I have 1994 C4 LT1 and I want to replace the battery. I have searched the forum for other posts and now I am confused. Some say the delco batteries can leak others say you should go with a gel (optima) battery etc. I store my car in the winter and because where I am storing it there is no electricity I start it up once a month and let it run for about 30 minutes. So I need a battery that can sit for a few weeks (negative terminal disconnected) and be able to hold a charge to support my once a month starting. Can anyone give me suggestions on what battery to buy. Also has anyone had a dealership replace the battery and if so were you satisfied and what did it cost. I am thinking about doing it myself. Thanks for the help.

 

I would go with a Optima yellow top 34/78

 

Changing the battery is pretty simple. The gill requires removing some fender Torx and two 10 MM IIRC bolts on the gill back, top and bottom. Take your time and it's easy.

I neatly cut away some of the foam rubber type seal by the top bolt head as not that large of a mass is needed and it obstructs the bolt. The bottom needs an open end to get in the gap. Take note of where the gill is unless its not lined up well. When you finish you can take the time to make sure the gill and other body parts line up nice.

Depending on how long you run it every month, the battery won't be getting well charged. Store the battery at home or use a float charger.

 

Take out the battery and store it at home. Give it a charge before installing in the spring.

 

The Optima is a fine battery but not for a '94. The battery comes with both side terminals and top posts. The positive top post can easily touch the strut that runs above the battery tray. Some have machined an arc out of this strut so that the Optima will be safe. Some have installed a non-conductive cushion between the terminal and the strut.

The Acdelco Platinum battery is an AGM battery and can be found with side terminals only.

AGM has the lowest shelf loss of any auto battery.

Delphi also makes an AGM called the Freedom.

 

While a disconnected battery will lose some charge, a battery maintainer will be more than enough to keep it at full strength. It can even sit for 2-3 months without the maintainer connected.

There had been a number of posts regarding the Optima batteries and many were negative. There was a point where members reported the red top batteries failing after just a few months. Also, the re-charge procedure for the Optimas is not the same for a wet-cell typical auto battery. Keeping a manitainer on it may not be a good deal.

Aa mentioned, the Optima batteries have top posts in addition to the side posts. There is not a lot of space between the diagonal firewall brace and the postive post. Some people cut the post down, but that is not a good idea according to the Optima website.

The Yellow Top is more of a deep-cycle battery that is beter suited for heavy electrical use like a car with big amps for sound system or where heavy cranking power is needed like big equipment or high compression motors. For general street use, it's really overkill.

If you go with an AC Delco battery, get the "Professional Grade" version. Most auto parts stores that sell AC Delco stuff only carry a retail version. Go to an AC Delco supplier or a reputable auto repair shop for the Professional Grade.

Some people like Interstate batteries. I just put one in my 87 so I'll see hopw well it works out. The car is really for autocross use so it doesn't get daily use. My 02 has a AC Delco Professional Grade battery in it.

 

We run a lot of optima batteries in everything from daily drivers to our corvettes that sit all winter. The red top in the 79 has been in use for 4 years without issue and sits for 5 months straight before cranking up a 650hp engine. They have never failed me so I would recommend one but the AC Delco battery in our 99 Monte just got replaced....that was also a very good battery.

 

I just picked up a Duralast from AutoZone for like $80 after the core refund. I've always had good experiences with Duralast batteries, and they have a 9 YEAR warranty.

 

The "Optima" in a C4 using the 34/78 post "layout" leaves "considerable" to be desired. You will need to modify the "brace" and "NOT" attempt to trim the + top post. It "IS NOT" an accepted install "modification". You will need to be sure it's anchored properly and insulate the top + post in some fashion. I believe that requires some additional attention.
I believe if you buy any premium Group 75 battery from a local vendor who will be there if you have a warranty issue you'll be fine.
A battery "maintainer" is certainly a plus to an install for a vehicle that will see considerable storage!

 

Daca,

I'd suggest either the AC Delco (professional version as mentioned earlier), or an Interstate, but use the correct battery for the car, it's not worth the risk or work of modifing the frame to allow for 'special' batteries.

All batteries have a self-discharge rate, regular wet cells are the worse, true 'maintenance free' are better, GEL are better yet again (but do not work with our charging system), and AGM best (but pricey and known to just 'fail' with no warning).

Whereas the idea of taking the battery home is the best, it prevents being able to start the car once a month (a good thing, assuming you are also moving it), AND keeping the alarm activated.

Any chance the place you store it has sunlight?

If so, consider a small solar panel with a diode that can charge during the day (and the diode prevents discharge at night).

There are many of these available both in the car world and in the boating world.

Remember you probably only need a max of 1 amp/day (to offset the self discharge rate), so bigger is not better in this case.



However,

 

 

I just replaced my 3rd Delco (since 1985) in my '85 Corvette with an Exide Orbital AGM battery. (The last Delco was installed in 2001 and recently started leaking acid from the positive terminal.)

The Orbital was part # ORB75DT-84 It is a dual terminal battery where the side terminals are actually attached to the top terminals. There were absolutely no modifications necessary... other than cleaning up the mess from the leaking Delco.

I have always had good luck with Delco's in the past, and would probably have replaced this one with another if it hadn't started leaking. I have Obrital's in 4 of my vehicles and have had no problems with them thus far. The oldest is about 5 years old. The Orbital is not inexpensive, but it is an alternative and fits well in the C4.

Good luck... GUSTO

 

It would be interesting to see a "snapshot" of the Exide AGM 75DT-84 installed in the C4. It certainly looks to be possible fit. The top post layout looks a little different than the Optima and if the + post clears the brace and it can be anchored easily in the tray it might do well. I would still isolate the top + post I believe with a large rubber cap.

 

It clears the brace easily in my '85. It also comes with caps already on the top posts, as well as caps on the side terminals should you need to use the top posts. It anchors exactly as the Delco with the factory hold down.

Good luck... GUSTO