ddub

Didn't know what section to put this in, figured this one was close enough.

I had a Yellowtop Optima 51R laying around I wasn't using, decided to swap it into my rx8.

Stock battery weight = 35.0 lbs and Optima 51R = 27.4. Weight savings of 7.6 lbs, not too bad.

The battery terminals were already in the correcnt position, made installation extremely easy. Took about 2 minutes tops.

Here are some pics, I took a closeup of the specs on the battery so I wouldn't have to type them out.

Nemesis8

iTrader: (3)

Looks like a good fit. What's your opinion on the battery cover? Are you still using the vent from the front?

ddub

Yah the vent is still there.

I haven't used the battery cover since I did the ground, it doesn't fit anymore.

Also the 51R "fits" in the battery tray, but it is much much smaller haha. But with the tie down tightened a bunch and the battery pushed to one side, whichever you want, it is sturdy as a ****. Can't budge it.

Nemesis8

iTrader: (3)

My cover has been removed also - that damn vent blows crap into the engine bay. Mostly Doug Fir needles.

ddub

Hmmm interesting. Haven't had any issue with that yet. Maybe I'll just remove the vent.

Nubo

The 51R is pretty small. The 35-series (yellow-top D35) is a better choice for this application unless the weight difference is an overriding concern. D35 weighs about the same as stock. Still fits the battery enclosure with the required air-space for cooling, but has significantly more capacity than the D51. I understand you already had the 51 on-hand, just putting this out there for anyone considering an Optima yellow

CA... 51R=625/D35=810
CCA..51R=500/D35=650
AH....51R=41 /D35=48
RC....51R=70 /D35=98

p.s. Keep the cover and vent -- it's designed to keep cool airflow over the battery. The rotary engine compartment is hot and heat is the enemy of batteries.

ddub

I put it in for the weight savings. If it had been the same weight as stock I would've left stock in and sold the Yellowtop, it's brand new and was not getting used.

As far as the cover, I could not care less. I'm not new to rotaries in any way, had a high modified 2nd gen. No battery cover OR vent in it, never a single issue. It is there as a safety measure but is definitely not needed, especially if you keep the cooling panels, heat shields, and etc in/under the engine to keep the flow proper.

truemagellen

I put in a 34 Yellow top

If Optima finally came out with the 34R Yellow go with that though (I had to make my own extended setup)

Ducky

Got Pics of that custom extension? I also have the wrong side Yellow top (though it came off my offroad rig =)

MrWigggles

Yes, you need the 34R to get the reverse battery posts otherwise you have to do a custom extension.

I got the 34R in the Red Top Optoma. I have the 2004 manual RX-8 which has an ultra wimpy stock battery. The 34R gives me a lot more run time and no dimming lights when the bass hits.

The yellow top 34 might be a little bit better but I doubt there would be much difference.

Finding a 34R in stock might be a little difficult depending on where you live.

-Mr. Wigggles

Wurmfist

FYI: I looked all over the web today looking for a 34R yellow top and came up with nothing. I just don't think they make them. I need the yellow top because of my amp, so I'm going to go with the 51R instead of having to rewire. 51R is still going to be tons better than my stock 04 battery which is currently dead and not holding a charge.

truemagellen

I looked for the 34R Yellow Top too with no luck and decided to just get the 34 yellow and redo the connections myself

hitman408

With the 34r fill the battery cover fit ?

MrWigggles

I'm not sure why you guys are so insistant on the yellow top versus the red top. These are all spiral wound batteries from the same manufacturer. If you go by the internal resistance, cranking amps and amp hours, you'll see the Red top is nearly identical to Yellow top.

http://www.optimabatteries.com/publi...D34_082104.pdf

http://www.optimabatteries.com/publi...34R_082304.pdf

The Yellow Top has 10% better amp hours and internal resistance*, the Red Top has 10% better cranking amps and weighs 10% less.

Oh ,and the Red 34R is cheaper, has longer warranty and fits without modification.

-Mr. Wigggles

*The slight advantage the yellow has in reduced internal resistance will likely go away with any extra wiring you need to do to make the 34 Yellow Top fit vs. the plug 'n play Red Top 34R. The resistance difference between the yellow top and red top is or 0.2 milliohms - equivalent to 6" of 6 AWG.

MrWigggles

Yes, the cover fits fine.

With either a 34 or 34R you will need to elevate the battery slightly with a 3/4 standoff (can be plywood, MDF, whatever)

Since the 34 series is bigger than stock it is also wise to notch the standoff so that the fresh air duct is not obstructed.

-Mr. Wigggles

Wurmfist

The difference between the red top and the yellow top is that the red is for starting purposes only. If you don't have any extra electronics in your car then a red top is fine. But the red top is not meant for deep discharging, if the demands of the alternate can't meet your electronic needs then it's going to discharge the battery. The red top isn't made for that and will eventually fail if that happens to much. That's what the yellow top is for. You can discharge it completly dead and recharge it back up and it dosen't hurt it. It also maintains current and voltage during the discharge cycle.

My point is if you have amps, and subwoofers, and your lights and stuff dim to the beat of your bass, then you are discharging your battery because these alternators aren't that strong. So you need the yellow top. If you don't have all that stuff, red top is fine.

truemagellen

your missing the point of the Yellow top...

it is a Deep Cycle battery...the Red is not

anyone who does audio work understands your red will suffer an early demise after constant deep cycling

StealthTL

iTrader: (1)

Don't you see the problem with having two huge red cables running to the ground terminal, in an otherwise all-black battery box?

Someone, maybe even you, is going to hook a booster/charger to that red terminal, and fry the ECU.

You have a deep cycle so you can drop the battery to the point where it won't start the car. You need a boost, one of your buddys will "help you out" one day, and you will be ordering a new computer.

You should put some black shrink tubing over the red parts nearest the battery box, or even just black tape them, but you do need to get them "gone".

S

VVVV - (similar system, fixed.)

MrWigggles

So the average RX-8 owner is in a SPL competition every week? I didn't realize that. We are talking about a drop in replacement for the stock battery not a cluster of batteries for a 3000+ Watt dB monster.

WHY ARE YOU DEEP CYCLING? With 50+ amp hours, you can listen at HIGH volume for almost an hour without the car on. Even if it is Yellow Top you shouldn't just play 'til its dead on a regular basis.

Have you considered that the reason the Yellow Top warranty is only 1/3 as long as the Red Top is because they know that Yellow Top is going to be abused? They sell the Red Top with 3+ year warranty to average users and the Yellow Top with 1+ year warranty to aggressive users. It marketing more than technology differences.

-Mr. Wigggles

truemagellen

Mr. Wiggles you always have fire in your posts

I have my reasons for deep cycling

LiL BenNy

so the best for audio is D35 YELLOW TOP OPTIMA BATTERY? i have 2 10w6 JL's and a 500.1 amp and my lights dim plus my stock battery is crap bc i drained it once by accident lol... anyone know part number for the yellow top?

Wurmfist

No we aren't in an average SPL competition, but my HID lights DIM to my bass on a 600 watt amp. So we aren't talking compition class here. It is a problem and I am discharging from my battery with 600 watts BECAUSE the alternator can't keep up. It's that simple. If you want to buy more than one red top then that's fine for you, but I will skip the BS and buy a yellow top and save myself. And the stock 04 battery is crap. But like I said, if you don't have amps then i'm sure the cheapest red top is fine.

And have you ever stopped to think that maybe a superior battery dosen't need the piece of mind of a prorated warrenty because it's not going to fail in that time anyways?

Wurmfist

The 51R should be fine for the rx-8. UNless you are running 3000+ watts, and in which case you should probably be using an extra battery just for that. The 51R already has the posts reversed so you can just pop it in, unlike the 35 or 34, you have to mod your cables for it to fit.

MrWigggles

A Red Top 34R is superior to a Yellow Top 51R in EVERY electrical category.

A Yellow Top 34 is very very slightly superior to a Red Top 34R in terms of series resistance by .2 milliohms. However, if you think .2 milliohms is that big of a deal (which it isn't), you will still likely create .2 milliohms with the additional cabling necessary to make the 34 fit in your battery box which is designed for R batteries. (once again, 6" of 6 AWG cable is more than .2 milliohms. Keep that in mind.)

I'm running 900 Watts with my Red Top 34R and my HID's don't dim (there's a write up on my system in this forum). Your stock battery very well might be bad so my guess is any Yellow Top or Red Top will improve your situation. The Red Top 34R or the Yellow Top 51R will be the easiest to install. The only reason to go with the 51R is because of the reduced weight or if you just don't need the extra performance of the 34R.

-Mr. Wigggles

Wurmfist

Yeah that's exactly it, anything is better than the stock 04 battery, and the 51R will provide me with everything I need. I know obviously the RT34R has more amps, ect, ect, ect. But the RX-8 dosen't really need that. I don't have a winch on the front of it and I just need it to run my amp and start my car. I don't need 1000 amps to start a RX-8.