flat battery

alright guys

my car has recently had a new battery, alternator and water pump

i have been drivng the car for over a month with these parts fitted, however

last night the car would not crank enough to fire the engine, i got a jump start as it was 1am and drove home

i went to the garage this morning and there is not even enough power in the battery to operate my alarm

i think there is something draining the battery, how can i work out what it is?

i have a sub and amp in the car also, but this is wired off the ignition through the stereo and has also been fitted for ages.

what can i do, i am without a car, some one please help me

I'm making the assumption here that both the battery and alternator are in good order. You could get the battery checked, but seeing that it's new, you should be OK.

Same with alternator.

Now, assuming you got a jump start last night after the car had been resting and it drove OK, would imply that the charging circuit is OK. Otherwise the battery would drain as you were driving along.

Do you have a test light. If so, try this.

Make sure no accessories are switched on. Detach the negative battery terminal and attach one one of the test light to the cable and the other to the negative terminal. The light should not glow. If it does, you have current drain somewhere and this could be causing your battery to drain.

It's then a case of disconnecting fuses one at a time until you source the current drain i.e. light goes off when you repeat above test.

This does make the assumption though that you have nothing on while car is turned off and all accesories are off. You could replace test light with ammeter - current should not exceed 0.5 amps.

Good luck.  :wink:

1. Charge battery fully
2. Remove alternator plug
3. Does car crank in morning?  If so Alternator is at fault (usually its the regulator)
4. If not recharge battery fully THEN check load with an ammeter otherwise you'll be testing the load of a flat battery which wont be much at all .

5) To check load remove + lead and check on an amps setting with a meter between the +lead of the battery, and the + of the battery itself.

6) Assuming its got a 240ah battery it will take 24hrs to drain at 1amp load per hour or 1/60amp per sec… 0.5 amps is quite a lot and would mean you have around a 6w (watt) load, presumably a lamp of some sort

That should get you started, or you can skip it all and replace the alternator regulator