For anyone thats thinking about this install here you go.

The only thing to know is that the Pos + lead will not reach the Optima's Pos + post. this is because of the way mazda intergrated a fuse into the cable. The fix is very easy.

First off take out your old oem Battery and snap on the big spacer on the bottem of the red top. you need this spacer to bring the battery up to the right level so the oem battery hold down will work.

After snaping on the spacer, place the battrey in the tray.

Next you need to modify the battery cable. +pos

here you can see the problemb

heres the parts you will need

now.. take the battery cable and cut off the crimped on end so the new cable is about 2"s

then slip the cable in the copper 4 guage lug

now remove the oem battery post clamp

now take a 3/4 inch x 5/16 stainless bolt and attach your new cable to the old one.

next clamp the new cable to the + pos post on the red top .

before you close it all up tape up the new copper lug and cable.

enjoy your new 910 cranking amps :)

pic of the copper lug. you can also just crimp a new eyelet on the new battery cable, but i like the lug connection because i can add to it later and i know its always tight ..

finished

ohh i took pics with the cover back on the battery box but i deleated them by mistake. the cover does fit just like normal.

Engin spins a bit faster now.. instant start

Very nice... again! Great little DIY, thew! :D

thew,
Nice work!

For future buyers, it looks like the RedTop 34R (http://www.1st-optima-batteries.com/red_top_battery.asp) would work better for the RX-8 by avoiding the need to extend the positive battery cable.

The 34R is also rated a little higher, but it length is 10" vs 9.4" for the 75/35 - so fit need to be verified.

rx8cited

Thanks alot...I can go out and buy my red top now, knowing that i can install it in my car...great DIY.

Very nice work…. I was thinking in doing something similar, but so far my OEM battery is doing its job. If you wish of not doing the mod, Optima is starting to offer a battery that meets the OEM Specs (Group 35). The model is SC35R, and you can get it from http://batteriesareus.com/shop/product_info.php?cPath=21_22&products_id=61&osCsid=287177d5320f94ca136359a1637b1a65
Here is a picture of the battery.
Cheers!
:)

yes.. but Costco and sears dont sell it.. I asked the sears rep and they wont be carrying it :( also Costco only sells the 75/35 i guess its the most popular one..

so dont shy away becasue of the + pos post.. its a very easy fix.. took me about 5 mins.. took longer to post the pics hehehe

also i dont think it will fit in the box.. the 75/35 is very tight in the oem box.


Hey Omicron thanks for the nice words.. again.

By no means I was saying that your mod is bad... It is really good!:) I agree, this particular model is harder to find from a local battery supplier. If someone can get this particular model without going to through a lot of hoops, great... if not, at least they have an alternative with a more readily available battery:)

aye :) i know :) no offense taken :D

Sorry being a stupid Brit, what is the benefit of doing this over the stock battery?

A

Originally posted by Anthony
Sorry being a stupid Brit, what is the benefit of doing this over the stock battery?

A

Here are the Optima reasons. (http://optimabatteries.com/products/index.asp)

cheers,
rx8cited

PS: thew, how much was the battery and all the other required hardware please.

very nice

I had two optima's in my last car

nothing worst than a car dying on you

Originally posted by mikeb
very nice

I had two optima's in my last car

nothing worst than a car dying on you

Why two?

rx8cited

in my case i have a video system that draws power off the battery and i have had to jump it twice now.. once because of the trunk being ajar..

the other becasue the video system draind it..

the red tops are better for starting when the battery has been drained like in my case. the sstock oem battery is a POS.. is just enough to get the car going. the best mod you can make if you dont do anything else is to replace the stock battery .. even with a Diehard 1.. would be better than the oem unit..

:)

i spent 2.95 on the copper lug, and the battery cable cost 19.00


the Red top cost 99.00 at costco. I have seen it online for 79.00
but then there shipping.


so all in all i spent about $125.00 for a first class battery.

Why two?

rx8cited


I had one optima just to run the four compressors I used for the air ride suspension :D

Thanks!!!!

I would strongly recommend getting the proper reverse terminal battery. Lengthening the positive terminal to fit the 75/35 battery does work, but it introduces more points of electrical contact and more points of failure. Not to say it doesn't work, or you would ever have any problems with it, but I just like a nice, clean installation. Being able to easily buy the right battery online and pay a little in shipping, there's no reason not to.

Dale

not really.. 1st now I have a permanent Aux Pos (+) Post to attach extras. 2nd the battery is now much easyer to get out of the box becasue the pos lead will now move :)


Anyway as an electrician I can tell you that adding the copper lug like i did and the extra 2 inches of cable will not add any signafigant resistance at all!

So again .. dont let this stop you from getting that Red top at Costco for 99 dollars. or online for 79.. if you can find the other one !! than by all means get it :) .

p.s. if you do find the grp 35 please link the online seller here..

thanks again

happy Zoom - Zoom

romulus,

Thanks for pointing out the existence of the Optima RedTop 35 and the URL you provided - $94.95 delivered, no tax outside Nebraska.

When I replace my battery (stock battery working fine - no need to replace it yet), it's going to be with a group 35 which should drop in perfectly with no extra costly hardware required since I don't plan on hanging any "extras" off my battery, the posts are correctly positioned, and I prefer a clean, stock-looking install. I'm not sure if it will be an Optima.

rx8cited

rx8cited,
You are welcome! :)

Q: Was there any weight savings between the stock and the optima?

OK, I searched first before posting about Optima batteries.

I just wanted to record the fact (with pictures) that there is an Optima that fits the RX-8 with *no* mods to the car wiring harness. It has to be the model 34R Optima battery. This is the "reversed" terminal one mentioned a few times. Yes, it fits. Items used:

(1) Optima model 34R battery
(1) Optima AD24R battery tray - to raise the overall height

Below is a top view of the battery. Note the slight clearance around the edge toward the passenger side and toward the front.

This is an offset view of the battery in the tray, just for further clarification.

OK, and now, for completeness, the stock battery cover is in place. I did not really need to include this one, just being sincere (and compulsive?).

All this was done just so someone else who uses search will be able to find this thread and *see* that it fits with no electrical changes whatsoever.

Also - I am a big fan of Optima products. I broke the alternator belt on my RX-7 in Chicago, IL in rush hour. I drove all the way home to Kalamazoo, MI with an Optima 75 (the smallest one they make) as my sole power source for the ignition, etc.

I totally copied you and am very happy with the Optima battery "mod". Thanks for posting these instructions.

Good info.

How much did you pay for this battery?

Based on my measurements, the Optima group 35 battery should also drop in with no nasty extenders required. Did you consider that one?

Consider posting your info in http://www.rx8club.com/showthread.php?t=33340 as it's relevant.

rx8cited

It was requested that I post this reply here. The other thread has info that may be of interest. I apologize for the new thread, I thought it needed to stand on it's own for search purposes. Anyway:

http://www.rx8club.com/showthread.php?t=38452

Answers:
I paid $151 for 34 R battery and tray. I am sure you can do better.
The Model 35 should work also - smaller, 4 lbs lighter. Then again, I would rather stuff the battery envelope with all the watts possbile -
Scotty: "I'm givin' it all she's got, Cap'un!"

yes and when i put mine in that was all that was offerd

yes and when i put mine in that was all that was offerd

Where did you buy your battery from? Do they now sell the 34R or 35? I found that Sears, Costco, and Pep Boys did not stock those models.

rx8cited

i got mine at costco .. thats why i did the mod because it can be found here.. but i understand it can be bought on the web now.

i got mine at costco .. thats why i did the mod because it can be found here.. but i understand it can be bought on the web now.

Yep, one can get them RX-8 friendly battery models on the web or by calling a battery dealer in the yellow pages if in a hurry.

rx8cited

Better yet use this battery and not modify anything. Way better than an optima and it's a true deep cycle dry cell with a 6-10 year service life. And 1200 cranking amps for the 1st 7 seconds, very low internal impedance.

OK, I searched first before posting about Optima batteries.

I just wanted to record the fact (with pictures) that there is an Optima that fits the RX-8 with *no* mods to the car wiring harness. It has to be the model 34R Optima battery. This is the "reversed" terminal one mentioned a few times. Yes, it fits. Items used:

(1) Optima model 34R battery
(1) Optima AD24R battery tray - to raise the overall height

Below is a top view of the battery. Note the slight clearance around the edge toward the passenger side and toward the front.

As a point of reference to those who may come upon this thread in the future; a Service Bulletin from 12/15/2004 describes a design feature of the battery system which requires clearance between the battery and case. Cool air is ducted around the battery inside the case to reduce the temperature experienced by the battery. A battery that is physically larger than stock could reduce or eliminate the cooling and result in reduced life.

http://www.finishlineperformance.com/rx8/docs/01-042-04.htm

.....A battery that is physically larger than stock could reduce or eliminate the cooling and result in reduced life. .....

I disagree ....... in the case of the manual transmission anyway.

There's plently of extra room in the stock battery box to put a battery larger than my stock battery. The important point this Service Tip is making is that the battery box and cover are required and that the front of the new battery should be positioned the way they show with respect to the white painted area to allow for airflow ..... probably no further forward.

I bet the new MT RX-8 battery is a group 35 while the original stock battery is smaller.

If I need a new battery today, I'd buy a group 35 (which is not the same as a 75/35 battery BTW) as I took measurements months ago and know it would fit with room left for airflow.

Well, I just bought an Optima red top Grp.35. I will install it soon.

Very nice work…. I was thinking in doing something similar, but so far my OEM battery is doing its job. If you wish of not doing the mod, Optima is starting to offer a battery that meets the OEM Specs (Group 35). The model is SC35R, and you can get it from http://batteriesareus.com/shop/product_info.php?cPath=21_22&products_id=61&osCsid=287177d5320f94ca136359a1637b1a65
Here is a picture of the battery.
Cheers!
:)
Has anyone installed one of this model yet?

Does it require the height adaptor to fit in the RX-8? <http://www.batteriesareus.com/shop/product_info.php?products_id=116&osCsid=287177d5320f94ca136359a1637b1a65>

:confused:

I will be installing one on friday. I do have the hight adaptor just in case i need it. I will post pics.

Just got done! It did require the height adaptor. No more 300CCA for me...Now 720 ;)

Just got done! It did require the height adaptor. No more 300CCA for me...Now 720 ;)
Cool - thanks!

:) you guys can get the better yellow top at Super Autobacs for 130!!!!! =) group that fits the 8, we only sell usual one at Pep boys =/ if i use the yellow top, will it stop the dimming of my head lights while my bass hits? have a capacitor too! helps alot but still dims a little.

I'm a battery newbie.. what's the difference between the Red/Yellow tops? More juice? One for stereo stuff?

Recap GRP 35 works great .. but needs the height adapter.. cool. Need to get one soon. My battery sounds like it's dieing.

Red top Optimas are designed to be used as a starter battery in which provides all the cranking amps. A few discharge should be ok. Yellow top is better because it can handle multiple deep discharges specially if you have Hi power audio system. Also the voltage discharge curve is more even and hold longer than the red top. So, you can run your audio system a full blast without starting your car at longer time than the stock battery.

I actually saw an 34R Orange top (model #OT34R), I guess its a combination of yellow/red , may be worth investigating!

The 34R (R= reverse; orange top) is basically a red top from group 34. The only difference is the reverse post. Optima made this version to satisfy customers that has this configuration and has the room to use 75 and 34 group way before the group 35 became a standard option for some applications (mostly import vehicles).
I hope that this clears things some comfusions.
Edit: I found out that Optima got rid of the Orange top to avoid confusions. They are still make 34R but is red top.
cheers

I've installed the yellow-top version of the 35. Like the red-top 35, it's a good fit and has the terminals in the correct locations. I chose the yellow because it's supposed to better accomodate deep discharges. Since I sometimes leave the car sit for periods, that's a good thing. Also I suspect it might have a bit more "courage" in the event I ever have to go through a serious "deflood" attempt. It's supposed to hold voltage better through the discharge curve. It's got more than enough cranking amps to serve as a starting battery. Plus, it's yellow! :)

Purchased from Batteryweb.com. Delivery was quick.

Here it is in comparison to the stock. It's about as wide, but a bit longer. It's also a bit shorter, but the included adapter plate makes up the difference almost exactly.

There are a number of plastic bits that can be left on or removed depending on your application. Here they are, separated. The 2 gray ones of the bottom ends I left off to promote better airflow around the case. The thicker yellow one is the height adapter. The thin yellow piece can snap onto the other yellow piece. I left it off, again in the interest of maximum airflow, in deference to the Mazda battery tsb.

topplate info

edit - that's a 1-year replacement warranty as opposed to the 3-year warranty for the red-top. I imagine that's just due to the abusive nature of the applications that the yellow-top is designed for.

And the "installed" pic. Since it matches my "decor" it was a shame to have to put the cover back on. :) But it's needed to direct the cooling air and protect against shorts. The carrying strap is easily removed and so I did, for aesthetics (geeky, eh?). I put it somewhere in the garage where it's sure to be un-findable when the time comes. :D

This is probably about as big as you'd want to get and still fit the guidelines for allowing room for the cooling air to circulate. The only dimension in which there'd be room for more "battery" would be height, since the adapter plate was needed. But we're way past stock capacity already. It's hard to see in the pic because of the angles, but the front edge does fit to the midpoint of the "white paint" on the box. Due to the cylindrical construction of the Optima, it probably has better cooling properties than a regular box-shaped battery -- a better surface-area to volume ratio.

I can vouch that the "cooling airflow" thing is not a sham. There were a number of bugs and high-speed bug-parts in the bottom of the battery box. Might not be a bad idea to lift the battery once a year and clean them out of the air-channels that are built into the bottom of the battery box.

Sorry, I can't answer the question about dimming headlights and bass hits; I just have the stock stereo. Offhand I'd say the solution to that would be bigger capacitor, several caps in parallel, or modification to have a 2nd dedicated circuit for audio, with its own battery. The yellow-top would be a good choice in that application. You'd need to take some care with selecting and designing a safe and secure location for the 2nd battery. Try the audio forum for better answers :)

I think the yellow top was a good choice for me. Time will tell. I've had a few sluggish starts off the stock battery, but no floods. Want to keep it that way.

Good review Nubo! :)

Anyone else use the Yellow D35? I wanted to get some feedback on how it's going for them and if they needed to do any work to get it to fit? (eg.. extending cables, etc)

My stock batt is dead, I cant drive, and need to get one ASAP. I cant seem to find one in Hawaii so I will need to SUPER AIR EXPRESS that puppy so I wanna be sure I get the right one.

well my battery died today and while i was picking up a new one at autozone the guy behind the counter says, "i can hook you up with a optima red top if you pay with cash." first thing i notice is that the positive terminal is on opposite side of the battery. i ended up getting the battery anyways because he only charged me $80 and the battery was marked as $129. got home and did a search for "optima red top" and this diy thread came up. followed the instructions and intall was less than 10 minutes. this forum rocks! :ylsuper:

hmmm...$80 if you pay cash, did he sell it to you out of the back of his trunk? Or did he slide it across the counter and make sure no one else was looking when he did it?

Anyway, my question is this - I've read through the entire thread and got fairly mixed messages. I have slow starts on occasions which is more embareassing than anything else because I'm sitting in a car with less than 10,000 miles on it and it sounds like a '84 choking for life tring to start up. I have a 650 watt amp that starts with the engine, but I never just let the audio run, nor do I want to. I just want strong starts and a long life. I'm thinking the red is for me or should I go with the yellow? The numbers also confuse me, I just want plug and play, no "mods" needed. So do I want the 35 series? I'm a n00b, pardon my ignorance...

Anyway, my question is this - I've read through the entire thread and got fairly mixed messages. I have slow starts on occasions which is more embareassing than anything else because I'm sitting in a car with less than 10,000 miles on it and it sounds like a '84 choking for life tring to start up. I have a 650 watt amp that starts with the engine, but I never just let the audio run, nor do I want to. I just want strong starts and a long life. I'm thinking the red is for me or should I go with the yellow? The numbers also confuse me, I just want plug and play, no "mods" needed. So do I want the 35 series? I'm a n00b, pardon my ignorance...
Have you had the No-start work done on your car? If not, head for your dealer and tell them you are having problems with slow starts. They should replace your battery, starter motor and plugs with upgraded units under warranty. It makes a huge difference in starting the car.

See the service bulletin at the link below:
http://www.finishlineperformance.com/rx8/docs/pdf/01-004-05-1448e.pdf

No, I mentioned it to them and they said that "it's the nature of the beast" type answer, that rotaries are like that. It's getting worse actually, the guy who changed my oil (I was lazy) wasn't able to start it and almost flooded it today which would have sucked. I'll try taking it to a northern VA dealer this week since I'll be heading out of town for a while. Thanks.

No, I mentioned it to them and they said that "it's the nature of the beast" type answer, that rotaries are like that. It's getting worse actually, the guy who changed my oil (I was lazy) wasn't able to start it and almost flooded it today which would have sucked. I'll try taking it to a northern VA dealer this week since I'll be heading out of town for a while. Thanks.
You might want to print out the service bulletin and take it with you.

Are they going to give me shit since I have an Amp installed into my battery. That's what I'm worried about the most I geuss.

Are they going to give me shit since I have an Amp installed into my battery. That's what I'm worried about the most I geuss.
Hard to say. One dealer is not necessarily the same as any other so you can't predict how they will view something like that. If the dealership is customer friendly, they probably will do the service without question. If they don't, take it to another dealer.

Well, I dropped it off this morning as I plan on going to a wedding (leaving tommorow) so they have time to do it. Also I asked them to fix the rotor rust which is quite bad on my car that many people have commented on it. So here's keeping my fingers crossed I'll get both jobs done as they are both questionable.

Since we're on the topic of Batteries, do folks here who've changed out their batteries performed the Idle learning procedure afterwards?? As these cars have got tons of electronic/computerized components, I would think that it may be significant...

"Idle learning procedure" Huh?
Are you referring to the DSC calibration procedure?

... or whatever it's called. I think it's different for every car and maker - basically, it's allowing the car's computerized & electronic system to "re-learn" after a change in battery, removal of old dead battery, etc.
This is normally done by Idling for a period of time, or slightly revving while idling, and turning on the radio, A/C full blast, etc. & basically let everything calibrate again. Every car does this slightly differently, but above description just about covers the basics.
Don't know, but maybe not even doing any of this makes no difference since I think most modern cars eventually re-calibrates itself eventually anyway.

... or whatever it's called. I think it's different for every car and maker - basically, it's allowing the car's computerized & electronic system to "re-learn" after a change in battery, removal of old dead battery, etc.
If you are just replacing the battery, i.e., disconnecting/reconnecting, you will not erase the Keep Alive Memory which I believe contains the information you are referring to. There is a way to clear KAM, but a specific procedure must be run. See the following thread for more information:
http://www.rx8club.com/showthread.php?t=27548

Just as a sort of thanks I geuss, I dropped the car off Wednesday and they just gave me a call saying they finished all the work. I was surprised I didn't get treated like crap because I had a 650W amp hooked into the battery, but the replaced the works with the battery and spark plugs and on top of that I had asked for them to do the rotor cleaning (because mine were rusty as hell, and they replaced them. Where's one of those questionnare thingies because that kicks ass!!

Just as a sort of thanks I geuss, I dropped the car off Wednesday and they just gave me a call saying they finished all the work. I was surprised I didn't get treated like crap because I had a 650W amp hooked into the battery, but the replaced the works with the battery and spark plugs and on top of that I had asked for them to do the rotor cleaning (because mine were rusty as hell, and they replaced them. Where's one of those questionnare thingies because that kicks ass!!
Did they replace the starter motor? That's the biggy.

As far as the brake rotors go, don't be surprised if they rust up again. The paint the manufacturer uses is not suitable for the environment these rotors experience. Best approach is to paint them yourself with a high-quality, high-temp caliper paint like G2. Like this: :)

I'm honestly not even sure what all they did as I am nowhere NEAR the car until monday, then I'll know all the specifics. he said he just followed the MRI's or whatever that I left in my seat.

I'm also sure it will rust up again, but not as bad. It sat for months in the back of a car lot not being looked at or cared for because it was on hold for me, so they were AWFUL. When I go to paint my calipers I plan on painting them as well. Quick/free fix for now.

It sat for months in the back of a car lot not being looked at or cared for because it was on hold for me, so they were AWFUL.
Yeah, if you look at other cars at a Mazda dealership you will see some pretty ugly rusted rotors. Even on the showroom floor. I don't understand that. :nono:

I've installed the yellow-top version of the 35. Like the red-top 35, it's a good fit and has the terminals in the correct locations. I chose the yellow because it's supposed to better accomodate deep discharges. Since I sometimes leave the car sit for periods, that's a good thing. Also I suspect it might have a bit more "courage" in the event I ever have to go through a serious "deflood" attempt. It's supposed to hold voltage better through the discharge curve. It's got more than enough cranking amps to serve as a starting battery. Plus, it's yellow! :)

Purchased from Batteryweb.com. Delivery was quick.

Here it is in comparison to the stock. It's about as wide, but a bit longer. It's also a bit shorter, but the included adapter plate makes up the difference almost exactly.


Update on Optima batteries:

I've had great use out of my Yellow-Top, but recently I've been researching electric cars and ran across some negative reports on electric vehicle discussion lists. These are people who are REALLY into all aspects of deep-cycle batteries. Optima used to be a favorite but may not be so any longer. Check the thread below if you're interested. There are other more technical threads on that group that go into it in more detail.

I was going to replace my Optima with another yellow-top when the time came but this gives me pause. I still want a good deep-cycle battery. The Odyssey batteries are still getting a lot of praise.

http://www.diyelectriccar.com/forums/showthread.php?t=15085&highlight=OPTIMA

Better yet use this battery and not modify anything. Way better than an optima and it's a true deep cycle dry cell with a 6-10 year service life. And 1200 cranking amps for the 1st 7 seconds, very low internal impedance.

That is 550 CCA. And several pounds heavier than Optima 35 red.

http://www.batteriesplus.com/pc-28947-28947-PC1200-A.aspx