Blue Seas New Smart Charger


Keeping batteries fully charged is a science that cruisers have to master sooner or later. If todays high-capacity AGM batteries arent managed properly, valuable amp hours in can permanently trickle away through sulfation, as we saw in our test of AGM batteries (See Fighting Sulfation in AGMs, PS May 2015). Good battery management means complete re-charging that matches the charging profile of your battery, and this means an accurate sensing of battery voltage. As we saw in our recent report on battery monitors (see Best Battery Monitor Test Update, PS October 2017) a good monitor will also keep track of temperature, as this can be a limiting factor in charge acceptance rate.

Blue Sea smart BatteryLink system

The Blue Sea BatteryLink waterproof 20A charger is the big brother of the popular 10 amp version. Of course, the more powerful 20-amp version has ability to attend to a larger battery bank-up to about 200 Ah. Like the BatteryLink 10A it is compact, measuring about 5 x 7 x 2 inches and the internal components are sealed, so it can be mounted close to the battery bank and low in the hull without worry.

The critical element is the internal 65 amp automatic charging relay, which detects when a charging source is present and automatically combines the two batteries to be charged simultaneously. It links them when a DC charge above 13 volts is applied to either battery-no matter the source. When there is no charge, or the load on one battery falls below a pre-set level (12.75 volt) it disconnects them.

When you hook up to shorepower, the BatteryLink becomes your shore charger, effectively taking the place of a 20A three-stage charger, maintaining two bank systems of between 60Ah to 200 Ah. The small unit will appeal to midsize cruisers looking for a robust single system to maintain their batteries and prolong their life. Scheduled for release in 2018, it is not yet priced .

Practical Sailor has been independently testing and reporting on sailboats and sailing gear for more than 45 years. Supported entirely by subscribers, Practical Sailor accepts no advertising. Its independent tests are carried out by experienced sailors and marine industry professionals dedicated to providing objective evaluation and reporting about boats, gear, and the skills required to cross oceans. Practical Sailor is edited by Darrell Nicholson, a long-time liveaboard sailor and trans-Pacific cruiser who has been director of Belvoir Media Group's marine division since 2005. He holds a U.S. Coast Guard 100-ton Master license, has logged tens of thousands of miles in three oceans, and has skippered everything from pilot boats to day charter cats. His weekly blog Inside Practical Sailor offers an inside look at current research and gear tests at Practical Sailor, while his award-winning column,"Rhumb Lines," tracks boating trends and reflects upon the sailing life. He sails a Sparkman & Stephens-designed Yankee 30 out of St. Petersburg, Florida. Darrell is booking speaking engagements in Colorado, Idaho, California, the Pacific Northwest, and British Colombia this summer. You can reach him by email at