Originally Posted By: kozanoglu
Deka makes interstate too? Will look. Thanks.
No Deka does not make Interstate batteries. Johnson Controls (JCI - pretty much the largest battery manufacturer in the world) has strategically bought up a lot of "smaller" battery operations over the past 10 years. JCI's umbrella includes AC Delco, Costco (Kirkland), Interstate, Eveready, Energizer, Optima, some Yuasa batteries, and some Sears Die Hard batteries (and many more). There is no difference between the brands anymore, so an Interstate battery is very similar to anything sold in Walmart these days. No longer what they used to be (especially Optima batteries). JCI has mastered the art of making batteries that perform satisfactorily for the warranty period, but not long afterwards
Deka batteries (East Penn Manufacturing) make a good product. Obviously, they are not without failures, but that can happen in any mass produced product. However, they are not the cheapest battery in any category.
Exide makes decent batteries, and offers a new AGM product (Exide Edge AGM). Their Edge AGM battery employs carbon/graphite additive in the negative plates to help increase charge acceptance, so this is good for people who routinely drive short trips, especially in the winter. Lots of studies on carbon additives have taken place over the past 10 years, and Exide have pulled the trigger on the technology in an entire product line (other companies I'm sure are using carbon as well, but perhaps to a lesser extent). Although Exide's quality control may not be as "perfect" as the other two players in the US battery industry, they do make good products, and are priced in between the others.
In terms of technology, AGM batteries have several advantages over flooded batteries. The main advantage being that the plates are sandwiched in between glass mat separators, instead of polyethylene envelopes. The group of plates with the glass mat separators in between them must be compressed in order to fit into the slot in the battery box. The compression results in much better growth and corrosion performance compared to flooded batteries (since any corrosion cannot cause shedding of lead or paste due to compression, and growth is also controlled for the same reason). Also, the compression results in better utilization of active mass, meaning that you get more capacity from an equivalent AGM battery compared to a flooded model. They can usually also handle reasonable discharging better than flooded batteries (not very deep discharging though, otherwise desulfation may be necessary as stated in a previous post).
The disadvantages of AGM batteries are that they are harder and more costly to produce. Also, the amount of compression between cells must be equal or very close to equal. Cell to cell differences in compression / electrolyte level, or any other manufacturing anomalies usually result in greatly reduced life, which is why some people don't get a better life from an AGM battery compared to a flooded battery. These disadvantages especially apply to circular or orbital AGM batteries such as Optimas. Equal compression is very tough to achieve when you're rolling up lengths of positive and negative mesh rather than compressing an individual group of grids. Just a hint, this "might" be the reason why their quality suffered when the plant was moved out of the US, even though all equipment is exactly the same
Can't give away much more than that, but put 2 and 2 together...
