What is the difference between DC and AC power?
DC (direct current) power is drawn directly from the battery and will run several types of RV appliances, like lights and water pumps. AC power (alternating current), is what is used in your home. An inverter in your RV converts your DC battery power into AC for A
What is the difference between a pure sine wave and a modified sine wave inverter?
All AC devices can run with pure sine wave power. Modified sine wave power replicates AC power, but not perfectly. While modified sine wave inverters are much less expensive, many devices run poorly when it is used — for example, portable tool chargers, high-end TVs and stereos, CPAP machines, and microwaves.C-powered devices such as TVs, hair dryers or coffee makers.
Do I need a pure sine wave or modified wave inverter ?
Advantages of Pure Sine Wave inverters over Modified Sine Wave inverters:
a) Pure Sine Wave has very low harmonic distortion and has no spikes or steps to the waveform. It is the same as utility-supplied electricity.
b) Inductive loads like microwave ovens and electric motors run faster, quieter and cooler.
c) Reduces audible and electrical noise in fans, fluorescent lights, audio amplifiers, TV, Game consoles, Fax, and answering machines.
d) Pure Sine Wave will power the following devices that will not normally work with Modified Sine Wave inverters:
Laser printers, photocopiers, magneto-optical hard drives
Some fluorescent lights with electronic ballasts
Power tools employing “solid state” power or variable speed control
Some battery chargers for cordless tools
Modified Sine Wave works well for most applications, but we recommends our Pure Sine Wave inverters (also called True Sine Wave) since they will operate all loads the same as if they were running from utility power.
Why would you need an inverter?
The mains electricity supply that runs your appliances at home requires a 240 volts AC (Alternating Current) supply. Automotive batteries supply a much lower voltage (mostly 12 volts or some are 24 volts) DC (Direct Current). An inverter converts 12 (or 24) volts DC to 240 volts AC, allowing home appliances including phone chargers, computers/laptops, TVs, coffee machines, Etc to be run in recreational applications such as 4WDs, caravans, camper vans/trailers or boats Etc. This means you can still have some of your home comforts while you are “off grid” whether you are camping, enjoying the great outdoors, or simply getting away from it all.
If you want to run 240V appliances from an inverter, the first thing to do is to choose a suitable size inverter. The second thing is to choose a suitable size battery bank to run the inverter. The easier part is choosing a suitably sized inverter. This will depend on how much 240 volt power you need and this will be determined by what appliance(s) you want to run. Required supply power is normally specified on a Compliance Plate on the back of an appliance and this is the important figure to go by.
Some power calculations are not straightforward, for example:
Similar to power tool battery chargers, some variable power appliances such as phase controlled variable speed power tools as well as appliances with half wave power control can draw very high peak current, also requiring larger inverters than suggested by their stated power rating.
The power of a microwave means the rated (or “cooking”) power. The electrical power consumed by the microwave will be much higher than the rated power, so to run a microwave you should choose an inverter based on the figure on the compliance plate rather than the cooking power label on the front.
Some power tool battery chargers may appear to have a relatively low Average Power consumption, but have a very high “Peak Power” need. E.g. a 200W charger may require a 700 Watt or even 1000 Watt inverter to cover the “Peak” current.
In most cases, you will only be able to run one high power appliance at a time, so for example, trying to run a kettle and a toaster at the same time is likely to result in inverter shutdown and/or over-worked batteries and/or cables.
The more difficult part is choosing a suitably sized battery bank. This will depend on how long you want to run the appliance(s). This is further complicated by the peculiar ways various battery types charge and discharge.
A high power appliance (such as an air conditioner) running for a long time (such as all day or night) will require a very large battery bank and may not be practical.
A low power appliance running for a short time will only require a smaller battery bank.
Once you have determined your required inverter size and battery size, the remaining important factor is to get the installation right.
You must use the recommended cable and fuse types/sizes and that all joints and connections are sound and suitably rated. Cables that are too long and/or thin will have too much voltage drop, resulting in premature shutdown of the inverter and/ or overheating of the cables/fuse-holders/connections. Taking shortcuts on installation will lead to unsatisfactory appliance performance and frustration instead of an enjoyable camping holiday.
What size inverter do I need?
Sizing your inverter is a difficult task, and is not made any easier by different brands and manufacturers rating the power of their units at different temperature ratings. The power output of an inverter is dramatically decreased as its internal temperature rises, this is sometimes called its 5, 10 & 30 minute rating; but in reality if the inverter cannot remove the heat quick enough, then the output power will rapidly drop off. Many of the inverter brands on the market are rated to supply full output power up to 25°C and start to de-rate the output power from this point on. Some industrial models with supply full output upto a staggering 40°C.
Basically, add up all of the AC loads you want to run, then determine if you want to run all of these items at the same time. If not, choose the largest load in the system and size the inverter 50% more to cover peak surge loads.
How big an inverter do I need to purchase ?
The answer to this question depends completely on what you wish to operate from the inverter. Create a list of the items that you want to operate and find out the power requirement for each of these items. Most items will have a manufacturer’s power rating on the label near where the AC cord is located on the item. If it is rated in Amps, then using the formula Watt= Volts x Amps, you can multiply the Amp rating of the equipment x 115VAC to get the Watt draw of the equipment. If the items will be running concurrently, then the total watt requirement of each item needs to be added together to determine which inverter power level is required. And remember also that many appliances have a start-up current requirement that is significantly higher than the continuous power rating, so if in doubt, it is always best to buy a larger inverter with higher surge capability.
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 run my appliance ?
This depends on the amount of battery capacity you have, and what loads you are operating.
Can I use my computer with an 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.
My inverter is running very hot, is this alright?
Power generation creates heat, so yes your inverter will get warm. For this reason it is important to keep your inverter in a location that is cool and dry, and installed in an orientation that will help assist with ventilation (e.g. you are not blocking the intake vents or fans with clothes or tools). If your inverter gets too warm, it will simply shut down until the unit cools down. As mentioned above, the hotter your inverter gets, the less AC power it will deliver.
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.
How do I install an inverter?
Connect your inverter to a battery.
Connect the cables to the inverter first and then to the battery.There may be a small spark when you first make the last connection to the battery, which is perfectly normal (this is the capacitor powering up).
On the AC output side,you can simply plug a device directly into the inverter AC outlet, or hardwire the inverter into your application.
What type of environment conditions must I consider to when installing an inverter/charger ?
All 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.
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