> 我的电池好象没有到过14.4V, 哪怕是在另一辆没毛病的车, 开过以后, 马上测也不到14V.
That's perfectly normal. Have you tried to measure the battery voltage when the engine is runing(idle)? The reading should be around 14.4v with good alternator. If it's much lower than that, the alternator is bad.
> 我刚刚做了检查:
1) 换了一个好的电池用上去, 一会就从13.35 跌到13.15.
2) 对电池Jump 一下, run 了十分钟, 测一下是13.30, 过了大约1分钟, 就跌到12.90.几乎不能发动. 再等一会, 还会跌.
The normal battery voltage(fully charged) is about 12.5v~12.6v, measured without engine running. Right after you turn off the engine, you could get reading like 13v, which doesn't truely represent its charging state. You need to wait an hour to take measurement.
Do you have a battery charger? If not it's probably worthwhile to buy a battery charger for your older car. Running the engine for 10 minutes is probably not sufficient to charge the battery.
> 看起来很象是漏电或者您说的alternator而不是电池本身的问题．
If it's not alternator or battery problem, 漏电 is another possibility.
