Hi Members i just wondered if my battery is on its way out, went for a drive for a bout 20miles checked battery with one of those meter with lights on said battery ok,1 day later check again only half full low battery after two days i started it and the time clock and radio did not work for about 2/3 minutes it did come back on looked at battery for a code can see a number ending with 12 so is that 2012 the battery is a exeide battery the alternator is ok any thought the car jazz 1.4 2003 dave.
After 4 to 5 years a battery is living on borrowed time (unless it is a really good quality one like Yuasa Silver or lifetime battery), they gradually lose capacity over the years, but so slowly it does not get noticed. We are lucky in UK being a temperate country, in hotter areas like Africa and southern USA batteries can fail in as little as 18 months (the heat kills the chemistry in battery). On a decent battery the terminal voltage should ideally be about 12.5 / 12.6 volts when checked a couple of hours after a decent run or after charging at home. Modern cars sometimes have battery in boot (cooler than engine bay) or have insulation and ducting around the battery to try to keep it cool and prolong its life.
The recent spell of hot weather we had in UK will have damaged quite a few car batteries, but they normally fail in winter when extra demand is put on them starting cold engines, and from headlights, wipers, heated screens and mirrors etc.
Modern alternators are normally bullet proof but if you want to check charging voltage it should be around 13.8 to 14.2 with engine running at about 2000 rpm, below 13.4 is a danger sign.