trickydicky Posted August 10, 2011 Share Posted August 10, 2011 hi, having never used an inverter before we are not sure which one to buy.we need one that will allow us to use a normal hairdryer,watch tv ocasionally, maybe use the laptop and an iron. will a 300w do this please.if not, what do we need to buy. Link to comment Share on other sites More sharing options...
sshortcircuit Posted August 10, 2011 Share Posted August 10, 2011 A quick answer would be no. The hairdrier/iron will be the heaviest users. How many watts is the hair drier and then add at least 50% for the size of the inverter. Hope this helps. Link to comment Share on other sites More sharing options...
scramblers Posted August 10, 2011 Share Posted August 10, 2011 The basics are: Watts = Volts x Amps or Amps = Watts/Volts This little equation holds true for mains voltage as well as battery voltage. A typical mains hairdryer takes 1200 watts, using an inverter it would take 1200/12 = 100 amps from your battery. Providing your wiring didn’t burn out or your fuses blow, your battery would be put under a considerable strain trying to deliver a current it wasn’t designed for. I use a 600 watt inverter directly wired to the battery. This is used to charge phones, laptop, run the mains satellite receiver and a 300 watt hairdryer (used only sparingly). The TV and iron are 12 volt. I also use a solar panel to ensure that the leisure batteries are kept charged. Hope this is useful. Link to comment Share on other sites More sharing options...
Brian Kirby Posted August 10, 2011 Share Posted August 10, 2011 If you look at the appliances you list all will have a rating plate that says what Wattage they are. You can more or less forget the TV and the laptop, but look at the hairdryer and the iron. You will need at least the rating of the most hungry of these plus 10%, if you are confident you will never try running more than one at a time. However, that is only half your problem. Say the hairdryer is rated at 1.6kW at 220V, or about 7Amps. For this you would need an inverter of at least 1.8kW capacity. To get 1.8kW from 12V, which is what will go into your inverter, you would need to draw 150A, with wiring and fuse rated at 250A. All this has to come from your habitation battery, which will be designed for deep, and not rapid, discharge. Add to this that you may spend several hours with the TV, or laptop, or both, on, so you will now have a low drain over a longer period of time. You need to estimate both what will be the maximum amount of current you will draw at once (the iron or the hairdryer), but also how much you will draw over time (the Amperage of any of your appliances, in whatever combination you may use them, multiplied by the time you think they will be used per day, multiplied by the number of days you expect to be static before moving). One figure will be Amps, the other Amps x time, or Amp Hours. Your battery should not, ideally, be discharged below 60% of its capacity in Amp Hours. Suffice to say you will need a very large battery bank, and it will take considerable driving time to replenish. Clive or Brambles will be able to advise on appropriate capacity, on charging times relative to capacity, and on the best type of battery to suit both types of use, but for the time being I would only say think hard about this. You will almost certainly need to add a solar panel to keep up with discharge, because of the driving time needed to replenish a large battery bank that is deeply discharged. When you cost it all out, I think you will find trying to use the iron, or the hairdryer, via an inverter, is vastly more expensive than the odd trip to a campsite, and paying for a 230V supply for a night or two. Link to comment Share on other sites More sharing options...
tugga Posted August 10, 2011 Share Posted August 10, 2011 Hi Tricky Dicky I too have the problem of drying my hair when not on EHU and so I bought one of these as they are only 500W and very efficient (I have fine hair) and only takes a few minutes to dry. http://www.chemistdirect.co.uk/opal-london-hairdryer-to-go---white_1_157758.html It is very light and compact too so will store in any small place. Hope this helps. Link to comment Share on other sites More sharing options...
hallii Posted August 10, 2011 Share Posted August 10, 2011 Whatever you decide to do get a good inverter. The cheap ones are very optimistic as regards the power rating. I have a brand new 600w inverter (cheap) that won't run 300w without shutting down. It's all a bit complicated but some appliances have a start up surge and the inverter will sense this and shut down. So get a good one and make sure it is not working anywhere near it's maximum rating. I bought a Maplin one and it is good. It will run 600w and it doesn't even get warm. H Link to comment Share on other sites More sharing options...
scramblers Posted August 10, 2011 Share Posted August 10, 2011 hallii - 2011-08-10 8:07 PM Whatever you decide to do get a good inverter. The cheap ones are very optimistic as regards the power rating. I have a brand new 600w inverter (cheap) that won't run 300w without shutting down. It's all a bit complicated but some appliances have a start up surge and the inverter will sense this and shut down. So get a good one and make sure it is not working anywhere near it's maximum rating. I bought a Maplin one and it is good. It will run 600w and it doesn't even get warm. H I use the same inverter from Maplins, it is excellent. http://www.maplin.co.uk/600w-dc-12v-to-ac-230v-power-invertor-48724 Link to comment Share on other sites More sharing options...
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