Here's a summary I posted recently. It may help you
I’ve read many posts on batteries over the years on the Forum and I thought it might be useful to post up my thoughts. I’ll accept that I am a little biased and I’m not a fan of AC Delco batteries but I’ll try to be objective not emotional.
I’ll admit, my experience has colored my views. My son’s 98 Camaro had a stock AC Delco battery. It gave good service (6 years) but it eventually leaked. Luckily I caught it before it damaged the car and all it did was leak acid on the garage floor. My own 02 Vette suffered a terminal failure after only 18 months and 8000 miles. It didn’t leak but it died without warning. Luckily I was stranded in the garage not the Mojave Desert. I replaced it with an Optima Red Top which was at that time was well respected. It gave me good service for over 2 years when the car was a daily driver. I then shipped my car to England and the battery sat hooked up for 2 months in transit. Although it fired up with a jump start, the battery would never hold a charge after that so I replaced it with a Yellow Top. In that case I was happy that I knew that I’d killed the Red Top by discharging it. I’d agree that the reputation of the Red Top has since suffered and there do seem to be a lot of failures where I often wonder whether it’s the car not the battery that’s at fault. JMHO. I now have an Optima Yellow Top which is doing well but stays hooked up to a Battery Tender when not in use.
There are a number of major types of batteries on the market and the type of battery which suits you depends on your useage. Here’s a good tutorial on the types of batteries on the Optima page:
The key facts that I take from that tutorial are that:
“a starting battery is designed to deliver quick bursts of energy (such as starting engines) and has a greater plate count. The plates will also be thinner and have different material compositions. A deep cycle battery has less instant energy but greater long-term energy delivery. Deep cycle batteries have thicker plates and can survive a number of discharge cycles. Starting batteries should not be used for deep cycle applications as they will be quickly destroyed. The so-called Dual Purpose Battery is a compromise between the 2 types of batteries. A Gel or Gelled Acid battery is just a “non spill” version of the normal Sulphuric Acid battery. Silica Gel crystals are added or dissolved into the Acid to form a paste or Gel to stop the Acid being a liquid. There are Starter, and Deep cycle Gelled Acid batteries. These are gradually being superseded by AGM batteries. AGM batteries still use Acid, but in this case it can’t spill because it is Absorbed (A) into Glass (G) Mat (M). These offer more cycles, greater performance whether Deep cycle or Starter types. So this is a superior technology to Gelled Acid.”
When you look for a replacement the shop manual quotes the GM spec for the Vette which requires a Cold Cranking Ampage of 500A and a reserve capacity of 80 minutes. The stock battery part number is 19002277 model # 75P-7YR. There are plenty of choices that meet that spec.
Changing the battery is straight forward.
Disconnect the negative cable first
Disconnect the positive cable
Remove the battery hold down retainer bolt (13mm IIRC)
Lift out the battery
Clean the terminals before reconnecting
Reattach the positive cable and torque to 15 N-m (11 lb ft)
Reattach the negative cable and torque to 16 N-m (12 lb ft)
Reinsert the battery hold down retainer bolt and torque to 18 N-m (13 lb ft)
Don’t forget that if you have a stock radio, turn the security feature off before you start or the radio will lock up.
Battery performance is a difficult one to pin down. I ran a battery poll which started back in August 06 and as of 17 Feb 08 it had about 733 posts (as of today 756 posts) so its getting there as a sample. Here’s a snapshot on that date:
My AC Delco is still performing well 259 35.33%
My AC Delco died but caused no damage 154 21.01%
My AC Delco died and damaged my car or resulted in problems 34 4.64%
I now have an Optima Red Top and it has performed well 204 27.83%
I now have an Optima Red Top but it has given problems 45 6.14%
I now have an Exide and it has performed well 26 3.55%
I now have an Exide but it has given problems 6 0.62%
I now have another type of battery and it has performed well 106 14.46%
I now have another type of battery but it has given problems 13 1.77%
Here’s the link:
Now I’m no statistician but I work with those guys. This can never be scientific because the questions are not perfect. What it does do is give a good subjective view on the major trends.
To get a true figure for the AC Delco (which admittedly is the main battery in use), you need to look at the first 3 lines.
For the AC Delco of 447 total (259 + 154 + 34), there were 188 failures of which 34 caused damage. That’s a failure rate of 42%
For the Red Top, of 249 total (204 + 45), there were 45 failures which is a failure rate of 18%. As it’s an AGM battery its unlikely to damage the car which is why there are only 2 categories.
The samples for Exide and others are too small to be relevant but I’d say the Exide does well.
The poll has probably run its course now because even the best OEM battery is due for replacement by now. What it showed me is that there was too high a failure rate on the original batteries and even though the latest battery is redesigned and probably much better, there are probably many C5 Vette owners out there with an original battery that has a high chance of either failing or leaking and causing serious damage.
The early OEM AC Delco battery had a problem and was prone to leaks. When it leaks, acid drips down first onto the battery tray and then works its way down into the wheel well into the area which holds the PCM. On its way it affects the wiring and the vacuum lines and can cause strange electrical and associated problems.
Toxdoc posted up his experiences after his battery leaked and its worth a read to decide whether you want to take this risk
Here’s another members experiences:
Here’s the problem:
Here’s a pic of the type of damage that ensues:
So, others may disagree with my analysis but of course that’s what a discussion Forum is for.
There’s a lot of discussion on the versions of the AC Delco batteries which are out there. Corvette Forum Member timd38 pointed out that “The AC Delco battery in the picture was made by Delphi, thus the leak issue. Since that time Delphi abandoned the battery business and they are now made to GM specification by Johnson Controls. You can tell the new one ones because they have a different cover on the battery that has service caps that are not to be opened.” Member Dave68 advised that GM started fitting AC Delco AGM batteries in 2001 but that while these won’t leak, they suffer the same weakness as a Red Top, namely that they don’t take well to being discharged. The new top post AC Delco batteries were fitted from 2003 onwards.
In sum it appears that there are 3 types of GM fitted batteries out there:
The original Delphi made batteries fitted from 97 to 01 which are prone to leaks.
Redesigned AGM batteries fitted from 01 to 03 that may die early if discharged.
Further redesigned top post batteries which should be OK. These latest AC Delco batteries have supposedly been redesigned to strengthen the case and should fix the leak problems. In the interest of fairness this is a link to the latest spec:
You need to know which battery is fitted to your car.
It’s an indisputable fact but the C5 has a small drain on the electrics even when idle. If you leave the battery hooked up for months on end, there’s a good chance it will be dead when you come back to it. If you think you may have an excessive battery drain, Bill Curlee posted an excellent guide on how to check for current draw and you can find it here:
If all that fails and you end up with a dead battery, the signs are:
Weak or no lights on the instrument panel when you turn the key
Clicking from the relays in the passenger footwell (the dreaded chattering relays) when you try to start,
Instrument panel lights that dim when you try to start.
There may be others.
I’d say best advice is that if you plan to leave the car idle for longer periods, invest a few $$ on a Battery Tender. This will give the battery a gentle trickle charge and keep it topped off. If your car sits outside, you can buy a solar powered equivalent which may do enough to keep the battery happy. All I'd say is don't neglect the battery for months on end and then complain when it's dead.
So what do I think is the advice I’d offer to a new C5 owner?
Firstly, when you're buying, check that the battery has not leaked. A new battery doesn't mean the old one hasn’t dome damage. Take a good look around the battery tray.
If you have an original side post AC Delco check for leaks, particularly if its pre 2001. If it has been discharged, it has probably been taken out of the car and the leads may have been over-torqued on reinstallation. Over-torquing stresses the case around the side posts. Better still, change it as a precaution because the older AC Delco’s are
prone to leaks and particularly vulnerable around those side post connections.
If the thought of a leak worries you, buy an AGM battery. If not, there are cheaper batteries on the market. Ultimately its your $$ and your risk.
If your car is a daily driver, don’t worry about drains. It will almost certainly fire up like a Champ every day. If you regularly leave your car for a week or longer, buy a Battery Tender. If you have an AGM battery, make sure the tender is designed for that type of battery.
Bottom line for me is that I have no axe to grind either way but I have my views, colored by experience. I’m not an AC Delco fan but I’ll happily accept that the 03 onwards batteries are better quality. It’s your choice but hopefully this thread will allow you to maker an informed decision rather than rely on instant judgements from a single thread.