The battery in my KR is going flat in about 4 days after charging it up, the battery is only about 2 months old and the previous battery done the same thing, so I don't think its the battery, I checked the voltage when the engine was running and it was charging at close to 14 volts, I have a funny feeling the air con is sending it flat as it didn't happen in winter, the new battery is a heavy duty battery I bought from super cheapauto for $125, I bought one of those jumper starter battery packs the other day as I was getting sick of asking someone for a jump start, anyone have any ideas what might be the problem?

cheers

$125 sounds like a shit battery from supercheap. How many CCA?
Close to 14....should be 14.4v

Sounds like its not getting charged enough. Air con doesnt have anything to do with it, Alternator does though

Yes , sounds like a charging issue. Check the ign light on the dash at night. Sometimes they will be just flickering enough to be seen at night, but not during the day. Also check that the boot light is not staying on with the boot shut.

Sometime worn starter brushes will give problems similar to a flat battery, but if it starts off the booster, then it is probably OK.

A couple of things you can try:

(1) Start the car, test the voltage - should be 14.4V when it settles down.
Turn on lights, emergency lights, aircon, radio - voltage should be 13.5 or higher - if not, rev the engine to 2,000 rpm and look again.
If it dips to 12v or less your alternator is not putting out enough juice.

(2) Look for current draw when switched off - lights that stay on, like parkers, dim glow from headlights, boot light, brake lights.
Disconnect one side of the battery and use a ampmeter to check for current draw.

PS I use $60 batteries from a local parts (7 plate, 330cca) place in both a 2.6L and 3L Ts - work just fine, last 3 or more years, nothing wrong with cheap batteries!

Thanks Madmax I will check all the things you said, its cooled off the last couple of days and I haven't used the air con and its starting fine, maybe the alternator isn't charging enough and with the air con on its just taking that much extra power away, thanks so much for your advice ...cheers


A couple of things you can try:

(1) Start the car, test the voltage - should be 14.4V when it settles down.
Turn on lights, emergency lights, aircon, radio - voltage should be 13.5 or higher - if not, rev the engine to 2,000 rpm and look again.
If it dips to 12v or less your alternator is not putting out enough juice.

(2) Look for current draw when switched off - lights that stay on, like parkers, dim glow from headlights, boot light, brake lights.
Disconnect one side of the battery and use a ampmeter to check for current draw.

PS I use $60 batteries from a local parts (7 plate, 330cca) place in both a 2.6L and 3L Ts - work just fine, last 3 or more years, nothing wrong with cheap batteries!

That rules out lights staying on. Have you checked "obvious" things like slipping belts, or corroded battery terminals?
IIRC an aircon clutch only draws 5 amps. Perhaps you should try starting the car with the aircon off, then use it, and switch the aircon off before you turn the car off? There is a slim chance that if the aircon switch is left in the "on" with the engine off, its clutch continues to draw power (? - clutching at straws here, shouldn't be happening)

Hi Madmax, I just had the car running at idle with all the accessories on and lights on high beam and I checked the charge ar the battery, it was only 12 volts, with all the accessories off and lights it was only charging 12 and a half volts unless I reved it it would go up to 13 volts, must be the alternator I think, all the belts are fine and the battery terminals are clean. I'll keep my eye out for a new alternator I think.




That rules out lights staying on. Have you checked "obvious" things like slipping belts, or corroded battery terminals?
IIRC an aircon clutch only draws 5 amps. Perhaps you should try starting the car with the aircon off, then use it, and switch the aircon off before you turn the car off? There is a slim chance that if the aircon switch is left in the "on" with the engine off, its clutch continues to draw power (? - clutching at straws here, shouldn't be happening)

Hi Madmax, I just had the car running at idle with all the accessories on and lights on high beam and I checked the charge ar the battery, it was only 12 volts, with all the accessories off and lights it was only charging 12 and a half volts unless I reved it it would go up to 13 volts, must be the alternator I think, all the belts are fine and the battery terminals are clean. I'll keep my eye out for a new alternator I think.

An alternator will never fully charge a battery

There is a slim chance that if the aircon switch is left in the "on" with the engine off, its clutch continues to draw power (? - clutching at straws here, shouldn't be happening)

Funny things do happen. The battery in my Liberty was going flat every couple of days. Finished up being a fault somewhere in the ABS, which would hum away all night with everything turned off. Disconnected the ABS electrics with the intention of getting it fixed at the dealers workshop. That was 3 years ago, works fine without it.:wtf:

weird or what? lol Them electrons have a mind of their own . . .

Just in the off-chance that it may help, I once had a 1985 Toyota Corona which was draining the battery every week or so.

Turns out that it was the boot light staying on, even after the boot was shut fully, thus drawing power 24/7 in that car! Not sure if 2nd Magna/Verada boot lights stay on if you open the boot when headlights are off.

Another thing to check for is the glove box light, and whether that's staying on after you shut the glove box.

It may seem such a small and trivial issue, but with older vehicles every extra bit of current draw takes its toll on the electrical system. (I admit my Corona had alternator issues though!)