Way to many threads here but I found this and thought I'd share even though its probable been brought up before...
"Lightweight battery, odyssey, braille, etc. Information:
I have spent close to 8 hours researching batteries, and wanted to share much of what I found, which is not always clear on previous threads. I am sure some will disagree with some of my statements, I am not saying any of this is 100% fact but I have read A TON on this subject before coming to these conclusions. These are random:
1) You can get away with a very lightweight low power battery in the NSX if you don't have a lot of aftermarket stuff, drive your car frequently, and don't live in a severly cold climate. You can save around 15-20 pounds of weight instantly by changing the battery.
2) The battery world is a big scam. There are a handful of battery manufacturers, everyone buys from them, then re-badges and sells for whatever they want. The specs are manipulated wildly at times, there is no real standard. Many companies have multiple websites and multiple names for the same battery (and multiple prices).
3) The two best known brands: Braille and Odyssey... at this point, I really feel braille is severely overpriced. They are made by Deka, rebranded and sold for A LOT MORE. All manufacturers say that their "internals" are different, but I have seen some internals and they look identical to me. Believe what you want. Deka also makes "Big Crank". Both Big Crank and Deka can be had for a lot less than the matching Brailles. The Dekas are sold under many other names as well. Braille lists PULSE CCA's on their website... this is a ******** term. You have to read their CCA's.
4) Odyssey is made by Enersys. Enersys sells the same battery under the "hawker energy Genesis" brand for less money. A lot of performance shops sell DynaBat which is purchased from Hawker and sold for more money. These are all enersys batteries.
5) Odyssey terminology... the batteries can be bought in various iterations. For example PC680, PC680MJ, PC680MJT. Same battery. MJ stands for Metal Jacket. T refers to the top post. You can adapt a standard 680 by buying an SAE post. The metal jacket is to protect the battery, not to protect the environment the battery is in. One of the main culprits in killing battery performance (like radiator performance) is heat. The MJ units keep more heat away from the internals. In a mid-engine car, this is not so much an issue. Just as the NSX radiator stays cool, so does the battery. I don't feel the MJ is necessary, but some may disagree and can chime in.
6) The performance of these batteries can be had for as little as $25 using UPS batteries. I saw many accounts of various racing forums of people using these, but they do not take vibration as well. Here is a battery that will crank over your NSX just fine at $25:
http://www.batterymart.com/p-12v-20a...battery-3.html
I'm not recommending this, but just showing what a $300 battery has internaly is not all that different. Battery basics are the same, there is a lot of marketing involved. I am thinking its the same with Duracell and Energizer. I don't think there is magic inside.
7) Big Crank (Deka) has some models listed standard, and "L". EXT15, or 15L. The "L" refers to a reversal of the polarity. Look at the pictures and select the correct one.
8) Another couple of options are Yuasa and Gruber Power, these will work with the right adaptor post and are very reasonably priced:
Gruber Power
A pretty informative article here, at least look at the pics, it is funny the resemblence:
Stealth 316 - Dyna-Batt Battery
I just wanted to provide info of what I have found. Right now I am leaning toward getting a Big Crank EXT15L to save some weight.
I looked into making your own batteries (especially with lithium cells). I was not able to come up with anything really cost effective, but can tell you for sure that $1995 for a Braille is making the CEO a lot of money"