There has been some confusion on this subject, and a few have requested additional help to understand hows and whys of it all.... So here we go:
First, allow me to explain how the system works in basic use, and then I will give two mildly technical explanations so you can understand how it does it and the differences in Inverter types…. When you have an external source of 240v power, i.e. plugged into something like a caravan park, resort, station, or whatever; all of the power points in your caravan will deliver the 240v mains power. When you are in the Bush and want power, and all the same power points deliver 240v power just as if you were plugged into mains power, (if you have the top of the line Inverter system that has the automatic change-over). The primary use for the larger inverters is the quick reheat of meals on the road. You can cook double portions before then next leg of your journey, and store in fridge-freezer; then when you are on the road with a different sauce or whatever it is a three minute meal instead of 45 minutes in the hot weather when you are trying to get somewhere. The microwave is also commonly used for a quick coffee or tea in one minute with a travel mug while on the road, in a quick stop without even turning off the tow vehicle… The other primary use is TV-Computer-VCRs and the like. In general, only electronics, nothing with a heating element like a room heater…
Now the first technical thing you might need to understand is the difference between the cheap “modified sine wave” units and the “pure sine wave”. (You technofreaks just relax while I put this is layman terms for the benefit of those that are not as electronically oriented OK? Now back to the rest of you that requested this… Do you know that curved up and down line on an oscilloscope, like on TV in the science movies? That up and down curve is AC which means Alternating Current, which is your normal mains power.. And the frequency here is 50 cycles per second, called the Hertz… OK so far? That is a nice clean curved loop up and down.. The “modified sine wave” units are the cheap ones you see for sale in the magazines, and they have “modified” the sine wave clear out of existence… It is only a only a square wave, and what that means is they will not run or will put a noise line in TVs and can cause problems or BE DEADLY to computers; and will not run digital electronics like the new microwaves in most cases… The cheap square wave inverters are really only suitable for power tools… The new Pure Sine Wave inverters run everything, and are actually a CLEANER power supply that you get from 240 mains power. The mains power actually can have little dirty spikes in it from local large machinery turning on and off like on SWER (Single Wire Earth Return) lines out on Stations, or nearby lightening strikes. Even the automated switching of power relay stations or transformers and such in the larger city grids can cause spikes or “surges”, and the inverter eliminates those “surges or spikes”… That is why at home they talk about plugging your computer into a “surge protection device”…
The second technical concept to understand is the Auto-switching feature: This concept in the
Bushtracker Auto-switching Inverter system, is the basis for a UPS (Uninterrupted Power Supply) backup system for large Computer systems to continue running if there is a power failure.. I basically robbed the engineering concept. (Its OK, public domain material now). We have designed the van to actually run like a great big UPS system. The UPS unit is a trickle charger, an inverter, and a gel battery, and the whole thing is on a relay… Now the relay closes in 3 milliseconds, (.003 seconds), when there is a power failure, and the inverter picks up the load automatically as it is just sitting there on standby… In that case the computer, or your whole van, never notices the power failure. Soooo, when you are plugged in, the inverter is locked out to protect it from “surges and spikes”. And if it is on “standby” it will take over all the 240v outlets as soon as the van is disconnected from the mains power…. It in effect senses the “Power Failure”, the relay closes in .003 seconds, and the inverter has taken over all the outlets…. OK? In this respect, the
Bushtracker is like a giant UPS system.
Hope this has been a help...
Cheers, from the stg at
Bushtracker