Emergency Battery Help


GEE-TEE

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
May 1, 2009
617
Calabasas, California
I beleive my Battery is on its last leg. The battery seemed low yestarday and I usually keep the Cooltech tender on and the light turns green after an hour or so. I plugged it in yesterday after a short drive when the Volt meter showed low. It stayed on the tender over night and this morning the light is still red. I am very nervous as Im headed to Rally Tuesday and dont want to chance anything. Please help!!I know there has been changes to the size of the recommended DieHard Battery and one of the guys said the Sears Battery #28850747 works. Can you guys give advice on any alternatives if I cannot find this one at Sears today?
 

Gierkink

GT Owner
Mark IV Lifetime
Oct 5, 2005
672
Wellington, FL
When Roush homogenized the European GTs for Ford they added a heavier-duty battery to the car. It is the Optima Yellow Top battery Model number D34/78. I've had these in my car since new and they work perfectly. I've replaced it twice myself with no problems. You can get them anywhere including Autozone... just Google the battery and model number. Good luck.
 

GEE-TEE

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
May 1, 2009
617
Calabasas, California
Thank you. I assume replacement is pretty dummy proof???
 

Specracer

GT Owner
Mark IV Lifetime
Nov 28, 2005
7,081
MA
Just heavy and awkward to reach in and over the fenders.
 

Howard

GT Owner
Mark IV Lifetime
Apr 26, 2007
1,135
Florida/North Jersey
Odyssey 75/86 (PC1230) also works well and (I think) was the supplier to Sears. I installed it in my car in May.

Howard
 
Last edited:

AJB

GT
Mark II Lifetime
Le Mans 2010 Supporter
Jun 28, 2006
2,943
Bloomfield Hills, Michigan
AS INSURANCE--- take along one of those 'all in one' tire compressors, light and STARTER BATTTERY packs that they sell at SAMS or any Auto store. About $85.00. I had one with me at VIR Rally and it 'saved the day' since I left the ignition 'on' during my trailer ride from Detroit and the battery was dead on arrival.
GT started right up.
AJB
 

Art138

GT Owner
Mark II Lifetime
Jan 4, 2011
624
Weston,FL
If you want to keep the original look, buy the red top like the one which came with the car. I peeled the old sticker off and placed it on the new one. Optima part number 8025-160 Model 25 (at Autozone,Pepboys). My Original Redtop lasted until last year.
 

Specracer

GT Owner
Mark IV Lifetime
Nov 28, 2005
7,081
MA
Ahhh the memory, did the same thing rally 1, best thing I could have done, because a tall guy wandered up and asked if I needed help. Explained what I did, he offered a jump, it was McGowan, been buds ever since, never made the cocktail reception, was just chatting outside. A great friendship began because of a dead battery...

And I still use the same battery to this day, and before anyone asks yes, I have speedhuts.



I left the ignition 'on' during my trailer ride from Detroit and the battery was dead on arrival.
 

GEE-TEE

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
May 1, 2009
617
Calabasas, California
I found an Optima Yellow top d3478. On my way to pick it up thank you...
 

Blue Moose

GT
Mark IV Lifetime
Le Mans 2010 Supporter
Apr 12, 2006
1,139
Chandler,Arizona.
Just heavy and awkward to reach in and over the fenders.

Looks like you found the battery you need and please remember to avoid setting the battery on top of the fender or putting your elbows on the fender for leverage when lifting / lowering the battery in and out as they are aluminum and could dent more easy than steel.

See you at the rally!
 

GEE-TEE

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
May 1, 2009
617
Calabasas, California
Thank you all. Just installed and car starts fine and guages seem all good. The volt meter seems to be little below the mddle but Im sure it will charge up as I drive it. Also strangeley enough when I plugged in the Tender( Cooltech) after the red light is blinking now!!! I hope this means it needs to charge it up as the voltage is low. I didnt mess with any of teh connections which cooltech put in for tender. Should I be concerened? Im going back to return the OEM core for my $15 later. Should I buy a new Tender? They had the same kind.
 

GEE-TEE

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
May 1, 2009
617
Calabasas, California
I wanted to thank you guys all for helping remedy my anxiety yesterday. Allthough lifing the battery in such weird angle trying to not lean on fenders was killer on my back. Especially in near 100 degree sauna tepratures. Wow what a big task it became. My son kept making fun of me and was asking Dad, why are you sweating so much?

Anyways, have new battery-Will travel. Thanks to my familiy here. C U Soon in Sonoma.
 

Gierkink

GT Owner
Mark IV Lifetime
Oct 5, 2005
672
Wellington, FL
Glad it worked out. Have fun at the Rally.
 

GEE-TEE

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
May 1, 2009
617
Calabasas, California
Thank you especially bud "Gierkink". The Cooltech specialist "Ryan" did offer to come down today to install it but my ego got the better of me and I wish I had now as the back is killing me. Lots of Advil tomorrow morning!!! Not to mention Cooltech also spruced up my car with new shoes and A/C charge etc last week so I should be good to go. Looking forward to rally.
Thnx again,
A
 

RALPHIE

GT Owner
Mar 1, 2007
7,278
I'm a little worried that your voltmeter is not showing a charging condition - should be to the right of the centerline. Perhaps you should have your alternator checked, as you don't want to be running solely on battery power. Check with Kendall before leaving.
 

Xcentric

GT Owner
Mark II Lifetime
Jul 9, 2012
5,213
Myakka City, Florida
+1. With the engine running, voltmeter shows charging voltage, not battery voltage. Blinking red light on the battery charger doesn't sound right either.
 

PL510*Jeff

Well-known member
Mark IV Lifetime
Le Mans 2010 Supporter
Nov 3, 2005
4,876
Renton, Washington
I'm a little worried that your voltmeter is not showing a charging condition - should be to the right of the centerline. Perhaps you should have your alternator checked, as you don't want to be running solely on battery power. Check with Kendall before leaving.

For sure have your alternator checked. And have it checked on an old fashioned analog tester. Over a wide range of engine rpm's. Digital testers run everything on low rpm test loops.

We found that my alternator, recently replaced at 98,000 miles, had diodes intermittently and quickly opening and closing at 4,500 to red line engine speeds. And was not capable of generating enough electricity to operate all the electrical needs of the car and charge the battery too. And thus the GCM (gauge control module) was attempting to shut off non-essential things - like gauges - to allocate electrical resources to keep the motor running.
 

GEE-TEE

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
May 1, 2009
617
Calabasas, California
Thanks Ralphie, Jeff and Xcentric. Now I am worried again. The blinking red light issue is resolved and was a long story as I went and bought a new one and then discovered a loose connection. Anyways, I also went and bought a charger for the battery and brought it up to 100% as I knew sometimes new batteries needed a fresh charge. Now all looks good but the Volt Meter is still showing a small click before the Middle. So, Im gonna cross my fingers as its Laborday and Im not gonna bother the Pond family now. Do you guys think I am OK? Maybe I should have a phone number for a local transport service just in case!!! :(

Yes in case any of you are wondering I am a total Tard when it comes to this stuff. Thats why I am here... :)
 
Last edited:

BlackICE

GT Owner
Nov 2, 2005
1,416
SF Bay Area in California
Easy way to check is putting a voltmeter on the battery terminal. Start the car the voltage should rise above the 12.6-12.8v to around 13.3V or higher. If you rev the motor a little the voltage may be even higher but not more than 14.5v. Some cars do overcharge batteries and run 15v or more when the engine running. If you are not getting more than 13v on the battery at idle something is wrong with the cars charging circuit.

This is with all accessories turned off.
 

FBA

GT Owner
Dec 5, 2010
1,663
31.022340° N / 44.846191° W
When you top off the battery manually, you may not see the system fully charging until a drive it for a bit. It senses the capacity and varies depending on charge state. The system won't attempt to charge hard if the battery is already fully charged. Drive it for a bit at speeds before you worry about the charging system. All of my vehicles show from under to over the mid-line depending on battery state. I can see 13.5-14.5 depending on much of a charge and what the ambient temps are. My GT is no different.