Alternator in Alaska

Winter is a sustained electrical load

Short Alaska winter journeys ask the charging system for everything at once: headlights against a dark afternoon, the blower at full, a heated rear screen, heated seats, and a battery that has just given up a large amount of current to a cold start.

An alternator that is merely tired copes in July and cannot keep up in January. The symptom is a battery that goes flat repeatedly and tests fine each time it is charged — the battery is not the fault, it is the thing reporting one.

Cold and darkness together: the heaviest electrical load of the year falls in the months with the least driving.

The connections corrode before the machine does

Damp air works on the exposed side of an alternator: the terminal stud, the plug on the regulator, and the earth strap between engine and body. A resistance in any of those looks exactly like a failing alternator on a meter at the battery, and is a fraction of the price to fix.

Check the charging voltage at the alternator's own output and then at the battery. A meaningful difference between the two is a connection, not a machine.

An alternator breathes whatever the road throws up

The case is ventilated, because the machine has to shed its own heat. On unpaved roads that means it is drawing dust through itself continuously, and the dust ends up on the slip rings and in the bearings.

A whine that rises with engine speed rather than road speed is a bearing. It is worth catching, because a seized alternator bearing does not stop at the alternator — it takes the belt, and everything the belt drives goes with it.

Frost heave over permafrost moves a road surface between visits, and gravel highway miles come as standard.

The climate, in a number

Anchorage's normal winter snowfall is 74.5 inches. Every one of those days is a day the cooling fan, the air conditioning clutch and the blower are all drawing at once, and the alternator is what carries them.

What goes on the roads in winter

The transport department anti-ices with a brine that is 23.3 percent sodium chloride, and falls back to sand once it is too cold for chemicals to work. What is spread on the road reaches the alternator through the same wheel-arch opening that cools it, and a case packed with salted grit runs hotter than one that is clean.

Why this one here

Short dark days mean lights, heaters and defrosters running constantly, which is a charging load a marginal alternator will not meet.

Ruts, and what they do

Studded tyres are legal here and widely fitted, and over a winter they wear grooves into the pavement. On the busier roads around Anchorage those ruts become deep enough that a car will follow them whether or not the driver wants it to.

Driving in a rut is a continuous steering load. Getting out of one — to change lane, to pass, to turn — means climbing the ridge between grooves, which is a lateral impact on the tyre and the steering.

What else Alaska does to a car

Studded tyres rut the surface and the grit that fills those ruts is thrown at everything underneath.

Distances between towns are long enough that a no-start is a recovery rather than an inconvenience.

What we hold, and what it costs

5 options from Bosch, Cardone, Denso, Remy and Valeo, from $239.99 to $309.99. Prices are firm — where we have no price we publish none.

We are a reseller rather than a manufacturer: we source the part, check it over and sell it, and we confirm it against your year, make, model and engine before it ships rather than asserting a fit on the page. We ship anywhere in Alaska, including Anchorage, Fairbanks, Juneau and Wasilla.