Any battery is better than halfords lol, I believe bosch have a five year guarantee

I might get a Bosch (or Motorcraft, do they still make batteries ? ) next time, I intend keeping my car for around 10 years, accidents or rust allowing ! I always thought if Halfords give a 4 year warranty their batteries must be pretty good ! I think you can get a Halfords battery with a 5 year warranty.

I just don't think they have calcium types, u bought one for my focus (years ago when I thought if it's the same shape it will be fine) and it wasn't calcium, I was quickly corrected as to batteries not being the same....

on modern cars batteries will discharge to s low voltage after 4 weeks it will discharge quicker if it already had a low charge from short journeys so in 11 days it will be too low if low already add to that a faulty cell will prevent proper charging some batteries may last 6 weeks theres many factors influencing that temperature if its garaged or not how long the cars used what electrics you use and for how long.stick with the bosch ebays the cheapest place i think

In all honesty Justin I havnt a clue how it lasted as long. never gave it a thought as I just thought that was normal.

I have even had the car sitting on the driveway for 3 and 4 weeks without being used and still never a problem. but last year it would have been easily 5 weeks.

As a very rough indication of what can go on with a small current drain over long time I did some sums

Some rough estimations here but it still shows what's going on.

If battery has 12.7V on it once surface charge has diminished, I'm going for 11V being cut off voltage for the car not starting (probably higher in reality).

So the voltage can drop max 13%

If there's a background current drawing say 50mA and car is left for three weeks that's going to pull 25Ah.

Open circuit voltage is representative of the battery's state of charge so on the one hand you've got 13% of voltage to play with, but if Focus has a 60Ah battery then you've used 42% of it's capacity over the 3 weeks.

So you can see what's going on....I've erred on the safer side with the figures, the voltage where the car can't turn over to start is probably higher plus you'll also get an amount of voltage decay over the 3 weeks - not loads but it all adds up.

To help the situation you'd be looking at reducing the background/quiescent current, running higher capacity battery (packaging/size issues and costs tend to put manufacturers off this) or other solutions such as a twin battery system where big beefy battery is used purely for cranking then smaller auxiliary battery is used to power up most of the electrical gubbins in the car. Course the length of time the car is stood for has big effect in my sums too.

Simples?

Just had the AA out to my 2010 1.6 tdci, as battery was flat after a week of not driving. Battery is good, but has a drain of 0.3 amp. Is this drain normal. As he couldn't find the source, and said it could be normal. He suggested I ran the car up every other day for 30 minutes to charge the battery.

So the AA man in essence said it's normal to have to run the car every other day to keep the battery charged? load of tosh imho just because he couldn't fine the fault.

There's obviously something amiss for your battery going flat all the time, and while the AA man may not be able to find it that doesn't mean it's normal.

If you can measure the current draw then try pulling some fuses and see if it drops. Try the audio system first.

Agree entirely with troy. If your handy with a multimeter do that, if your not or want it to be more simple, search eBay for parasitic drain tool

Having a quick Google, there seems to be a lot of modern cars that the vehicle electronics drain the battery. Most go flat within a week.

The more electrical toys they build in now creates lots of opportunities for unexpected conditions to occur which can keep modules awake, batteries not recharging to 100%, actuators continually trying to reach parked position and so on.

It's a real minefield of potentials and that's assuming the battery reached the dealer in a decent state with all the battery care procedures followed through manufacturing and transportation.

For battery leak detection search eBay item number 400433639239 and look up fuse adapters too.

This post is obviously nearly a month old now.

Just to update my ST has lay in the garage from around the start of December. probably the 1st week in December.

My Focus Diesel wouldn't start this morning. so thought I would try giving it a jump off the ST. I recon the car has lay up for at least 7 weeks. garage is not heated or anything and as soon as I pressed the start button it burst into life.

Wish I could say the same about the other Focus.

Diesels are heavier on the battery at start in the cold. They load it while heating the glow plugs as well as the starter motor. The latest cars have so much electrical stuff going on constantly (alarms, key fob signal monitor, door handle monitors, memory/ecu/bcu refresh and keep alive) they will never last as long as more basic models

I`ve been using an Oxford Solariser (solar charger) and my Focus started fine after being left for 17 days, it might even have been 3 weeks but I can`t remember for sure when I parked it up at work ? ! ?

I messed about a bit with a couple of voltmeters and the "Solariser" and was a bit concerned to see that in overcast conditions (but at midday, not dusk ! ) it was only giving out about 6V ! That is to say it wouldn`t actually be charging the battery at all, to do so would require it to produce at least 12.5V. My conclusion is that particularly in the winter it can`t be putting that much charge into the battery, possibly 4 or 5 hours a day on average ? And that`s at a maximum quoted current of 80 to 100mA !

Has anyone else had experience with solar battery chargers ?

When the sun came out today I did a few crude experiments with the Oxford Solariser.

In the direct sunlight it was giving out about 20.5v. Angling it towards the sun didn`t seem to make much difference to the voltage but did seem to make it more stable on the reading. The voltage does seem to vary but the only way I could actually check that accurately would be to use a scope.

Moving the little solar panel into the shade of a hose over the road reduced the voltage to around 16.5v, again it was varying.

Lastly I put the Solariser in the shade of our car port (though it seemed still reasonably bright to me ! )and the voltage dropped to around 5.

As the above quote states when I check it in cloudy weather it was about 6v