Hi Andy, alternators aren’t really my specialty, so I spoke to some folks who deal with them on a regular basis for more insight into the high-amp units. An alternator specialist would be able to provide the best information for your specific application, because there can be a lot of factors for a specific application, beyond the rpm range, materials used, wire gauge, delta vs. wye windings or both, etc... High output alternators can produce more amps at idle, but part of their output depends on their design and some can be designed specifically for low rpm use, but an alternator specialist really is the best person to ask about your specific needs. Voltage regulators can vary, but a typical range is approximately 13.7-14.7 volts.
redneck, automotive engineers generally design products like alternators, for a broad range of uses. They expect most will be used in daily drivers, but do design some degree of flexibility for more demanding applications. At some point, the demands of a specific application may exceed the capabilities of their original design, which is where the aftermarket often enters the picture. In some specific applications, the factory will incorporate specific upgrades for parts that will see demanding use, such as police packages. GM’s B4C police packages in the early-1990s included 105-amp alternators. By 1994, they upgraded to 140-amp alternators. The Ford Interceptor packages have been using 200-amp alternators since 2004 and their 2011 units will be equipped with 220-amp alternators.
These constant upgrades are a response to the increasing presence and demands of modern electronics in these vehicles. Even with LED light bars, most squad cars now have onboard video and computer systems and they can often spend up to 18 hours per day at idle. Even with these upgraded alternators, failure is not uncommon and the two departments I spoke to indicated they replace alternators in squad car units anywhere from 3-4 times during the life cycle of a car to as often as once a year. I’m glad the vehicles in your previous job didn’t run into mechanical difficulties and it’s quite possible that they were ordered and equipped with higher-output alternators, to handle the unique demands placed upon them.
The SAE cold amp output rating of Jeeps has varied over the years between 37-78 amps and that number tends to decrease as a vehicle is warmed up. Even a high-output alternator listed at 270 amps, may only have an output of 150-160 amps at 800 rpm, so a stock alternator rated at 90 amps could see a similar decline in that rpm range.
The vehicles I photograph tend to be street cars capable of running low-11s or quicker and the quicker they are, the less reliable they are on shoots. Most of these guys (particularly the late-model Mustang guys) view their alternators as horsepower-robbing accessories and will under-drive stock units. Few maintain their batteries when their vehicles aren’t being driven (which isn’t regularly), so they often show up at a shoot at less than a full state of charge. Pan-blur shots are generally done at less than 30 mph and as quietly as possible and front and rear ¾ shots are all stationary. If the car doesn’t shake too much at idle, we can leave the engine running. If the cam is too lopey, we may have to shut it down and re-start it every time we re-position the car or camera. Some cars can only handle 20-30 minutes of this, some last for an hour or more.
Other examples could include a guy at a car show, who decides to cruise around the fairgrounds with his stereo and air-conditioning both at full-blast, only to find out his car won’t start at the end of the day. A Jeep-specific example could be a guy who spent the day on the trails, parked his Jeep at the trailhead at the end of the day, then started it to load it on the trailer, started it again to unload it and put it away for a few weeks at less than a full state of charge with no battery maintainer. Even a small parasitic drain can further discharge the battery and sulfation begins to become an issue. As this cycle gets repeated over time, the battery’s performance and lifespan diminishes.
The conversations you see about our batteries on the Internet, both good and bad, are a reflection of the volume of batteries we sell. No battery manufacturer releases production numbers or defect rates, but Optima does follow industry standards. If releasing that information becomes standard practice, I’m sure they’ll follow suit. P1atinum, I apologize for any confusion regarding the hypothetical statement I made previously, in an attempt to illustrate the relationship between the number of batteries we sell and the amount of feedback on the Internet regarding our batteries. I should have stressed the "even if"
Interstate Batteries is one of our retail partners and has over 200,000 locations. Some battery manufacturers would have a hard time even supplying each of those retailers with just one battery. That doesn’t even begin to take into account the thousands of auto parts stores and retailers like Costco and Wal-Mart, who all stock our batteries.
Optima tends to be a fairly conservative company, in terms of what we promise or promote out of our batteries. We don’t try to confuse our customers with proprietary battery ratings, we just stick with BCI standards, which allow consumers to compare apples to apples. We have run extensive fleet testing in demanding conditions, which allows us to claim our batteries will last up to twice as long as conventional batteries. If a battery has a defect from the factory, it will likely manifest itself well within the first three years of ownership, which is covered under our warranty.
We’ve eliminated pro-ration, to simplify the warranty process for both retailers and consumers and our warranties aren’t loaded with specific exclusions for things like batteries that have been discharged below 10 volts. While some companies choose to simply exclude warranty coverage in these situations, Optima has elected to take a pro-active approach in informing consumers about proper battery maintenance and appropriate applications. We now have a series of videos on YouTube that help explain these things. We also have people like me, trying to assist people who have questions or concerns about their batteries. If I don't come off as a salesman, it's because that's not my job.
Jim McIlvaine
eCare Manager, OPTIMA Batteries, Inc.
www.facebook.com/optimabatteries
