SHO is eating batteries

[wuzzzer]

My SHO is now my winter car. Last year I parked it in my yard all spring/summer/fall and started it a couple times in the summer and drove it around a bit. After having it sit for about 3 months I went to start it and it didn't even turn over, dead battery. So I put a battery charger on it and it didn't accept any charge. I figured no big deal, I'd pull the battery out and replace it when it was time to start driving it again. When I did that, that's when my alternator pulley had froze and resulted in me getting a new alternator and accessory belt. Drove fine all winter after that.

So, this spring a co-worker let me use her parking space in her apartment. Same thing happened to the battery. The SHO sat about 2 months, I went to start it and absolutely nothing. I jumped it with the Mustang and drove it around about 20 minutes. Went back the next day and again it didn't crank or anything. So last Thursday I brought the battery where I purchased it and they put it on a high charge for a day and it brought the battery up to 11 volts. I left it there until today and they had it on a slow charge since then and today the battery tested at 5-6 volts. They replaced the battery at no charge since it was under warranty.

Any ideas what could be causing this?? I don't have any aftermarket electrical accessories of any kind, everything is factory including the radio, lights, antitheft system, etc. I don't want to have to keep replacing batteries every year.

I do have a battery tender that I've been using for my trolling motor battery. Unfortunately there's nowhere to plug it in where the SHO is parked. I know I could just yank the battery and put it back in when I'm ready to drive it and thankfully the SHO's battery is very easy to get in and out but I'd rather not have to do that all the time either.

I should add that this winter I parked the Mustang on November 1st, drove it to my brother's place on January 1st, started it sometime at the end of February and then put it back into DD status at the beginning of April and never had any issues with the battery.

 

[Evil5oh]

I would like to know as well...I have the same problem, if the car sits for more than a couple weeks the battery is drained unless I disconnect it when I know its gonna sit for a while.

 

[whiteman_01]

Any chance the computers stay on while the car is off, like newer vehicles? As for a battery tender you could get a solar one. A friends R32 came with one. He also said that the dealer that he worked at kept them on all the cars in there lot cause the computers would just drain the batt otherwise.

 

[SHOWYA]

For the time i had my SHO it has actually manage to **** 2 Optima red tops. Thank goodness for that warranty they have! My car did sit for months at a time with out starting for the batt to go bad.

 

[ThatShoGuy]

something must be stayin on try pulling fuse's till the battery dont die anymore i know its time consuming but thats about the only why i know of...

 

[SHOZ123]

This happened to my car. It turned out to be the football. If I let the car sit for two weeks it would drain the battery. You are going to have to pull the fuses while watch an amp meter to see when the amps drop.

This needs to be done with the door shut though as the interior light relay will skew the results. You can pull the interior light relay out and work from the inside of the car but the problem may be in this circuit. The modules need about 15 minutes to drop out and the normal current draw should be less than 50mA.

If a battery is drained down and left to sit it will **** the battery. The plates sulfate up when sitting in a discharged condition. Car batteries are especially susceptible to this.

 

[wuzzzer]

Well, I guess I'll just pull it and put it on a battery tender while its not in the car.

 

[wymjym]

newer cars have more sophisticated electronics. Todays cars can have lots of things going on when the car is 'off' but they still don't pull as much amperage as older (gen lll sho) cars with just a clock,alarm,radio memory.
I think the easiest approach you might want to take is to use a shut off switch.....like this one

http://www.eastwoodco.com/shopping/...emType=PRODUCT&RS=1&itemID=1373&keyword=25009

except go to autozone or wallyworld, they have very similar for 3.95 + tax. Install it and when you know you will not be using the car for some time (weeks ++++) just raise the hood and turn the switch. Yeh you'll loose the power locking and clock+temp but at least your battery won't go south on you right away.

wj

 

[n8rsk8r]

I would like to know also. The SHO & Mustang both do this

 

[wuzzzer]

I guess one question I should ask is it ok to disconnect the battery and leave it in my car? Or should I have it in my house on a battery tender?
If its ok to leave it in the car should I disconnect the negative and positive cables or just the negative cable?

 

[SHOZ123]

As long as it is clean and fully charged it should be able to sit for 3-4 months with no harm disconnected. FWIW I installed a quick disconnect on my battery back when I was having problems. Still comes in real handy for long storage times or to quickly clear the KAM.

 

[wuzzzer]

Thanks Paul. Can I just unhook the negative cable? Not that its a big deal to do both as long as I'm under the hood already but I just was curious.

 

[SHOZ123]

Either cable will do.

 

[n8rsk8r]

Honestly if you take the neg off, then at any point the neg touches another ground then the circuit is live again. Never, Never, Never take the ground off first, always the Negative is the first to be hooked up, and last to be taken off.

 

[DavidT]

me too...
I had a new Odyssey battery ruined because of this.
I tried to trace the draw as Paul described. I THINK I narrowed it to the RCU fuse. SO I installed a switch. However I still think I have a problem. I wonder about the GEM module..
If I have to open the car door multiple times (without starting the car) then the battery possibly gets weak. Leaving the car door open for even semi short periods of time is also risky!

 

[Mr95Gl]

Did you ever resolve this issue? A brand new Motorcraft battery was put on Saturday, and that's already dead. I've had the car sitting since Sunday. Went out today, and it's totally drained.

 

[wuzzzer]

Well, apparently something in my car is drawing power from the battery while sitting. I disconnected the terminals for the last 6 weeks or so that my car sat before I started driving it for the winter and it fired up just fine after I reconnected the battery.

 

[DavidT]

would it be possible to install a **** switch in-cabin? Would it have to be battery cable wire running to the **** switch?