Hello all, here's what is going on that has me a little baffled:

The car sits for more than 12 hours and the battery is dead. Seems to happen quicker in either colder or hotter weather. When the temp is moderate (70-80c), the battery will hold a charge well. When I place it on a charger, it will intermittently indicate an error code that states a cracked cell. I have the car for a little over a year and am on my third battery. After I install the battery, it seems that it works well for a week, then goes bad.

Obviously there is something damaging the batteries, but am having trouble determining exactly what is. The load and charge on the battery is well within spec (according to the manual), I have been over and through the wiring harness (especially after changing the headgasket, which is a whole other story that took me a total of 30 hours to complete - what a pain) and there are no bare wires or grounds that appear to be faulty.

My last guess would be vibration. The car has new shocks and struts (rides really nice), no excessive engine vibration or excessive engine heat (even after installing a Megan header the heat inside the engine bay is minimal, actually seems cooler). The battery hold down is not too tight, but does not allow for movement.

Has anyone else experienced this or have any suggestions? I have searched on several forums and am unable to find anything that remotely sounds like the same thing. Any info would be appreciated.

I really don't think vibration has anything to do with the battery going bad that quickly, and that is quickly 3 batt's in less than 1 yr.!

Do you have a lot of stereo accessories on standby constantly?

No audio....just the stock stereo. The only things that I have accessory wise is an AEM Wideband, Oil Pressure Gauge, and Apexi Neo but they are running on switched on power and this problem predates all of the accessories.

It seems that when the weather is mild, there is not as much of a drain...it occurs mainly when the weather is either too cold or too hot.

WHAT brand of battery are you using? and don't say valuecraft cause autozone sucks my ass. i recomend an Optima. i bought a used one 5 years ago and i have never had a problem with it.

dsm/mitsubishi service manuals https://www.mediafire.com/folder/5k14qlaulb9s1/dsm_mitsubishi

service manuals(my whole collection) https://www.mediafire.com/folder/ac51jwwa3g1n1/automotive_manuals

I would guess that the alternator isn't working as well as it could.

It's not an Autozone battery. it is an official Mitsubishi battery that I got at the dealership about a month and a half ago. I thought about changing out the alternator, but all of the voltage test come out ok (doesn't mean the amperage is ok, though). Had thought about getting an Optima battery, but don't want to spend $140 on a battery that will also get destroyed.

double check the wiring going from the alternator, the crappy 8 or smaller guage that they throw on there is just pathetic, it gets corroded or fried and then just won't pass as much power, I rewired mine with 4guage wire, works great, if you can't get power to the battery the alternator may show just fine but still isn't getting the job done. if you've been going through batteries like oil changes then it has to be something else wrong with the charging system

Erik P.
Official 2GNT thread Hijacker
Some say that he's driven over more Covenant than he's shot, and that his grenades aren't where you'd expect them to be...
All we know is, He's not The Stig... But he is The Stig's Spartan cousin!

I have checked the wiring from the alternator...seemed to be ok. I would agree that based on the amperage that the alternator is supposed to deliver, the wire could be better. I might get to this part of the project this weekend. Eventually I will get around to the turbo stuff....eventually.

another thought I had would be check for shorts that could be draining the battery, every time a battery gets drained it's only about 75% as effective as before, and this is a cumulative effect. hunting shorts sucks nuts but that might be your problem. try putting an amp/voltmeter at the alternator while running (yes i know this sucks) and then testing the amperage and voltage at the battery while still running, if there is any major diff then the wiring to the alt will be a major problem, if not, start huntin.

Good luck!

Erik P.
Official 2GNT thread Hijacker
Some say that he's driven over more Covenant than he's shot, and that his grenades aren't where you'd expect them to be...
All we know is, He's not The Stig... But he is The Stig's Spartan cousin!

I have tested the voltage on the battery both on and off, voltage seems to be ok although i did not check the amperage....will do that. Also noticed something last night: when I opened the passenger door, the dome light only came on for a sec then flickered out....works fine for the drivers door....so gonna check that switch....maybe, just maybe that may have something to do with it.