Alternator?
 

So my Supra is in storage and has been getting started once a week. I just installed a optima yellow top before it went to storage. My family called to let me know that the battery was dead. It has been cold there so I didnt think a whole lot about it. So I went home and fully charged the battery, now it is dead again after a week or so. Thoughts? Alternator?

Thanks in advance.

BP

Sounds like you have a current draw somewhere. A volt meter will help find it. You could place the leads onto each battery post, then pull fuses one at a time to see which circuit is drawing current.

The voltage meter will read a bit higher when the correct fuse is pulled. Then go from there.

Also, whenever storing the car for more than a few days, remove one of the battery terminals from the post.

Fwiw, I agree with all of Mr.Nickleye's diagnosis & advice...in addition, note the following:

1. Optima batteries (and similar eg. NAPA Orbital) are notorious for quickly going 'bad' after sitting discharged, for just a few days! Other standard 'wet' car batteries are more tolerant to this, but sitting in a discharged state for extended periods of time is one of the worst things you can do to a battery.
2. If a battery is not too far gone, it may be possible to 'recondition' it with a pulse-charger, like this one:
   http://www.battery-rechargeable-char...r-package.html
   (note that there are several others too, for example this one)
3. If you'd prefer not to remove your battery terminal, consider purchasing a trickle charger to keep your battery's charge topped off AND feed the current draw. Be sure to get an 'intelligent' automatic trickle charger though, because one of the only things that'll kill a battery faster than letting it sit discharged is overcharging it. An 'intelligent' multi-stage trickle-charger will automatically detect when the battery is full and then the charging current is reduced. Lastly, although it might be possible to get a reconditioner/desulphator PLUS charger all in one unit, most inexpensive/affordable reconditioners/desulphators don't offer enough of a trickle charge to keep your battery charged (amhik).

Thanks for the help. So if I can get it fully charged again, just disconnect the terminals and I should be ok till it starts getting driven every day again? Maybe I'll see if optima will replace it for me, it should still be under warranty. Any other ideas? I will for sure be installing a capacitator for the stereo this year as well. I bought the yellow top because I thought it would be better for this sort of thing.

Possibly not. It depends how 'good' your battery is. Fwiw, I suspect that it's at least partially fubar'd...

Again, imho keep your Supra hooked up to an intelligent/automatic trickle charger.

Yep it is a good battery, as long as you keep it fully charged and don't let it sit in a discharged state...

Well it has been sitting discharged for 2+ months now then. I talked to optima and they will replace the battery under warranty so when i get the new one ill just leave it till I can start driving it again. Yes?

Any easier ways to find what is drawing power when the car is off?

Honestly, I'd recommend putting a charger on it when you first get it, just to be sure its charge is completely 'topped off'. After that, yep just leave it disconnected until you start driving.

There's an 'old wives' tale about not letting it sit directly on a concrete floor, but that myth has been 'debunked' afaik.

No...at least not that I'm aware of. The procedure that Mr. Nickleye described is about as straight-forward as can be.

Generally though, an unmodified/factory/oem vehicle doesn't draw very much current at all when the vehicle is sitting. Many abnormally high current draw situations associated with prematurely dead batterys are related to mods/upgrades. I'd suggest you start the fuse-pulling exercise with any circuits associated with any aftermarket electronics modifications on your Supra, such as boost controller, fuel controller, gauges, turbo timer, security system, stereo system, etc...

So Im getting a new battery free of charge from Optima, sounds like it had a short in it. Could this have been the real problem, or do I still need to find the draw?

BP

It's likely that was the primary problem, but if I were you I'd measure the new battery after 1 day of sitting in the car, and if it's unusually low, I'd get back on the troubleshooting path...