kath an pete

this is th second time this has happend if i leave my sti wagon 97 import for 3 days will not start would it be the battery are the alternator?

MrNoisy

iTrader: (28)

Have you recently installed any gauges or a new stereo?

kath an pete

no not installed any gauges or stereo,had to get a jump start goin to get it looked at weekend.

MrNoisy

iTrader: (28)

Hmmm, aftermarket alarm or tracker fitted?

kath an pete

its got a cat 1 alarm fitted

Eternal Rage

iTrader: (7)

My Guess is dodgy charge rate on battery.
My Legacy is the same, cant have stereo on without engine running or it wont start etc.
Halfrauds offer a free check to see if it is the Battery thats at fault IIRC.

MrNoisy

iTrader: (28)

You can bet the free check will always indicate the battery's dead though ;o)
Alternator possibly - you really need someone with a voltmeter to test it.

Eternal Rage

iTrader: (7)

Last time i had to do it they checked it in front of me, printed out the results for me and it confirmed 78% charging efficiency, they recommend replacement when it dips below 60% i think, but cant recall exactly.

Either way it wasnt that and it ticked a possible problem off the list.

John 37

Checking an alternator's easy. Measure the battery voltage with the engine running between 2000 & 3000 rpm and nothing switched on. It should read between 13.8 and 14.2 volts. Now turn on the lights and rear screen heater. The voltage should still be in that band. If it's significantly out, look at the alternator. Otherwise suspect the battery. If it's more than 3 years old, it's suspect anyway.
If you want a second check, get a stabilised battery charger (not the normal unregulated type) and leave it on over night. Turn if off and turn the headlights on and have a cuppa. After 30 mins you should still be able to start the car. If you can't, replace the battery.
If the car passes all these test, measure the current drain from the battery with the car locked. You may need to dissable the bonnet alarm switch. I don't know what it should be but as a guess, anything over 50mA sounds excesive.

John