I've had a Westco and the clone from Napa, and wasn't very impressed with either for the price. After the Westco failed within two years (removed in winter, driven <4,000 miles/year) I wrote to them about the issue, and their response was that the average life of these batteries was 2-3 years. They wouldn't offer me so much as a discount on a new battery. The Napa has lasted longer so far, comes with a longer warranty, but I can no longer get it to hold more than about 12.2V. I paid less than $225 for it, but still don't think it was worth the money.

My next battery I think will be a wet cell, because these AGMs cost more and don't seem to offer any performance benefit.

In terms of "performance benefit," the only real advantage to an AGM battery is that, since it's located in the trunk, it doesn't contain a bunch of free electrolyte which can slosh around and eventually find its way down to the metal surface of the body, thence causing corrosion.

In the mean time, I will invent a battery which consists of a small rotating flywheel of infinite mass whose outer edge travels at 0.9c, suspended by a frictionless bearing, in a total vacuum. It will last forever and start every engine in the world simultaneously, but the first hard corner you take will rip the car in half (and also create a supermassive black hole which destroys all of time and space.)

Joe has moved from engineering to marketing.

Like the new Meme.

I believe it is a clone of the westco. It looks the same as the westco with a different label, same CCA, and the same part number (8AMU1R)

EDIT: It us underneath the Eastp Penn umbrella. The brand is called Pow-R Surge. Naturally I thought this was random el cheapo battery. It was after I removed it I noticed it looked like the Westco, has the same labeling (8AMU1R), and that East Penn Canada has the Pow-R Surge brand batteries on their website.

True, and is the reason I went for an AGM despite the price and relative scarcity, in the first (and second) place.

However, in my experience the AGMs on offer have definite drawbacks to good flooded batteries - namely availability, price, and as it turns out, durability and cranking performance. If I could buy a new OEM-spec Panasonic, I'd jump on that, but I'm talking about what I've found to be available.

In the meantime, I've found that sealed flooded-cell batteries don't generally leak or outgas excessive amounts, and even if they did, our cars have a handy-dandy little venting system to keep these gases from festering inside the trunk, and live in a plastic tray which offers some protection from small amounts of acid getting to the tasty, tasty unibody. Even Mazda sells a flooded-cell as the OEM replacement, so I've concluded that a good flooded-cell battery may well serve my needs better than the mediocre AGM ones on offer.

I ended up just tossing an Autocraft silver in mine. It even came with new vent tubes. Been working like a charm so far. I let the car sit for 5 weeks outside and then moved it in and out of the garage about 6 or 7 times, then tossed it on the battery tender to charge it back up. And starting my piss poor tune is not easy or quick, 10-30s of cranking depending on temp. (I am slowly getting the tune sorted out, down to 5s or so now).

Am I the only one here who just goes to Advance Auto and gets whatever they have in stock for the miata and use the online coupons to get 30% off?

I did that for both my cars this year. Managed to get the battery for my Fit for $80 out the door after finding a $40 off somewhere.

I go to the local Interstate battery place, and ask for "blems". If they have them, it's about 40% off list. If not, they'll call me when one comes in. I've never had to wait long.

On top of that, my company gets all it's batteries through them, so I get an additional discount. 10%, I think.

i dont get the point of all the battery hoopla. no battery in the right size has enough cca to really last any long period of time. i think most come in at 320cca. just buy w/e has enough warranty that youll get a discount when its in its replacement range. interstate is really good about that

It's not about the battery lasting a long time - its more about how much CCA the battery can output when the temperature drops significantly. A lot of the oem style 320CCA batteries decide to give up around -20C