SoundwaveFD

iTrader: (5)

I was wondering if anyone has had any problems with fitament issues of installing an Optima Red Top battery 35 series in a 3rd gen stock location? I am in the market for a new battery and Optima is tempting, but I have heard that you need a bottom height adjuster for a 93 RX7 and Optima could not tell me if I'd be able to close my battery box over it? I also heard the terminals are in a different location that is too far away from the battery cables but I read that in an old thread so maybe it is not the case with the new 35 series. I have also heard that Optima reliability has gone down hill lately.

If anyone has had any experience with any of these issues any help would be appreciated.

Thanks,
Drew

ObliqueFD

iTrader: (32)

I recently purchased a 35 series red top for my RX-8 and it has been the best battery I've ever had. It came with two types of spacers so you shouldn't have any height problems. I have a 51R yellow top in my FD that has been good too. It's about 4 years old and is still going strong.

DaleClark

iTrader: (55)

Most Optimas have the battery terminals backwards to where it should be. I don't think they make that 51r battery any more either, BTW.

Really, just a good parts store battery is fine. I've been using Duralast batteries from Autozone with no problems. Get one that FITS is the big one if you have the stock battery tray/cover. I've seen SO many FD's with hacked up battery trays and boxes due to people using the wrong battery, it just looks terrible and it's crappy to hack something up on the car to make a maintenance item like a battery fit.

Also, I've yet to see anything on the Optima batteries that really make them special for me. To me it's just a battery with a lot of marketing and a fancy package that nine times out of ten doesn't fit for crap. I wouldn't waste money on one.

Dale

SoundwaveFD

iTrader: (5)

Yeah, I'm with you Dale. I'm a bit worried about fitament issues. I'm pretty sure I'm just going to go with a good Interstate battery and call it a day.

Drew

NVMYRX-7

iTrader: (24)

It only needs to happen ONCE (post #13)

If you get a smaller battery along with a tray, you can always return it to stock without doing anything special to your cables.

https://www.rx7club.com/3rd-generati...y-tray-991376/

Akagis_white_comet

iTrader: (4)

I'd like to make a few factual corrections regarding Optima Batteries, in order to prevent misinformation.

Battery Group Size and terminal location are standardized per BCI Regulations that pre-date the FC. Here is more information on dimensions, terminals and polarity:
BatteryWeb, Inc. - BCI Group Numbers, Dimensional Specifications, Polarity and Terminals
Therefore, a poorly reasoned install is the fault of the installer failing to read, not the battery.

I have used both a Failzone Duracrap and an AGM Battery comparable to an Optima (Deka Intimidator) back-to-back and witnessed a BIG difference on my 20B FC. Having seen firsthand the difference, I swear by AGM batteries now. The only flaw I can see with an Optima Battery is its Six-Pack design, a logical observation made apparent by Deka in their sales literature here:
Automotive Batteries: Deka's Complete Line of Lead-acid Batteries for Passenger Cars & LTV

The gaps between the Spiral Cells in an Optima battery's have no lead in them, so they produce no power. Deka Intimidators use the normal six in-line form factor, filling the space entirely for maximum power production. Superior AGM technology coupled with the maximum space utilization of an oldschool Lead-Acid battery. This is why Aaron Cake selected one for his FC, and why I have one as well.

Earlier this year, I did a back-to-back test between a Duralast Group 35 battery (purchase in 2008, approx 3 years old) and a new Deka Intimidator Group 48 battery (very similar specifications). The Duralast one had been run dead a few times but always perked back up after charging, reflecting what could realistically happen in 3 years of usage. Charged to a full 12.6v, it instantly fell on its face to 8v as soon as the key was turned to crank the engine. The Intimidator had no problem with cranking the engine multiple times while diagnosing iffy cables, never dropping below 10v. Even after being drained and recharged using a Battery Tender brand charger, it performed exactly the same as it did before, outlasting the Duralast battery by at least 5 crank attempts (10 seconds each) with an average draw of 125A each time. This information was found as a result of testing different cables (Soldered welding cable vs Premade from the parts store) and different starters (Duralast vs Mazda) while logging the results of every combination. The results are here:
https://www.rx7club.com/build-thread...888195/page11/

By the end of this test, the Intimidator had been drained and recharged about the same number as the Duralast battery had since I bought it. The difference is that the Intimidator is still brutally strong while the Duralast was completely ruined and out of warranty.

Also, I want to point out another big difference: AGM batteries don't contain liquid acid so they cannot be spilled. They also do not emit hydrogen gas when charging, making them safe for mounting inside a vehicle. It can also be drained and charged back up (with an AGM charger, such as one from Home page - Batterytender.com) twice as much as a standard battery. That alone justifies the extra expenditure. Compared to the previous Group 35 from Autozone that was $100, the extra $60 or so was well worth it to upgrade to an AGM battery, an extra 15AH more capacity, and is only 2" longer in length and 1.5" shorter in height than stock. This is an extra 20lbs of reliability that paid for itself the first month I had it. Pretty sure I won't notice the extra weight with a 3-rotor

Because it's in my storage bin, I made a battery box to fit the 9A48 and fabricated a simple spacer out of extra 2" square tube to go back to a Group 35 temporarily in case of the unforeseen. Look at Page 12 of my build thread above and you'll see that because of the way I designed the box and made its cables, the battery's terminal location is irrelevant due to the Group 35 being taller, clearing the box and STILL fitting under the unmodified lid.

Remember, there is good reason why we don't buy parts at Autozone...

turbojeff

iTrader: (30)

I've got the 51r optima yellow top with a custom SS tray for extra IC room and less weight in front of the tires but then again I'm biased.

I've got two 51r trays left.

RENESISFD

iTrader: (13)

I too am a huge fan of AGM batteries. There is no acid to spill causing the severe corrosion issues some cars have where the battery is located. That alone is enough to convince me to use them.

NVMYRX-7

iTrader: (24)

Listen to this man; it only needs to happen ONE time!!!


It's really just simple math
51r AGM battery+Turbo Jeff battery tray+CTEK charger= WIN

SA3R

I have an AGM in my car, in factory location, and the factory battery box fits over it great. No acid to spill, no hassles, looks stock.
I forget the brand, but I can look at it when I get home from work if anyone's interested in trying to match the part number in the US. One of the best batteries I've ever had, and I got it at a department store..

prrex4ever

iTrader: (3)

I have had great luck with optima also, I had a red top in the stock tray with no hacking or issues.

adam c

iTrader: (2)

Your Deka battery may be a good one, but to test it against a 3 year old battery that had been run dead a few times????? What kind of test is that? Certainly not a fair one that proves ANYTHING!!!!

I bought my Interstate battery 3-10-07. It is almost 6 years old, and is still going strong.

Tem120

iTrader: (5)

its fair I have the Duracrud from autozone I've had it replaced 3 times in the year I've had it .

and working on its 4th now .

I messed up , and put an underdrive pulley on my alternator . which means if I idle alot my charge slowly dies . ( traffic ) , and aslong as I dont put stress on my battery it works fine , BUUT the other day I gave a jump to an old lady who was stranded . and it damn near killed my battery it went to 10 V and has not recovered since that day . its at 11.5 and wont go higher . the car still starts fine . BUT if I'm in traffic to long the volts start going down and driving at night is bad . this is AFTER the jump .