Nubo

Optima users - Any opinions on which Optima battery might be best for the RX-8?

The Red top is maximized for starting power, which might be helpful in getting maximum starting rpm. It's been proposed on the forum that the flooding issue might be helped by having the engine spin faster on startup. I realize the battery isn't going to magically double the starting rpm, but maybe even a little improvement is a good thing.

The Yellow top is optimized for deep discharge. If I run into hard-starting issues and need to repeatedly perform the WOT-start to cure a flood, the battery could be deeply drained at the end of the episode. A deep cycle battery would be better able to handle that punishment.

Also, I won't be driving the car every day. At least once a week though; and more often in winter (I bike to work frequently).

It doesn't get much below freezing here.

Right now I'm thinkin' "Yellow car - Yellow battery", but that's dumb :p

Doctorr

Red is probably the way to go, you will never make use of all those 'cold cranking' amps, but it's nice to know they're there....

The yellow top is optimized for deep discharge cycles, which means a more rugged construction, higher price, and LESS cranking amps.

Different strokes.

I remember reading that there isn't a size that will properly fit the '8.....I hope someone can correct me and let us know which is THE one, they are on sale, $30 off, at my local Costco this week....
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doc

S3/P3/E2

Prowl around on here (like I need to tell either of you two about that), but it seems like I saw someone on here just the other day with a red top under the hood. Honestly, I'd like to know as well since I've thought of doing the swap as well to a bigger "electric bleachers" CCA battery.

S3/P3/E2

Found it, although no mention of the battery size...

https://www.rx8club.com/showthread.p...threadid=18836

romulus

I am not sure if I would go with optima. Don’t get me wrong they are the best in the market as for deep discharge and for starting. My concern with the optima is that the Red and Yellow top the terminal are opposite, meaning the positive post is located facing in the in the front of the vehicle (terminal closer to the side) not in the back of the vehicle as the stock battery. You can turn the battery around but by doing that you will have to stretch the positive cable because is farther away. Also with the 60A fuse attached I am not sure if that will fit.
I did some research and Optima has the Orange top. It’s the same specs as the Red but it the terminal orientation is reversed. I think that will fit better.
In my case, I am leaning towards the Exide Orbital batteries. Its pretty similar as the Optimas in performance and size but it has the terminal closer to the edge. They also have a model that has double terminal see picture. I am not sure if the double terminal is discontinued but is worth to check it out in you local auto part store.

romulus

This top-view drawing illustrates post placement on the Optima Model 34R battery (Orange top).
Note orientation of positive and negative posts.
Model 34R top dimensions are 6.8"W x 10"L. Height is 7.8" including posts.
Case height w/o posts is 6.7". Base measures 6.8"W x 10"L.
Battery has removable comfort-grip carry strap.

romulus

Here is another model with post closer to the edge
This top-view drawing illustrates post placement on the Optima Model 75/35 battery.
Note orientation of positive and negative posts on both top and front (GM Style) of battery.
Model 75/35 top dimensions are 6.8"W x 9.4"L. Height is 7.6" including posts.
Case height w/o posts is 6.6". Base dimensions are 6.7" x 9".
Battery has removable comfort-grip carry strap.
Height adapter is included; it can be used on top or bottom of battery and adds 1.25" height.

Foureagles

Current (no pun, really) Optima technology makes the red & yellow top virtually interchangeable. The red is optimized (again, no pun) for rapid discharge, thus slightly higher CCAs, while the yellow has a bit better long-term recovery profile. Many of the Jeep ilk now use a yellow as a primary battery, due to their circumstances which place a high priority on battery performance in near-dead mode.

I'm surprised to learn that an orange top (which I presume slots between the two in performance, rather than just hue) is offered, because the differences in the red & yellow are so slight. Maybe they just like filling-out the color spectrum for marketing reasons, and a green top will be next.

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rx8cited

FYI, Costco sells the Optima Red Top for $99.99. I noticed they had the group 75/35 size available. Sears had them for $129.99. /rx8cited

neit_jnf

Anybody thought about lightweight dry-cell batteries? I know there're people that use them for the RX-7's

Sea Ray

Isn't the optima a dry cell?

S3/P3/E2

I thought it was a dry cell at first but evidently instead of flat plates inside the battery it uses a spiral coils of cells in series with each other. Anyone else have better light to shed or a better description?

241Commuter

The Optima uses conventional lead-acid chemistry, but fully sealed and a novel "plate" configuration (if you can call it that). I looked into the Optima for my boat. I was hoping to see a battery that had a 100+ Ah reserve in either the yellow or blue top to replace my group 29/30s. These batteries don't come close.

I've seen enough posts from people who have cranked their flooded 8's until the battery died trying to get it started. I vote for yellow.

Nubo

It's what's referred to as an AGM battery. That's Absoptive Glass Mat. The acid is held in contact with the plates by the mat. It's liquid, but captive like a bit of water in a paper towel. Here's an article from Miata-net about the "original" OEM Miata battery which was a Panasonic AGM. That battery was absolutely miniscule, but mine lasted about 7 years, including a couple of Ohio winters. That battery was very finicky about charging, though. Apparently Optima has gotten around that limitation.

The Miata-net article:

http://www.miata.net/garage/battery.html#orig

CCarlisi

I have a yellow top in my rx7 and couldn't be happier. I have let the car sit for weeks at a time with the alarm on and it still starts without a problem. The nice thing about deep cycle batteries is their output doesn't degrade as the charge level is reduced.

o_town_racer

I've got an Optima red top in my C5 and love it! There had been problems with the factory batteries dropping dead for no reason and also battery cases cracking and the acid killing the electronics below. I chose the Optima for performance, strength of the case, and resistance to any leakage.

Tirxer

would the optima batteries fit the rx8?
should it be changed after the break in period or it can be changed anytime

RX-8 friend

This is a common question, and I just posted the following in the RX-7 Forum:
From someone who has lived in "winterville" for 30 years:
Regular lead acid batteries are designed for high current discharge, but meant to be kept at least 60% charged at all times. If you "deep discharge" them, even once, their life will be shortened. Repeated deep discharges will kill them within a year or so. "Deep discharge", as the Optima site points out, is less than 60% charge left - ie leave the lights on till the car just barely starts. The Optima Red top is this type of battery.

"Deep Discharge" lead acid batteries are designed to withstand this type of treatment. Their life will still be shortened, but not by much. They are not very good at high current discharge. It can damage them, and shorten their life. I'm talking a discharge current number equal to or greater than the battery amp/hr rating. For a battery found in an RX-7 or RX-8, that would be a current greater than 50-70 Amps. To draw that starting a rotary, the temp. would have to be below about -20 C (or about 0 F), or you'd have to have very heavy oil in there.
The Optima Yellow top is this type of battery.

Just for reference:
RX-7 max. starter current = 90 Amps (typical less than 50). RX-8 is the same.

So, my answer would be yellow top would be fine, red top also fine. There is a "small" Optima now available as well.

If you want to extend the life of your battery, "improve" weight distribution, and make working under the hood easier, install a larger Optima in the trunk. Also frees up room for a blower

rxtreme

iTrader: (1)

I noticed you quoted "improve" weight distribution. Since this car has near 50/50 weight distribution, how would putting the battery in the back improve it any?

RX-8 friend

That's why it's in quotes. Some 3rd Gen RX-7 owners (a car also with 50/50 dist.) claim it improves it (but they put it in the cab on opposite side from driver in storage bin).

Main effect is to move weight closer to c/g so the car will turn faster.

Nubo

I've been considering that option. I think it might help me get over my "Miata separation anxiety"

gunit28vp

sorry folks if this is a dumb question, but what ive drawn from this thread is the red top has more power but the yellow top has more longevity, is this correct if not could some one break it down im not sure im grasping which is better for the 8 thanks in advance

thew

ok .. just got my red top 75/35 installing it now.

Gunit the red top is a better cold craning battery. the yello is good for starting when the battery is almost dead.

But there both great batteries. Still buy the red top.

rx8cited

After you install and test it, please let us know what differences you find with the car.

rx8cited

psionic1

Will the Red Top just go right in with out any alterations?