12-Volt Booster Packs

Wal-Mart's EverStart booster delivers a lot of cold cranking amps for the money, but lacks a light. The versatile Xantrex Powerpack 300 Plus, is a do-it-all booster and a good choice for smaller boats.

It was a lot to ask—12-degree air temperature and a big, cold diesel with an enfeebled battery. We tried both of the bigger boosters (which were chilled to the bone themselves) and neither answered the call. When it warmed up to 30 degrees, things got better.

A few months ago, we were working on an evaluation of cabin heaters in the workshop of our executive editor. The workshop is set up more for work on rope, deck hardware, and marine coatings than for things electrical, and when it came to the 12-volt-powered heaters, we found that our 10-amp DC power supply wasn't up to the task. Nor did we have a charged 12-volt battery on hand. We scratched our heads for about 15 seconds, then the executive editor said, "Wonder if this'll work," and hauled out of the shadows a new, in-the-box Xantrex Xpower Powerpack 300 PLUS that he had lying around, waiting for its moment.…