Engine Systems Fault issues (Battery)

[Cheepah]

Hi everyone, I was wondering if anyone might be able to help me out.

I have a 06 Ford Focus Mk2 Ghia, and the battery is knackered in it, had to get a couple of jump starts the past while on it if i skipped out on driving it for a day, or in one case it completely killed the battery by using the wipers once or twice with the engine off. My plan is to get a new battery now over the weekend, but today its had another issue. So for the whole time i've been having the battery issues, it does throw up Engine Systems Fault on the dash, but today now the car sounded like it was struggling bad to keep itself going, and had to turn around and head home before even getting out of my estate. It also seems to very slightly rev itself while sitting idle. I bought the car roughly 2 months ago now (It had passed its NCT exam just days before i bought it) and the battery issues became apparent soon after I got it home, but usually just running the car every day or so kept it going. It's gotten to the point now where i know i need the new battery. 

My question is, is it possible that the battery is the sole issue to all these problems, or would there have to be other issues with the car causing some of these symtoms. I'm a new enough driver so im pretty clueless with this stuff, and seeing as im out of a job come next friday, I'm hoping its just the battery, and not the case that i get a new battery and more and more issues appear after.

Thanks a million to anyone who can even attempt to help.

[catfish79]

I’m thinking You have a problem with the alternator.

[isetta]

battery? alternator? we don't know what engine you have, some have a one way clutch on the alternator pulley, they can fail so that the alternator is not being spun at the correct speed.(as happened on my brother's 1.8tdci - on that engine the pulley is a separate unit from the alterntor itself)

when running it really wants a voltmeter putting on the battery terminals to see if voltage looks high enough for alternator to be doing it's job. It could easily be just the battery though.  do you know someone with a voltmeter?

A very rough test. with engine running on tickover speed, switch loads of stuff on, headlamps, heater fan, heated rear screen, heated front screen, when you do this does it make the tickover go down slightly, may be momentarily? if so that suggests the alternator is working harder to keep up (and putting a drag on the engine) which suggests it might be a good alternator. But also now rev it slightly, do the headlamps go brighter? if so, that is another sign the alternator might be fine.  This is not conclusive and is only a rough indication.

Some batteries have date stickers on. can you see one, is it old? but age is relative to make and model of battery, eg. a Bosch should last longer than unknown budget batteries

[YOG]

If you are sure "the battery is knackered", fit a new one first, and see what happens.