How To Install Boat Battery Charger

Do-it-Yourself: Installing a Battery Charger

Basic system for installing a battery charger

The basic components of a battery charging system.

By Tom Burden, Final updated: iii/10/2020

Earlier the advent of multi-stage battery chargers, batteries were oftentimes damaged past over- or under-charging while on shore power. Boat owners often had no choice only to plow the automotive type ferro-resonant charger off except when they were on board. Fifty-fifty and so, the charging voltage was frequently too high and the resulting gassing killed many batteries. Today, quality marine chargers use multi-stage charging, monitor the voltage in the batteries, and may be left on continuously if they are installed correctly.

Before Yous Start

Determining where to locate the charger is an practise in compromise and then common to many boats. The charger wants to be relatively close to the batteries—but not too close. One of the nigh common mistakes in charger installation is locating it directly in a higher place the batteries. While keeping the DC cables between the charger and the batteries short is important, batteries give off gasses that cause and promote corrosion during charging. Placing the charger too close to the batteries, where information technology is exposed to these gasses, will shorten its life, particularly if the batteries are liquid electrolyte.

Almost chargers must remain dry, only at the same time they need adequate ventilation. If the charger must be located in a cockpit locker or lazarette, be certain and tuck information technology in a dry corner—not directly under the hatch. Do not stuff all Declension Guard required life jackets tightly around it or coffin it behind other gear. Give it some breathing room so it can stay cool.

The ProSport 12 battery charger

The ProSport 12 marine battery charger ensures that all available charging amperage is fully utilized to meet the unique demands of each onboard battery. Later the batteries are charged, the charger monitors and maintains the charge only as needed—reducing its AC ability consumption.

Ancor stainless steel wire cutter, stripper and crimper

Ancor's stainless steel wire cutter, stripper and curling handles 10-22AWG wire sizes. It's a very expert tool for this task.

If you lot have a pocket-size boat that by its nature is moisture (sport gunkhole, line-fishing boat, personal watercraft) and want to install a bombardment charger, you need to purchase a sealed or fully encapsulated charger. These chargers are designed for apply in enervating environments and can operate fifty-fifty when fully submerged (however, this is non recommended).

Boats with gasoline engines must use chargers that are ignition protected and conform to the advisable UL specifications, which include testing in an explosive environs.

West Counselor safety tip: Unplugging the shore power cord before working on the AC system is expert practice, but please recollect to turn off the main breaker inside the boat as well. A dock-mate may retrieve your cord accidentally became unplugged and do you the "favor" of plugging it in while you are working on the organization.

The right tools for the job: You will need common hand tools, and a quality mitt crimper that can handle a variety of terminals suitable for wire up to #x. If wire larger than #ten is needed, you lot will have to purchase pre-terminated cables or make them up yourself. A drill motor might also come up in handy.

Craftsmanship tip: Ac wiring is the virtually unsafe wiring on the gunkhole and preventing chafe is critical. A discarded section of the outside jacket, leftover from stripping out a cable, can often exist used equally chafe protection.

Installation

One time the location for the charger has been selected, it may be attached in place. If the charger weighs more than than a few pounds it should probably be through-bolted. If information technology is of modest weight, and the bulkhead or structure information technology is to be fastened to is sufficiently thick, then screws may be used. Be sure to utilize stainless steel fasteners.

The wiring for the charger is adequately straightforward, with the DC wiring going from the charger to the batteries, and the AC wiring coming from the Air-conditioning distribution panel to the charger, or an outlet box adjacent to it. We will consider the DC wiring offset.

Skilful wiring practice is to claw up from the device toward the source. In this case the bombardment is the source. You might think the charger is a source; well, that's correct merely not unless the AC power to it is turned on. The idea is to limit one's exposure to a alive circuit. Thus, nosotros hook up the source—the batteries—last.

Importance of Wire Size

Information technology is critical to use the manufacturer's suggested wire size between the bombardment and the charger. This will have a disproportionately large impact on how well your battery charger works. The wire size required will be based on the distance from the charger to the batteries; longer runs crave proportionally larger wire. If the wire is too small, the resulting voltage drop tin can cause the battery to be chronically undercharged and increase charging time. How come?

Most marine chargers do non have dissever voltage sensing inputs. They depend on measuring the voltage inside the charger for the "sense" voltage used to command the charger output. If the wire is sized for 3 percent drop at total electric current and the charge voltage is xiv.0V, that ways there would be 0.42V drop in the wire solitary. Thus, the bombardment would be at 13.58V not the desired xiv.0V. This problem is almost severe during high-current charging. In fact, when the battery is full and just requires a few tenths of an amp to maintain the bladder voltage, the problem goes abroad.

And then why bother? Two reasons: Commencement, pocket-size wires slow the charge rate long before the bombardment is total. 2d, if there are house loads consuming current, the voltage drop from the charger to the batteries will cause the batteries to be maintained at too depression a voltage. This is particularly a problem for liveaboards and worsens with lower float voltages. In fact an intermittent load such every bit a refrigerator, which comes on regularly and consumes several amps, will lower the average voltage seen at the battery; everything looks fine with the fridge off but when checked with the fridge on the voltage falls by ii or three tenths of a volt.

DC Wiring Connections

Waterproof ring terminals

Waterproof Ring Terminals include a brusk length of agglutinative-lined heat shrink tubing to protect the wire termination.

Grounded inlet for a battery charger

A grounded inlet for a battery charger, slap-up for a gunkhole without a shore power organisation or distribution panel.

The DC cables should be connected to the charger as directed by the manufacturer. Wire nuts, common in household applications, must non be used. If a wire-to-wire connection must exist fabricated it should exist done using a butt splice, preferably 1 with adhesive heat-shrink tubing and secured inside the wiring compartment on the charger. If the charger is a potted type and has cables embedded in information technology, do not extend the wires. If the DC wiring is terminated with alligator clips they should exist cut off and terminated with proper ring terminals to prevent the alligator clips from causing a spark, which could atomic number 82 to a battery explosion.

When connecting the wires to the battery, put the charger wire on top of the big battery cables, not under them. Spray or coat the terminals with a corrosion preventative. Attempt to use closed barrel terminals and rut shrink or record over the last (Ancor Waterproof Ring Terminals are excellent in this application). The most common wiring failure is corrosion caused by acid and gas wicking up the wire leading to eventual failure. Sealing, corrosion preventatives and routing wires so the terminals are abroad from the battery caps help prevent failures due to corrosion. If your system uses a shunt in the negative of the bombardment system, do not connect the charger negative directly to the battery. Information technology must connect on the same side of the shunt as all the loads and sources on the gunkhole. At that place should only be i cablevision between the shunt and the battery.

Air conditioning Wiring Connections

The AC wiring can be as uncomplicated as plugging the charger into an extension string and running that to an outlet in your garage. This would be appropriate for a line-fishing boat, ski boat or runabout. If a permanent installation is desired information technology is likely to fall into one of two categories: 1) the charger is the merely load on the boat and thus is wired from the shore ability inlet to the charger; 2) the boat has a distribution console (Air conditioning billow panel) and the charger is wired to a breaker in the panel. Let's consider each.

i) If the charger is the merely AC device on the boat you may install a compact shore power inlet that accepts a standard straight blade extension cord. Locate information technology in a protected spot within accomplish of the Ac cord on the charger, cut off the charger's Ac plug, and connect it to the AC inlet. Spray the terminals and wire ends with a corrosion preventative as you get in up.

2) If the boat has an AC distribution panel you lot will want to supply the charger from one of the excursion breakers in the panel. Before working in the distribution panel, be sure all AC sources are off (this includes inverters and generators that may supply the panel). There may already be a circuit breaker designated for the bombardment charger. If non, option an unused billow of 15 or twenty amps for the new charger circuit. Run an appropriate marine-course, three-conductor AC cable betwixt the panel and the charger.

Following our good do of working from the load to the source during hookup, nosotros first make up the charger. It will probably accept an fastened AC wiring box for connections. Typically these boxes have knockouts that allow the cable to enter from a variety of directions. Information technology is best to enter from the bottom, if possible, with the sides as second pick. Top entry should be the last choice since it makes it easier for water to enter the wiring compartment. Be certain to use strain relief connectors; do non run the Air-conditioning cable through the knock out alone as information technology might abrasion. Do not overtighten the strain relief, as it can crush the insulation and cause a brusque or a hot spot. All information technology has to exercise is concur the cable in place.

Proper Connections

Every bit with the DC connections, the Air conditioning connections should be made with crimp type connections—not wire-nuts. For extra protection, apply record on top of the connections or apply butt splices with adhesive-lined rut compress tubing. When folding the wires into the wiring box, be certain they are not pinched or rubbing against screws or fittings in such a way equally to cause chafe.

Now to the Ac panel. Exist sure the cable is securely fastened along its length and equally it enters the panel space. Tie it into the wire loom such that it does non bind the panel equally it is opened. Locate the AC neutral and ground and connect the white and green wires respectively. The black wire volition connect to the circuit breaker.

Xantrex two-bank charger

We installed this Xantrex Truecharge2 ii-bank charger on our 30' Newport sailboat. Information technology's permanently wired to a breaker on the distribution panel.

Startup and Examination

Before starting up the arrangement, check all connections for tightness. Check the battery voltage for a reference. Select the appropriate charging government, and so it volition follow the correct charging sequence and use the correct voltages for your flooded, gel, AGM or other compatible bombardment chemistry, per the manufacturer's instructions. Energize the Air-conditioning circuit by plugging in shore power and turning on the appropriate circuit breaker. Spotter the battery voltage, it should begin rising almost immediately. This indicates the charger is operating.

Allow the charger to go through a complete charge bicycle, noting the maximum voltage during acceptance and the final float voltage. If necessary, adjust the charge regimen to meet the specifications required by your batteries. If in that location is a larger disparity betwixt the manufacturer's specifications and your reading, y'all may accept a voltage drop in your wiring. Check all connections for tightness and be certain the wire size is adequate.

If the boat is a liveaboard with heavy loads be certain to check for voltage drop under full load at the charge voltage and the float voltage. Check the voltage at the charger and at the batteries. They should rail within 0.one volts or then.

Checking Charger Output

You lot may as well want to ensure that the charger lives upwards to its rating. You can exercise this past turning on DC load upwardly to equal to the current rating of the charger to run into if it can maintain the charging voltage. Ideally the charger volition be able to sustain full rated output at both the acceptance and float voltages. If it cannot maintain full rated output, reduce the load to about 75 percent of rating and examination once again. If it cannot maintain 75 percent, you may want to call the manufacturer to encounter if they rated the charger under optimistic conditions.

It is all-time to be nowadays during the first few hours of operation of any new charging source and not to plow on a new installation and walk away from the boat for several days. It's important to verify the batteries are happily being float-charged by the new charger.

1 terminal circumspection. Some bombardment chargers stay in acceptance or absorption stage until the charge electric current falls to a specific level (perhaps three amps). That is, the charger will go on to hold the batteries at 14.4 volts indefinitely if there is some load on the boat that exceeds the target current. We discovered this on a reliable but simple 3-phase charger that we sold several years ago, and it was responsible for overcharging some of our customers' batteries. Modern chargers, like those from Xantrex, volition utilise a timer in improver to the current acceptance of the batteries to cause them to revert to float mode. This prevents extended times at high voltages, and is an fantabulous feature to specify—peculiarly if you alive aboard.