Technical battery draining

[Bravaboy20]

Right,
my car battery went flat, i changed the battery all was well, 4days later again the battery was flat, i thought logically, ok the alternator had gone, i replaced the alternator (from a breakers), recharged my battery all was fine, a week later battery went flat...tested the alternator with my dads meter, not charging the battery, replaced the alternator again with a refurb unit last thursday....today my battery was flat.....ive checked all the connections of the battery and alternator......
anybody got any ideas?

 

[Gregovic]

Obvious question, do you have anything hooked up inside the car that could drain power? (12 to 220 volt converter, phonecharger, etc. These consume power, even when they are not plugged into anything else) Even a small drain can kill a battery. And once it goes below 20% charge or so it'll start sulfating, lose capacity and drain even faster.

Is the alternator working now, and what voltage does it deliver?(Should be over 13,2 and below 14,4 volts)

Do you make short trips with the car? After the car is started you've drained a lot of the power out of the battery, so any car trips need to be long enough to charge the battery again. (This takes something like 3 miles at least) This means many small trips can kill the battery very fast.

Another factor is cold, a discharged battery contains water and loses capacity when it gets colder. It can even freeze when it gets cold enough. If that happens the battery can't deliver any power whatsoever.

 

[m20b25]

Does your heater fan work on all 4 speeds? I had a draining problem before connected to lack of fan speeds

 

[skaramazoo]

As far as I know never should a car battery go below 80% its full capacity. Once it gets below that 80% level it should immediately be recharged and restored to 100% capacity. Only this way one can ensure longevity of life for their battery.
In this light, frequent short trips - as has been already pointed out - are a true battery killer.
With the battery hooked up to the electrical circuit and ignition switched off it would be good to measure for drain with a good accurate Amp meter.

 

[Gregovic]

Also very important, what kind of battery did you install? There's many different types, sizes and power ranges in batteries. And you can't always assume the battery in the car is the right one. (Turns out mine was underpowered as well) 45 Ah 400 Amp should be the right size for the Brava. (Something heavier will probably also fit as the battery tray is pretty spacious)

 

[Bravaboy20]

i tend to do 5/6 mile trips, no nothing connected inside, could a short on the starter motor cause this? or something else? the battery i have is smaller went to a battery specialist and they said it was the right battery... its really irritating me now

not noticed any problems with the fan :S

 

[m20b25]

Are the poles clean? Dirty poles can cause a draining effect. How new is the battery in question?

 

[rallycinq]

Grab the meter again, set it to amps and check for a draw between the earth pole and the earth cable.

Cheers

D

 

[Bravaboy20]

new is about 4 weeks old, the poles are clean....
i appear to have solved the problem now though....i had a blown bulb on my rear passenger side lights, since ive changed the bulb ive had no trouble starting it whatsoever....lets hope this was the issue