
Should I buy one of those mains-supply car battery chargers also?
Thanks

 

[Jen319]

I'm not an expert.....but that sounds like an alternator problem to me...

if you put in fully charged battery? and it started fine first time?...but now won't?
that suggests that the alternator is either not working or not producing enough current to recharge what is taken from the battery

...I may have made that all up though LOL

Hopefully someone else will see this that knows what they're talking about

ETA:...My dad just suggested to me that you should ...
check for electrical faults EG: the luggage light constantly staying on etc...
if you have a Volt meter check the battery is reaching upto 13.5 v...if it's below 12 it's not much good...
....according to my dad

Hope something there is helpful, Good luck

ETA2: My dad just thought of something else...check the fan belt that runs the alternator...is it slipping, cracked, damaged?

 

[sr_steve]

Like Jen said possibly alternator

 

[mdmuddin]

Hmm... Funilly, it started up fine today, even though it was stationary since 2pm yesterday.
As for alternator, I was under the impression that if that plays up, the battery will go flat even whilst driving (or more likely whilst driving) as the drain in the batt whilst driving cannot be compensated for by the faulty alternator. That's what happened to my bro-in-law.
Any DIY tests in mind for me to identify if it's okay?

 

[frank]

Any DIY tests in mind for me to identify if it's okay?

yes, like jen said, a volt meter will verify if its charging, and the alternator can discharge while not running if a diode has failed

 

[mdmuddin]

okay, thanks