Simple electrical upgrade - Sail Magazine

Simple electrical upgrade

Our 1973 Norlin 34 project boat had been used mainly for club racing in its latter years, and it showed. Among its many outdated systems was the battery-management setup. It was no worse than what I suspect can be found on many other boats of that vintage, but it would not suffice for extended cruising.The two Group 27 90AH deep-cycle lead-acid batteries, one for house
Author:
Publish date:
Social count:
0
cranking_battery

Our 1973 Norlin 34 project boat had been used mainly for club racing in its latter years, and it showed. Among its many outdated systems was the battery-management setup. It was no worse than what I suspect can be found on many other boats of that vintage, but it would not suffice for extended cruising.

The two Group 27 90AH deep-cycle lead-acid batteries, one for house loads and one for starting, sat side-by-side under the nav-station seat. The charging cable from the 60-amp alternator went to a four-position battery switch—Off/Battery 1/ Battery 2/Both. The battery capacity was inadequate to cope with the demands of night sailing or a weekend on the hook, and there was no way of telling the state of charge. The cables were a mess—ancient, cracked, and corroded at the terminals, not to mention mostly the same color—black, whether they were negative or positive. Basically, the electrical system was a disgrace, and I lived in fear of a fire.

Since both batteries had died last winter, I had every excuse to come up with a cost-effective solution that would bring Ostara’s electrics into the modern world. This would involve enlarging the house bank; finding somewhere to put a dedicated starting battery; simplifying the switching; adding a battery combiner; replacing all the cables; adding a small solar panel to trickle-charge the house bank; and installing a battery monitor.

Battery choices

My first purchase was a pair of Group 27 90Ah deep-cycle flooded lead-acid batteries. This would almost double the house-bank capacity. Why flooded? Simple economics. They were half the cost of similarly sized absorbed glass mat (AGM) batteries and a third the cost of gel-cells. If I were living aboard, I might have reconsidered, but for weekend sailing and the odd week away, flooded batteries would do fine. With regular monitoring, good winter care, and an eagle eye on the electrolyte levels, you can get a good few years out of lead-acid batteries. The combined capacity of 180 AH would be marginal for many boats, but it was adequate for Ostara’s modest electrical draw—chartplotter, VHF, stereo. The nav lights, anchor light, and interior lights are all LEDs, which dramatically cut power consumption, and the Tacktick sailing instruments are solar-powered. There is no refrigerator.

I also bought a Group 24 starting battery, along with a battery box. I had to make room for the second house battery under the nav seat, which meant the starting battery had to be relocated.

Switching questions

The most common way of switching between two battery banks is the Off/1/2/Both four-position selector switch. Switch to “1,” and the house bank draws from that battery, and only that battery is charged while the engine is running. In the “2” position, house loads are drawn from the #2 battery, which is also the only one charged. “Both” combines the batteries for charging and also for discharging. This is where you can come unstuck; you quite properly select “Both” for starting the engine and to charge both batteries when running under power, only to forget to switch over to your house battery when the engine is cut. Next morning, you realize you’ve drawn down both batteries to the point where there’s not enough juice between them to start the engine.

Because we often sail with children and novices and wanted to eliminate any possibility of confusion, I decided to make the charging system idiotproof—well, foolproof at least. As the first step I bought a Blue Sea Systems Dual Circuit Plus battery switch. This switch isolates house and starting battery circuits. Switch to “on,” and current goes from start battery to start circuit only, and from house battery to house circuit only. You cannot mistakenly run down the start battery. If you need to combine both banks for starting, just switch to “combine.”

Related

Stearns Photo

Racing the Solo Mac for a Cause

There are plenty of reasons to do a Chicago-Mac race, and Rich Stearns, who has done literally dozen of ‘em should know. This year, though, he’s doing the Solo-Mac for an especially important reason: to help those with prostate cancer.“Two years ago, I was diagnosed with prostate ...read more

TOTW_PromoSite

SAIL's Tip of the Week

Presented by Vetus-Maxwell.Got a tip? Send it to sailmail@sailmagazine.comRafting dangerOne unseen danger when sailing yachts lie alongside one another for a convivial night is that if they happen roll to a wash or begin to move in an unexpected sea, the spreaders can clash ...read more

180615-01 Lead

A Dramatic Comeback in the Volvo

After winning three of the last four legs in the Volvo Ocean Race (and coming in second in the fourth), Dutch-flagged Brunel is now tied for first overall with Spanish-flagged Mapfre and Chinese-flagged Dongfeng following the completion of Leg 10 from Cardiff, Wales, to ...read more

MFS-5-2018-Propan-SP02

Tohatsu LPG-powered 5hp Propane Motor

Gassing it UpTired of ethanol-induced fuel issues? Say goodbye to gasoline. Japanese outboard maker Tohatsu has introduced an LPG-powered 5hp kicker that hooks up to a propane tank for hours of stress-free running. Available in short-, long- or ultra-long-shaft versions, the ...read more

180612-01 Landing lead

Painful Sailing in Volvo Leg 10

It’s looking to be a case of feast or famine for the 2017-18 Volvo Ocean fleet as it continues the epic struggle that has been Leg 10, with it having been all famine thus far. Painful is the only word to describe the light-air start in Cardiff, Wales, on June 10, as the 11-boat ...read more

01-13_07_180304_JRE_03695_4605

Tips From the Boatyard

Within the Volvo Ocean Race Boatyard sits a communal sail loft which provides service and repairs for all seven teams sailing in the 2017-18 edition of the race. The sail loft employs only five sailmakers who look after 56 sails in each stopover. If you’re thinking, “wow, these ...read more

sailCarwBasicsJuly18

Sail Care for Cruisers

Taking care of your canvas doesn’t just save you money, it’s central to good seamanship  Knowing how to take care of your sails and how to repair them while at sea is an important part of overall seamanship. The last thing any sailor needs is to get caught on a lee shore with ...read more

Ship-container-2048

The Danger of a Collision Offshore

This almost happened to me once. I was sailing singlehanded between Bermuda and St. Martin one fall, and one night happened to be on deck looking around at just the right time. The moon was out, the sky was clear and visibility was good. Still, when I thought I saw a large ...read more