You have likely seen them at farm equipment dealerships and automobile repair shops: battery booster packs with built-in cables and clamps to jump-start dead batteries. The answer to your unvoiced question: "Yes, they work great on farms.”
Whether called booster packs, jump-starters or battery boosters, the concept is the same: They're batteries designed for short-term, high-amp discharge, in a carrying case that includes built-in cables and clamps.
The advantage of jump-starters is their ability to start an engine without being connected to a 115-volt outlet or without the hassle of getting a vehicle close enough to use jumper cables.
Jump-starters are built around absorbed glass mat (AGM) batteries. These batteries use an acid gel or paste, rather than the liquid acid in conventional "flooded plate” batteries, and a plate construction that increases longevity and vibration resistance.
"AGM batteries can be tipped sideways, even held upside down, and they won't leak acid,” says Jim O'Hara, vice president of marketing for Clore Automotive, manufacturer of Booster PAC and Jump-N-Carry jump-start units. "We use a different type of AGM battery with lead plates, a different kind of acid paste and internal connectors, all designed to handle rapid and large discharges of electricity necessary for jump-starting. That discharge creates a lot of heat, so it takes a special design and components to stand up to that type of use.”
Jump-starters are rated in cold cranking amps (CCA), cranking amps (CA) or peak amps (PA).
CCA is defined as the current (amps) that a jump starter can deliver for 30 seconds and still maintain voltage greater than or equal to 1.2 volts per cell at 0°F.
CA is the same thing but at 32°F, and PA is a short-circuit amp measure that loosely approximates the instantaneous power delivered during a jump-starting procedure.
The right juice. Jump-starters built around a single 12-volt battery will generally start vehicles ranging from an ATV up to a four-wheel-drive diesel-powered pickup. Larger jump-starters that incorporate two 12-volt batteries in their case offer up to 1,500 CA and are capable of starting large diesel-powered farm equipment.
"Weight is a quick indicator of the power,” says Patrick Clarke, director of engineering for Schumacher Electric. "It simply takes more plates in a battery to create more power, and more plates mean more weight.”
Smaller single-battery jump-starters suitable for starting cars and light vehicles weigh as little as 10 lb. A farm-duty unit capable of starting a dead four-wheel-drive tractor on a frosty morning requires two batteries and can top 40 lb., but it comes in a tidy case with a built-in handle, cables and internal "smart” recharger.
Clarke says the type and length of power cables built into jump-starters also indicate power and quality.
"Ag equipment needs at least 4-gauge wire, maybe even 2-gauge wire if it's a two-battery unit,” he says. "Be wary of copper-clad cables. Solid copper cables cost more, but they transmit power better. Solid copper cables generally have good insulation that stays flexible in cold weather.”
Prices vary from $45 to more than $500, depending on power and quality.
"There are consumer-grade units, and then there are professional-grade units,” Clarke says. "Farmers would probably be happier with professional-grade units because they are more powerful and durable.”
You can e-mail Dan Anderson at firstname.lastname@example.org.