It isnt -40 celsius all year round where I live, so in the summer I would be concerned about the heat.

I noticed the 75/35 instal in the dyi thread uses the optima height adapter.
This adapter lifts the battery along its perimeter and is hollow in the middles, so even thought the battery will physically cover the vent hole it would be still be able to flow under the battery. Right?

 

Yep, I reckon.

I naively thought your summers would be a little cooler than they actually are. I was surprised to discover your mean July maximum temp was around 26 deg C. I learnt something today, so it's been a good day!

Gomez.

 

The red top Optima 35 is 33 pounds, the yellow top 37.2.
http://www.1st-optima-batteries.com/

How does that compare to the new Mazda recommended battery?

 

That's difficult to answer since it appears there is miscommunication between Mazda and Interstate Batteries with respect to which particular model battery Interstate is supposed to be supplying to Mazda dealers. Mazda speced a 640CCA battery in the TSB, but Interstate is apparently shipping a 550CCA battery (see previous post) with the same physical dimensions. In any case, here are the weights for both batteries and you can take your pick:

MT-35, 550CCA-37 lbs
MTP-35, 640CCA-40 lbs

 

I installed the 51R yellow top Optima and it was a piece of cake. It only weighs 26lbs or so and is a full 2 inches smaller side to side (when looking at it mounted in the car). So, it has lots of extra room for air circulation, is lighter and is the same height and length as the stocker so you can use the OEM mounting hardware.

Chris....

 

The 51R has larger nads than the old OEM, but smaller grapes than the new OEM?

 

Received the following from Trussville today:

"I have the answer, Interstate has sent us the MT-35 Batteries by mistake and will be picking them up and replacing them with the MTP-35"

See p.2, post #22 in this thread for the specs on these batteries.

 

I just got my optima 35 installed by Batteries Plus. I will post a pic when i get home and sych up my camera. Install was simple and there is plenty of room for air circulation. $99 + tax. I'm happy now.

FYI. The dealer tested my stock battery last week, 305CCA was measured.

 

My OEM battery is 490 CCA. Maybe it's a Canadian thing?

 

Ah so, the new OEM batt is actually an Interstate MTP-35 then, correct?

 

You got it. Heard from Trussville again today confirming that the position of the battery posts is the same as the original battery, so installation should not require any mods to the cables. You can go to the Interstate web site (www.ibsa.com) and find your local dealers. I plan to pick up an MTP-35 locally myself.

 

Probably so. The shop manual shows 3 different batteries. In the US, at least in my car, the 50D20L CCA is rated right around 300. That model is the lowest rated of the 3 batteries.

 

Anyone ever check their stock battery's electrolyte level? Mine were a bit low when I checked them last summer.

 

Dang..

Off the Interstate site:

This is one of the most powerful batteries in the industry, with one of the longest warranties in the business. With Silver Calcium alloy, it has 22% more life! With up to 800 cold cranking amps and a guaranteed warranty.......

Cranking Amps: 800
Cold Cranking Amps: 640

Why would the RX-8 need such a beast? Just curious.

 

I imagine bigger is better when it comes to our flood prone baby. That way we get more chances to start her up before having to call Mazda and have her towed away due to a dead battery caused by flooding .

Damn, I'm itching to buy a new battery, but my stock battery is working so well, I cannot justify it .

 

Rx8cited is probably correct. Since you are in Hawaii, you may not have experienced an engine turning over slowly in very cold temps. The efficiency of batteries drops dramatically in cold temps, so the rotors turn more slowly when cranking and the battery will lose it's effective power fairly rapidly when cranking the engine. If you read all the posts in this thread you saw that Mazda apparently provided a much more capable battery for our Canadian cousins because it gets really cold in some areas north of the border.

However, it gets pretty cold south of the border from time to time as well. I guess Mazda didn't know that so they gave the US cars a battery that is somewhat inadequate, particularly in some hard-start situations. If your US car floods, or is otherwise hard starting in cold temps, the battery may run down before you get more than a couple of 7-8-second cranks to start the car. So then it's off to the dealer for service, when you might have been able to start the car with a few more cranking opportunities.

Personally, I think Mazda would be smart to replace the original OEM batteries with a more capable model like the MTP-35 and possibly avoiding some of the trips to their dealers for non-starting problems.

 

Isn't too much cranking amps detrimental to what an engine was designed for? Can't it cause damage?

 

I don't know, but this battery, with 640CCA, is the battery that Mazda is providing as the replacement for the original OEM battery, so ya gotta think they considered that when they made this selection. I guess one thing that might be affected negatively would be the electrical components of the starting system, i.e., starter motor, solenoid, etc., but I can't imagine Mazda "blessing" this battery if that was a problem. I guess time will tell as they install these batteries in the cars.

 

No, too many CCA can't hurt the car. It's just there if you need it. Like horsepower, if you never ask for it you will never get it.

QUESTION ???

Does anybody know how many Amp-Hours the new 0000-80-MT35-WB Mazda recommended replacement battery is? The owners manual only gives the AH spec on the current battery and the TSB gives the new CCA rating but I haven't seen the new AH rating. In other words, It should crank better cold but will it sit in my driveway between snow storms and still start after a few weeks. My current one doesn't.

 

Good question. That battery is actually the Interstate model MTP-35 and the AH rating is not given on the Interstate web site (www.ibsa.com). At least I couldn't find it. You could try e-mailing them, but I have done that for a different question and never got a response.

 

Good to know that it is an interstate. I have used their Megatron batteries before and they are good.
In another part of their site I found the Reserve Capacity rating of 100.
http://www.ibsa.com/www_2001/content...oduct_auto.asp

From another battery site I got this:

To convert Reserve Capacity (RC) to Ampere-Hours at the 25 amp rate, multiple RC by .4167. More ampere-hours (or RC) are better in every case.
http://www.pacificpowerbatteries.com...AQ/dcfaq4.html

Which brings us to 100*.4167 = 41.67AH. which makes it the worst one yet. However this is at the 25A rate so it really doesn't mean much other than it is close. If anybody knows what the RC of the original battery is then we could compare apples to apples instead of apples to snails.

The part number actually looks like it is an MT-35 not the MTP-35 but then the CCA wouldn't be right in their chart.

I guess I'll wait to see if you get an email.

 

[QUOTE=Go48You could try e-mailing them.[/QUOTE]

Oh, that was me emailing them. I'll try. Do you know if it is the MT or the MTP. I'll ask for both.

 

[QUOTE=MX6_2_RX8]Read the entire thread (is that RTFT? ) and you will find the answer to your questions. It IS the MTP-35 as verified by Trussville Mazda.

 

Of couse, that is intended to indicate how long you can expect the engine/car to continue to function if the alternator fails to provide a charge to the battery. Not sure how you would translate that to the car sitting idle in a garage for a period ot time with presumable a very low drain on the battery. I'll see if I can find the RC spec for the original Yuasa battery.

EDIT: The RC rate for the Yuasa 50D20L battery, which I assume most US cars have, is 78 min, so the MTP-35 is apparently a bit better in that department as well.

 

I thought I had RTFT but I have read a lot of battery threads and low and behold, you're right, it's in there.

Here's what I got from interstate.


" Thank you for contacting Interstate Batteries. These batteries are not rated or tested for amp hours. However, the old rule of thumb used to be that RC X .6 = amp hours. So you could assume that these batteries are close to 60 amp hours."

In any case, I agree if you are paying for it get the MTP-35. If Mazda is picking up the tab the MT-35 should be fine. I'm in the latter camp I hope.