can anyone help,i have a problem with my car it was fine the other day i drove for some distance so the battery should have been well charged,yet the next morning it would not start has the battery was flat,so i put a new battery on and it started fine,yet the next day when i got up for work it was flat again,i tested the alternator with a multimetre and it read ok,dose anyone have any ideas what it could be,can a alternator draw power from the battery when it is not running?thanks for reading:confused:
Assuming you didn’t leave something on which is draining it, it sounds like a poor ground connection somewhere - common on older cars.
Normally around here the word flat usually refers to tires, while a battery would be dead, so I guess from the terms you use you don’t live near me or I’d offer you a jump start 
It sounds like perhaps something is draining the battery while the car is sitting. Hook up a amp meter between the battery and the car, while the car is off, if there is a drain pull each fuse and check if that solves it (then replace it), this will help you find any parasitic drain. You could also take the wire off the alternator to check it.
That’s also an issue when the battery goes bad, especially newer batteries. It can just stop holding a charge. You can drive just fine one day, but not be able to start it in the morning.
You used to be able to note a difference in how the battery started the car when there was a problem holding a charge, but often nowadays, you lose the entire charge overnight and that’s the first indication anything is wrong.
How exactly did you check the alternator? What exactly does “read ok” mean?
It’s possible for the alternator to draw power from the battery but it’s not a very common type of failure. More likely you’ve got either a bad alternator / voltage regulator that isn’t charging or you’ve got a parasitic drain somewhere, which could be anything from a short to a relay sticking on to any number of things. You can find a parasitic current draw somewhere by measuring the current being pulled from the battery when the car is turned off. If it’s excessive, pull the fuses one at a time until the current level drops to normal. That will at least tell you which circuit has the problem.
In a case such as yours, there is usually something draining the system that you don’t see. A light or switch is most likely. Check the glove box light. Electric antennas are notorious for shorts that drain the battery.
Since you have a multimeter, you might be able to check for the bad circuit yourself. The concept is to connect your meter between the negative battery cable and ground with the setting on the DC AMPS. Set it on the 10AMPS unfused setting or you will likely blow the meter. Turn everything off that you can find and keep the doors closed. See how much current is being drawn. At first there will be a spike in current. Then within seconds it should taper down from maybe 200ma to as low as 15-20ma. If it’s more than 50ma then something must be draining extra current. Begin pulling fuses until you find the offending circuit. If the circuit is something like interior lights or the antenna, you can safely leave the fuse out while you use the vehicle and see if this solves the problem. Then you can hunt down the short at your leisure.