Battery has died on me twice. Is my alternator alright

[jcmiro]

I just bought a new battery about a year ago. IN the last two months my battery has needed jumping twice. Mostly because of stereo use while the motor is not on. I think I need a new battery but my mechanic says it may be my alternator. I used a multimeter and its reading 13.65 at the alternator. Does it need maintenance or do I need a new battery or both.
Cheers

 

[chilibit]

The Aussies on lcool.org talk about dual batteries more than you can imagine. Diesels, coolers and long pulls to the next piece of civilization probably. Batteries can be very intolerant of a near total discharge. A second, isolated, battery might bring peace of mind. What was the state of the battery when you measured 13.65?

 

[jcmiro]

Whats do you mean state of the battery, voltage? I didnt measure it just jumped it and ran it for a while.

 

[Desert Nomad]

I put in an optima yellow top and haven't had any isuues so far, out in the desert i sometimes use the roof lights + rear lights for hours and have the stereo on for tunes (aftermarket speakers + amp). Either get a heavy duty battery such as the optimas or run a dual battery setup as chilibit said, some keep a second battery soley for cranking the motor over

 

[chilibit]

Whats do you mean state of the battery, voltage? I didnt measure it just jumped it and ran it for a while.

The output of the alternator is related to the state of the battery. If the battery is mostly charged then the value you measured is in the ball park. If you measured just after a jump start then you might see something a bit higher. I have read that the alternator is a misery to replace but that might only be for diesels. I do not know from first hand experience. If you routinely draw your battery down to very low levels then you might consider a battery designed for such deep discharges (deep cycle). The more elegant and more expensive solution is the dual battery setup. If your rig is biased toward expeditions then I would go with the dual setup in a heartbeat. But that is just me.