Flagship Marine
12-24 Volt DC Systems

The Pros and Cons of operating Marine HVAC systems with the ship's 12-24 DC Volt power supply.

Operating marine air conditioning systems with the 12 or 24 volt DC ship's power supply is possible, and in many commercial and military applications and some recreational applications, desirable, but for the typical recreational boat owner it's frequently impractical for numerous reasons:

Operating with 12 or 24 volts DC current is often limited by the lack of a sensible and adequate power supply.
It's foolhardy to run a 300 HP engine at fast idle while at anchor to spin an alternator that requires only a few horsepower.
On a smaller engine, the large alternators required (200 plus amps) usually require multiple belts and may place an unacceptable side load on the front crankshaft bearing, voiding the engine warranty.

It's impossible to overcome the V=I/R formula, whereby a typical 16,500 BTU air conditioner that requires about 13.5 amps @ 120V, requires about 135 amps @ 12VDC, therefore you will need about a 200 amp alternator with beefed up engine wiring harnesses to comfortably produce a continuous 135 amps to operate a single, typical 16,500 BTU air conditioner.

The voltage drop is very high with low voltages, therefore with 12 volt HVAC equipment you will need to run very heavy, battery cable like, power supply wires, which are not only expensive, but also heavy.

Running off of the batteries is also usually impractical because you will need a huge bank of batteries to operate the air conditioning equipment overnight, and you would certainly give your alternator an incredible workout in the AM, possibly overwhelming it.

For smaller recreational applications, we usually recommend the consumer consider a small (2,500+ watt) portable generator if one wants to operate the air conditioner overnight. It's extremely important to avoid carbon monoxide poisoning, somewhat limiting the possible locations where the generator can be placed, and we always recommend the use of at least one high quality CO detector on board!!

Other manufacturers do supply 12 volt HVAC equipment, however because the components are such small specialty runs on the assembly line they are usually very expensive. We believe it's actually less expensive and far more desirable to purchase one of the many highly efficient, reliable and relatively inexpensive inverters so that you can utilize the lesser expensive, standard, over-the-counter air conditioning equipment. An added benefit is the elimination of your battery charger because these inverters usually have very powerful and sophisticated battery charging circuits in addition to the inverter!

If, however, you wish to run the AC while underway and you do have or can install a large alternator, this can be a very sensible installation. We have done just this as a test on a USCG 47 MLB several years ago with great success. The existing alternators were huge and under-utilized, and they now heat and cool the entire vessel with two 16,500 BTU Flagship Marine units via a Trace inverter while underway, and on the shore-power while dockside.

Our OEM relationship with Xantrex Technology, Inc.(they recently purchased Trace Engineering, Statpower Technologies, Cruising Equipment Corporation and Heart Interface), enables us to pass along very substantial savings to our customers as evidenced by the few models that follow:

After many years of experience powering Flagship Marine a/c systems with inverters, we now endorse the PROsine line of Xantrax inverter/chargers and are happy to offer them at very aggressive prices!
For example - to power any of our units up to 20,000BTUs, we recommend the PROsine 2.5 KW model:
Our factory direct price is only $1,999.95!
Includes standard remote control and battery temperature sensor. PROsine 2.5kW Inverter/charger (12VDC model #805-3025) -╩Retail price = $2,600.00


Prosine 2.5 - True Sine Wave Inverter /Charger

Available in 12 or 24-volt versions, the Prosine 2.5 inverter / charger provides up to 2500 continuous watts (4,000 watt surge for up to 5 seconds) of true sine wave output and combines this with a 100-amp, continuous-duty multistage power factor corrected battery charger.

Prosine 2.5 provides clean, regulated, output and offers distinct advantages over other wave forms. Features automatic overload, short circuit & low-voltage protection, over-temperature and AC back feed protection circuitry, built in transfer switch and a two year warranty.

A standard remote control panel and battery temperature sensor is included with the Prosine 2.5.

Offering a revolutionary power to weight ratio, Prosine technology has become a benchmark for premium integrated power systems.

Designed to replicate the electrical output produced by utility companies, true sine wave is the only electrical wave form that can power high-end electronic equipment such as laser printers, sound systems, and plasma screen televisions.

Motors and battery chargers will run better and cooler on true sine wave inverters.

Prosine 2.5 comes with a pre-programmed charge cycle for gel or lead acid batteries and regulates the voltage and current delivered to the battery without overcharging.

Manual equalization allows you to recondition lead acid batteries when necessary.

When recharging batteries, Prosine 2.5 will reduce its current draw when AC loads are operating to keep within the limits of the AC input breaker rating. Batteries can be recharged when AC equipment is operating since remaining current is available to recharge batteries.

Built in Transfer Switch - An integrated 30-amp transfer relay provides seamless transition from shore to inverter power. When utility AC power fails or is disconnected from the unit, a quick 20-millisecond transfer takes place and Prosine 2.5 begins delivering AC power to loads on the system. When utility AC becomes present again, the control circuit waits 8 seconds and Prosine 2.5 verifies the stability of the AC source. Prosine 2.5 synchronizes the inverter to the AC source for a smooth, seamless transfer back to utility power. The microprocessor inside Prosine ensures that the inverter is synchronized with the line to provide a smooth transfer if utility power fails.

The Standard Control Panel is used to report information about Prosine operating parameters and the inverter / charger's external AC and DC power sources. The standard control panel has five separate functions: the Battery Status LED display, the Faults Display and Reset Button, the Inverter Status Indicator and On/Off Control Button, the Shorepower Indicator, and the Charger Status Display and On/Off Control. Use the Temperature Sensor to adjust the charge formula in real time according to actual battery temperature to ensure that batteries are fully charged even when temperature fluctuates.

Compact, Lightweight and Easy to Install High frequency switching technology results in a lighter weight and compact design making installation into tighter spaces possible. Prosine 2.5's actual weight is 32 lbs. (14.5kg).

Peak inverter efficiency 89% No load current draw, in load sense mode <3 W Idle circuit adj. load sensing OFF, 10 W, 25 W, 50 W [dip switches] No load current draw, inverter idle 60 W Output frequency 60 Hz ▒ 0.05% (crystal controlled) Output waveform Sine wave <5%THD Input voltage range 10-16 VDC (20-32Vdc) Output voltage (at no load) 120 VAC RMS ▒ 3% Output voltage (over full load & battery voltage range) 120 VAC RMS -10% / +4% Low Battery Cut-out 10 VDC, 10.5 VDC warning (20 VDC, 21 VDC warning) High Battery Cut out 16 VDC (32Vdc) Protection Automatic overload, short circuit , over-temperature Reverse polarity (fuse)
CHARGER Battery capacity selections 50, 75, 100, 150, 200, 300, 400, 500, 600, 700, 800, 1000, 1200, 1400, 1700, >2000 Ah Charge Rate 12V (24V) 100A (50A) Charger Power Factor Rating .99 Charger Efficiency >80% Charge banks 1 high current Charge control 3-stage with manual equalize Temperature compensation 3 settings or optional sensor. Electrolyte compensation flooded or gel. Input voltage range 90-135 VAC. AC service setting [max. cur rent draw] 10 [8], 15 [12], 20 [16] , 30 [24] amps. Transfer Relay rating 30 A PROsine 2.5 12-volt, [24-volt] GENERAL Transfer Time Inverter to AC zero seconds, [8 second delay] Transfer Time AC to Inverter (including detect time) 20 milliseconds Regulatory Approvals CSA/NRTL approved to CSA 107.1, UL 458 and UL 1741, FCC Class A

Dimensions (L x W x H) 20 x 15 x 5.5" 508 x 381 x 140 mm Weight 32 lbs, 14.5 kg Operating Temperature Range (power derating above 25íC) 0-60íC Inverter mode, 0-50íC Charger mode Storage Temperature Range -30íC to 70íC

Questions? Our Customer Service & Tech Support Team is Here to Help
800-316-6426 | sales@flagshipmarine.com

Flagship Marine, Inc., 2427 SE Dixie Hwy., Stuart, Florida 34996 - USA
Phone: 772-283-1609 Fax: 772-283-4611 Wats: 800-316-6426 sales@flagshipmarine.com

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