The alternator can supply 110 amps rated and appears to have a 30% margin (not unusual). Typical full loads on the stock system appears to be about 41-42 amps maximum. This would allow about a 500 watt class a or class b aftermarket sound system, class d of upwards to about 800 watts at rated alternator output.

This particular car (07+) has a current sensor that is an integral part of the charging circuit and this sensor is used to determine the state of the battery. With the sensor not functioning as design the system then follows the whims of the alternator IC when may not be optimum for battery maintenance.

I have noticed that many who mention battery problems also have grounding kits which include this bypass cable around the stock negative lead that has the current sensor. If you measure the current flow to the battery you may well see that after the car is running for a short period that the draw will rapidly drop to about 5 amps and then will slowly drop to somewhere less than 2 amps (which is where my meter starts to not give accurate readings, ct based amp meter). The stock cable is of sufficient gauge for any load placed on the system, that is it is capable of carrying full car operational loads and if those loads are not present it is capable of carrying all aux loads up to the limit of the alternator reserve capacity above static loads (in excess of 70 amps continuous). In short there is no need for an additional cable on a stock system, and consider that it bypasses a key component of the charging system it may present a negative influence on another key component, the battery.

As far as the battery holding a charge with the stock sound system in service for a couple of hours it is a substantial load. Even fairly short term draw downs on a repeated basis can lead to early failure for batteries using conventional technology (ie lead acid based).

My best experience with batteries have been with Interstate batteries which have lasted as long as 10 years, one of my worst has been with what many see as 'thee' battery and that is with an Optima deep discharge battery which lasted about 1 year.

For OEM batteries I typically have gotten from 2-3 years max from them.

 

Don't we have 4 years waranty on battery? As you go you pay more. like first year free next 25% pay and go on. Could be wrong.

 

Actually so do the replacements in many if not most cases.

The issue I would see is the list price assuming we are only speaking of battery economics.

If the OEM battery installed by the dealer over 4 years of yearly replacements cost the same as a non oem battery which lasts the same 4 years I would certainly go with the non oem battery.

To me batteries are a little like insurance policies, you may pay more over the long run for a premium battery that last longer so as not to worry about your car starting in the morning. I look at the whole car as what earns me the money to pay for the house and everything else, that is why I always have two.

 

+1, having them replace the crappy battery that went out on you in the first place is like using 99 cent stuff, it doesnt work O.O

 

so mine went out yesterday. my mom tried to start up the car but failed so i go home and jump start it. i drove it around for 5-10min? then in to the garage. 12 hours later, in the morning today it wont start agian.
when i go home from school, im going to jump start and drive for longer? 30min? i was told 5-10min was not enough. if it dies again tomorrow, ill have to buy a bttery? not covered under warranty? (car is 1year and 6months.)

also someone told me if i use the tech filled modern cars such as the335i to jumpstart, it might **** up the 335i's electrical stuff? is this true?

 

my 07 OEM battery went dead last month. Went Duralast Gold also. Replaced the connectors also with some heavy duty ones. Starts really well now

 

It can take three to six hours of run time to fully charge a dead battery.

 

I don't know what you guys do to your batteries that makes them die in 3 years.


I had my car since Sept 05.
It has 90k on it and I'm still rocking OEM battery.

 

Running a battery down to zero even two or three times can send it to the grave quick. It calcifies the plates and ruins it's ability to take an d hold a charge. Even once is really bad. A wet cell battery should never be allowed to drop below 10.5-11 volts.

 

32 months on my stock battery and have drained to where I needed a jump twice. I will go with the Duralast Gold once this one is toast. If I can get a full 3 years out of it that would be cool to!

 

My next bat is going to be an Optima! (AZ summers eat bats for lunch)

 

This is slightly OT, but I've always had batteries which were maintenance free and have no idea how to check/refill Gs stock battery. It's probably quite simple, but can those of you who added water mention the steps?

Am also getting to the point when the battery will need a replacement. Probably will go for Duralast Gold as it seems to be the consensus here... although I may just drop by Costco and get a Kirkland brand one (which Costco will definitely replace if it fails before 3 years are up).

 

i bought my g in 04, drive it daily, 80k miles and my battery still works. sounds like i might be due for a replacement...

 

Add me to the dead battery list, replaced with yellow top. Wasn't a perfect fit for me as the OEM top bracket was little too wide, but I got it in there.

 

This sounds well thought out to me. My OEM just died after about 3 years and 53k miles. That sounds about average for nissan batteries. Everyone praises the Optimas, even those who don't have them. I just went out looking for one, but the local stores wanted $215 (and I see them online for ~$150). So I'm surprised to hear you say that they might not have any benefit or last very long, but otherwise your reasoning seems clear. So I just picked up a battery (not interstate brand, but made by the same manufacturer) for $79+tax+core. Sounds like that's inline with what you recommended, so we'll see how it goes