Agm battery
Instructor
Joined: Feb 2014
Posts: 194
Likes: 1
From: Moon, VA
I tried the AGM red top. When the power went out at the Florida house and I was gone for the season the charger did not resume charging. It discharged completely and would not come back up when I returned the next season. The charger that GM sells for the vette does not power back up automatically. Make sure that if you use a trickle charger for the off season that you use one that does. I now use the Battery Tender brand with a lead acid battery. I have seen way too many of these red tops returned to the auto parts store. I am still a fan of Gel Batteries, but I only use the Odyssey brand. I own 3 of them now and have never had an issue with them. I have even had one that froze when the charger quit charging on my Generac home generator and after being down all the way for months charged right back up and is still in use today. Yes the cost is high but the reliability is unbeatable. When the lead acid battery dies in my C5 it will be replaced by an Odyssey.
Advanced
Joined: Dec 2015
Posts: 85
Likes: 27
From: Smithtown New York/Naples Florida/Flint Twp. Michigan
I would be careful with using the ctek. The one that I have does not power back up after the house power drops out. I am a snowbird and when I returned the AGM red top was completely dead and would not charge back up. Returned it for a full refund. If you are not seasonal like I am you should be ok. Just keep an eye on it.
Thread Starter
Drifting
Joined: Aug 2014
Posts: 1,626
Likes: 174
From: North pole
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Racer
Joined: May 2016
Posts: 442
Likes: 79
From: Metro Detroit
97-00 came with 78 group
01-04 came with 75 group i beleave 75 is a little lighter and smaller in size.
I have an 01 and I purchased the 78 AGM. Its a little bigger then the group 75. I didn't feel comfortable the way the hold down bracket contacted the side of the battery given its slightly larger size. I modified the hold down bracket with a dremel and I was content.
I Just put the battery in last fall. As others mentioned, a good battery tender goes a long way to extending the life of a battery in an infrequently used vehicle.
The 5 Top-Rated Battery Chargers Editor's Picks Brand Rating Best Overall pick:
BATTERY TENDER® 12V Junior Automatic Battery Charger 4.6
01-04 came with 75 group i beleave 75 is a little lighter and smaller in size.
I have an 01 and I purchased the 78 AGM. Its a little bigger then the group 75. I didn't feel comfortable the way the hold down bracket contacted the side of the battery given its slightly larger size. I modified the hold down bracket with a dremel and I was content.
I Just put the battery in last fall. As others mentioned, a good battery tender goes a long way to extending the life of a battery in an infrequently used vehicle.
The 5 Top-Rated Battery Chargers Editor's Picks Brand Rating Best Overall pick:
BATTERY TENDER® 12V Junior Automatic Battery Charger 4.6
Last edited by Bossdog; Apr 17, 2020 at 07:45 PM.
Heel & Toe
Joined: Jan 2024
Posts: 19
Likes: 6
I wonder if a Super Start Platinum AGM Battery Group Size 78, good for my 98 Corvette? Has anyone used that kind of battery brand? I'm really desperate trying to find an agm battery, and that's the only one they got at the closest O'Reilly Auto Parts near me.
This is the specs of this battery:
This is the specs of this battery:
- Battery Type: AGM
- Height (in): 7-1/4 Inch
- Length (in): 10-3/4 Inch
- Width (in): 6-7/8 Inch
- Terminal Type: Side Post
- Weight (Lbs): 43 Lbs.
- Voltage (V): 12 Volt
- Cold Cranking Amps (CCA): 750 CCA
- Cranking Amps (CA): 860 CA
- Group Size (BCI): 78
- Reserve Capacity (min): 120 Minute
- Positive Terminal Location: Side Left
- Flush Manifold Vent Cover: Yes
Melting Slicks
Joined: Mar 2023
Posts: 2,917
Likes: 1,675
From: North Coast
The trouble is most people are not educated on AGM batteries and they are the ones who have issues and often toss good batteries.
Race Director
Joined: May 2003
Posts: 14,137
Likes: 2,984
From: Iowa
St. Jude Donor '03 thru '26
I wonder if a Super Start Platinum AGM Battery Group Size 78, good for my 98 Corvette? Has anyone used that kind of battery brand? I'm really desperate trying to find an agm battery, and that's the only one they got at the closest O'Reilly Auto Parts near me.
This is the specs of this battery:
This is the specs of this battery:
- Battery Type: AGM
- Height (in): 7-1/4 Inch
- Length (in): 10-3/4 Inch
- Width (in): 6-7/8 Inch
- Terminal Type: Side Post
- Weight (Lbs): 43 Lbs.
- Voltage (V): 12 Volt
- Cold Cranking Amps (CCA): 750 CCA
- Cranking Amps (CA): 860 CA
- Group Size (BCI): 78
- Reserve Capacity (min): 120 Minute
- Positive Terminal Location: Side Left
- Flush Manifold Vent Cover: Yes
Heel & Toe
Joined: Jan 2024
Posts: 19
Likes: 6
Although, in regards to the battery tender, will it still be useful to have, even though it's my daily driver/only car? I know I'm a bit suicidal lol
Instructor
Joined: Nov 2016
Posts: 244
Likes: 103
From: Pueblo West CO
If your daily driver needs a battery tender, you have a terrible parasitic draw, and rather than a tender you need to fix that problem.
Heel & Toe
Joined: Jan 2024
Posts: 19
Likes: 6
Still, that advice you gave me is gold! I really appreciate the advice. Though my AGM battery is brand new (Well not really, sticker says 09/23
), and with a 3 year warranty, and things are ok now, you never know how things might be later on down the road. So this advice would prove useful to me when it happens. 
Melting Slicks
Joined: Mar 2023
Posts: 2,917
Likes: 1,675
From: North Coast
Yes for cars that sit AGM batteries can hit that threshold where a normal charger will not bring it back up.
There is a diode that needs stimulated below 11 volts and it will act like a bad battery. Manybtoss out hood batteries after trying yo charge with a Non AGM battery.
i recommend AGM but if you buy one get the proper charger or a tender to keep it topped off. If you do you will be fine. Daily drivers should not have issues if the charging system is working properly.
There is a diode that needs stimulated below 11 volts and it will act like a bad battery. Manybtoss out hood batteries after trying yo charge with a Non AGM battery.
i recommend AGM but if you buy one get the proper charger or a tender to keep it topped off. If you do you will be fine. Daily drivers should not have issues if the charging system is working properly.
Drifting
Joined: Sep 2017
Posts: 1,959
Likes: 691
From: Avon Lake OH
Yes, if you let an AGM battery sit in a C5 for say 2-3 weeks or longer, without the proper tender/charger then you may have an issue.
You can bring an AGM battery "back from the dead" by doing what I had to do here;
https://www.corvetteforum.com/forums...post1605347652
You can bring an AGM battery "back from the dead" by doing what I had to do here;
https://www.corvetteforum.com/forums...post1605347652
Race Director
Joined: Jan 2002
Posts: 19,557
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From: I love you & miss you Linda
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