Thanks for everybodies help with my previous questions,heres another,The truck I will be driving in a little over three weeks has 12v and 24v power,most trucks probably do but im a bit thick 
and dont know how I will plug in a tv,fridge etc as I dont know how you connect things to the power supply,apart from an inverter,which I did nt know existed til this happy family of truckers filled me in.now there is lots of types of inverters and Iāll get to the point now ,HOW MANY WATTS WILL I NEED to power me FRIDGE and TELLY?thank you kindly,Love Bikemonkey 
Hope its not the Ā£200 one!!!
i recently bought two inverters mate, a 150 watt and a 600 watt. i have been advised on here in the past that skytronic are the best inverters to buy.
click here tlc-direct.co.uk/
have a look on the website at transformers and inverters page they are on there mate. if your not sure exactly what your looking for, give them a ring and ask them and tell them its for a lorry and someone will know exactly what you need and in my experience they really do know what they are talking bout mate. i ordered both mine from website and they were both delivered next day 
they are the cheapest skytronic inverters i have found.
no doubt other people will give you suggestions, this is only based on my personal experience mate
thwe fridge will no doubt be either 12 or 24 volt so wonāt need an inverter. You can also get TVs that run on 12 volt so that also wouldnāt need an inverter, only if it is a mains only one will you need an inverter for it and 150 watts will be more than enough for that.
The 12v supply in a truck comes from the 24v supply. It is then dropped to 12v from 24 by a little electronic gadget, called a dropper funnily enough. If you have the option. it is better to use 24v bits rather than 12.
In a 4 series Scania, the dropper (at least in mine anyway) is found in the cubby-hole above the windscreen, on the passenger side. Somewhere on the dropper you will find a label which will tell you what input voltage it takes (24v), the output voltage (12) and the maximum output power, in watts. Donāt get a multi socket and then plug in lots of things it, when they will add up to more than the max output of your dropper. If youāre lucky, you will just blow the fuse, if not ā ā ?
Different makes of truck have the droppers in different places. Just look around your cab and you will find it. It will have six or eight fins (or more) on it to disperse heat and either three or four wires going into it. If you want to see what one looks like, have a look in any shop that sells CB bits, they will have a few on sale.
Inverters look very similar but bigger and have one or two household sockets on the end. If you buy one get a 24v one. A 12v inverter will have to plug into the dropper, so you will be restricted by the max output of the dropper.
Power inverters (we call them convertors here) should be avoided whenever possible. They invariably reduce efficiency, create heat, make noise, and when they start to fail, provide enough current oscillation to ruin many DC appliances. You are far better off buying DC devices in the first place, then buying a power converter f(as opposed to an inverter) for the rare occasion that you will need to actually plug it into a wall socket.
Ditto, there are many many devices that run on 12 or preferably 24vā¦ If not for trucks, then for caravansā¦
12v appliances will draw TWICE as much current from the truck as an equivalent 24v deviceā¦ So in theory you could plug in TWICE as many 24v items before blowing anything upā¦
Besides, a mains fridge, small or large, will not only be noisy, but also is NOT meant to be moved about or jolted all the timeā¦ A DC fridge works using an electronic heaty cooly thing and is NOT effected by movement or has noisy pumpsā¦
Luv
Chrisieā¦ 
One more thing to consider: cheap inverters often create radio and TV interference.
i use the inverters alex and so far i have not had any problems at all whatsoeverā¦should i be expecting some then?
Iāve been using the same inverter for about six years now and never had a minutes problems with it or the items it has powered so I wouldnāt say you should expect problems Margate. Having said that of course any item can fail.
i know things can fail neil, but it was this post that made me think a bitā¦
AlexxInNY wrote
Power inverters (we call them convertors here) should be avoided whenever possible. They invariably reduce efficiency, create heat, make noise, and when they start to fail, provide enough current oscillation to ruin many DC appliances. You are far better off buying DC devices in the first place, then buying a power converter f(as opposed to an inverter) for the rare occasion that you will need to actually plug it into a wall socket.
margatemafia:
i know things can fail neil, but it was this post that made me think a bitā¦
From a purely Physics point of view Alexx is right. From a practical point of view though, inverters are a very useful tool.
Talking Physics/Electronics, the thing with inverters is that most of the time when youāre using them, youāre converting the 24V DC from your batteries into 240V AC with the inverter, and then plugging an appliance into it that converts that 240V AC straight back down to a low voltage DC feed to actually power the appliance. So there are inevitably inefficiencies here. The ābestā way to do it is to just get 24V DC appliances.
Back in the real world though, 24V DC appliances are invariably more expensive than their 240V AC couterparts (mainly a supply and demand thing, that one), so it is, in general, cheaper to buy a 240V TV/DVD/Microwave/Whatever and power it from your 24V DC batteries with an inverter. The efficiency thing isnāt usually relevant, as youāre running the engine to charge the batteries up each day anyway, so the small amount of wasted electricity is insignificant.
The only thing to be a bit careful with is high power stuff (anything more than a couple of hundred Watts), as this will need a bigger inverter and will need a fairly heavy duty connection to the battery. If you have a truck of your own you can simply wire it straight in with some fat wires (and an appropriate fuse of course), but that isnāt so easy if you have to shareā¦
Paul
I mainly use mine to power the laptop these days, itās a 150 watt model. I used to use a 24volt DC adaptor for it but I found I can run it for far longer on the Invertor than I can on the DC adaptor with regards to the effect on the batteries so I stick with that now.