Group 58 Battery alternatives; specifically AGM options.

Buffalo5Spd

New Member
Joined
Sep 7, 2021
Messages
38
Reaction score
20
Location
Grand Island, New York
Another battery bites the dust after winter storage. I could make ammunition for a small army with the lead scrap from all of the batteries I’ve sent to the grave prematurely storing cars and campers for the winter.
I bought the car last September and the previous owner had a Duralast silver battery installed in March 2021.

My question is, what AGM battery(s) will fit well in the Oem bracket? Yea I know it’s going to need heat shielding and will be more expensive but if I can get 5-6 years or more out of it it’ll be worth it to me. I currently have an AGM in a car that was built in November 2014 that’s still going on the original battery. If I can even get close to this I’d be thrilled. The car is a 95’ GT convertible with no mods. I do apologize if this topic was specifically discussed previously but I didn’t find any information about what sizes fit what years. Thanks guys!
 

ttocs

Post Whore
Joined
Oct 9, 2009
Messages
29,577
Reaction score
4,445
Location
Evansville Indiana
switching to an agm battery is not going to fix the problem at hand, that you have some kind of draw on the system. The mach/premium amps are known to be a battery draw and even if they have been bypassed, if the one in the dash is still hooked up to power it will kill a battery. You can actually see the amp if you pull the carpet back on the console on the drivers side and disconnect it if it is there otherwise it only takes a few seconds to disconnect the battery and then hook up an amp meter to measure the draw, then you start pulling fuses one at a time till you see the draw go away. When it does you know what circuit has the draw and you can narrow down what the problem is.

But if you do go agm you do need to either figure out how to shield it from heat or move it to the trunk.
 

badass98svt

Well-Known Member
Joined
Jan 11, 2006
Messages
3,025
Reaction score
672
You don't keep your car on a trickle charger when not driving it? There's your first issue.
My 98 is on its 3rd battery since 1998, and I only drive it in the warm months, about 1500-2000 miles a year.
I used to daily drive it back in the day too.
 

KJ-00-GT

New Member
Joined
Aug 19, 2021
Messages
58
Reaction score
106
As the others said disconnect and or charge battery's in storage vehicles. I have five vehicles that are stored for the winter, I don't disconnect the battery's anymore but I do rotate trickle chargers at least once a month for a week at a time on each. Only replaced a battery once due to winter storage and that was before I started doing the above routine.
 

96blak54

Legend
Joined
Feb 21, 2011
Messages
8,502
Reaction score
1,754
Location
Ky
My recommendation if it is outside is to get a solar waterproof battery tender from Amazon. Worked great for my verts
Matt12eagles is right. Battery tenders extend battery life really good. They work especially good on riding mowers and motorcylces. Why not on a car battery. Beats spending $150 for a new one every couple of years.

But ttocs is on to something with parasitic battery draw. If anyone here has the electrical knowledge with these cars, its him. Ive read countless threads that ttocs has helped out someone stuck with an electrical issue. Threads like that totally redeems him worthy over his political views.
 
OP
OP
B

Buffalo5Spd

New Member
Joined
Sep 7, 2021
Messages
38
Reaction score
20
Location
Grand Island, New York
I did have a tender on it the clamp fell off lol. I haven’t had one die that quickly before so I think ttocs is on the right path with paracitic loss. I have the tools for that job. The car sat several times for a week or more last summer so I didn’t immediately think of something draining power.
I definitely know about insulating AGMs under hood they don’t like heat. I was just hoping someone had a good starting point for an AGM size to swap in. I should have disconnected it but I didn’t, that’s on me. Just want to get it going as the salt is currently washed off the roads and I know a good AGM will hold a change if disconnected for storage next year.
Thanks everyone for the laughs and of course for the advice.
 
OP
OP
B

Buffalo5Spd

New Member
Joined
Sep 7, 2021
Messages
38
Reaction score
20
Location
Grand Island, New York
100% agree with you ttocs. I am after the better characteristics of the AGM in general but the resilience to discharge damage in particular. At the very least it will buy me some time figuring out what’s drawing power without leaving me stranded.

And to address the particulars of the car it has about 12,800mi and is not modified. It’s a loaded convertible with the Mach sound system. Only thing I wish it had was the optional minidisc player.

If I find the Mach amps pulling power when they shouldn’t I’m considering wiring in a relay to isolate them from battery power.
 

Attachments

  • FF01F945-E0E0-4AC0-9799-76DCB5969590.jpeg
    FF01F945-E0E0-4AC0-9799-76DCB5969590.jpeg
    63.2 KB · Views: 3
  • AB3892EC-45EC-4461-AB4C-91AE0FCC8D3D.jpeg
    AB3892EC-45EC-4461-AB4C-91AE0FCC8D3D.jpeg
    65.5 KB · Views: 2
  • D124F51F-DC65-49C8-A803-FC5AD1D0F715.jpeg
    D124F51F-DC65-49C8-A803-FC5AD1D0F715.jpeg
    71.4 KB · Views: 3
  • 0809B4A6-703E-4830-BD1D-C71A52352039.jpeg
    0809B4A6-703E-4830-BD1D-C71A52352039.jpeg
    46.8 KB · Views: 2
Last edited:

tinnocker

Member
Joined
Apr 12, 2021
Messages
131
Reaction score
66
I had the battery drain on my 94GT and searched the forums. Some said it was the 95/95 computer and ttocs said it may be the radio which I believe it probably is. I wiggled wires, unplugged the engine and trunk light and finally give up. I felt it was easier to just buy a trickle charger than trying to diagnose it. I tried to buy ' Made in USA' and went with Battery Tender. Found out when I opened the package that it was made in China! It would take about 2 weeks of sitting without driving to drain my new battery. All is well now with the B.T.

Buffalo, if the relay works on your Mach amp drain, post some pictures and where to find the Mach amp feed wire.. There have been many post about the drain problem.
 

ttocs

Post Whore
Joined
Oct 9, 2009
Messages
29,577
Reaction score
4,445
Location
Evansville Indiana
It only takes a minute to disconnect the battery and insert the amp meter to test and the mach amp fuses would be the first I would check. If it is them and you want to keep them a relay to disconnect the ground to them should stop the drain.

I always wanted that minidisk player myself... I had a sony for a little while but the lack of music on the format and the expense of the recorders just didn't allow them to last long. Sony screwed that format all up.
 
OP
OP
B

Buffalo5Spd

New Member
Joined
Sep 7, 2021
Messages
38
Reaction score
20
Location
Grand Island, New York
I’ll start with the sound fuses in a week or two. Going to the Caribbean for a wedding tomorrow.
I had high hopes for minidisc, ohh well. I still have a few of them kicking around here somewhere lol. Thanks for the help with where to start it’s much appreciated.
 

CobraRGuy

New Member
Joined
Jan 18, 2020
Messages
23
Reaction score
19
Location
Fremont, CA
Something you should check is the recommended float voltage of the battery and float voltage the trickle charger is using. The manufacturers of both should be able to give you those.
The reason I mentioned this is because when I got my 2018 F150 with the 5.0, I pre-wired it for a battery tender and started using my Delran Battery Tender Jr. on it. I've tried both the larger/heavier older, and the smaller/lighter newer ones. What I found is that my auto start-stop feature stopped working because the truck thought the battery voltage was too low. I stopped using it and the auto start-stop has worked fine ever since. This truck came with an AGM battery from the factory, as did my wife's Edge ST which also has that feature. My conclusion is that the battery tender was floating the charge at too low of a voltage. The truck's charging system is clearly working as it should.
As far as true group 58 AGM batteries, there are none that I have ever been able to find. Oddyssey makes an AGM battery with the same dimensions (LxHxW), but there is no lip for the Mustang's hold-down wedge. You would need to find a different hold-down mechanism, but it is short enough and would fit the tray just fine.
Optima also makes one that will fit but the posts are not in exactly the same places; they're closer to the center of the battery. I know the stock battery cables on my car would not reach because there's like NO SLACK in them.
I ended up buyng a "Duracell" group 58 which has better amperage ratings than most and has a very good warranty. Since my Cobra R has no auto start-stop feature (I'm pretty sure of this, <big grin>), I do keep it on a battery tender since it gets driven so little.

Perry (CobraRGuy)
 

96blak54

Legend
Joined
Feb 21, 2011
Messages
8,502
Reaction score
1,754
Location
Ky
Run the wires and mount a battery box in the trunk. Now use whatever battery you want.
 

Latest posts

Forum statistics

Threads
76,085
Messages
1,470,121
Members
14,059
Latest member
Kevin.goat

Members online

Top