Power Inverters

What size of inverter do I need?

Choosing the right size of inverter depends on the power requirements of the appliances you expect to operate at any given time. You should consider both the continuous and surge power rating of your appliance. The continuous rating must be high enough to handle all the loads that may run at the same time. The inverter must also be capable of handling the starting surge of all loads that may start at the same time. Loads typically take many times their continuous rating to start.

How long can I operate my inverter?

The length of time you can operate an inverter depends on the amp-hour capacity of your battery bank.

Can I use a computer with my inverter?

Both sine-wave and modified sine-wave inverter output will operate a computer, including a laptop. However, some monitors and laser printers can only be powered by sine wave output.

Is it possible to run an air conditioner with an inverter?

Yes, it is possible to operate a small air conditioner in the 5000-9000 BTU range using a higher-powered inverter and battery bank with the right capacity for power. Select an inverter and battery combination that takes into account the startup surge required by the air conditioner.

Should I leave my inverter on when shore power is available?

When shorepower is available, you may leave your inverter ON or OFF. There are advantages and disadvantages to both methods. If the inverter is left ON, you have immediate backup AC power if you lose shorepower. You may not be aware shorepower is lost until your batteries are fully discharged. If you choose to leave your inverter OFF you have the advantage of knowing when you have lost shorepower. This, however, is at the expense of losing automatic backup power capabilities.

What is automatic AC transfer switching?

All Xantrex Inverter/Chargers incorporate an automatic transfer switch. This switch senses when outside AC Power is present and transfers the load from the inverter to the source of incoming power (shore or generator). The unit also automatically switches from invert mode to charge mode.

Using a polarity tester with an inverter

When I check the 115 volt output of a Xantrex inverter with a three light polarity tester, all three lights come on. There is no fault description for the tester covering this. My ground fault outlets do not trip. Is there a problem?

No. What you are seeing is normal if you are testing the output of a Modified Sine Wave (MSW) inverter. The device you’re using is for use with household utility power; the internal wiring of the inverter causes this symptom.

Can I install an inverter without a fuse?

No. A fuse (or circuit breaker, depending on the location and nature of the application) is an integral part of the safe installation of many Xantrex Technology Inc. products. If your installation does not meet the recommendations and specifications in the user guide, it is possible that an unsafe condition may be created, which could result in a fire. Your insurance company may not be obliged to cover damages in this case.

Follow the installation guidelines in the manual for optimal performance and safety of your Xantrex Technology Inc. power conversion product.

Remote on/off switch for Prowatt and Portawattz

The remote on/off switch for Prowatt and Portawattz products is part number 808-9000. It includes 20 feet (6 meters) of cable and works with the following products:

Portawattz inverters (1000, 1750, 3000).

All Prowatt inverters over 800 watts, whether 12 or 24VDC and whether domestic or international.

The remote switch can be purchased through Xantrex E-store www.xantrex.com/estore (under Accessories) if your local Xantrex dealer doesn’t carry it.

The Prowatt and Portawattz models mentioned above can be controlled remotely by an external dry-contact switch. You can find more information on the electrical requirements of the switch at our support FAQ under Prowatt products entitled Prowatt 1000/1750/3000 Remote Control.

NOTE: This switch does not work with XPower Plus inverters. For the XPower 1200 Plus and XPower 1750 Plus inverters, the correct remote switch part number is 808-9500. It is also available through Xantrex E-store. Do not use the electrical information at the above-noted FAQ for XPower Plus inverters.

Voltage measurement issues

I’ve installed the modified sine wave inverter and it’s working okay. However, the output voltage doesn’t seem right. There is 124 vac between the hot and neutral pins but the safety ground is not at 0 volts with respect to the neutral pin. Instead, the safety ground appears to float about halfway between the neutral and hot pin voltage. Please explain what’s going on!

This FAQ applies to Xpower, PROwatt, Portawattz, Jazz and Xantrex inverters, including the inverters integral to Powerpacks.

Your inverter is designed to have loads plugged directly into it and not be permanently connected to an AC distribution system. The fact that the inverter is not a permanent installation means the US NEC (United States National Electrical Code) doesn’t apply, and the NEC is the main place where the requirement resides for single-phase 120Vac or 240Vac systems to have neutral bonded to earth. The US standard for inverters of this sort, UL458, does not have a requirement for a bonded neutral on the output of inverters.

Regarding the voltage that the you are measuring, the ground does not float halfway, rather the neutral is not at 0 volts. The grounding is correct, in that loads plugged in will have their chassis held at the same ground potential as the chassis of the inverter, but the neutral has approximately 60V on it instead of the usual 0V. The impact of that is minimal, since wiring and equipment connected to the neutral side of the circuit are required by safety standards to be treated as if they were at 120Vac. This is because there are many receptacles that are wired backwards or 2-prong plugs that are not polarized. As a result the 60V neutral is not accessible to the user, and any shock hazard presented is mitigated by lack of access.

The main safety agencies, CSA, UL, and ETL, have all approved inverters with this half-voltage on the neutral scheme, and the manuals contain warnings not to AC hardwire any of these inverters.

Do I need to install my inverter near my batteries?

Ideally an inverter should be installed within 10 feet of the battery bank. If you increase this distance, you will need to use larger DC cables to compensate for a drop in voltage and DC ripple.

Can I install my inverter/charger in a gasoline engine compartment

All Xantrex Inverter/Chargers are not ignition protected and therefore should not be installed in a gasoline engine compartment. They are approved for installation in a diesel engine compartment.

What kind of environmental conditions must I consider when installing an inverter/charger?

All Xantrex Inverter/Chargers must be installed in a dry, well-ventilated compartment. While most units are designed to withstand corrosion from the salty air, they are not splash proof. The units also require a fresh air supply to operate properly.

Batteries & Chargers

Need a replacement AC charger cord for a Powerpack?


Size = 5.5mm X 2.1mm (.22″ X .083″)


AC Adapter for Powerpack Series (except Powerpack 1500) :

Standard spec is 13.8 V@1amp, but any adapter between 13.5V-13.8V / 0.5 -2A is acceptable. Generic replacements are available in electronic hardware stores like Radio Shack or can be purchased online from : 


The Xantrex part number is 074-1004-01.

What type of batteries should I use in my Inverter/Charger installation

Xantrex recommend using only high-quality deep cycle batteries in Wet, Gel or AGM (Absorbed Glass Matt) technologies to be used with Xantrex products. Deep-cycle batteries are designed specifically for a deep discharge and a rapid recharge. Wet cell batteries include 6-volt (golf cart) batteries and require some maintenance. Gel cell batteries and AGM batteries are sealed and typically require very little maintenance. Do not use starting batteries for inverter applications.

Battery Technology & Maintenance Overview

Battery Overview

A battery is a device that stores energy while it is being charged and releases energy while it is being discharged. There are a lot of different battery technologies, but lead acid batteries, which consist of plates of lead dioxide and spongy lead, immersed in a sulphuric acid solution contained in a durable housing, are most appropriate for use with inverters and mobile power solutions.

Lead acid battery technology has come a long way since 1859, the year it was invented. You no longer have to check the state of charge with a hygrometer, or top the batteries up with distilled water. Batteries are now safer, more reliable and in some cases, virtually maintenance free. Lead acid batteries are recommended for use with inverters because:

  • They are low cost, widely available and easy to manufacture
  • They are durable and dependable when properly used and stored
  • The self discharge rate is lower than that of other battery technologies
  • There’s no memory effect
  • They can produce a lot of current very fast, which is important in inverter applications.

Deep Cycle Verses Starter Batteries

Lead acid batteries are suitable for applications requiring a big, sudden discharge of current (what you need to start the engine on a boat, or in a car or RV) or a slow, steady discharge of current (to run your scooter, or watch a TV). These two classes of application generally require different battery technology, but they share some chararacteristics. Lead acid batteries of similar amp hour capacity will require about the same length of time to recharge, and all lead acid batteries are damaged by heat, and by storage in a discharged state.

The technology for starter batteries is simple. Many thin plates of lead in the electrolyte give lots of surface area, thus lots of potential current. This is the kick you need to get your car to start on a frosty morning.

Thick plates make batteries better suited to deep cycling – the type of battery that works best with an inverter. Thick plates aren’t the best for short high current use. If you have a quality deep cycle battery, you can discharge and recharge it more than 1500 times. A starting battery can be discharged perhaps 30 times before it will no longer accept a charge.

Because of the differences in the way the lead plates inside the battery are placed, the battery charging requirements are slightly different for the two styles of battery. Batteries that are not charged in accordance with manufacturer’s instructions can over gas (referred to as “boiling”) if overcharged, or sulfate if undercharged. Improper charging reduces the battery capacity and life cycle; that’s why it’s important to use the right charging technology to protect your investment in your batteries.

Unless they are properly charged, you won’t get the rated capacity back out of the batteries. There’s no free lunch: You can’t take energy out that you haven’t put in. Further, you’ll shorten the life cycle of any battery if it’s not properly charged. This is because the sulfur crystals which are deposited on the active material of the plate during discharge (while you are running your inverter or DC load) will not be forced back into solution during the charge cycle. Over time, these crystals become harder and thicker, reducing the access of the electrolyte to the plate and ultimately reducing the battery’s capacity.

How big a battery is needed?

Check the FAQ https://www.xantrex.com/support/howlong.asp for the Xantrex Technology Inc. battery calculating tool. You will need to know the wattage of the product or products you wish to run in order to use this tool.

Batteries last longest if you only discharge to 50% of capacity and then recharge as soon as possible after the discharge. If you want to run a 1 amp light for 50 hours between charging, you would need a battery which will deliver about 100 amp-hours. Although you can discharge a battery much further than this, you will begin to decrease the battery’s cycle life. A good deep cycle battery might deliver 1,500 (or more) discharges to the 50% level. By increasing the discharge to 95% you can reduce cycles to a hundred or so. So don’t undersize your battery bank, or you will be buying batteries much more often than necessary.

Gel Cell, Absorbed Glass Mat (AGM) or Liquid Cell (Flooded Lead Acid) Batteries?

Which type of battery you buy depends on your application, your charging system, your budget, your willingness to trade convenience for cost, and weight considerations. Some advice applies to all types of batteries. The following advice is not meant to supersede specific product instructions or cautions supplied by the battery manufacturer.

  • Unless your battery charger can be programmed to output the appropriate charging cycle for different battery types, use only one battery chemistry – Liquid (also called Flooded), Gel, or AGM. Different battery types on one bank may result in undercharging or overcharging, and reduce the battery life. This may require you to replace all of the batteries in your system at once.
  • Check the Xantrex Charger (XC) line of battery chargers (available in 2005) for a battery charger which can charge different types of lead acid batteries at once. The Truecharge series works well with up to three banks of one battery type.
  • Never mix old batteries with new ones in the same bank. While it seems like this would increase your overall capacity, old batteries tend to reduce the new ones to their deteriorated level.
  • Regulate charge voltages based on battery temperature and acceptance (manually or with sensing) to maximize battery life and reduce charge time.
  • Ensure that your charging system is capable of delivering sufficient amperage to charge battery banks efficiently. A rule of thumb is that for every amp of alternator you can have 4 to 5 amp hours of battery capacity. For example, a 100 amp alternator can support 400 to 500 amp hours of battery capacity.
  • Keep batteries clean, cool and dry.
  • Check terminal connectors regularly and clean in accordance with the manufacturer’s instructions to avoid loss of conductivity.
  • Add distilled water to flooded lead acid batteries when needed. It is important to adequately submerse the plates in solution, and also not to overfill which will cause loss of electrolyte when charging due to the volume expansion of electrolyte due to gas bubbles generated within the acid electrolyte. Most flooded batteries have a piece of plastic sticking down from the vent cap/filler opening inside the cell a certain height above the plates, which provides a visual depth indication when to stop filling with distilled water. Using a flashlight, watch for the acid solution’s meniscus forming when the liquid level hits this level. Don’t overfill much past this point.

How many batteries do I need?

There are a few factors that need to be considered before you determine the quantity of batteries needed. First, consider the type of battery you intend to use with your application. Next, determine the size of the battery and the number of amp hours you require between charge cycles. Most people have a 400-450 amp-hour battery bank, but this depends on use of your system.

Why do my batteries go dead when I use the Inverter/Charger in inverse mode?

A Xantrex inverter takes available battery power and converts it to AC power to operate household appliances. In many cases there are additional “hidden loads” that will draw power from the inverter even when they are turned off. Some examples are: TV tubes being kept warm and microwave & VCR clocks. In addition to AC loads, there may also be DC loads that draw power from the same battery bank as the inverter. These loads can include CO detectors, accent lighting, bay lights, and water pumps. Phantom loads may consume over 70 amp hours per day and most banks will be depleted in about three days with the inverter running with no loads on connected.

Battery type comparison chart

Gel Cell
Better for rough service environments•Leak proof.

Can be installed on its side with small drop in performance.

Less susceptible to low temperatures.

When charged correctly does not vent much gas.

Low self discharge rate.
Higher initial cost than Liquid Cell

Electrolyte cannot be replaced

Charging tolerances are tighter; cannot be charged over 14.2V without damage

Not ideal for use with automotive or unregulated chargers

NOTE all lead acid batteries sulphate if left discharged and require maintenance charging

Leak proof when tipped or if case is cracked

Used for both deep cycle or starting batteries

Can be installed at any angle (except upside down)

Shock and vibration resistant

Minimal gas release when
charged properly

Low self-discharge rate

Can be submerged in water without internal damage (battery terminals will corrode)

Many charge cycles when properly charged
Better performance for DC loads
Highest initial cost of all three types

More weight per Ah than wet cells

Electrolyte cannot be replaced

NOTE all lead acid batteries sulphate if left discharged and require maintenance charging
Liquid Cell – also called Flooded Lead Acid
Lowest cost to purchase by amp hour

Less sensitive than the other two styles in accepting higher charging voltages and less expensive / less regulated charging methods

Good deep cycle performance
Can spill corrosive battery acid

Must be installed upright

Requires regular maintenance

More quickly damaged if left discharged

NOTE all lead acid batteries sulphate if left discharged and require maintenance charging

Not suitable for high vibration environments

What is three-stage charging?

Multistage charging ensures batteries receive optimum charging, but with minimal wear and tear, regulating the voltage and current delivered to the batteries in three automatic stages:

  • Bulk: Replaces 70-80% of the battery’s state of charge at the fastest possible rate.
  • Absorption: Replenishes the remaining 20-30% of charge, bringing the battery to a full charge at a slow, safe rate.
  • Float: Voltage is reduced and held constant in order to prevent damage and keep batteries at a full charge.

Backup Power Systems

What Appliances do most people use during an outage?

In residential settings, refrigeration, gas- or oil-fueled heating systems, and lighting are most common. Electronic appliances such as computers, home entertainment components, and security systems don’t consume much electricity and can easily be added to a home’s backup subpanel. If you use pumps to supply water, keep a basement dry or pet fish alive, include these items in your backup power plans. Many gas appliances require only a small amount of electricity and should be included on the sub-panel. Comfort and convenience appliances such as fans, coffee makers, microwave ovens and garage door openers are other items your may want to use during an outage.

In an office setting, computers, printers, modems, fax machines and telephone systems are the most common equipment to run along with lighting. It makes sense to include whatever you need to keep your business functioning efficiently. Just remember that the more things you power, the bigger your system will need to be.

What appliances can a Xantrex system run?

Almost anything. But appliances that require exceptional amounts of power are best to avoid, if possible, as they are very expensive to run from batteries or a generator. Examples include central air conditioners, heat pumps, electric hot water heaters, electric clothes dryers, electric ranges and electric space heaters.

How long can the batteries run the system?

Xantrex dealers can customize a system with any battery run time you need. The recommended battery bank size for a generator/recharged system is eight hours, so that you can keep your generator turned off all night. (This type of “quiet period” is a standard, field-adjustable feature on Xantrex SW Series systems.) Systems that include solar panels for recharging should have larger battery banks in order to take full advantage of available sunshine.

How is the system recharged?

Xantrex backup systems recharge themselves automatically whenever utility power is available. To be able to recharge the system during a power outage, a propane-, natural gas- or diesel-powered generator can be included in the system. Xantrex SW (sine wave) inverters can automatically start and stop a generator as needed during long outages. All Xantrex systems can also be recharged using renewable energy sources such as solar panels.

What kind of batteries do the systems include?

Xantrex Powerpack backup electric systems use special high-quality electric storage batteries.

For inverter/chargers, sealed deep-cycle batteries are often specified, because of their ease of installation and maintenance-free design. Non-sealed batteries may also be used, but require special installation and regular maintenance. Xantrex inverter/chargers do not come with batteries.

Why should I choose a Xantrex system over a generator-only system?

Xantrex systems provide clean, quiet, instantaneous power backup that requires no fuel. When used in combination with a generator or solar panels, a Xantrex system can deliver the “best of both worlds” – protection from long power outages, instantaneous transfer and high reliability, all with minimal generator run time, fuel consumption and noise.

How fast will my system respond to a power outage?

Xantrex inverters typically transfer to battery power in less than 16 milliseconds (less than 1/50th of a second). Worst-case transfer time is 34 milliseconds (less than 1/25th of a second). That’s too fast to notice and fast enough to keep any modern computer running. Inverters in the SW Series run in synchronization with utility power and in many cases will transfer to battery power in less than one millisecond.

How do I install my Xantrex system?

A Xantrex backup inverter is connected to a home electric system by a qualified installer to meet local building code requirements.

Where will my system be installed?

Xantrex systems are usually wall-mounted near a home’s main electrical (circuit breaker) panel. However, systems can be installed anywhere it is convenient to place the battery bank and other equipment – including outdoors, if you choose a Xantrex enclosure.

How do I decide which system is right for me?

For protection from long outages, include a generator or solar panels in your Xantrex system. Shorter outages can be handled by a battery-only system. Solar panels are significantly more expensive than a generator, but can provide year-round electric bill savings and require no fuel or maintenance.

Xantrex top-of-the-line systems, using sine-wave SW Series inverters, come in three power output levels and integrate easily with a generator for automatic starting and system recharging. Several lower-cost Xantrex systems are intended primarily as battery-only systems. Your Xantrex dealer can help you select the system that best meets your needs and answer any additional questions.

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