AutoMeter Battery Extender
by Hib Halverson
You may own Cadillac Vs which are parked or stored for long periods. If you do, it’s possible you’ve had a dead battery. Even the best battery, when not connected to anything, slowly discharges because of the chemical processes at work inside it. Once hooked to your car’s electrical system, besides that tiny, self-discharge rate, when car is locked and the electrical system is in “full sleep” mode, a battery has a small, constant load on it from things like: keyless entry receiver, clock and anti-theft devices. Even with the doors closed and locked, there are still those small electrical loads.
If such a period of non-operation is several weeks, it is possible the battery may discharge to the point of a no-start condition. Then, you either charge the battery or jump-start the car. These full-discharge-then-recharge or deep” cycles reduce battery life. The durability of typical automotive batteries is significantly reduced if they’re subjected to deep cycles on a regular basis. Even premium batteries, such as the Odyssey Extreme and Performance series units used by the V-net in our product test vehicles, both of which are more tolerant of deep cycles, cannot be subjected to frequent, regular deep discharge/recharge cycles without eventually having their performance degrade.
The solution to this problem of batteries getting discharged when a car is not operated for a number of weeks is a “smart” battery charger which is designed to keep vehicle batteries charged during long periods of non-operation. Typically, they have two charge rates: a maximum rate of between 1.5 and 5-amps and a maintenance rate of between 220-milliamps and 1.0-amps. Upon connection, if the battery is partially discharged, a smart charger, such as the AutoMeter “Battery Extenders” tested for this article, brings a battery up to full charge using a three-amp or five-amp rate. At that point, the device’s microprocessor senses battery voltage at a nominal level and backs-off the charge rate to between 0 and 250 milliamps, depending on load. It “floats” the charge current at that level which is just enough to keep the battery at its optimal charge voltage, which depending on battery type, is 12.6-12.8-volts. This feedback-controlled, reduced-charge rate eliminates overcharging and extends battery life. There is no need to monitor an AutoMeter Battery Extender. Just plug it in, connect it to the car and forget it.
The first-generation AutoMeter Battery Extender was one of the early entries into “smart” battery charger business, which today is huge with a plethora of products from a variety of manufacturers. The original Battery Extender (PN 9201) proved to be quite a successful product selling about 50,000 units in 20 years on the market. We should add that two decades is an amazing life span for a product like a battery charger. In 2015, AutoMeter redesigned the Battery Extender product line incorporating more modern technology, an enlarged feature list and more competitive pricing. This second design AutoMeter charger line, known as “BEX” was released in three versions, 1.5-Amp, 3.0-Amp and 5.0-Amp. Of those three, the 5-Amp, BEX-5000 sold out in a matter of weeks, so we had to wait a number of months for AutoMeter to restock and provide a unit for testing. Additionally, the first BEX-3000 we tested did not function properly and a second one we obtained had the same problem. It turns out that the first run of 3000s were defective and there was a delay while AutoMeter addressed the defect with a circuit design change before more BEX-3000s were available. It wasn’t until the Fall of 2016, we had our two BEX models and began testing.
One advantage of the BEX units over the first gen Battery Extenders is the new design’s three modes of operation: “charging”, “maintenance” and “desulfation”. The first two modes are standard for any smart charger and were available from the old 9201s. What’s new is the “desulfation” mode. Lead-acid storage batteries can have a problem called “sulfation” where lead-sulfate crystals develop on the plates. When a battery becomes “sulfated,” it’s ability to hold a charge is degraded. Mild cases of sulfation can be mitigated by “pulsing” the charge voltage and current which can “knock” the sulfation off the plates. If an AutoMeter BEX-series smart charger senses sulfation is developing, it goes into the “desulfation” mode where voltage and current are varied in a way that causes the lead-sulfate crystals to separate from the plates.
Another improvement of the new Battery Extender design is that the unit’s housing is made of a lightweight plastic and is sealed making the device water-resistant to the IP65 standard which means that, not only can it stay dry during a three-minute spray with a water jet, but it’s, also, completely impervious to dust. In our testing, we found the new, sealed housing not as valuable as an anti-moisture-and-moisture measure as it is an “anti-critter” measure. We have several of the old Battery Extenders in service and one of them is used outdoors under a carport. We’ve found that insects, especially little spiders, like the interior of the first design Battery Extenders so much so that two or three times a year, we have to unplug it, then use shop air to blow though the housing’s exterior vents to get rid of partially eaten insects, spider poop and spiders (dead or alive). In short, we definitely like the hard plastic housing used by AutoMeter in the new Battery Extender design.
Three other features of the BEX-series chargers are: automatic overcharge protection, reverse polarity protection and spark-free connection. With the first two systems, there’s very little chance of screwing-up a battery by not paying attention to how long it’s connected nor connecting red to black and black to red. With the third, you don’t have to worry about a little spark when you connect the second cable and we’ll remind you, now, to always connect the positive cable (red) first and the negative cable (black) last.
We like that all Battery Extenders always come in a kit which includes two sets of leads. One set has traditional spring-clips on one end and another set with ring terminals on one end. Both sets of leads connect to the charger with a quick-disconnect mechanism. The ring terminal set is good in a case where the Battery Extender is always connected to the same vehicle.
The final advantage of the new BEX line is that they are priced lower and, in the cases of the BEX-1500 and BEX-3000, a lot lower than the first generation products were priced. We can thank a modern circuit design, lower component costs and lower-cost manufacturing for that.
Our favorites are the BEX-3000 and the BEX-5000 Battery Extenders because they are compatible with all types of lead-acid batteries: wet cell (or “flooded”), absorbent glass mat (AGM) and gel cell batteries. Both have a selector button the used to “tell” the charger the kind of battery to which it is connected. In spite of it’s low price, we don’t recommend the BEX-1500 because batteries in most -V’s are AGM. While the BEX-1500 functions with AGM and gel cells, it’s optimized for wet cell batteries, only, and, in our view, that negates the value of its low price.
The BEX chargers safe ambient temperature range is -4°F to 122°F. Outside of that range, they may malfunction or just fail to function. All of the BEX series chargers use the normal AC current available in North America. The actual voltage range the charger will tolerate is 108 to 132-volts AC. The BEX-1500 and BEX-3000 have a 12-volt output. The BEX-5000 has 6-,8-, 12- and 16-volt outputs which are selected with a button on the device. When operating with at the first three voltages, the maximum charge current available from a BEX-5000 is 5-amps. When the 5000 is run in the 16-volt mode, max. is 3-amps.
For more information on AutoMeter’s BEX line of smart battery chargers, see the battery charger section of AutoMeter’s web site. http://www.autometer.com/test-equipment/chargers.html#1&profile=products